Fukushima nuclear accident: Saturday 19 March summary

Last Saturday the the crisis level at the Fukushima Daiichi nuclear power station was rapidly on the rise. Hydrogen explosions, cracks in the wetwell torus and fires in a shutdown unit’s building — it seemed the sequence of new problems would never end. A week later, the situation remains troubling, but, over the last few days, it has not got any worse. Indeed, one could make a reasonable argument that it’s actually got better.

Yes, the IAEA has now formally listed the overall accident at an INES level 5 (see here for a description of the scales), up from the original estimate of 4. This is right and proper — but it doesn’t mean the situation has escalated further, as some have inferred. Here is a summary of the main site activities for today, followed by the latest JAIF and FEPC reports. You also might be interested in the following site map:

Another large cohort of 100 Tokyo fire fighters joined the spraying operation to cool down the reactors and keep the water in the spent fuel ponds. The ‘Hyper Rescue’ team have set up a special vehicle for firing a water cannon from 22 m high (in combination with a super pump truck), and today have been targeting the SNF pond in unit 3. About 60 tons of sea water successfully penetrated the building in the vicinity of the pool, at a flow rate of 3,000 litres per minute. Spraying with standard unmanned vehicles was also undertaken for 7 hours into other parts of the the unit 3 building (delivering more than 1,200 tons), to keep the general containment area cool. The temperature around the fuel rods is now reported by TEPCO (via NHK news) to be below 100C.

Conditions in unit 3 are stabilising but will need attention for many days to come. Promisingly, TEPCO has now connected AC cables to the unit 1 and 2 reactor buildings, with hopes that powered systems can be restored to these building by as early as tomorrow (including, it is hoped, the AC core cooling systems), once various safety and equipment condition checks are made.

Holes were made in the secondary containment buildings of Units 5 and 6 as a precautionary measure, to vent any hydrogen that might accumulate and so prevent explosions in these otherwise undamaged structures.  The residual heat removal system for these units has now been brought back on line and these pools maintain a tolerable steady temperature of 60C. More here. These buildings were operating on a single emergency diesel generator, but now have a second electricity supply via the external AC power cable.

Why are they concentrating on these activities? Let’s revisit a bit of the history of last week. The spent fuel pool still has decay heat (probably of the order of few MW in each pool) that requires active cooling. When power went out on Friday, the cooling stopped and the pool temperature has been rising slowly over the weekend, and probably started boiling off (and a large volume may have also been lost due to ‘sloshing’ during the seismic event). The pool is located on the 4th floor above the reactor vessel level. It remains unclear why they could not arrange fire trucks to deliver the sea water before the fuel rods got damaged and started releasing radioactivity. Now the effort is hampered by the high radiation level (primarily penetrating gamma rays). This is the inventory of those spent fuel ponds that have been causing so many headaches:

In order to remove the decay heat after the reactor shutdown, the cooling system should be operating. Following the loss of offsite power, the on-site diesel generators came on but the tsunami arrived an hour or so later and wiped out the diesel generators. Then the battery provided the power for 8 hours or so, during which time they brought in portable generators. However, the connectors were incompatible. As the steam pressure built up inside the pressure vessel, the relief valve was open and dumped the steam to the pressure suppression chamber, which in turn was filtered out to the confinement building and the hydrogen explosion took out the slabs.

The sea water was then pumped in by fire trucks and the reactor pressure vessels are now cooled down to near atmospheric pressure but the fuel assemblies are uncovered at the top quarter or third (the FEPC updates give the actual pressure and water levels). It appears that the pressure vessels and the reactor containment structures are intact, except the Unit 2, where the hydrogen explosion took place inside the containment and hence damaging the lower wetwell torus structure (but almost certainly not the reactor vessel, although the exact status is unclear). It appears that the radioactivity releases are mostly coming from the spent fuel storages than the reactor cores.

World Nuclear News has a really excellent extended article here entitled “Insight to Fukushima engineering challenges“. Read it! Further, you must watch this 8 minute reconstruction of the timeline of the accident done by NHK — brilliant, and really highlights the enormous stresses this poor station faced against a record-breaking force of nature. As I’d noted earlier, just about everything that could have went wrong, did. But valuable lessons must also be learned.

The IAEA and Japanese government has reported the potential contamination of food products from the local Fukushima area via radioactive iodine (mostly vented as part of the pressure relief operations of units 1 to 3). This is a short-term risk due to the 8-day half-life of radioactive iodine (and a small risk, given the trace amounts recorded), but precautions are warranted, as discussed here. What does this mean?

In the case of the milk samples, even if consumed for one year, the radiation dose would be equivalent to that a person would receive in a single CT scan. The levels found in the spinach were much lower, equivalent to one-fifth of a single CT scan.

… and to further put this in context:

The UK government’s chief independent scientific advisor has told the British Embassy in Tokyo that radiation fears from the stricken Fukushima nuclear power plant are a “sideshow” compared with the general devastation caused by the massive earthquake and tsunami that struck on 11 March. Speaking from London in a teleconference on 15 March to the embassy, chief scientific officer John Beddington said that the only people likely to receive doses of radiation that could damage their health are the on-site workers at the Fukushima Daiichi plant. He said that the general population outside of the 20 kilometre evacuation zone should not be concerned about contamination.

As to the possibility of a zirconium fire in the SNF ponds, this seems unlikely. Zr has a very high combustion point, as illustrated in video produced by UC Berkeley nuclear engineers. They applied a blowtorch to a zirconium rod and it did not catch on fire. The demonstration is shown about 50 seconds into this video. The temperature was said to reach 2000C [incidentally, I visited that lab last year!].

The the Japan Atomic Industrial Forum has provided their 12th reactor-by-reactor status update (16:00 March 19).

Here is the latest FEPC status report:


  • Radiation Levels
    • At 7:30PM on March 18, radiation level outside main office building (approximately 1,640 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 3,699 micro Sv/h.
    • Measurement results of ambient dose rate around Fukushima Nuclear Power Station at 4:00PM and 7:00PM on March 18 are shown in the attached two PDF files respectively.
    • At 1:00PM on March 18, MEXT decided to carry out thorough radiation monitoring nationwide.
    • For comparison, a human receives 2,400 micro Sv per year from natural radiation in the form of sunlight, radon, and other sources. One chest CT scan generates 6,900 micro Sv per scan.
  • Fukushima Daiichi Unit 1 reactor
    • Since 10:30AM on March 14, the pressure within the primary containment vessel cannot be measured.
    • At 4:00PM on March 18, pressure inside the reactor core: 0.191MPa.
    • At 4:00PM on March 18, water level inside the reactor core: 1.7 meters below the top of the fuel rods.
    • As of 3:00PM on March 18, the injection of seawater continues into the reactor core.
    • Activities for connecting the commercial electricity grid are underway.
  • Fukushima Daiichi Unit 2 reactor
    • At 4:00PM on March 18, pressure inside the primary containment vessel: 0.139MPaabs.
    • At 4:00PM on March 18, pressure inside the reactor core: -0.002MPa.
    • At 4:00PM on March 18, water level inside the reactor core: 1.4 meters below the top of the fuel rods.
    • As of 3:00PM on March 18, the injection of seawater continues into the reactor core.
    • Activities for connecting the commercial electricity grid are underway.
  • Fukushima Daiichi Unit 3 reactor
    • At 2:00PM on March 18, six Self Defense emergency fire vehicles began to shoot water aimed at the spent fuel pool, until 2:38PM (39 tones of water in total).
    • At 2:42PM on March 18, TEPCO began to shoot water aimed at the spent fuel pool, until 2:45PM, by one US Army high pressure water cannon.
    • At 3:55PM on March 18, pressure inside the primary containment vessel: 0.160MPaabs.
    • At 3:55PM on March 18, pressure inside the reactor core: -0.016MPa.
    • At 3:55PM on March 18, water level inside the reactor core: 2.0 meters below the top of the fuel rods.
    • As of 3:00PM on March 18, the injection of seawater continues into the reactor core.
  • Fukushima Daiichi Unit 4 reactor
    • No official updates to the information in our March 18 update have been provided.
  • Fukushima Daiichi Unit 5 reactor
    • At 4:00PM on March 18, the temperature of the spent fuel pool was measured at 152.4 degrees Fahrenheit.
  • Fukushima Daiichi Unit 6 reactor
    • At 4:00PM on March 18, the temperature of the spent fuel pool was measured at 148.1 degrees Fahrenheit.
  • Fukushima Daiichi Common Spent Fuel Pool
    • At 10:00AM on March 18, it was confirmed that water level in the pool was secured.
  • Fukushima Daiichi Dry Cask Storage Building
    • At 10:00AM on March 18, it was confirmed that there was no damage by visual checking of external appearance.

At 5:50PM on March 18, Japanese Safety Authority (NISA: Nuclear and Industrial Safety Agency) announced provisional INES (International Nuclear and Radiological Event Scale) rating to the incidents due to the earthquake.

Fukushima Daiichi Unit 1, 2 and 3 Unit = 5 (Accident with wider consequences)

Fukushima Daiichi Unit 4 = 3 (Serious incident)

Fukushima Daini Unit 1, 2 and 4 Unit = 3 (Serious incident)

(No official provisional rating for Fukushima Daini Unit 3 has been provided.)



  1. Barry a quick correction,

    the Tokyo Fire Department’s elite search and rescue team is called “Hyper Rescue.” They have special equipment and training to fight hazardous material fires as well as conduct rescue searches for tsunami and earth quake victims.

    Here is an article on the from 2005:


    Also a picture from of a Hyper Rescue team training:



  2. “Chief Cabinet Secretary Yukio Edano said levels of radiation exceeding safety limits stipulated by Japanese law were found in some samples of spinach and milk from the Fukushima and Ibaraki prefectures but authorities said the radioactive iodine-contaminated food posed little risk.

    Tainted milk was found 30 kilometers from the plant and spinach was collected as far as 100 kilometers (65 miles) to the south, almost half way to Tokyo.”




  3. Weird, my original post didn’t show up. Anyways, Barry just a quick note.

    The special vehicles don’t carry a title. Hyper Rescue is what the elite search and rescue teams from the Tokyo Fire Department are called.


  4. “Samples of tap water taken yesterday in Tokyo and five nearby prefectures showed traces of radiation that were within acceptable levels, the Japanese government said.

    Radiation was detected in water in Tokyo and the prefectures of Tochigi, Gunma, Saitama, Chiba and Niigata, Japan’s Ministry of Education, Culture, Sports, Science and Technology said today in a faxed statement.

    Tochigi Prefecture’s reading of radioactive iodine-131 was 77 Becquerel per kilogram, the highest among the prefectures, while the level of iodine found in Tokyo’s Shinjuku district was 1.5. All the numbers were within the 300 Bq/kg limit, the ministry said. ”


    So the level in Tochigi has reached 25% of the legal limit? Good thing the wind has been blowing out to see all week.



  5. “Chief Cabinet Secretary Yukio Edano said levels of radiation exceeding safety limits stipulated by Japanese law were found in some samples of spinach and milk…”

    Barry, any information on relative legal safety limits in various countries?
    I believe that Japanese limits are among the strictest (lowest levels allowed) in the world, meaning much larger safety margins remain when “legal limits” are passed?


  6. The fuel rods in the spent fuel pool are generating generating as much heat as a fluorescent light tube, about 120 watts for 3-4 meter rods so 30-40 watts per meter of rod. This really isn’t that much, and the sattelite images show clear vision into the fuel ponds, meaning they are open to ambient cooling. The rods are shaped like thermal radiators, a very efficient cooling mechanism.

    In order for the steam-redux reaction to occur, over 900 degrees Celcius is required. If the top is open to ambient I’m having a hard time seeing how this could generate much hydrogen. Putting it in my thermo model with the relevant thermal conductivities and geometries I cannot get >900 degrees celcius from this, even with poor ventilation. The temperature readings are also well below boiling point of water and sattelite images show water in the ponds. So I’m still sceptical that a hydrogen explosion in the fuel ponds itself was the cause here. Theres lots of other stuff like motor pump oil that can support combustion quite well.

    Does anyone has more info on this?


  7. I’d be really interested to hear about the other nearby nuclear plants – Onagawa is far closer to the epicenter, I believe. Obviously there were no serious problems there (since there’s been no media circus!) but why not, what problems did they have, does this tell us anything about design features, age, etc?

    (I realise that now perhaps there are more interesting things to think about, but if you get a moment.)

    By the way, excellent site Barry, congratulations. I hope your hosting company isn’t charging you extra for all the traffic you’ve deservedly been getting in the last few days. I saw an earlier suggestion about a donate button, not such a bad idea methinks, especially if you post the site’s costs and income.


  8. Pingback: Quora

  9. Nikkei, I rescued your post from the spam queue – things with multiple links often get sent there automatically. Thanks for that info, I’ll update the post when not on my iPhone.

    Ben, WordPress.com cover the hosting costs for me, so I only pay for yearly domain registrations etc. I prefer not to take any donations as I want people to always know that I undertake this work this because I think it is the right thing to do, not for any mercenary motivations (however small!)


  10. Would also like to express my appreciation for your work. This is the place I come to when I want to know what is going on over there.
    Wonder how many hits you are getting. I think there is a lot of I told 5 people about your site and they each told 5 people and they in turn told 5 more people going on.


  11. Barry, thank you for this update. It’s also very interesting to see the NHK timeline because it shows something that has been ignored by the media (in my country, the US)–and that is this: the safety features at Fukushima _worked_.

    When the quake hit, the reactor was scrammed (I hope that’s the proper term), and the cooling system went into action. It was the effects of the tsunami that stopped the process.

    Some here in the US have been claiming that the reactor designs were faulty and that the crisis was created by human error and greed. The NHK reconstruction blows those myths apart.

    Thank you for your updates and for giving us information based on hard facts, not fear mongering.


  12. There have been many discussions here to effect “Japan is known for Tsunamis… this is an expected event and should have been planned for..”.

    IShortly after the Tsunami hit there were some suggestions from at least one scientist suggesting this was a once in a thousand year event, believed to be last duplicated in 869 A.D.:


    If true (and I am not in a position to have an opinion) then all the criticisms of too low Tsunami barriers around the plant, etc., may be unrealistic. Taking once a millennium events into consideration in the engineering would then lead to other impossible scenarios such as a major volcanic event depositing meters of ash on the plant and all the surrounding infrastructure (such as the power grid). Or meteorite impacts, and on and on…

    I too am impressed that, given the horrific natural events the plants are even in a condition that allows the operators to continue remediation efforts. Every day that the local radiation levels are such that even limited access is doable is a great day :-).

    Much discussion here has been directed at the “zero tolerance” aspect of nuclear energy, resulting in things such as legal limits allegedly far, far below realistic levels of danger. In normal times that may be a good thing- err on the side of caution and little seems to be known as a fact regarding effects of low level radiation…

    But these are not normal times for Japan. I hope babies in evacuation centers don’t go hungry while mildly tainted (and possibly perfectly safe) milk is
    declared unfit. This is a trade-off of multiple and conflicting risks. Maybe. Although arguably the problem of feeding the evacuees may be more related to distribution problems than supply problems.


  13. I understand the radiation levels are low here in the West Coast of CA, however I have 2 questions:
    1 – what if the actual particals of cesium-137 and iodine are breathed or taken into the body? is this a 30 year dose?
    2 – How does the rain affect levels? Is there any hope rainy weather will wash away our woes here and in Japan?


  14. Regarding drinking water, here’s a link to the specific measurement figures in Tokyo:

    (strange URL, but it worked for me)

    And the WHO has a document, “WHO Guidelines for Drinking-water Quality (GDWQ)” which provides a reference point — section 9.3. PDF available at the WHO website.

    I am a lay person, so I will omit my uneducated opinion and leave the rest for the experts…


  15. bks

    I think the punching of holes in the roof was a precaution to prevent a explosion no matter how remote. They already have 3 severely damaged and one slightly damaged building from explosions. The spent fuel ponds in 5 & 6 now have temporary diesel power and may soon have outside power. Cooling is going on and these ponds never had any real containment. There may have been some filtering of air going out of the building, but if the spent fuel never heated up the amount of radioactive material being released is miniscule. With cooling there will not be a hydrogen explosion, but the situation is still dynamic and if they lose those diesel generators, there will be a problem, so cut a hole in the roof in case that happens. Unlikely, but we have seen lots of unlikely or unanticipated events.


  16. Pingback: Fukushima AC cables connected to reactor buildings 1 and 2 – power systems may turn on tomorrow after safety checks - forex world | forex world

  17. Morgan, on 20 March 2011 at 3:07 AM said:

    >>1 – what if the actual particals of cesium-137 and iodine are breathed or taken into the body?

    The cesium will leave your body eventually in about 4 months, just as the radioactive potassium found in all bananas does.

    Click to access Cesium.pdf

    Iodine 131 has a half life of 8 days.


  18. Barry, thank you so much for your outstanding information compilation effort. Please keep up the great job despite the insults and other personal attacks.

    The French media are hysterical about this accident. It is great to read your daily post to balance their superficial and confusing reports.

    From the ABC TV One Plus Interview, I understand you feel “ashamed” of mixing facts with opinions. Please don’t be ashamed! Opinions (and emotions) are what makes a difference between a great blog and a boring technical report.

    Now one question: how can Cesium and Iodine be released in the atmosphere? Does this require a breach of the Zircalloy rods? or do those particles pass through the Zircalloy?


  19. “Meteorologists predict the wind direction will change today, taking dangerous emissions across Tokyo, 250 kilometres to the south.”

    It will be very interesting, then, to look at the real-world data in Tokyo over the coming days.

    The above is the dose rate in Tokyo, in uSv/h, updated regularly. The doses are absolutely negligible.

    There is also a lot of very good data coming out of the KEK experimental physics centre in Tsukuba, just outside Tokyo.


    Above is their real-time gamma dose monitor.

    They also have some very high resolution gamma spectroscopy data, showing the levels of several different significant fission products.


    These fission products are definitely from Fukushima, and they are there at detectable levels – but these instruments are incredibly sensitive, and these levels are absolutely harmless.

    We’re talking about, for example, 2 nBq (yes, nanobecquerels) of Cs-137 per cubic centimeter of air at the moment.


  20. Small detail that troubles me:

    “Then the battery provided the power for 8 hours or so, during which time they brought in portable generators. However, the connectors were incompatible.”

    I’m a truck-driver – not a scientist – but I restore antique electronics as a hobby. Incompatibility is what the hobby is all about, as one works to repair 70 year-old equipment. So… I keep wondering why incompatible plugs would stymie them. Can’t even big, fancy plugs be cut off and cable elements spliced together? Even allowing for several magnitudes of complexity beyond what I deal with, I still can’t see why some “snipping and twisting” couldn’t have been done.

    (I realize I may be merely be demonstrating how ignorant of all this I am… but curious anyway))


  21. François, unless the clad on the spent fuel rods catches fire and produces smoke, which I think is highly implausible, then only way the Cs would disperse is via releases of volatile particulates that have accumulated over the years in the pond after being shed in minute quantities from the fuel rods. The I that remains will have virtually no radioactive isotopes.


  22. Luke Weston

    I believe the standard SI method of reporting would be to use Bq per cubic meter

    So 2 millibecquerels per cubic meter or a decay of 1 atom every 500 secs in that volume of air. Indeed miniscule. They must be processing huge volumes of air to detect anything.


  23. Morgan, levels are not merely low on the West Coast of CA, whether that’s California or Canada, they are completely and utterly negligible.

    The essential thing to understand about radioactivity is that vanishingly low amounts can be detected. Many orders of magnitude lower than any possible health impact. So “X has been detected” is a statement that says absolutely nothing about health impact.

    In the case of Fukushima, the low actual releases combined with the enormous distance across the Pacific mean that there is no chance – zero – that there will be any health impact on your coast.


  24. François – My understanding is minor damage – much less than melting – of the zirconium cladding can release traces of caesium and iodine from the fuel rods into the coolant. If that coolant is vented, as happened at Fukushima, that would certainly be detectable, since ultra low levels of radioactivity are both detectable and identifiable.

    Luke, I didn’t realise there was such a unit (of any use) as a nanobecquerel. That would be one atomic decay every billion seconds, ie. every 31 years.


  25. Damen, I agree with you that I don’t think a little problem like “connectors” would have stopped an engineering crew desparate to feed power into a machine. However, voltage levels, max rated power or some other detail of generation characteristics could have. If the generators were simply too small to drive the pump, for example, that would do it.


  26. Luke Weston

    I wonder if you now agree that your assertion made in your


    post, that they were not injecting seawater into “any part of the nuclear reactor or the Nuclear Steam Supply System itself. It is an injection of seawater into the containment structure surrounding the reactor pressure vessel” is incorrect? If so an amendment to that assertion is warranted, as it is still part of the main part of this website. Not everyone is going to read through all of these discussions. If you cannot insert a statement to that effect, I think Barry should do so.


  27. Some may be interested (relieved?) to learn that on page A8 of today’s Washington Post is a one column article titled ‘Radiation risks low, according to science.’ How about that…one week later, 8 pages in, it was finally time to report something based on some real science! And the article did just that, dispelling a lot of the hysteria for the public. Better late than never, I suppose.


  28. Thanks Joffan,

    Exactly what I was wondering. I think your surmise about under-powering the pumps will turn out to be an approximation of the real problem. I know with my old equipment under-powering one part of a circuit (say, a resistor gone out of it’s original tolerances) can actually cause too much current flow in other parts (like output at the plate of a tube) and over-heating/burning. I bet under-powering those pumps is just as bad.



  29. I note that the oil refinery fire at Cosmo Oil Co in Chiba, which started with the earthquake, is still burning as of this moment. It has been spewing tons of pollution into the air, no doubt the intense heat has been hampering efforts to put it out, and those downwind are in real danger of being effected should they breath the smoke.

    Yet this event gets little coverage.


  30. Cutting torch relies on the material being cut to begin oxidizing–this is what the Oxygen feed does.

    I have a question about the wetwell torus thing. If the suppression pool is supposed to scrub steam discharge, then does the primary vessel vent into the “light bulb,” and steam conducts through those pipes and bubbles up inside the suppression pool water?
    If so, that means the volume above the suppression pool is the low-pressure side. Does it vent to the atmosphere, and where?
    Also, if the inside of the “light bulb” is an area that reactor steam would vent to, is it a place where one can enter and walk around, or is it forever off limits because of radiation from the core?


  31. There must also be lots of natural gas pipeline and powerplant explosions. And coal plant fires maybe?

    What about major oil terminals (storage)? Storing millions of liters of gasoline is dangerous even without a 9.0 Richter earthquake.

    Wind turbines damaged? Killing anyone when falling over?

    We hear virtually nothing about this.


  32. Damen,

    Western Japan uses 60 Hz, while the eastern part uses 50 Hz. I heard the Fukushima systems use 50 Hz, but somehow the portable generators they brought in were the 60 Hz kind. I don’t know enough about electronics to say how hard it is to convert, but I’m as surprised as you that they weren’t able to jury rig something.


  33. @Luke Weston:

    Isn’t that demonstration ignoring the issue of the presence of water vapor? From “Safety and security of commercial spent nuclear fuel storage: public report” (National Academies Press, 2006)

    The ability to remove decay heat from the spent fuel also would be reduced as the water level drops, especially when it drops below the tops of the fuel assemblies. This would cause temperatures in the fuel assemblies to rise, accelerating the oxidation of the zirconium alloy (zircaloy) cladding that encases the uranium oxide pellets. This oxidation reaction can occur in the presence of both air and steam and is strongly exothermic that is, the reaction releases large quantities of heat, which can further raise cladding temperatures. The steam reaction also generates large quantities of hydrogen….

    [With a loss of coolant] These oxidation reactions can become locally self-sustaining … at high temperatures (i.e., about a factor of 10 higher than the boiling point of water) if a supply of oxygen and/or steam is available to sustain the reactions…. The result could be a runaway oxidation reaction referred to in this report as a zirconium cladding fire that proceeds as a burn front (e.g., as seen in a forest fire or a fireworks sparkler) along the axis of the fuel rod toward the source of oxidant (i.e., air or steam)….


  34. “Holes were made in the secondary containment buildings of Units 5 and 6 as a precautionary measure, to vent any hydrogen that might accumulate and so prevent explosions in these otherwise undamaged structures.”

    I’ve read comments to the effect that after Three Mile Island, the U.S. Nuclear Regulatory Commission required mandatory retrofit of “direct vent” devices to get accumulated hydrogen out of the reactor without risking explosions or overpressure from such accumulations.

    (Even though at TMI, the “hydrogen bubble” risk inside the reactor turned out retroactively to have been negligible, due to inept calculations by NRC engineers.”

    It appears that the Fukushima units lacked any such direct venting. So the operators vented free hydrogen from the reactors into the interior of the reactor buildings, where it explosively recombined with oxygen. And did the damage now easily visible in photographs.

    I have also read comments which claim that the NRC require devices inside of the reactor vessel to attempt to mitigate hydrogen accumulation before having to vent it externally. There has been no mention of any such devices at Fukushima.

    Is this a case in which Japanese regulatory authorities and utility management adopted a “not-invented-here” mindset and ignored nuclear best practices from abroad?

    There is some precedent for this in an Asian cultural context. Back in the 1990s, the Korean airlines had an absolutely dismal safety record, racking up a string of serious accidents.

    Outside audits revealed that those firms were culturally insular and nonstandardized in their practices, and failed to stress such key aviation safety principles as Crew Resource Management.

    The Korean carriers listened to the auditors, and overhauled everything about how they trained, planned and flew. Their safety records are now comparable to other global airlines of similar size and reach.


  35. Hi everyone, sorry for intruding, and thanks for the marvellous work you’re doing with your blog.
    I just have a question, related to the last comment from DV82XL (and the first tim I saw written an issue I thought about from the first day)

    I saw many different places on fire just after the tsunami hit, as well as many tanks scattered about in the country after the withdrawal of the wave.
    and also, from the NHK video, on the very front of Fukushima Daiichi one can see two huge tanks (several thousands mc, it looks) of presumed fuel for pumps, vanished after the wave.
    My question is (i ask here because this is the more accurate and competent place I found to now): is there a measured assessment of the toxicity and radiation emission of fires from oil, gas and other flammable materials, and more there is a way to know the effects on the quality of exposed vegetables and water after five days of rain and snow who passed through several chemical product fires?

    thanks to whom would answer, and a pray for all the dead and survived japanese


  36. ah, sorry i was forgetting…
    about the strange connection troubles of the emergency mobile equipment, I know that Japan has two big zones of electric power frequency, 60Hz in the west and south and 50 Hz in the east and north. hence the troubles also for providing power from the west region in the first days. it could have happened that the equipment had a different frequence ?


  37. You need to get temperatures over 900 degrees Celcius for significant hydrogen redux reaction to occur. I’m not buying this at all for the spent fuel pond, as it is open at the top to ambient air. The fuel rods are shaped like radiators, basically very efficient space heating devices, and would convect loads of heat away. Remember that the heat per fuel rod per meter in 3 month old fuel is similar to a standard fluorescent tube office light. My thermo model doesn’t show anywhere near those temperatures would be reached, especially if part of the bottom of the fuel rods were still submerged in water. The sattelite images show a clear opening to the ponds.


  38. @ Stead: I will tell you what I know.

    The lightbulb area is the drywell. It has steam pipes connecting the bottom of the light bulb to the torus, which is actually seperated by valves and might be called a secondary containment (the concrete superstructure might then be called ternary containment, but this is not common use).

    Pressure relief valves vent the overpressure, with any hydrogen or volatile fission products that might be present under accident conditions such as at Fukushima Daiichi, via the steam pipes at the bottom to the torus. That is the wetwell, it has steam pipes ending under water so any steam that comes through will condense under water. This is quite effective as you can imagine, given the direct contact of water with steam. But this trick only works up until the normal atmospheric boiling point of water, after that it gets less effective and pressure also builds up. When that happens and you still have no active cooling, as was the case at Fukushima, you must relieve the pressure to a stack which has filters such as carbon filters or resin ion filters. This filters out any possible fission products that are not noble such as cesium, strontium and iodine. However it is of course not 100% efficient, a small fraction of those fission products are going through the filters, and that is why it is being detected in small quantities in the area and in agriproducts such as milk.

    But this does vent the steam to the environment, relieving pressure. The steam that is used as coolant for some time has become activated and will quickly decay to stability, but of course this means a hard spike in radioactivity. Wait a few minutes and its gone.

    People should not be going within the confines of the lightbulb. It is not good for your health. There is a biological axial shield around the reactor pressure vessel that should keep radiaton okay, but not a place you want to stay for long. Also if steam vents you are deader than a doornail.

    Hope this helps. I was not too familiar with Mark I containment for BWRs, unfortunately I had to take a crash course over the last week, so some of my info may be incorrect.


  39. DV82XL said:

    “I note that the oil refinery fire at Cosmo Oil Co in Chiba, which started with the earthquake, is still burning as of this moment. ”

    Really! I’ve been wondering about that. I remember a report that it was still burning on Tuesday but then I read a single line article somewhere that claimed operations at Chiba had recommenced. This seemed very unlikely to me so if you have more info on the situation I’d appreciate the link.


  40. a quote from that telegraph article I just linked to:

    “One employee said TEPCO staff had attempted to jump start emergency cooling system using car batteries and small diesel generators after back up systems failed. “


  41. By the way, if this was unclear, the Mark I design vents the overpressure to the top chamber where the crane is. This is done to make sure short lived radioactive material decays before entering the outside air, which is good practice in plants around the world. This is why there was a hydrogen explosion – there is normal air in that space and it does not take much to ignite hot hydrogen gas. Normally catalysts, called recombiners, would make the hydrogen bond with the oxygen to make water again. Unfortunately these require external power to work and this was not available. This is an important area to take lessons for older BWRs, I think. Make sure they have redundant battery power to work for a week.


  42. @Marion Brook

    “Researched by Industrial Info Resources (Sugar Land, Texas)–Cosmo Oil Company Limited’s (TYO:5007) (Tokyo) refinery in Ichihara, Chiba, remains offline due to a fire in the natural gas tank farm. The fire broke out following last Friday’s magnitude 9.0 earthquake. All units are currently offline and personnel remain unable to enter the complex due to the fire.

    For details, view the entire article by subscribing to Industrial Info’s Premium Industry News



  43. @Stead, on 20 March 2011 at 12:59 AM said:

    “Looks like it washed away their diesel fuel tank farm”

    That’s something I’ve been wondering about. Can anyone confirm that the tanks were above ground and that they were washed away? Or are they underground and intact perhaps.

    Regarding the 50Hz/60Hz issue on the generators they bought in – TEPCO is a local power company it knows Japan uses 50Mz & 60Mz. Hard to believe they’d make such an error.

    Map of Japan power grid http://upload.wikimedia.org/wikipedia/commons/c/cb/Power_Grid_of_Japan.PNG


  44. ‘Here in Chiba, people are freely going outside, kids are playing in the park, we still walk our dog twice day. The tremblors are becoming less and less frequent (I finally got an extended nights sleep last night) and their strength seems to be decreasing (keeping our fingers crossed). There certainly are still reminders of this disaster with the constant news on TV, the huge lineups for gas stations (there is still a major shortage here due to the oil refinery fire in Chiba) resulting in lines of 50+ cars just to get into each gas station, and continuing shortages on the shelves of supermarkets especially for things like fish and mean, bread and yes instant noodles.’


    I presume from that that the oil refinery fire is now out, but the article is not specific


  45. @ Phil Daniels,

    here’s a google map link to Cosmo Oil plants in Ichihara, Chiba, just half a mile NE


    if those oil tanks are aflame, would I live in Tokyo, just cross the bay on the left, would be much more worried than by the danger from Fukushima (I assume the cancer threat is the most feared about this incident)


  46. @Cyril R
    According to MIT the total decay heat for the 548 fuel rod assemblies removed from Reactor 4 on 30th November 2010 is currently over 6 MW (somewhat over 0.2% of the operating thermal power) http://alobar.livejournal.com/4338326.html. I had understood that the decay heat should be obtained as a fraction of the thermal power, not the electrical power, so if experts can confirm this,
    the energy generated within each rod in nearly 12kW. Contradicting this number, I have just looked at the Wikipedia page http://en.wikipedia.org/wiki/2011_Fukushima_I_nuclear_accidents, where the conditions of each reactor are tabulated, a total power level for the pool of reactor 4 given to be only 2 MW, from http://www.bmu.de/atomenergie_sicherheit/doc/47114.php. The pool actually contains 1479 rods in total. If Wikipedia is correct, does this mean the 548 fresh fuel rods were removed after only a short time in the reactor, and MIT are wrong, or is Wikipedia and its reference wrong?

    Does anyone know the details?

    Experts: in computer model simulations of loss of cooling to spent fuel ponds, is conduction to the surrounding concrete structure included?


  47. Regarding power, this post comes from chavv in another thread:

    “People will also ask, why did it take TEPCO so long to start running a new power line to the plant? That would seem like the first thing to be done the minute flood waters had receded.”

    Because pumps does not work on regular 220V/110V electricity, they need higher-voltage – 6KV or even more. And high currents too – pumps are quite powerful devices – more than 100KW
    Making such high-voltage lines is not so easy…
    Due to this problem they also couldn’t use ship for giving electricity, usually military ships work with 400V
    (all this is based on info from atominfo.ru forums)


  48. Thanks Barry for keeping the site going and not caving to the onslaught of personal attacks.

    The situation is not getting worse it seems. This is a good thing, at least from my perspective.

    I hope I helped you and others here in a technical sense understand what appeared to be the issues as we all sifted through the random media reports.


  49. Thanks Hank. According to your reference the peak clad temperature remains below the rapid oxidation hydrogen redux reaction, the results are slightly more pessimistic than my iterative thermo model, but the conclusion appears the same: if the roof is opened the hydrogen explosion from spent fuel pool is not a plausible scenario.


  50. Cyril, your pretty close.

    The primary containment pressure boundary consists of the drywell and the torus in a technical sense.

    What is confusing to laymen is there are two other boundarys for radiation release prior to reaching the primary containment.

    The fuel pellet itself along with it’s cladding (zirconium fuel clad tubes), then the reactor pressure vessel and it’s associated system isolation valves. The fuel pellet contains most of the fission product gasses produced due to exposure quite well, until it fails. Most of the fission product gases that build up inside the zirconium tube are outer edge reactions….

    As you said energy is then released via steam mixture to the Torus (suppression chamber) below water level to try and condense the steam. When the Torus water level reaches 100C or 212F it can no longer quench the energy of the steam mixture.

    At that point, pressure rises due to essentially steam being dumped into a closed volume. Venting must occur to prevent overpressurizaton of the primary containment and permanent failure (complete breach and continued release).

    The venting that was done appears to have been to what is technically called the secondary containment (reactor building). Without power there was no complete path with ventilation fan dilution to the stations vent stack. This was bad.

    The hydrogen mixed in with the vented steam gas mixture collected at the upper elevations (refueling floors). Ultimately resulting in the explosive concentrations and reactor building damage seen in the photos….


  51. To Phil Daniels:
    I’ve seen a japanese clip that clearly shows two cylindrical objects they said were the tanks, placed in open air, almost directly at the waterside just north of the warf. Those were washed away.


  52. Pingback: Relevant News 20/03/2011 « Fukushima Facts

  53. Quick summary of news before Barry updates
    Hyper rescue team trucks pumped water into number threes building for 13.5hours yesterday and levels of radiation 500m away dropped by about 500micro-sevs to 2906micro-sevs (at 9pm)
    5 & 6’s spent fuel pools temperature has fallen steadily since the generators for have been working (5 started first with 6 coming online a little later) 5’s at 43.1c and 6’s at 52 (as of 3am this morning)
    Difficulty in site access means that number four hasn’t been doused with water in awhile so the jsdf is going to Spray today… So time…
    Also the reactors earthquake Proofing had not been finished so they actually hadn’t been proofed to withstand 600gals of energy… No. 3 was only proofed for 441gals but the energy was 507gals… Etc…


  54. Hi, thanks for your detailed infomations.

    Let me ask a question.
    I and my family live in Tokyo, Japan atm. My father is arguing that “We should leave Tokyo and go west for our safety! The plants are in danger! We are in danger of death!”. I’m skeptical about that because the effect of the current (or “the worst” future) radiation on Tokyo seems to be minimal and Fukushima plants themselves seem to be getting better.
    How do you think about this?


  55. mostly physical rotational speed limitations :) unless you increase the frequency alot higher then insulation issues become more apparent due the corona effect of high frequency AC.


  56. Changes in voltage have to be insulated against. The overall power equation will show that changes in voltage will also cause current changes, limitations in heat disipation. Lower the voltage, amperage rises, I squared R increases, heat increases and sometimes max smoke due to insulation failure….

    Changes in frequency for rotational machines are more mechanically limited with in reasonable frequency bands of variance …..


  57. Actually its not that simple because control systems may not work on frequencies other than what they were designed for, and as well as mixed frequencies, there are mixed line voltages in Japan (220/110) per phase.

    Any rate the reason I mentioned this mixed system is because it causing problems getting power restored in the country. There are two independent grids, and no matter which way you look at it, this is not wise.


  58. According to the ministry, traces of cesium have also been found in tap water in Tochigi and Gunma in addition to the radioactive iodine found in the two prefectures as well as in Niigata, Chiba and Saitama.
    To put this report into perspective, which some previous commenters (including bks) failed to do. So don’t worry too much those of you in Japan.
    “But the dose of the radioactive substances poses no threat to human health even if they are taken in.

    The Nuclear Safety Commission of Japan limits an intake of iodine at 300 becquerels per kilogram of water and of cesium at 200 becquerels.”



  59. Put a multitester on the line , sit at the engine and play the gas. I fought my way through a Einsturzende Neubauten concert on a mine sweeper that way once. The carvers cut out at less than 20V diff. It got quiet only once.


  60. I suspect the two clindrical objects could be the emergency diesel fuel oil tanks that were rumoured to be above ground and washed away by the tsunami. Causing a big design issue for this event.


  61. Selfigniting, thats the difference,.. that and havin’ a thing with words.. I picked up this story about the hydrogen: Hydrogen/steam mix does not selfignite, but as the mix reached the cold roof, the steam condensed, the mix changed and went boom. Never tried that. Does it work that way?


  62. From Wikepidia, not enough time to do the monkey explaination of the corona effect…. The wife is already eying me about how long I have been on here….


    A direct current flows constantly and uniformly throughout the cross-section of a uniform wire. An alternating current of any frequency is forced away from the wire’s center, toward its outer surface. This is because the acceleration of an electric charge in an alternating current produces waves of electromagnetic radiation that cancel the propagation of electricity toward the center of materials with high conductivity. This phenomenon is called skin effect.

    (CORONA EFFECT as I called it)

    At very high frequencies the current no longer flows in the wire, but effectively flows on the surface of the wire, within a thickness of a few skin depths. The skin depth is the thickness at which the current density is reduced by 63%. Even at relatively low frequencies used for high power transmission (50–60 Hz), non-uniform distribution of current still occurs in sufficiently thick conductors. For example, the skin depth of a copper conductor is approximately 8.57 mm at 60 Hz, so high current conductors are usually hollow to reduce their mass and cost.

    Since the current tends to flow in the periphery of conductors, the effective cross-section of the conductor is reduced. This increases the effective AC resistance of the conductor, since resistance is inversely proportional to the cross-sectional area in which the current actually flows. The AC resistance often is many times higher than the DC resistance, causing a much higher energy loss due to ohmic heating (also called I2R loss).


  63. @CyrilR 9:16 AM

    Latest JAIF report Mar 19 22:00 Re R4 SFP ” Water level low; Preparing water injection; Hydrogen from pool exploded.”

    Yesterday I posted:
    Picture of R4 building http://i.dailymail.co.uk/i/pix/2011/03/18/article-1367524-0B3B46E800000578-690_964x641.jpg

    This looks like R4 building explosion was outward, not damaged inward from adjacent R3 H2 explosion Mar 14 11:01. JAIF and IAEA both say that R4 building was damaged by R3 explosion. Latest JAIF spreadsheet info does not show any R4 building explosion. Although JAIF does not indicate it, there are Wiki reports that R4 building had explosion 06:00 on Mar 15 with fires afterwards.

    Mar 14 BNC comments discussed R3 building damage but not R4 building damage. JAIF report Mar 15 10:30 shows R3 severely damaged but R4 building undamaged. Subsequent JAIF reports show progressively more damage to R4 building.

    R4 had no fuel in it, so any R4 building damage could not come from venting Reactor 4 H2 to building. Diesel and lube oil (implicated in R4 building fires) do not form explosive vapors.

    That leaves the R4 SFP fuel assemblies as the only source of H2 for a R4 building explosion.
    Therefore the R4 SFP fuel assemblies must have become uncovered by water and heated to 850-950C on Mar 15 to generate H2 and cause explosion.


  64. Questions to ponder, answer, or ignore as you all see fit:
    (and I apologize if they have already been addressed on the site)
    1a. The WSJ reports that Tepco delayed using seawater to cool #1 in order to save the reactor from permanent damage.
    ( http://online.wsj.com/article/SB10001424052748704608504576207912642629904.html?mod=e2tw )
    But I also read that #1 was about to be retired in March. Is this true that the reactor was to be retired, or was it likely to be inspected then have it’s license renewed?

    1b. After the Niigata earthquake the Kashiwazaki plant was shut down for months, so is it plausible that Tepco would take any risk to protect an asset that was likely to never be used again?

    It seems that if the #1 reactor really was at end of life, it goes a long way in acquitting Tepco from the charge of gross indifference for financial gain (a characteristic the press loves to attribute to corporations) and instead points toward poor understanding of the severity of the situation and an overwhelmed response team.

    2. Has seawater ever been used to cool a reactor by direct injection in the past? How about spent storage pools?

    3. The reactors seemed to blow up a few hours after the seawater injection started on each respective reactor. My understanding is that the explosions were all from H2, which could have accumulated while hot and exploded hours later, even though cooler temperatures meant it was being produced at a lower rate,…. but my experience with He tells me that it does not hang around for long outside a solid enclosure. Maybe they only vented hours after beginning the injection? Does this sequence make sense to those who are experienced with the technology? It bothers me that all the explosions seemed to happen hours after seawater injection started.


  65. Yes true, R4 had done a full core offload to the pool so heat generation would have been greater from the fuel pool. What I don’t understand though with that theory is why they have not attacked R4 as aggressively with water….

    It is credible I guess that R4 pool emptied and due to the large hot load of fuel ended up in a zirc water reaction zone producing hydrogen… I am just not sure about that yet to buy it. But the building did explode….


  66. Are you sure? If you know you’re gonna release hydrogen into a confined space, wouldnt you keep the sparks away? I mean, sparks dont occur all that often. Static electricity release maybe? I cant imagine that place to be ‘sparky’ for any reason.


  67. Maybe there is some technical explaination of how hydrogen from unit 3 could migrate to unit 4. Not knowing all the design features could be the answer….

    It is possible they shared some portion of their ventilation systems as paired units….


  68. Steven Chu, Winner of the Nobel Prize for Physics and pro-nuclear Secretary of Energy, will be on many of the Sunday Morning (EDT,USA) TV talking-head news shows. Should be interesting!



  69. I can’t remember how I came across this link, but the experiments described in it are mind blowing. They actually blew up test reactors to see how far the radioactive material would go. They tried to get maxium release and most of it came down very locally, counter to all the models they had. These experiments would not be allowed anymore and I’m surprised they ever were.

    Click to access RealismApp1a-attch.pdf


  70. @bchtd1parrot
    One confirmed death from a crane accident, two workers missing… That’s all the news I’ve heard in japan about deaths and missing people at daiichi and daini

    Jsdf are spraying water on number four now, eleven trucks in total… They sprayIng is going to finish this morning to allow time for power cables to be connected
    The fire department is also preparing to spray tonight from 6 until morning


  71. I noticed this moderator comment away back and though it should be re-iterated after reading some of the latest comments from overnight.

    This comments contains multiple instances of unsubstantiated personal opinion which violate the BNC Commenting Rules. BNC is a science based blog and authoratative references are required to support opinions/appraisals.References are being checked and comments found to have edited reported information to suit the poster’s comment will be deleted and may result in permanent banning as a troll.
    Please check the Commenting Rules before submitting your comment.


  72. One of their conclusions is that:

    “If realistic consequence scenaros are considered, it becomes apparent that evacuation of very large areas is neither needed nor effective. The principal threat to the majority of the population is the passage of a dispersing radioactive cloud. This cloud would contain mostly the noble gases xenon an krypton. Against this threat, sheltering may be the best option in the short term (hours and days), and time then exists to determine what long-term actions (months and years) are required. There is no acute need for evacuation.”
    [Please supply link to the above quote]


  73. I wondered if they could possibly be using something like linseed oil and have had spontaneous combustion. Well, maybe:

    Previous Article

    J. Eng. Gas Turbines Power / Volume 133 / Issue 5 / Research Papers / Nuclear Power
    Investigations and Countermeasures for Deactivation of Hydrogen Recombination Catalyst at Hamaoka Units 4 and 5
    J. Eng. Gas Turbines Power — May 2011 — Volume 133, Issue 5, 052918

    The hydrogen concentration in the outlets of off-gas recombiners increased at Hamaoka Units 4 and 5, and their reactors could not continue the startup operations. Therefore, we investigated why the recombination reactions were deactivated …. Two types of deactivation mechanisms were found …. decrease in the active surface area of alumina as support material due to dehydrative condensation. The other cause was the catalyst being poisoned by organic silicon compounds. Organic silicon was introduced from the organosilicon sealant used at the junctions of low-pressure turbines. We also found that a boehmite rich catalyst was deactivated more easily by organic silicon … the organic silicon poisoning the catalyst surface. …the linseed oil that used to be used at the plants was applied again as sealant in the low-pressure turbine casing instead of organosilicon sealant….”

    Pure speculation, that’s an oil ‘sealant’ rather than ‘lubricant’ but if someone left an oily rag or an open can when evacuating the site, that’s a possible ignition source.


  74. IF someone can find a clearer picture pre accident please do so. This image seems to show units 1 & 2 sharing a common vent stack. Units 3 & 4 also sharing a common vent stack.

    To get there you would have to a ventilation interface, which could explain the hydrogen explosion on unit 4 despite an empty reactor vessel….

    I am looking for confirmation or denial of shared vent stacks between unit 1& 2 along with units 3 & 4.


  75. @em1ss: “any after quake shake of the building with damaged structural components could have resulted in a static discharge though….”

    yes, I was about to mention that.

    My recollection from following Sky News and CNN was that the reports of most of the explosions emerged near simultaneously with reports of the most major aftershocks in the area of the power plant..



  76. A good question raised here about why the hydrogen explosion on unit 4 may have identified another significant design fault with these units….

    A shared vent stack by paired units……


  77. Ms Perps
    Have you seen the number of visitors to this post? Overnight comments will be moderated, but due to the overwhelming value of the site it is not closed for comments overnight. That would under the current circumstances be inhumane to my opinion.This is not standard operational business i assure you. Please… i mean… please.


  78. I know that some people currently resident in Japan find their way here looking for information that will help them make decisions for their personal situations. I have written a commentary on this, to which I link below. I hope this is acceptable to the moderators here, and in fact, if you find the article helpful, would welcome it if you displayed a link to it in a visible place on your website until the acute panic especially in Tokyo has subsided.



  79. Barry – would it be possible to start an evolving new thread that specifically captures and addresses what went wrong as regards design, implementation, operation, regulation, redesign/modification, accident event and response. I think this is about to become the main focus of media reporting and you might want to get ahead on that one and see what can be pieced together. I am happy to contribute a basic doc regarding design considerations and failure analysis processes for some context. This must all move soon to how what has been happening.happened in these spaces and how they map to what is being done to today and what is being proposed in G4..

    Its oerson nice to feel that my mind is now on this rather than the direct event, feeling currently that the authorities may well have gotten over the hill – which is a matter of significant relief.


  80. I hope she’s not commenting on our discussions, which I believe to be mostly technical in nature…. I try to prefice opinion with statements of opinion….

    Technical information has not been edited (not enough expertise/time anyway) We leave that for Barry. Links to popular media, government information etc are checked and only edited if found to have been interpreted/edited by commenter’s to suit their own opinion.


  81. Again, no time to read all posts, maybe this has been discussed already? And I know benefit of hindsight and all that, but spent fuel rod ponds on the 4th floor?, in the most earthquake prone area of the planet? Jeees!!!


  82. @William Fairholm
    That sounds like an entirely different way of thinking, but it might make sense. Specially since evacuation itself isnt entirely safe. The story itself is totally cruel. Lets try make a small disaster to see what a big one looks like. The data is very valuable, assuming its correct.


  83. unclepete
    A niner didnt hurt it. Besides, the further down the pond, the longer the way between pond and core. straight down is not an option. The main structure is a very solid construction. Its not the fourth floor of an ordinairy building.


  84. wouldn’t open anyways…. The vent stacks look like radio towers if anyone is trying to find a better photo. The one I had seemed to show one centered between the paired units….

    Which logically would then imply an interface between units due t the common stacks for containment venting. Ultimately hydrogen too…


  85. @bchtdf1parrot Ok , you are correct. But Barry mentioning the “sloshing” before.I must admit I did not think of that , but the japanese engineers would be familiar with that , wouln’t you think? Again, hindsight is great in a situation like this.


  86. The stack left of unit 1 may not be a vent stack which is why I say possibly two for units 1 & 2. The other two stacks are centered between the units and in my judgement vent stacks for elevated release….


  87. hmmm, that seems to conflict with the sketch barry provided though of the unit locations…. Still unclear as his site sketch shows units 1 & 2 in the middle of the site. 3 & 4 to the left.


  88. I am still struggling with reaching a zirc water reaction on decay heat in an ambient environment that quickly. But it’s possible I guess to happen and generate enough hydrogen to blow Unit 4 reactor building up.


  89. em1ss, on 20 March 2011 at 11:34 AM — Good evening!

    From left to right the units are 4, 3, 2, 1 and then furthest right 5 then 6. The single vent stack furthest to the right is, in my opinion, for the Centralized Radiation Waste Treatment Facility.

    In any case, that 3 & 4 share a vent stack clarifies several matters for me.


  90. Would those peole who are pushing the “5 people have already been killed at Fukushima” please tell us how they have been killed.
    I can find no reference to anyone dying from radiation poisoning, but several to people having been crushed or having a heart attack.
    All you do is create FUD to frighten people in Japan and around the World. I have relatives in Japan and all I want to hear are the FACTS not someone’s sick, premature interpretation of what has/will happen. That is wh
    I think Barry should ban these obvious trolls but that is his decision.


  91. @bchtd1parrot 11.08
    Sorry – I don’t understand your point. I think the MODERATOR was saying people who post their comments should check the rules before posting and that the mods were checking links for outrageous editing of them to suit the commenter’s opinion. Good on ’em. I agree the task is mammoth – maybe they are working in shifts:-)


  92. Re casualties from radiation, ABC has this in a story today:
    “Six workers at a quake-stricken nuclear power plant have been exposed to high levels of radiation but are continuing working there, an official at the Tokyo Electric Power Co (TEPCO) said.

    They have been exposed to more than 100 millisieverts of radiation.

    “There has been no adverse effect on their health,” TEPCO’s Takeo Iwamoto said. It was not immediately known if they had been reassigned to different tasks.”

    As I understand it, the injuries & missing people are to do with either the tsunami, or the blasts from the hydrogen explosions – no casualties so far from radiation.


  93. Here’s photos of R1 – 4. The R4 shot seems to indicate that the side with most damage is towards the turbine bdlg, not R3.


    The time sequence for R4 also indicates a H2 explosion in R4.

    As far as R3 vent vapors going to common vent stack and then backflowing to R4 and ending up in the building top, I think that is unlikely. High stacks have chimney draft effect which sucks on both R3 and R4 if common connection.


  94. Ms Perps
    Anyone having loved ones on that plant is not going to be watching the news, this blog or any other. He or she is going to be sitting before some altar, burning insence by the ton praying to all gods the door bell wont ring. This is a time of emotions. The question: “Did anyone cry wolf?” sounds like “Someone cried wolf!” only two blocks down the street. Thats a fact of life.
    We hold the fort in case someone comes with a question and when he does we answer. No matter how ignorent the question. Someone finds a feed, he dumps it here. We look at it for answers. You will not find remarks here concerning cars, women or football.


  95. I worked at Tengiz with a single 300 m tall poured concrete stack serving 4 SRU/TGU units. Inside stack were 4 separate large SS pipes, each venting a unit separately, not interconnected.

    Common stack does not mean commingled. Would have caught this on Hazops review.


  96. bchtd1parrot
    I think we are singing from the same songbook here but we are both on a different key:-). BTW I am a long term visitor/commentator to BNC (from the outset) and am well aware what is to be found on BNC. Please don’t patronise me there are more important issues than male chauvanism rigt now.


  97. At Tengiz, the two vertical large dia SS vent pipes were inside the common poured concrete stack. The pipes were separated by at least 2 feet. If one pipe was damaged, the gases from that hole would have gone up the inside of the concrete stack and vented at the top. If 2 SS pipesdamaged, the same thing would have occurred. Since press inside stack is atmospheric, there is no delta pressure driving force to send gases backwards into units.(or R bdlgs)


  98. No male chauvenism on this side, i am a bit like a doggy in this kind of situation. Someone points a finger, i bite. This is no time to blame whoever for whatever. Thats what i believe. Thats not meant to partonise anyone, least of all someone who is, like you say, singin’ from the same songbook. I do not mean to offend you or any other in any way. That risk i will run later. I’m sitting on a brainfart i cant let fly without an active monitor, too risky. And for what its worth, i’m glad youre here.


  99. Two bits I recall– units 3 and 4 share a common control room. And the “negative air pressure” system” when operating kept any radiation away from the operators in the control room. That (warning, logic …) must mean it pulled away anything vented from the reactor and fuel storage in the form of gas, and so would also include hydrogen).

    So (warning, pure speculation) a failure of the ventilation fans/negative air pressure system would mean that any gas that should have been pulled out and through a carbon filter in the usual way would instead go — wherever the wind took it.

    I know it takes very little difference in air pressure to change airflow around and through a building–a breeze will do it, and the airflow will change with the wind direction.

    So assume first it accumulated at the top of Unit 3, and when that blew off, remembering it was near freezing and no heat, would they have closed doors inside the building to stay warm? Without forced ventilation, some of the lightweight hydrogen could have been carried through the common control area, wherever that is, and ended up in Unit 4 — whatever there was could accumulate in whatever dead air space there was in the upper reaches of Unit 4. The different explosion–lower down–might be from hydrogen being carried in through a common shared building or vent, but trapped inside below the roof deck space? Add one ignition source …

    I recall for gas combustion appliances (heaters, hot water heaters) of the type built for “sealed combustion” (they breathe outside air and exhaust to the outside) the installation rule is that both the intake and the exhaust vent have to be on the same side of the building, perhaps even concentric — because if they’re around a corner from each other, airflow over the building can be enough to reverse the airflow through the combustion chamber.

    End wild speculation. Time will tell.


  100. @David B Benson 12:42: Isn’t H2 generated from R4 SFP low water and hot fuel assemblies a potential source? Is it probable?, well we at least know that it didn’t come from R4 reactor vessel or primary containment since that had no fuel assemblies. The H2 backflow from R3 (damaged at the time) to R4 via common vent stack seems to me to be unlikely.


  101. Thanks Leo, so U4 explosion must have been from U4 SFP. What bugs me is that ( Correct me if i’m wrong) that SFP has concrete damage to some depth. That doesnt make sense to me. Its just a bit of bang gas. Large surfaces like the roof ok, but concrete? Considering its the same kind of concrete that survived a 9.0 quake and its a part that would not likely be challenged by the quake itself, that seems odd.


  102. bchtd1parrot: Earthquake is strong shaking motion laterally and is considered in design. A confined vapor explosion of H2 and O2 creates strong outward pressure blast force and could rupture walls. The only thing that confuses me is that the green platform and machinery in the R4 photo did not looke overly damaged…however it was surrounded by blast not trying to confine blast.


  103. Leo Hansen, on 20 March 2011 at 12:54 PM — I find that source for the #4 explosion highly improbable for two reasons, one being the location of the damage to the external structure. That does not mean I disregard that possibility; it only means that it is now but one of three possibilites none of which seem very likely.

    The damage assessment will eventually be done and presumably we will be able to read (at least) the conclusions of the resulting report. In the meantime I’m a bit disapointed in WNN to have so firmly stated a conclusion which is at odds with a helicopter siting of water still remaining in the #4 spent fuel pond [before the various rewaering exercies to that #4 SFP].


  104. http://www.world-nuclear-news.org/RS_Fuel_pond_work_at_Fukushima_1903111.html

    “Holes have been bored through the roofs of reactor buildings 5 and 6 in an 11-hour operation to ensure that hydrogen can disspate naturally. Each unit has three holes measuring seven centimetres. Tokyo Electric Power Company did not say that hydrogen was being produced, but that the move to bore holes was a precaution.”

    Does anybody know how they managed to cut/drill/bore holes through the roof of reactors 5 and 6? From outside? From the inside?

    Also I would have thought that there would be “blast panels” or doors as part of the original design to prevent the kind of damage that was caused by the explosions/over pressuring that we have seen in #4.


  105. So we have several variables here. There’s the draft through the control room, the afterdraft from the blast at U3, the tendency of hydrogen to go up, the tendency of cold outside air entering through U3 to go down and turbulence of those last two. It must have been a hydrogen explosion, or at least gas. The crane is almost spotless. My explanation for that is that it suffered pressure from all sides meaning it was ‘inside’ of the explosion.


  106. I have worked in many control rooms and never was the HVAC connected in any way to process systems piping or vents. The reason is that process/safety sytems can have high pressure gasses that would backflow into HVAC and not be safe.


  107. Another image

    this one shows, just above-right of center, a white linear feature connecting the base of the tall tower and branching to both reactor buildings 3 and 4. I’d _speculate_ that is a ventilation duct meant to carry air drawn from both buildings and send it up and out the tower high above the site. (Those tall towers are ventilation exhausts? Anyone confirm? There are four towers — one between each pair of reactors, and one for the building off to the side that I think is the common storage pool.

    Anyone know? There’s something that might have been the same design between buildings 1 and 2, but incomplete — either broken or covered by darker material.


  108. Japan’s wind industry hails earthquake-resilient turbines

    Japan’s wind turbines survived last week’s earthquake and as a result utilities have now asked wind farm operators to boost power output to make up for energy shortages in the country, the leader of the Japanese wind energy association has revealed.

    (emphasis mine)

    Imagine the response from the wind farm operators… “Sure, not a problem. We’ll get right on to that. Just waiting for the wind to pick up…


  109. Latest news on NHK says that power is restored to units #5 and #6, and water temps in those SFPs are dropping significantly. Water cannons were directed at #4 this morning and now they are taking a break to get some electrical work done around there. Water operations to resume this afternoon. Equipment is being evaluated at units #1 and #2 prior to powering anything on there. 良し, that’s all from me for now.


  110. Did you watch the clip somewhere around the top of the post? Its only a simulation, but they indicated the halfway submerged rods as red hot from just over the surface. The way i see it, those rods start generating H2 the moment they stick their heads over the pool surface. They may generate heat like wild, but not or hardly conduct it.


  111. bchtd1parrot
    Thanks for that. I think all our nerves are a little on edge right now and not many of us have had a lot of sleep. Oh to be young again and be able to switch off and fall asleep as soon as your head hits the hits the pillow :-)


  112. @Tom Keen, on 20 March 2011 at 1:15 PM,

    Wow what kind of BS is coming from the Japanese wind energy association? I suppose they are going to claim they’re powering all of Japan now as if nothing else is running.

    We need a report of how the other nuclear plants are doing all around Japan at this time.


  113. Is it posible that the blast in U3 propagated through the interconecting structure causing a breach into U4? I do not know the geometry in there but blast/shock waves can do some pretty strange things with all of the phase transitions in those buildings (Multiple water pools, widely varing concrete densities, possible via with high pressure piping between/joining buildings etc.


  114. bchtd1parrot, on 20 March 2011 at 1:47 PM — I only raise the possibility of some lateral blast making its way into #4 without any outward sign of damage to #4. I have no means of assessing a probability.

    Hydrogen from #4 SFP would, one would suppose, be largely confined to the top story and damage would be to the sheet metal sides and the roof, as in #3. That concrete, much further down and on two sides was removed suggests that the hydrogen was down there, making the top of #4 SFP an unlikely source.

    It is quite difficult to reach a high enough temperature to oxidize zirconium using air or steam. This makes the spent fuel as a source unlikely, especially given the radiation readings for #3 versus #4.

    I’m not suggesting impossibility, but rather trying to obtain possible sources and routes for the hydrogen gas to create the explosion results in the aerial photograph. IMHO hydrogen from #3, by some route, remains a possible source.


  115. > response from the wind farm operators

    I’d guess that would be “defer shutting down for any routine maintenance, take a chance on running longer, do the maintenance during the middle of the lowest wind period even if it’s off-shift hours, and run closer to the redline if they have high winds before shutting down to protect the hardware” — what would you do, if you knew there was a need to wring out everything you could?

    The hydro plant operators, assuming there are some, could run their reservoirs down, trading off a risk of low water later for power now.

    I have no expertise in wind energy, but there are options, always, to wring more performance at more cost or more risk.

    And always, there’s conservation — besides the roling blackouts.


  116. Pingback: Tragedy in Japan « Sky Dancing

  117. Hank, that white linear thing, that would be the vent pipe right? They both bend into the direction of the stack, but what is that thing sticking the other way? A valve? A fan? And then look at the pipe at the top of the stack. Thats just one pipe. To my carpenters eye test too narrow to contain the two down on the ground. And its not a concrete or brick structure, its one pipe in an open steel stack. If the blast at U3 rips the inventory out of that connection into the stacks direction, there’ s your connection between 3 and 4.


  118. We have heard this all before – 40 years ago…..

    * * * * *

    Interview with Greg Minor,
    Former Senior Nuclear Engineer with General Electric

    In 1976 Minor with two other senior engineers from General Electric resigned because they had come to believe that nuclear energy represented a “profound threat to man”. Together the three experts had 54 years experience in the nuclear industry. Greg Minor is interviewed by Mike Rann.

    Rann: What prompted your decision to resign from General Electric.

    Minor: Well, it was a series of events that happened over several years, but some of the primary reasons include the
    fact that I began to see the link between the nuclear reactor programme we are using for commercial power and the
    weapons problem which is being proliferated around the world. There were also a series of accidents and problems occurring, such as the Browns Ferry incident in Alabama. This was a plant I had worked on and it came dangerously close to the accident we are all trying to prevent.

    Rann: What actually happened at Browns Ferry?

    Minor: Browns Ferry was a plant where we had done very careful and improved design to try to prevent a single event from wiping out all the emergency systems that are used to protect the reactor and protect the public from an accident. But what had basically happened was that a single event, a fire caused by a lighted candle being used by an electrician checking airflow in the cable spreading room – wiped out 1,600 cables which connect the control room with the reactor. In doing so, the fire – which burned for seven hours – wiped out all the safety functions of the emergency core cooling systems that are normally called on in an emergency condition to save the reactor from a dangerous situation. Fortunately it didn’t quite come to the condition where it needed those emergency core cooling systems. If it had, they would not have been available. (Two of Browns Ferry reactors, supplying 15% of the total electricity demand for the huge Tennessee Valley Authority, had to be “scrammed” when erratic readings began to appear on the controls. Browns Ferry was out of action for many months and repairs cost tens of millions of dollars. Until the Three Mile Island/Harrisburg incident in April 1979, the Browns Ferry incident was regarded by nuclear critics and advocates alike as potentially the most serious incident in the history of the nuclear industry.)

    Rann: The Browns Ferry incident was really the culmination of a number of very silly mistakes, particularly human
    error. If the safety and control systems could be made more foolproof, would this remove most of your doubts about
    nuclear power?

    Minor: Well, I think the thing we learnt from the Browns Ferry plant was that you cannot make them more foolproof.
    The thing that happens is that human element. Human error in either design oversight or the problems we didn’t
    foresee in designing the plant, or in the manufacturing where a manufacturer didn’t follow the quality procedures or
    the installation procedures, or maintenance problems. It was a maintenance problems that happened to catch Browns Ferry. But it could be any of those that would produce the accident in some other plant, regardless
    of how carefully you think you have designed it.

    Rann: Supporters of nuclear power say it is cleaner than other forms of power generation. They say it is less
    wasteful, less environmentally disruptive. When you look at the track record of nuclear power generation over
    the years, isn’t the Browns Ferry incident really the exception that proves the rule: the rule being that nuclear
    power is efficient and pretty well safe?

    Minor: Well, you have to be very careful in making that statement about cleanliness. A nuclear reactor is only
    clean if it operates exactly as it is designed and these incidents around the United States and around the world
    where reactors have released radio-activity into the environment, which they are not designed to release, and which ·
    really overrides the rule of cleanliness they all like to speak about. The Browns Ferry incident was, as far as proving the rule that reactors are safe and clean, I would say, quite the opposite. It proves that they are vulnerable and they were very lucky that this reactor accident didn’t go all the way.

    Rann: What about the potential benefits? Most proponents of nuclear energy would concede that the risk can
    never be zeroed, but don’t the benefits from nuclear power more than compensate for what the proponents
    describe as a very slight risk?

    Minor: In my opinion they do not. The risks are so large that it is hard to put it on a scale that we normally think of in
    any mechanical or technical disaster. The risks of a nuclear accident can be so devastating and so widespread and last such enormously long periods of time. We are talking about thousands and thousands of years of contamination of an area which may make it uninhabitable forever. These are dangers of a scale we do not normally think of.

    Rann: What sort of catastrophe, then, could have resulted from the Browns Ferry incident?

    Minor: The danger at Browns Ferry was that during the process of trying to get this reactor under control, when it experienced this devastating fire which was burning up the control cables, the operators had to relieve the pressure
    inside the reactor and in doing so they had to manually open some valves which normally they would not open. But in manually opening those valves they released the pressure but they also lost a large part of the cooling water that
    normally covers the reactor core, and that’s the concern. Because it you lose the cooling water and it gets below the
    surface of the core, then you begin to have core melting and the danger would be that this core melting would
    release radioactive material which was contained in there. If it went on further to melt out of the pressure vessel and out of the containing building, in a “China Syndrome” situation, then you would have that radio-activity released to the
    public and the environment. And that would be a very, very serious accident.

    [Mr. Minor is a anti-nuclear activist and was a consultant for the film “China Syndrome”.]

    Source: Adelaide Independent
    Adelaide, South Australia
    Volume 1 Number 1
    pages 6 – 7


  119. @ David B Benson 12:59

    The R4 picture

    clearly shows the R4side wall blown out is at and above the green machinery at the top of the SFP. Also see that concrete & rebar blown out not in, indicating an internal blast.

    Also blasts propagate thru open space and the presence of damage to walls only meant that the blast wave could propagate to there, not that H2 & O2 were present there.

    That said, I’m not sure why the R4 roof was not blowen off. Maybe we dont have that picture.

    Re R3 blast being ducted into R4 would only make sense if duct is stronger than R4 walls.


  120. A couple of people have mentioned their concern about the refinery fire in Chiba. Lack of information on this has been bothering me too. Usually this kind of event would merit ongoing attention.

    Anyway, this is the most recent article I could find:
    http://bit.ly/g6Cb0i (in Japanese).

    The following is a paraphrasing of the article, not strictly a translation, but pretty close fact-wise (if anyone has additional newer info, please post):

    As of March 16, 13:30 the fire is still burning. To extinguish the fire all the remaining LPG in the tank needs to burn itself out, which is expected to take a few more days. Water is being sprayed and other measures are being taken to prevent any spread of the fire. As well, efforts to extinguish the fire itself are continuing, but at this point the fire is still burning.

    The gas is the same type of gas used by people in their homes, so this fire is not expected to pose any health threat. There are some rumors circulating on the Internet about exposure risk especially in the case of rain, but “there is not truth to this” (Note: the article shows this as quote, but not attributed to anyone in particular).

    All operations are currently suspended at the facility.


  121. More good news re ratiuation levels


    Tokyo Electric Power Company says radiation levels around the compound at its Fukushima Daiichi nuclear plant are on the decline since water-spraying began in earnest on Saturday afternoon.

    The company told reporters that the radiation level at the plant’s headquarters building, located some 500 meters northeast of the No. 3 reactor, dropped to 2,625 microsieverts per hour at 8:30 on Sunday morning.

    The reading shows a drop of more than 800 microsieverts from 18 hours ago–about the time the water-spraying at the No.3 reactor began.

    Sunday, March 20, 2011 11:49 +0900 (JST)



  122. Leo Hansen, on 20 March 2011 at 2:19 PM — The #3 explosiions were clearly different events than the subsequent #4 explosion. The (presumed) hydrogen came from somewhere, possibly #3 or reactions in the #4 SFP.

    But the #4 explosion didn’t take off the roof and did take off concrete walls quite far down. One might suspect eartquake damage, but measurements at #3 were just over 500 gals and the units were designed to take 600 gals; quite unlikely that #4 concrete sustained any significnt damage.

    So I entertain the possibility of a route for hydrogen so that an actual explosion could destroy reinforced concrete and still leave the roof intact.

    Just trying to avoid leaving any credible alternatives out, thus not jumping to conclusions.


  123. David
    Thank you.

    Were those buildings designed for an internal blast? I remember seeing a hole on the side of one of the units that looked very regular, like a blow out pannel. I would guess that being a containment building it was designed contain what it could then fail. Would the design criteria be to hold the maximum overpressure and fail catastrophically or take a lesser load anf fail gracefully?


  124. bchtd1parrot:

    The difference in average power between 50 hz and 60 hz is 20%. So running a 60 hz pump on 50 hz power will probably just provide less pumping power. Running a 50hz on 60 hz might burn it out – you would probably be eating up all of the safety margin (typically 20%).



  125. Joshua, on 20 March 2011 at 2:55 PM — I don’t know. From my inexpert interpretation of the aerial photo of the blast damage to #4, I suspect that the exterior walls were in precast sections; the walls appear to have failed along the connections between those precast panels.

    That said, that form of construction wasn’t so common that long ago, but I otherwise have no way the explain, even to myself, that photgraph.

    Take it with a big grain of salt, please.


  126. Sounds like things keep progressing towards a safe situation – hope so.

    “The operator of Japan’s crippled nuclear plant is hopeful of connecting all six reactor cooling systems to external power by late tomorrow, a major step in bringing the nation’s nuclear emergency under control.
    Cables were connected to the No. 1 and No. 2 reactors yesterday and technicians were testing this morning before activating them today.”
    “Emergency services at the Fukushima plant were hopeful technicians could re-occupy the central control room this afternoon, making it easier to check various functions before external power was returned to the cooling systems.”


    Temperatures in the spent fuel rod pools at Fukushima Daiichi’s No. 5 and No.6 reactor buildings had been brought back to normal levels today and the firemen doused the No.4 reactor – the condition of which caused a panic in Washington on Thursday.


  127. This might be an interesting read:

    Idaho National Engineering and Environmental Laboratory
    INEEL/EXT-99-01318 December 1999
    Ventilation Systems Operating Experience Review for Fusion Applications


    “This report is a collection and review of system operation and failure experiences for air ventilation systems in nuclear facilities. These experiences are applicable for magnetic and inertial fusion facilities since air ventilation systems are support systems that can be considered generic to nuclear facilities. The report contains descriptions of ventilation system components, operating experiences with these systems, component failure rates, and component repair times. Since ventilation systems have a role in mitigating accident releases in nuclear facilities, these data are useful in safety analysis and risk assessment of public safety. An effort has also been given to identifying any safety issues with personnel operating or maintaining ventilation systems….”


  128. uh, yeah … sounds like the ventilation, as well as the cooling systems, needed power all the time.

    “…Fans showed many problems in the occurrence reports, followed by modest numbers of filter problems, the circuit breakers, motors, controllers and instruments, dampers, electrical connections, relays, ducts, gaskets, and switches…. Moeller (1975) cataloged other nuclear industry experiences. These experiences showed that fires and explosions have occurred in ventilation systems, particularly in power plant off-gas systems that handle hydrogen gas…. Moeller (1979) then cataloged other, later experiences with these systems…. An important event from 1976 was also mentioned there, ice buildup in the upper portion of an exhaust stack at a boiling water reactor. Exhaust air backed up into the off-gas building. The air was rich in hydrogen, and the hydrogen deflagrated. The off-gas building was demolished (Bertini, 1980)….”


  129. To Chris Warren at 2:15

    So? Any conflict of interest there? I am not making any accusation but your motive for posting that piece was not at all clear to me. What exactly are you trying to assert? I’m just curious.

    I’ll say right up front that in my opinion, that piece is just an example of the early format of anti-nuclear propaganda leading up to the golden opportunity of TMI where people could actually extol the horrors of a “meltdown” and the “China syndrome”. Except for the fact that nothing really happened.

    So please clarify your reason for posting.


  130. Cosmo Oil to Boost Processing at Yokkaichi, Sakaide Plants

    How do the fossil fuel industries get away with this? A 40 year old nuclear power plant goes down, the whole nuclear industry world wide is shaken by it. An oil refinery goes up in flames, and they just say “That’s okay, we’ll just boost supply from elsewhere. Don’t worry about the impacts!“. No one batters an eyelid.

    Can anyone confirm if there have been any fatalities from the Chiba refinery fire?


  131. K. Nyankoye, on 20 March 2011 at 3:45 PM said:

    I think anyone reasonably sensitive to the needs of the global community would see the points being made. I don’t want to appear didactic but:

    1) Greg Minor was a Senior Nuclear Engineer with General Electric

    He indicates that:

    1) Browns Ferry was a plant designed knowing the dangers if all the emergency systems were knocked out – but a nuke accident still erupted.

    This has been the case repeatedly for 40 years.

    2) We get the leading suggestion from Mike Rann (a Australian politician, who is now known as Mr “U-Rann-ium”)

    If the safety and control systems could be made more foolproof, would this remove most of your doubts about nuclear power?

    This suggestion has been floated regularly for over 40 years, now – with the results we now see.

    3) 40 years ago, nuclear engineers concluded: the thing we learnt from the Browns Ferry plant was that you cannot make them more foolproof. BP’s oil rig represents similar phenonema. Although it is more likely that commercial cots cutting is a greater source of risk in nuclear power. In every new technology – unforseen risks create catastrophe – eg NASA’s two space shuttles.

    Only slow learners need more than 40 years to lean the lessons. Browns Ferry, TMI, Chernobyl, Fukushima giver us one nuke disaster every 10 years (actually less than 40 years – the rate is one every 8.5 years. Improving safety does not reduce the risk if you increase the quantity.

    4) Next ancient (now refuted?) proposition by Mike Rann,

    isn’t the Browns Ferry incident really the exception that proves the rule: the rule being that nuclear power is efficient and pretty well safe?

    The best exposure of this nuclear “rationality” is simply to publish it.

    Nothing refutes the processes that has led to the modern nuclear nightmare better than the actual earlier words of nuclear pundits – eg Mike Rann. The real subtext is in Mike Rann, not the poor GE engineer being played by Rann.

    5) The next fabulation from Rann was his attempted suggestion that:

    don’t the benefits from nuclear power more than compensate for what the proponents
    describe as a very slight risk?

    I wonder what his answer is now?

    Imagine the risk in the future if Westinghouse or Chinese capitalists sell nuclear plants to Libya, Yemen, and Bahrain, and they are attacked in future political Middle Eastern volcanoes.

    In short there is no:

    conflict of interest there

    there is no:

    anti-nuclear propaganda

    and pefull most will see the inherent denial in suggestions that:

    TMI … nothing really happened.


  132. Pingback: “Japan nuclear plant power ‘close’” and related posts | topsaladrecipes.com

  133. @bchtd1parrot, thanks

    when I watched the vid, after I posted, I also noticed that, :oops:

    In here http://www.wickedmike.com/main-facts-about-the-japanese-tsunami-2011/ it states that the mg sets were in the basement. If that’s true then even if the tanks hadn’t been knocked over they presumably would have lost the MG sets due to flooding.

    As a former electrician I would be wary of running 50Hz pumps on 60Hz power, especially in a mission critical situation. Also there may be other kit to which they want to get power that’s more sensitive to power frequency. But if that was the problem then TEPCo should not have made that mistake, but maybe they didn’t actually supply it..

    @Tom – That statement has been there for several days, I guess it’ll stay like that as long as the real cooling system isn’t working.


  134. What if hey pumps are so damaged that they will not work once the turn on the power?
    Is it possible to fix them?
    If not will they have to continue what they are doing now for months or even years?
    Surely that is the biggest problem. If they cant get control within the next few weeks then what?


  135. ‘Defense in depth’ backup systems to keep nuclear reactors and fuel storage pools cool all seem to depend on electric systems.

    Safety depends entirely on electric motors driving cooling pumps. These motors are to be powered as follows; by electricity from the station’s turbines, by electricity from the grid, by diesel generators or by batteries.

    Electric supply lines, motors, control systems and generators are all easily damaged by seawater. Diesels on the other hand are not, as long as air intakes, exhaust and fuel supplies are placed high enough.

    If just one backup used pumps driven directly by diesel engines, by shaft, chain or belt, wouldn’t this add considerably to the overall safety?


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  137. @ neilvw, thanks a lot for the information, the oil refinery fire is bothering me a lot, for several reasons
    – it is far closer to big populated areas than the Fukushima plant
    – it looks that the toxic fuel is spilling into the environment, spent or aflame, while the Fukushima fuel is still all contained inside aiproof containers
    – I don’t know enough about refineries, but I cannot understand how is possible that a gas tank coulb BURN for many days a if it was a gas pipe connected to a large underground reservoir, instead of simply blast away
    – I read nothing about the health risks caused by free flame combustion in open air of oil derivates, and the consequent breathing of different oxydes plus the environmental pollution of rain washed heavy black smoke
    – we know the measurement of a Fukushima fart in µSv even 50 km away and two days after the fart happened, but I saw NO measurement data of any damage caused or inflicted to oil and oil related industry

    if somebody has more accurate news, please let me know more on the subject.


  138. Hello Professor,
    I’ve been following your updates the last couple of days and they’re great! My daily nwespaper is the FAZ, to which you gave an interview yesterday; it was refreshing to read opinions so contrary to the German media trend. And I agree with you that it is cynical to allow so much news space for potential dangers and consequences in a far-away country (Germany), when the misery of the people of Japan is real and tangible.
    Kind regards


  139. @BerGonella
    The burning tank you refer contains liquid petroleum gas. It has to evaporate to become combustible. It needs heat for that. The top of the tank is burning like a torch whilst the bottom is covered in ice. The greatest risk actually is the ice on the bottem. If it tears up the tanks lower level, the lpg floats out burning. Having the experience of standing face to face with about 120 kilos of lpg after opening the trunk of a car once i know it has to cook first. After a truck accident in a village south of Amsterdam some years ago 15 tons of lpg were vented smack in the middle of a village. What i do not understand about the burning tank is why they dont simply pump it empty.


  140. Here’s one i need to drop now for this here as i believe it is in the better interst of the post.

    The argument against deleting PARTS of text out of a comment is that it leaves the remaining text out of context and thus changes the message. I have noticed on this post that partialy deleted messages read totally beyond the intend of the initial message some times. Since the comments are not anonymus i suggest to consider full delete if any delete is needed or consideration of consequences for comment message when in need for partial delete. Being someone who sometimes depends on moderator intervention i would welcome this. Thank you.
    Point taken.


  141. Since there are obviously many very knowledgeable people here, I decided to ask if someone has any insight about how the situation at the 2nd reactor’s damaged wetwell torus should ultimately be managed?

    The water there is certainly heavily contaminated with fission products and it would seem that it would be a very good idea to try to keep it out of the environment. What can be done about this, after the more pressing issues have been dealt with? Is it already too late to do anything?


  142. I don’t know what is going on with the explosion at the spent fuel points, but all I know is this: if the bottom of the ponds are still covered in water at near ambient pressures (<200 kPa), I cannot for the life of me get temperatures over 800 degrees Celcius at the top of the spent fuel rods in my thermo model. And this is a pretty simple heat transfer situation, even with very poor ventilation it does not happen if there is still water at the bottom of the pond.


  143. I expect that the answer to this question is “No one really knows”, but I’ll ask it anyway.

    Let’s acknowledge that the GE/Toshiba/Hitachi Mark 1 reactors have done a remarkable job in containment. Despite being 40 years old, they have withstood an earthquake 7 times as severe as they were designed to do. Then they were hit with a major tsunami. Then there were these hydrogen venting explosions, various fires, and intermittent high pressures, temperatures, and likely partial melting from within the reactors. Along the way there have been hundreds of afterquakes, some as high in intensity as normal earthquakes. And perhaps another big earthquake is still to come.

    How does one intelligently evaluate the risk of a reactor rupture at this point? Should the thinking be: ‘Well, the reactors have taken this much punishment already. They’re probably also likely to withstand whatever else Mother Nature can dish out from here on in’? Or should the thinking be: ‘We’ve already pushed these reactors too far and gotten lucky. Any other event could well be the straw that breaks the camel’s back and cause a rupture’?

    In other words, as we focus on reducing the risk of meltdown rupture, we also still have to contend with the current risk of quake rupture, which could negate all of our meltdown prevention efforts thus far. What do we know about the current general structural integrity of the reactors (other than “containment has not yet been breached”), how great is the risk of quake rupture, how bad would it be if it happened, and how great an evacuation perimeter should there be, given this risk, balanced against the risks posed by an evacuation itself?


  144. @bchtd1parrot,
    thanks a lot for the explanation, I really did not know quite anything about LPG, knowing that it is really strange they do not try and pump it away, maybe it’s not possible to get close enough to the plant, because of fire.

    anyhow, this it is not a reassuring situation, indeed.
    I mean, now (if still aflame) the tanks are acting as big torches, but the risk of explosion of the “ice” is still clear and present?
    what if it happens, do we know anything about evacuation plans?
    and what about, of course, the pollution and the rise in cancer probability for the population in a 20 km range?


  145. David and Hank,
    David is likely correct that the tall structures are the offgas vent stacks which primarily vent the non – condensible gases from the units condenser. During normal operations this gas would be processed by the hydrogen recombiners prior to release. Without power, the recombiners do not function. I thought about this too after signing off last night.

    There are accident strategies though that use that path as a vent path from the reactor vessel (via main steam to the condenser).

    No ability to make a conclusion if it’s related to the explosion on unit 4 still for now.


  146. I guess no one has posted this yet: As of 19th 16:20, the LPG fire at the Cosmo Oil facility in Chiba has been put “under control without risk of spreading”. They’d put out a total of 6 statements over 9 days on the status since the fire started, all accessible directly from the main page of their website.


  147. Another thought that came to mind and I have been unable to confirm this except for links stating a fire had occurred early on in Unit 4.

    Most large generators are cooled with hydrogen. In fire situations depending on the location this hydrogen is vented through the turbine building roof. Since unit 4 initially only had a fire it is plausable that a generator hydrogen venting evolution may have contributed.


  148. @ BerGonella, what’s on fire is a huge tank of condensate (Butane, Propane), which burns fairly cleanly. It will have to burn itself out because it can’t be extinguished. It is doubtful any feeds to it are still delivering more HCs


  149. I don’t know if anyone has reported this here, but the latest JAIF reactor status report mentions that they are injecting seawater into the SFP of unit 2. This along with spray water to the SFPs of unit 3 and 4. This means they still have access to the normal ways of putting water into SFP 2, but maybe don’t have pumping to maintain cooling, but that is speculative. Still saying no outside AC power yet for 1 and 2. Does not mention if they will be injecting seawater into the SFP of unit 1

    Click to access ENGNEWS01_1300624909P.pdf


  150. My mental picture of these processes is incomplete (Showing I have a firm grasp of the blindingly obvious.)
    Can someone please comment on what is happening to the seawater after it is pumped into the plant?

    I’ve been attributing the low reactor pressures (<0.02MPa in units 2 & 3) to some sort of containment rupture which prevents pressurization above atmospheric and allows leakage of the injected seawater. So where is it going? Is it carrying fission products?

    Only part of the firetruck streams are hitting/staying in the SFPs. Again, are there fission products being carried away by the overflow?

    Early on, there was concern about salt precipitation from the evaporation seawater. Is this no longer a concern?

    Thanks for the level headed information. In contrast, a couple days ago one of our national news outlets referred to the "near certain death" faced by the plant workers. I think we all face that given enough time.


  151. We’re starting to see the effect on food supply — I thought relevant here at bravenewclimate as it has to do with contamination spread and geography.

    Samples of milk and spinach near the plant were found to be tainted. In the case of spinach, up to 54,100 Bq/kg of Iodine and 1,931 Bq/kg of Cesium. With these numbers, wouldn’t even the shorter-lived varieties of I and Cs require several months to reduce to international limits?


  152. sorry Ctch, but where have you found those figures? t
    the reading I found for the Tokyo water was very different (about 2.85 for iodine and 0.21 for cesium, as found HERE), can you confirm the figures, the unit and the source? it looks to me completely out of scale, given that is Bq/kg.


  153. With the caveat that I haven’t seen either the spinach or reports other than massmedia about it, it seems most likely that the reading is from particles _on top of_ the leaves, not inside them.
    So a good washing might be all that is needed to bring it down to safe levels.
    Though, except in cases of severe food shortages, I’d guess that it’s just easier to junk it.

    WRT now growing, not yet harvested spinach, it is hard to tell whether just a few heavy (clean) rain showers will be enough. It all depends on so many factors (particulate spread even over a field or in spots here and there, drainage, how it would be diluted etc).
    Best case scenario would be hose the field down with clean water, problem goes away.
    Worst case scenario would be unusable crop from this field for this growing season.


  154. BerGonella – I think Ctch is talking about the reports of tainted milk and spinach from farms/fields 30-50 km from the NPP.
    I too would love to see some more exact figures and sources for this.


  155. > Aspsusa, on 21 March 2011 at 12:44 AM said:
    > With the caveat that I haven’t seen
    > either the spinach or reports …
    > it seems most likely

    Speculation, unless you have some professional experience, is just baseless opinion. Why bother?

    You can look this stuff up.

    Assuming you’re a professional with access to an academic library, you can read the research on this; just for example:



  156. Why so nasty, Hank? :-)
    Do we have any good, exact, sources for the figures Ctch posted?
    I think I asked this yesterday (not in regards to the figures Ctch posted, haven’t seen those before, but the general reports about spinach and milk) but that might have been on some other site.

    What would you say the likelyhood of contamination ON spinach as opposed to INSIDE spinach would be?

    This type of data (measured contamination in produce) would be very interesting if we had exact locations and dates for it.


  157. > If just one backup used pumps driven directly by
    > diesel engines ….

    Have you seen the pictures of the diesel engines used at the plant? They are the size of locomotives, huge multi-story things. Starting a diesel requires turning the engine over with a starter motor. Yes, they could have designed in a huge tank of compressed air, or a huge windup spring, or something else as standby starting power, if the electricity failed, but nobody planned for this.

    Nor did they have a harbor to bring in a large ship to supply power, apparently. A deepwater port and dock, if one had survived, might have solved many problems.


  158. Cyril, it appears no one here can help you with your model, since you haven’t published it. You could get a blog? Looking in Scholar, near as I can tell, everything published is consistent, and much of the work on the subject is not published for the amateur reader. It appears that if you have a professional or academic institutional connection, you can download the models and computer code used for the cooling pool papers.


    “… open-rack storage for the remaining more recently discharged fuel. If accompanied by the installation of large emergency doors or blowers to provide large-scale airflow through the buildings housing the pools, natural convection air cooling of this spent fuel should be possible if airflow has not been blocked by collapse of the building or other cause. Other possible risk-reduction measures are also discussed.

    Our purpose in writing this article is to make this problem accessible to a broader audience than has been considering it, with the goal of encouraging further public discussion and analysis. More detailed technical discussions of scenarios that could result in loss-of-coolant from spent-fuel pools and of the likelihood of spent-fuel fires resulting are available in published reports prepared for the NRC over the past two decades. Although it may be necessary to keep some specific vulnerabilities confidential ….”


  159. Eagles Eyes, on 21 March 2011 at 12:14 AM said:
    Now a confirmation in the last JAIF report for U4 SFP: “Hydrogen from the pool exploded.”

    Actually they have been reporting that for several days now. I was doing other things/sleeping when this discussion got going or I would have pointed that out. Maybe we should accept that as the explaination, until proven otherwise. It seems to be the offical explaination as of right now.


  160. Aspsusa, the search term to use is “translocation” and you can look this up.

    There’s a reason people look first, and specifically, in milk for iodine and in spinach for cesium, after a radioactive leak. Why do you think that is? These are ‘sentiel’ sources. Spinach has a very high rate of translocation, moves water from the ground and from rain on leaves into the plant’s leaves and stems fast (wilts if not watered very regularly!).

    That’s what I’m encouraging you to do rather than speculate — read, it’s available. You can help people by making the effort to read and filter what’s there, or rely on people who do have time. Pure speculation without research wastes your time and the reader’s time to no benefit. Just sayin’. This is meant to be a science blog, not a chatroom, and citing sources is highly encouraged (and has been for years). The moderators have to sleep, the ordinary readers like us are asked to hold to a higher standard than at chatrooms. I’m not being nasty, I ‘m urging you to do your best to be helpful. I get the same, um, helpful advice (grin) and try to hold up my side.

    Try here, just as examples of finding a place to start:

    Look at p.111 here — an experimental comparison to determine whether putting plastic sheet over top of the growing plants changes the amount of fallout-derived cesium in spinach, among other plants and other elements:


  161. For example (wow):

    “This study describes the predicted response of Unit One at the Browns Ferry Nuclear Plant to a postulated loss of decay heat removal (DHR) capability following scram from full power with the power conversion system unavailable. In accident sequences without DHR capability, the residual heat removal (RHR) system functions of pressure suppression pool cooling and reactor vessel shutdown cooling are unavailable. Consequently, all decay heat energy is stored in the pressure suppression pool with a concomitant increase in pool temperature and primary containment pressure. With the assumption that DHR capability is not regained during the lengthy course of this accident sequence, the containment ultimately fails by overpressurization. Although unlikely, this catastrophic failure might lead to loss of the ability to inject cooling water into the reactor vessel, causing subsequent core uncovery and meltdown. The timing of these events and the effective mitigating actions that might be taken by the operator are discussed in this report.”

    Pages: 176
    Availability http://www.ntis.gov/search/index.aspx?frm_qry_Search=DE83012314
    PC A09/MF A01; 1.


  162. Luke Weston

    Looking at the top of the reactor vessel and then the cap sitting below in that image, made me think “Hey they screwed it on.” A few seconds of contemplation and those groves in the reactor vessel must be for the O-rings. Gives you an idea how large these reactors are.


  163. Thanks Hank! (I really mean that – having “translocation” as a word meant that my searches wrt milk suddenly turned up interesting stuff)

    Still, what _data_ do we have about this (where does Ctch’s figures come from)?

    With all the weirdly wrong and slanted stuff in the normal media, it is not that far fetched to question stuff like this (especially when not sourced).
    Within one week of a release of stuff, I still think the first place to look for the source of high activity would be _on_, not _in_. In a few weeks, totally different story.


  164. what I think about data is that maybe the ones displayed by Ctch were originally in micro- (or nano-) becquerel, and that the prefix got lost somewhere.
    just a guess, useless until someone founds the source


  165. For amateur readers like us, our best hope is to ask smart enough questions in public (showing what we’ve tried to do to learn) — and maybe attract the attention and help from someone who actually knows the field.

    Pardon the pun, unintentional.

    But seriously, logic isn’t reliable here. If we assume that fallout will be on but not in the leafy green plants in the first day or two, logic says wash them and then test the wash-water instead of looking in the plant.

    My old doctor used to remind people that ‘theory and practice are, in theory, the same, but in practice, not’ or words to that effect.

    Some plants are really good at taking in both water and nutrients (think airborne dust) from the leaves — “foliar feeding” — so to find out what’s happening takes experiments like those described.



  166. BerGonella, on 21 March 2011 at 2:22 AM said:
    “what I think about data is that maybe the ones displayed by Ctch were originally in micro- (or nano-) becquerel, and that the prefix got lost somewhere.
    just a guess, useless until someone founds the source”

    No, I think you are confusing becquerels and sieverts. Becquerels are counts per second. Sieverts is energy deposited in one kg of a human tissue after multiplier effects of different types of radiation. Thery are related but not directly. Becquerels from different sources have different effects since the energy of the source is not considered. That is one of the reasons they have different limits for different radioisotopes. Here is the link where the numbers come from.



  167. There are some vague, dodgy media reports of potential criticality in the Unit 4 used fuel pool.

    However, I’m skeptical until I see better reporting on it.

    Used fuel pool water is usually loaded with boron to keep it subcritical. Furthermore, if there is some kind of fuel-pool LOCA, you will have even less reactivity in the system because you’ve taken away the moderator, just like in a light water reactor.

    To me, criticality seems quite unlikely, especially if the water is lost.

    To get a criticality you would need to lose the pool water, then re-fill the water without adding more boron (plausible in an emergency LOCA situation?) and then disrupt the geometry, putting all the fuel too close together.

    If you actually get criticality in the pool, you would immediately strongly light up the gamma dose rate and neutron dose rate monitors (and nothing else around the plant could possibly be emitting neutrons) across the plant, so we would certainly know about it if it actually happened.


  168. One advantage of using becquerels is that you do not have to calculate anything. You get it directly from the detector, asuming they have measured in a way that is standard for that detector. Geometry makes a difference and can cause errors, but I doubt enough to make much difference as these levels are well above the standards.


  169. Can someone pls. create a rule-of-conduct-on-this-post listing link for this exeptional situation? It can then be rapidly referred to. It saves space, nerves and can filter out sensations of personal judgement. (engage the slip-up, not the person).
    We have thousands on non academix looking in here.

    I have no means to do it myself ( one hand on the ladder).

    Because of the “exceptional situation” moderators are literally “working to rule” i.e. the Commenting Rules established by BNC host at the outset. As a reminder to all commentors:
    BNC Commenting Rules
    Comments Policy — I welcome comments, posts, suggestions and informed debate, from a wide range of perspectives. However, personal attacks, insulting/vulgar posts, or repetitious/false tirades will not be tolerated and can result in moderation or banning. Trolls will be warned, and then disemvowelled.
    Civility – Clear-minded criticism is welcomed, but play the ball and not the person. Rudeness will not be tolerated. This includes speculation about motives or what ‘sort of person’ someone is. Civility, gentle humour and staying on topic are superior debating tools.
    Relevance – Please maintain focus on the topic at hand. Do not attempt to solve big problems in a single comment, or to offer as fact what are simply opinions about complex matters.
    Disclaimer — The views expressed on this website are my own or my contributors’ and do not necessarily represent those of the University of Adelaide or the Government of South Australia.


  170. @ William Fairholm 3:13 AM

    The “criticality” thing emanates, as far as I know, from a BBC information thread published on Wednesday http://www.bbc.co.uk/news/science-environment-12762608 in the form of the sentence :

    “More remarkably, the Tokyo Electric Power Company (Tepco), which owns the power station, has warned: “The possibility of re-criticality is not zero”.”

    Just googling now, I have not found a document containing this sentence directly on Tepco website.

    This has scared me totally (I am a layman), and, 4 days later, I still don’t understand.

    Hypothesis 1 : this is a mistake from a BBC journalist, but as this is not a smallish blunder, and as BBC is a serious institution, Tepco would have taken contact with BBC and some denial would have been published. Nope.

    Hypothesis 2 : this really comes from Tepco, this is quite founded, and I cannot understand _why_, even if they believe it, they would have transmitted such a scary information. Even if true, this is pointless and can only add to anguish.

    Hypothesis 3 : this really comes from Tepco, but this is unfounded, and this would be a gigantic blunder of their communication team. But no denial four days later ???

    I have no qualification to judge it from the scientific viewpoint, but from the communication viewpoint this is also a deep enigma, and I shall appreciate to read other views of what that may mean.


  171. Question on the dousing of the pools.

    Rather then dump water on it 24×7 they seem to be doing it in stages. Is this to give the fuel rods to come down to normal temperature smoothy rather then too fast?



  172. @ew-3
    There must be a plan behing it for sure. 24/7 dousing being an option. Another possible expl. comes from the fact that the seawater in evaporating leaves deposits that may obstruct later ‘clean’ cooling. Cooling with seawater is an option now, but not indefinitely.


  173. The chances of criticality are never zero. They limit to zero at best, like the odds of winning the lotto every week or a bird singing the complete works of Beethoven by chance. As a result the remark: “…is not zero..” in abdolute terms doesnt mean a thing. As for those fearing global disaster in this context: read Ted Rockwell’s contribution. It may be coming from the one side and be a bit heavy, but the man does know what he’s talking about.


  174. Jean-Luc

    Yes, I remember this from some days ago. I think I then read some old reports that discussed various scenarios for this. Can’t remember much of it or where I found it. The miscommunication/not correcting by TEPCO may be just that they are overwelmed.


  175. > Luke Weston
    > Used fuel pool water is usually loaded
    > with boron to keep it subcritical.

    Mr. Weston, once again, please, _please_ cite your sources for what you believe, and give us some idea why you consider them credible for the claims you make. When I try to check your facts, I often find different information. You could do this yourself.

    Pasting your sentence above into Scholar finds in the first page of hits:

    Click to access 20104883541.pdf

    “… BWR pools are filled with demineralized water while PWR pools are filled with borated water. The reason for this difference is that PWRs use borated water in the primary system for reactivity control, which mixes with the pool water during the refuelling operation. BWRs use the demineralized water for coolant….”

    If you have another source on this particular reactor, please post it.

    I appreciate your eagerness to present what you know, but it will always help if you would cite sources for what you believe.


  176. As far as I have experts at hand, a question which does not scare me but puzzles me, and whose answer must be obvious for the knowledgeable.

    This document http://www.meti.go.jp/press/20110317008/20110317008-4.pdf (in Japanese, but with little text, this is mainly a table) is on the Meti website – I know its existence from Wikipedia talk page. On this page, somebody translated its legend by “The first column is the total storage capacity, the second column is the spent fuel, the final column is the unused fuel”.

    The figures on the first and second column can be found elsewhere, and I understand them. The figures in the third column I have never met somewhere else (OK I am not reading everything written on this topic). What can they mean ?

    (Example : line “3” of the table. First column : 1220 ; second column : 514 ; third column : 52).


  177. Hank, please make the link i asked for. You know the demands better than most. By the way:
    @Hank Roberts, on 21 March 2011 at 1:09 AM
    I know for a fact that AGA in Holland has compressed air powered emergency equipment available. Anything from pumps over submergable generators to lights. Its not that this stuff doesnt exist. The general rule at emergency equipment is to keep it as reliable as possible, or k.i.s.s. as they call it.


  178. @dhill001, on 21 March 2011 at 12:11 AM

    The seawater is used as a coolant that is ‘consumed’ by the process. Either in the way of evaporating of seeping away. Both carry some radio activity likely, but content of fission product would render this method highly risky. It is to my opinion safe to assume this possibility is being monitored on site continuously. Radiation effects released due to the currently used method would disappate/decay in acceptable time relatively locally. In a non scientific way, try think of radiation as light. In that idea such a steamcloud would be a flash light, but stop flashing relatively fast. (Someone correct me if this is an incorrect illustration).

    As for the ‘certain death’ thing: We all face certain death, life’s a killer. Radiation is a funny customer. You may stand somewhere getting a full blast while someone standing a few feet away gets not one tenth as much. Add to that the fact that differt peoples different health condition and precondition respond differently to different kinds of radioactive influence and you will understand that there are both chances and risks for these men. Considering both in any way these men qualify as huahh courageous. They are there.


  179. This is beginning to sound like a lawyer thing. Assume its for real and do the homework on how bad bad is or drop the subject. Tepco doesnt own the truth and this is the look-for-answers post. No offense.


  180. Jean-Luc

    Yes I considered that, but from the information I’ve read that seems even less likely. There has been a debate and it actually might now been known that there was fresh fuel in SFP 4 waiting to go into the reactor. In this case it would be easier to get each fuel rod to criticallity, but they are noway as densely packed as in a reactor. Maybe if they all melted to the botton in a big lump and there was water above, recriticallity could occur. That would turn the water to steam above and stop the reaction, but there would be lots of radioactive material produced with no containment. Maybe that is what they were fearing. We will have to wait for a full report to find out what they were thinking and what actions good/bad/not necessary they were taking.


  181. @Cornelius, on 20 March 2011 at 10:23 PM
    The architectual static of the entire unit is quite rigid. This plant may not have been ready for the tsunami, but it is obviously earthquake resistant to an enormous extend.

    You have to understand, an earthquake is not an explosion. It is ‘merely’ a violent movement of the underlying terrain. Try imagine you have an enormous hand an would try to pick the whole thing up in one go. According to the statics, that should be possible. It would not just fall apart like a cardhouse. A very bad earthquake might lift the whole thing up or sink it down, but it is not going to throw it up, or make it bounce down .

    Stricktly speaking the containment structure is not ‘dependant’ on the underlying terrain to stay in one piece. This is something called ‘problem overkill’. Lets face it. Compared to the damage the tsunami caused, the damages to the structure due to a 9.0 quake are totally insignificant. That is quite an archievement.

    The explosions may have corrupted the structures integrity in absolute terms, but short of that it is to my opinion not to be expected the structures will show signs of ‘fatigue’ any time soon.

    (i would appreciate a second opinion or monitoring on this.)


  182. Have you noticed the general news / media loop the last 24 hours? I would call it almost a blackout, but that could be mistaken. Now replaced by the side show of war. In any case, there seems to be a large drop off of updates and progress reports on the nuclear crisis to just general and vague reporting. That’s not to say it means anything sinister, but, as a communications professional, this is disconcerting. Does it mean things are touch and go? Or does it mean TEPCO just doesn’t care to inform the public about their ongoing crisis? Either way it is a blunder to keep the public in the dark, assuming the worst.


  183. @ William Fairholm 5:47 AM

    Thanks very much for your comforting and precise answer. It is the first time I read an explicit suggestion that there might be “fresh fuel” in the pond, and am suprised to the extent that I am not sure to have completely understood your sentence : “it actually might now been known that there was fresh fuel in SFP 4 waiting to go into the reactor”. Have you a link to somewhere on the web where this is developed in more detail ?


  184. Jean, I have also read a count of all 11k fuel rods at the plant and read that #4 pool including X number of fresh fuel rods to be loaded into the reactor. I’m sorry that I no longer have that link (I will try to find it in the hundreds of pages I’ve read the last few days) but I do recall it was from an “official” industry source not from a news article.


  185. Shelby, on 21 March 2011 at 5:51 AM said:
    “Have you noticed the general news / media loop the last 24 hours?”

    I think that means they think this is not as much of a story anymore. Things serious, but improving, not getting worse each day as it was in the middle of last week. In Libya, you have the situation of a Dictator threatening to take revenge on his own people and the United National Security Council makes the strongest resolution ever: “All means necessary” to stop him. That is the new quickly changing news story. If you want to find stuff about Japan and even not nuclear disaster stuff, there is lots of it out there. You just have to go look instead of it being the top of the headlines for the mainstream media. Whether this good/bad/indifferent I’ll leave to each persons perspective. But not unexpected in my opinion and not sinister.


  186. Jean-Luc R., on 21 March 2011 at 6:05 AM said:
    “Thanks very much for your comforting and precise answer.”

    Ok hear is a link with pesimistic projections of what will happen with the spent fuel in SFP 4. About half way down they mention fresh as well as used fuel. The only thing I can say about their pesimistic evaluation is it didn’t happen. They spayed water into SFP 4 and there was no huge release of radioactivity. Whether there ever was a realistic probability of release will take a very detailed analysis. The experiment has been done and in this case nothing major happened. I assume they were spraying boron in with the water. My main concern was not causing criticallity, but releasing a good portion of the radioactive fission products in the spent fuel. Again, this did not happen.



  187. Aside — this may be helpful:

    From the NOTES link (top of the main blog page)
    To search BNC posts using Google:

    Let’s say you want to search for “solar” and “capacity factor”. Then, enter your search term into Google as follows:

    solar capacity factor site:bravenewclimate.com


    To search through BNC comments

    What about if you want to search through comments on BNC, rather than the blog posts? You can’t do this through the BNC site’s standard search box, because this only accesses posts. However, you can do it here:

    First, select the “comments” radio button. Then try typing in the following (for instance):

    fission products site:bravenewclimate.com

    The default option will show you the Most relevant results, but you can also click on Show the most recent.


  188. Jean-Luc R., on 21 March 2011 at 4:05 AM said:
    “As far as I have experts at hand, a question which does not scare me but puzzles me, and whose answer must be obvious for the knowledgeable”

    I should have looked at that link you provided earlier. If the translation you provided is accurate, I would assume this is fresh fuel and SFP 4 has the largest inventory of fresh as well as spent fuel. It is also near capacity, while the other ones are not. Why they then concentrated on SFP 3 first, I do not know. Maybe it had even less water than 4. If that was the case then water got out of there by some means besides evaporation. Sloshing or a leak. The only caveat is why would they have all this fresh fuel in all the SFPs, besides SFP 4 where they were going to load it into the reactor?


  189. Here is an update by the IAEA. It answers some questions about the SFPs.

    Unit 1

    Unit 1 experienced an explosion on 12 March that destroyed the outer shell of the building’s upper floors. No precise information has been available on the status of the spent fuel pool.

    Unit 2

    No precise information has been available on the status of the spent fuel pool. Authorities began adding 40 tonnes of seawater to the spent fuel pool on 20 March.

    Unit 3

    Unit 3 experienced an explosion on 14 March that destroyed the outer shell of the building’s upper floors. The blast may have damaged the primary containment vessel and the spent fuel pool. Concerned by possible loss of water in the pool, authorities began spraying water into the building in an effort to replenish water levels. First, helicopters dropped seawater on 17 March, and every day since then, including today, emergency workers have sprayed water from fire trucks and other vehicles.

    Unit 4

    This reactor was shut down 30 November 2010 for routine maintenance, and all the fuel assemblies were transferred from the reactor to the spent fuel pool, before the 11 March earthquake. The heat load in this pool is therefore larger than the others.

    On 14 March, the building’s upper floors were severely damaged, possibly causing a reduction of cooling capability in the spent fuel pool. Emergency workers began spraying water into the building today.

    Unit 5 and 6

    Instrumentation at these reactors began to indicate rising temperatures at their spent fuel pools starting on 14 March. Three days later, Japanese technicians successfully started an emergency diesel generator at Unit 6, which they used to provide power to basic cooling and fresh-water replenishment systems. Workers created holes in the rooftops of both buildings to prevent any hydrogen accumulation, which is suspected of causing earlier explosions at Units 1 and 3.

    A second generator came online on 18 March, and the next day, the higher-capability Residual Heat Removal system recovered full function. Temperatures in the spent fuel pools of Units 5 and 6 have gradually returned to significantly lower temperatures. (See graph at left.)

    Common Use Spent Fuel Pool

    In addition to pools in each of the plant’s reactor buildings, there is another facility — the Common Use Spent Fuel Pool — where spent fuel is stored after cooling at least 18 months in the reactor buildings. This fuel is much cooler than the assemblies stored in the reactor buildings. Japanese authorities have confirmed that fuel assemblies there are fully covered by water, and the temperature was 57 ˚C as of 20 March, 00:00 UTC.



  190. I agree with Damen Matson’s comment.
    I can buy a portable powersupply from Cat for about a million dollars. I am just a ordinary U.S. citizen. With a goverment that has connections to military equipment getting a generator onsite should be about as easy as getting media there. Onced dropped onsite the generator can be hooked up to their equipment (that is operable) using a temporary modification. We call it a temp-mod for short. If their equipment is not operable then get operating equipment in there and hook up to vents and drains on the piping system to get a flowpath. I would rather flood the place with borated water than overheat the core and spent fuel pool. I know the doserates are high but to get the situation under control as soon as possible is the desire.

    When it comes to Nuclear don’t be afraid to ask for help from experts. Pride can be recovered later, if needed. If they can hook up power to the equipment now, don’t know why they did not buy a portable generator and drop it outside the door and run the cables inside to the bus or motors. Even if you have to bypass the breakers and control switches in the control room. Get the pumps up and running.

    I agree with Damen Matson.
    Give me some cutters, butt-splices, cable, radio and a portable generator. Call me on the radio and tell me when you want the pump on. I will power it up till you tell me to turn it off. Many valves have manual operators so controlling flowrate can be done locally.


  191. William, becquerels are not really counts per second. They are a measure of atomic decays per second, whether or not they are detected – of course, mostly they are not. By contrast counts from a detector – often in “counts per minute” – depend on the protocol used, the nature of the sample, the type of detector, etc. To go beteen the two requires a great deal of careful figuring of what gets detected from any given sample.


  192. If you want to avoid radiation, where should you go? Either of Tokyo’s International airports would be a good start. And I mean from almost anywhere in the world. From there moving to some spots closer to the nuclear plants would reduce the natural background even further and therefore your radiation exposure. Japan has lower natural background than most other places. In some cases much lower. Now getting there would increase your yearly dose, by quite a bit, if you fly there.


    and here is radiological map of Japan by Prefecture. They don’t show readings for Fukushima and Miaygi where I know they have readings and they haven’t all week. Ibaraki has a high reading. 2040 nanoGrays/hr. This is about 10 times the world average background. They are using Grays instead of Sieverts and nano vs. the regularly used micro. Sieverts are just Grays converted by the type of radiation into an equivalent dose. At this level of general information, not important. Will be slightly higer in Sieverts.



  193. Joffan, on 21 March 2011 at 8:10 AM said:
    “William, becquerels are not really counts per second.”

    Yeah, I new that. I was trying to keep it simple, and allude to the complexities by my comment on geometries and standard methodologies, but I stand corrected.


  194. Jean-Luc

    I con not find the link but the document you can probably be found by Looking for my posts on the 18th.

    There is a report on loss of water accidents in spent fuel pools of decomissioned reactors. I think the date was Oct 2000.

    Basically is said IF the fuel rods get crushed IF there is no boron IF non borated water is then put in the pool then the fuel MIGHT be in a configuration for new criticality. They also say that the only kind of pools where this might happen are low density storage pools. They also say that MOX has not been evaluated.

    I believe that all of the pools at Fukushima I are high density storage pools with boron inserts in the racks and TEPCO has prieviously said they were borating the water, there might, at the begininning of the accident been a time where they were contiplating using non borated water if they ran out of boron.

    So at one point the chance or recriticality might not have been zero but still vanishingly small.


  195. Joshua

    Yes, that jogs my memory and I remember basically the same thing. Thought it odd that low density pools had a greater risk, but the lack of a neutron absorber explains that. High density pools could become critical under normal operation, so they have to have a neutron absorber.


  196. It has been night here in Australia so I have only just read comments earlier worrying about the levels of radiocativity found in milk and spinach. It was dealt with yesterday in some detail, with references, if you scroll back through the thread.
    In precis, the Japanesestated that the levels found meant you would have to drink a regular amount of milk 9500ml?0 per day for a year to get the same dose as from a CAT scan and that the health risks to humans were negligible.
    “Edano said the level of radiation from the average yearly consumption of the milk in question would be the equivalent of a single CT scan, and around a fifth of this amount in the case of the spinach.”

    Saturday, March 19, 2011 17:39 +0900 (JST)


  197. Just to correct my previous comment, I don’t think high density spent fuel ponds without a neutron absorber would become critical. They would become subcritical. I don’t think the density would support criticallity, but I haven’t read anything to support or disprove this view, so it is just my best guess.


  198. here: http://www.pref.ibaraki.jp/important/20110311eq/20110321_06/index.html
    we have a ten minutes interval reading of radiation in two (actually three, but the data for the third one, Daigo, is now suspended) towns in Ibaraki prefecture
    if you look at the table in the central part of the document, you can see on the first column the time, on the second the readings for Kitaibaraki, on the third the ones for Takahagi, both about a hundered kilometers SW from Fukushima plant (see the map here http://3.bp.blogspot.com/-U24HrN_cgms/TYY9Gl2EscI/AAAAAAAAAUQ/mp1LLKPEZyI/s1600/ibarakiken_1303-2003_upd01.jpg )

    the readings for daigo are missing, and I don’t know enough japanese to understand the reason.

    I cannot find any abnormal reading, or anything less than very far from threatening human health.

    I found those data on a blog mended by an italian living in Tokyo, I’ll watch sometimes to find more data.


  199. There is a new IAEA report out. They have added stable iodide doseages for evacuees depending on age. None for those over 40. They have added a table that seems derived from the JAIF reactor status reports, but has some slight inconsistances with them. The main one I could see is the JAIF report says they are injecting water into the SFP of unit 2 and IAEA says they are spraying like they are for units 3 and 4.


    Click to access ENGNEWS01_1300624909P.pdf


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  201. here an address for the environmental readings for several different places in Japan, and for different fields (air, drinking water and fallout).

    it’s late here, going to sleep. have you alla a good rest, or a good work, depends on where you live…


  202. @ Chris Warren
    You neglect to ment ion that the report also said this:
    “The Health Ministry said that radioactive iodine three times the normal level was detected in Iitate, a town of about 6,000 people 19 miles northwest of the Fukushima Daiichi nuclear plant, the Associated Press reported. That is one-twenty-sixth of the level of a chest X-ray and poses no danger to humans, a ministry official told the AP.”
    Are you deliberately trying to make people more fearful than they need to be? If so what is your agenda here?


  203. Has anyone ever modeled the mechanical effect of hydrogen explosions on spent fuel pool depth?

    In other words, how much water would be lost from the spent fuel pool simply by the explosive effects of a hydrodgen explosion at the top of the pool?


  204. @viverravid
    The chart you refer to indicates readings under 100micro sieverts and this is less than you would get(600 micro sieverts) from a stomach x-ray.(Check the chart on the “Why I stay in Tokyo” post)
    Are you tyring to frighten people here? If so what is your agenda?


  205. Ms. Perps

    I don’t think that just refering to data can be seen as trying to scare people. Unwarrented extraplolation, yes. Lots of people refering to information here, to reasure people. The data is to be used in an arguement. Those numbers are per hr, so if long enough in that field, then a legitament arguement could be made for health effects. Not likely they are letting anyone stay there. Question is if this is a general level for the area or a high spot. Remaining indoors if those are the readings outside would definitely be advisable.


  206. @Ms. Perps
    Definitely not trying to scare anyone. Was interested in any explanations as to why those sites were such an anomaly, and if people had been evacuated from there (you would hope so). The associated map shows the exclusion zone as a pure circle, with that area falling outside even the ‘stay inside’ zone. I’m familiar with what a 100 uSv/hr dose means, but it adds up to a bit over time if people in that area have not been given the ‘stay inside’ notice


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