Nuclear Open Thread

Fukushima Daiichi Open and Update Thread #5

The problems at the Fukushima Daiichi nuclear power plant continue to be worked on, with no short-term resolution in sight. Here are eight recent notable happenings, compiled from various sources (see list below):

1. Reports indicate that some fuel melted and fell to the lower containment sections of units 1-3, where it dispersed in a fairly uniform residue — but this does not seem to have breached containment in any of the reactor pressure vessels. Re-criticality of this ‘corium’ seems very unlikely, but no details can of course be confirmed until the reactor cores are finally dismantled — which may be years away.

2. Two automated PackBot robots entered units 1 and 3, took photos, and measured temperature, pressure and radioactivity within the buildings. Peak levels were 40-60 mSv/hr.

3. An anti-scattering agent is being sprayed on the ground around the damaged units (about 1,200 square metres in area) to prevent further spread of radionuclides (see photo above).

4. Excess radioactive cooling water continues to be transferred from unit 2’s basement and tunnels to a waste processing facility.

5. Further surveys are being made of the area surrounding the Fukushima evacuation zone and the exclusion area is being policed more strictly. Highest levels were measured at Itate, at about 4 microsieverts per hour (by comparison, the background level is 0.2 — 0.4  uSv/hr).

6. TEPCO have now released a roadmap plan for the restoration of stable conditions at the site, over a 3 — 6 month timetable, leading to a cold shutdown at units 1-3 and various other stability targets. They also released a 27-slide presentation on the timeline of the accident and current situation, that is definitely worth a look through.

7. This is a really useful summary post describing one of the pressing needs facing engineers at Fukushima Daiichi: Day 42: How is a core cooled? In short, heat exchangers are the key…

8. From NEI Nuclear Notes, Russia’s atomic energy chief (Kiriyenko of Rosatom) sees Fukushima as a strong policy incentive for moving more quickly to current- and next-generation reactor designs (I’ll have more to say on this topic in future BNC posts):

Kiriyenko said the impact from the Fukushima plant disaster would not only increase safety concerns but also quicken demand for new reactors to replace the industry’s ageing plants.

“There will be a need to build new plants more quickly to more swiftly replace previous-generation plants,” he said.

He added that Russia may speed the retirement of its older generation plants in the wake of Japan’s nuclear accident.


Please use this post to put any new comments about the Fukushima situation (including technical information, situation updates, analysis, questions, reflections, etc.). As such, I consider the earlier FD Philosophical and Technical threads closed — these strands of discussion can now be carried on here, as the pace of comments has died down to a small fraction of that at the height of the crisis.

Here are some other channels I recommend you check on regularly, for up-to-date situation reports on Fukushima Daiichi:

— World Nuclear News (the two latest posts are Changes to evacuation zones and Dust control steps up at Fukushima)

ANS Nuclear Cafe news and updates (includes links to official reports like JAIF and TEPCO and news feeds from NHK, NY Times, etc.), see also NEI updates

International Atomic Energy Agency (IAEA) update website (last updated on 21 April, has reactor status and radiation monitoring reports)

— Will Davis at Atomic Power Review blog continues to do an excellent job at providing regular updates and interesting technical analysis on the situation

Note that the Open Threads on are a general discussion forum; please follow the commenting rules, although the ‘stay on topic’ rule obviously does not apply as strictly here.

By Barry Brook

Barry Brook is an ARC Laureate Fellow and Chair of Environmental Sustainability at the University of Tasmania. He researches global change, ecology and energy.

378 replies on “Fukushima Daiichi Open and Update Thread #5”

“the global research effort into Generation-IV systems coordinated by the Generation-IV International Forum (GIF). In fact, six types of Generation-IV systems are currently being investigated. Four are fast neutron reactor designs, one is a thermal neutron reactor (very high temperature reactor, VHTR) and one is a supercritical water reactor (SCWR), which could be operated as either a thermal or fast reactor.”

“… to develop fast reactors that can also burn the minor actinides recycled from spent fuel. At the moment, when minor actinides are separated from the spent fuel, they end up in the waste, where they are responsible for much of the heat and radiation produced by the waste in the long term. By recycling the minor actinides back into the reactor, and by careful design of the fuel and operation of the reactor, they can be burnt in the core (transmuted) into less radiotoxic and shorter-lived radionuclides. This is not only an effective way of reducing waste quantities, but the recycling of the minor actinides along with the plutonium also greatly reduces the risk of proliferation because pure bomb-grade plutonium is at no point separated ….”


Ted Nation, in my country there is a moratorium on building nuclear power plants. How’s that for decision-making.

Nuclear is hampered for political reasons, which is allowed because the public is largely ignorant of the science and benefits, and is led astray by the effective fear campaigns of Greenpeace et al.

As a result the attitudes toward nuclear are decidedly hostile. Ignorance and fear are the things we must fix. Then things look much better for rapid nuclear deployment. People need to see how pathetic solar and wind are by comparing them direcly on energy productivity with nuclear and coal plants. People need to understand that energy sources that are not there 80-90% of the time are dangerous diversions from the collision course we’ve set ourselves into.


Ted Nation, on 10 May 2011 at 4:55 AM said:

Citing the accident, NRG is writting down $481 million it has invested in 2 Texas reactors.

Some basic facts.

Average cost of steam coal in Texas is about $30/ton. Compared to $80/ton in Florida and $90/ton in South Carolina

Source EIA –

So in Texas the economic case for building nuclear power is weak at best. At to that the fact that the Texas reactor was going to be a joint venture between NRG and Tepco(which is cash strapped at the moment) and the project doesn’t go forward.

On the flip side…Vogtle #3 and Vogtle #4 in Georgia(USA) are proceeding..VC Summer #2 and #3 in South Carolina are proceeding.

Nuclear isn’t cost competitive everywhere..and neither is coal, wind,oil,natural gas,solar,geo thermal or hydro.

Nuclear is ‘in the ballpark’ with steam coal at $80/ton(delivered price), natural gas(delivered price) at $6/Million BTU’s and oil at $36/barrel.

There may be other reasons to chose nuclear over fossil fuels…


Ted Nation, on 10 May 2011 at 4:55 AM — China is building NPP on-time and in budget. Just keep up on WNN.


If one is going to promote a largely nuclear solution, it is necessary to show how deployment would occur decision by decision.

Rubbish. It just needs to be allowed to compete (i.e. not banned), and compete fairly. If renewables, CCGT/OCGT and coal with CCS get subsidies, so should nuclear. If the externalities of burning fossil fuels are taken into account, and legislation put in place to prevent expansion, nuclear becomes by far the most practical, attractive (minus the bogey-man factor) option.


There’s a chart I’m looking for online, and I can’t find it. Can anyone help me find it?

I’m pretty sure it was published by Bernard Cohen, in one of his webpages or papers or books.

It shows a histogram of the number of fatalities caused by natural gas, and the number of press reports on the dangers of natural gas, the number of fatalities caused by electricity, the number of press reports on the dangers of electricity and the number of press reports on radioactivity, implying that one would expect to be able to extrapolate that level of press attention to a truly enormous number of deaths caused by radioactivity… a number that of course does not exist.


Cyril, on the chart (p4) of that JAIF link,

“Seawater at the point where High-level Water was flown out”
(assuming they mean “flowing out”)

is still above the standard concentration limit line.

But the “Sand Lances fished at the points around 40-60 km south of 1F” is down almost to the allowable food limit.


“In other Fukushima Daiichi news….

Feed nozzle temperature at No. 3 plant was about 192C at 6 AM on the 11th; the latest figure is 214.5C at 11 AM on the 10th. This increase is beginning to look worrisome; TEPCO needs to accelerate its efforts to cool this reactor plant. Looking at data from JNTI, the rate of increase is itself increasing….
8:30 AM Eastern Wednesday 5/11


An article in the Bulletin of the Atomic Scientists questions whether the NRC has taken adequate steps to protect existing reactors from damage from terrorist attacks or power failures like the one at Fukushima Daiichi. Specifically, it discusses what was released from the B5b requirements and whether the measures are sufficient and whether the release is consistent with passed NRC statements.

The Union of Concerned Scientists also has a post showing that Murphy is alive and well within the NRC. Their illustration is to contrast the scathing report the NRC issued after the shut down of the gas cooled Fort St Vrain reactor, for failure to take seriously the threat posed by nearby natural gas lines, with the current, even worse, situation with gas lines at the Indian Point plant.


Ted Nation, on 12 May 2011 at 6:45 AM said:

An article in the Bulletin of the Atomic Scientists question

It would appear that the article in the Bulletin of Atomic Scientists was written by a Senior Scientist at the Union of Concerned Scientists.

It’s not surprising that an article written by a staff member of the union of concerned scientists would agree with an article written by a staff member of the union of concerned scientist.

Unfortunately, circular references don’t count as ‘independent confirmation’.
Thanks for pointing that out – it saved me a lot of editing work:-) Better to let TN’s remark stand to illustrate your point.


@Hank Roberts

Full table of all temperature readings for unit #3 for the last 11 days. Some are going up, some are going down, some are flat.

Click to access en20110511-2-5.pdf

Then buried in this release

Click to access en20110509-1-3.pdf

May 7th 9:22 Suspended the transfer of stagnant water from the Turbine Building Trench of Unit 2 (Stagnant water with high‐level radioactivity) to the Radioactive Waste Treatment Facility in order to carry out piping work of Reactor Feedwater System for Unit3 Emphasis mine.


“… Japanese media outlets are reporting a downgrading of the condition of the reactor pressure vessel, in estimation, at Fukushima Daiichi No. 1. Now, TEPCO is saying that a serious leak in the pressure vessel has prevented the water from rising any higher even with the increased injection rate. The water, as guessed a number of times, is probably going to the primary containment.

Both TEPCO and NISA have apparently now decided that some fuel melt and relocation to the bottom of the pressure vessel has occurred, but also indicate that ccoling of the fuel in No. 1 plant is adequate for the moment. …”

This is quite a change — perhaps it would be worth editing the top post (or starting a fresh thread)?

Also note


Now, TEPCO is saying that a serious leak in the pressure vessel has prevented the water from rising any higher even with the increased injection rate.

My reading of the various reports is that the water level in the containment vessel isn’t rising as fast as expected.

IMHO Given the temperatures being report the water level in the containment vessel(dry well) being 4 meters lower then the bottom of the fuel rods is plausible. The water in the pressure vessel being 4 meters below the bottom of the fuel rods seems improbable.


“IMHO Given the temperatures being report the water level in the containment vessel(dry well) being 4 meters lower then the bottom of the fuel rods is plausible. The water in the pressure vessel being 4 meters below the bottom of the fuel rods seems improbable.”

this is what Tepco is reporting, after they repaired the instrument. it is also Tepco reporting the melt and Tepco reporting a big leak.



“It would appear that the article in the Bulletin of Atomic Scientists was written by a Senior Scientist at the Union of Concerned Scientists.

It’s not surprising that an article written by a staff member of the union of concerned scientists would agree with an article written by a staff member of the union of concerned scientist.”

It is reasonable to point out that the two articles were written by people that were part of the Union of Concerned Scientists, however, it is unreasonable to dismiss them by saying it is not surprising that one supports the other when they are about separate issues. Are the portions of the B5b requirements that were released reassuring and consistent with previous statements from the NRC? And separately, are the gas lines at Indian Point, with automatic shut off valve removed, a serious safety issue?

“the automatic shut-off valves relied upon to terminate the flow of natural gas from a ruptured pipe and lessen the threat to Indian Point’s safety equipment have reportedly been removed. The original safety studies for Indian Point credited the automatic shut-off valves with closing within four minutes to stop the release of natural gas. But the valves were removed from the pipelines by 1995 because they tended to close spuriously, thus interrupting the intended flow of gas.”


“…. after repairing a gauge in the No. 1 reactor earlier this week, TEPCO discovered that the water level in the pressure vessel that contains its uranium fuel rods had dropped about 5 meters (16 ft) below the targeted level to cover the fuel under normal operating conditions.

“There must be a large leak,” Junichi Matsumoto, a general manager at the utility told a news conference.

“The fuel pellets likely melted and fell, and in the process may have damaged…the pressure vessel itself and created a hole,” he added.

… Based on the amount of water that is remaining around the partially melted and collapsed fuel, Matsumoto estimated that the pressure vessel had developed a hole of several centimeters in diameter.”


Given the amount of shaking that the reactors got with the earthquake, I’d guess that a pipework fracture in one of the lower water inlet pipes may have been responsible for the initial leak. If it was a big enough crack, it may have resulted in the core draining into the dry well over the space of a few hours – particularly once backup power was lost.
I would have thought that some damage to pipework would have occurred with a magnitude 9.1 quake, and it’s certainly been the biggest concern I’ve had. Note, this is all my own conjecture & opinion – I don’t recall seeing anything talking about the condition of the pipework around & in the reactors.


All the “plugging” of leaks is happening at the downstream/downhill end, they’re making the leaking water slow down, spread out, and soak into the ground under and around the plant, when they plug the cable trenches through which it has been running out directly to the ocean.

In the press accounts when you see “liquid glass” they are referring to sodium silicate, aka “water glass” — it sets up as a soft solid. Kind of like Jello gelatin.



“… So-called water entombment operations to fill the containment chamber with water are continuing in an effort to cool the reactor. But the water level in the chamber cannot be clearly determined, and water is likely leaking from it, the utility said.

TEPCO said the temperature in the pressure vessel is stabilized at 100 C to 120 C but that the water-entombment plan, in which water was expected to be filled to about 1 meter above the top of the fuel rods, needs to be reconsidered. The company is considering increasing the amount of water injected into the pressure vessel, which currently stands at about 8 tons per hour….”


A bit more from the same yomiuri page:

“… The company believes that most of the 190 tons of water injected every day is leaking from the pressure vessel, which is likely to be damaged more seriously than previously thought.

More than 10,000 cubic meters of water had been injected into the reactor as of Thursday, exceeding the combined 360-cubic-meter capacity of the pressure vessel and the 7,800-cubic-meter capacity of the containment chamber.

It is highly likely that water is leaking from both the pressure vessel and containment chamber and flowing into underground parts of the reactor building and the adjacent turbine building, TEPCO officials said.

To proceed with the water-entombment, it is necessary to accurately grasp the water level in the containment chamber and the conditions of pipes that take in or release cooling water, experts said.
(May. 13, 2011)”


So in hindsight, it looks like all three scrammed reactors at the site leaked their primary coolant early on, and still leak water as it’s being pumped in.

When they say they “sealed the leak” they mean they’ve blocked water flowing out down by the ocean–but that means it has to be going somewhere else.

“… Tepco said on Friday that the discovery of leaking water from the stricken plant’s No.1 reactor could complicate its plan to set up a more permanent cooling system for the facility. Some outside experts have been skeptical for weeks about Japan’s plan to stabilize the Fukushima Daiichi reactors by January.

Kaieda said a delay in that timetable was now likely.

“I think this is a major factor that will require a change in Tokyo Electric’s road map for bringing the situation under control,” Kaieda said.

Earlier in the week, Tepco said it had sealed a leak of radioactive water outside the plant’s No.3 reactor. The No.2 reactor developed similar leaks which were sealed in April with liquid glass and other substances….”


A series of web pages: “An exploration of the science and health questions raised by the situation in Japan”

Excerpt following is from:

Q: “What do you think about the idea of studying health effects from the Fukushima Dai-ichi accident?”

A: “I think it would be very unwise. There just isn’t any evidence that there are enough exposed people at high-enough doses to expect to see any health effects that are measurable.”

Q: “But even if it showed no health effects, wouldn’t it be a good idea to use this opportunity to settle that question — or at least add more evidence on what low-level radiation doses actually do or don’t do?”

A: It just wouldn’t work. We have no idea what actual doses people got. I would not expect to see significant new data emerge from that type of project. And it would take 30, 40 or 50 years to get an answer….”


Running out of battery power?
No worries in the USA now — we have hand-operated cooling water pumps for backup.

“The NRC told members of Congressman Henry Waxman’s staff that … this situation would have been avoided at a US boiling water reactor because operators would have been able to manually operate the RCIC pumps, avoiding a core meltdown with an hour to spare….
… personnel would need to physically open and close valves in a room in the reactor building with no ventilation and no lights, and to measure the water level in the reactor vessel without any electrically powered instrumentation available…”


Coverage continues; this is from a Tokyo blogger who has posts going back to the beginning, some with details and pointers to sources.

“… Even after pumping more than 10,000 m3 of water, the water level in the 7,400 m3 containment is still below half, not even reaching the bottom of the RPV, let alone its top.

If the water level doesn’t rise further because of leaks then it seems quite unlikely that it will be possible to repair those leaks using manual labour, especially at dose levels of 10 millisievert and more per hour. Even when it looked like the plan might work for unit 1, it was questionable if the same procedure could then be applied to unit 2 or 3, which were already assumed to have a leaky containment.

TEPCO has not yet discussed any alternative plan if flooding the containment won’t work for some or all of the units….”


Not hand operated pumps, hand operated valves. You couldn’t pump enough by hand, we humans are too feeble for that. Steam driven pumps using decay heat generated steam work well. The valves will still need actuation. Manual can be done. The disadvantage to this is the hostile environment to humans, and while manual valve control is a useful worst case scenario backup, I’d prefer a much increased battery capacity.

I’ve asked a nuclear operator about this, and it appears only half a kWe is needed for the valves and controls. 1 month of steam driven pump decay heat removal (300 kWh) would thus only cost a few hundred thousand dollars in advanced submarine class lithium batteries. These can be put inside containment since they have no exhaust. So easy to protect them. A direct DC connection and you’re all set. These BWRs apparently make enough steam to run the turbine driven pumps for a month or longer…


Cyril there are obvious technical solutions to the majority of problems. in Fukushima, a higher wall towards the sea and better placement of the diesels would have been a good start.

the real problem is, that the nuclear industry is trying to avoid even small costs and prefers to accept higher risks.

at the moment, as shown by the links provided by hank above, we know that water is leaking. we know that we are pumping in water that does vanish. this is in contradiction to what Barry wrote in the original post:


“. Reports indicate that some fuel melted and fell to the lower containment sections of units 1-3, where it dispersed in a fairly uniform residue — but this does not seem to have breached containment in any of the reactor pressure vessels. ”


containment has been breached.


A higher wall would be good, but there’s always a possibility of a freak tsunami that just happens to be a meter higher than the wall. I’d prefer to just assume the plant will get flooded and make it resistant to that by having all electric components submarine grade and having diversity in decay heat removal, such as turbine driven pumps with lithium batteries, diesel generators, and gas turbines placed higher up with seperate electric circuits. This minimizes common mode failures (Fukushima is a giant common mode failure).

Its not fair to claim that nuclear industries are avoiding small costs. Chinese solar companies are dumping carginogenic byproducts into rivers and soils so that they can make a penny. Companies are in it for the money, whether solar or nuclear, and regulation must be enforced to prevent external costs as much as possible. Yet the external costs of nuclear are the lowest of any form of electric generation. Solar has 10x the lifecycle materials requirement which has severe external costs because of mining and manufacturing impact (they are very large).

We need to make technical adjustments to the old plants and keep them running because replacement with fossil or energy-that-is-never-there (both boil down to the same) is unacceptable, it will increase external costs. Meanwhile we need to look to the future and build modern Gen III+ plants with passive features while developing and engineering Gen IV to commercialiation stage.


@Hank Roberts 10:33 AM

Thanks for your link to the interview with Evan Douple, associate chief of research for the Hiroshima-based Radiation Effects Research Foundation. I think Douple’s closing remarks captured the scientific viewpoint:

Given what you said about the impossibility of doing the kind of long-term study you mounted of the atom-bomb survivors, can we learn anything from the current episode?

On the basis of our current estimates, there shouldn’t be measurable numbers of cancers. So you won’t be able to count them, ever. But once the dose estimates are put together and extrapolated, you should be able to make a crude estimate of the health effects, based on the RERF data. And I think that estimate will surprise a lot of people.

And they’ll be surprised because?

They’re so low.


The Atomic Power Review blog is reporting that Unit 1 definitely lost containment and speculates that a corium/concrete reaction may have been the source of the hydrogen that produced the explosion that destroyed the reactor building.

“NHK is carrying the report, from TEPCO apparently, that there is a hole in the bottom head of the pressure vessel at No. 1 plant.”

“TEPCO has reported over 3000 tons of highly contaminated water in No. 1 plant turbine building, with the amount increasing fairly rapidly. There is now absolutely no doubt in any quarters that TEPCO has lost containment on this plant.”


Oh my god we’ve lost containment! We’re all going to DIE!

DIE I tell you!

Oh wait. No one’s dying of radiation.

Ted, you might want to check out how BWRs work. It’s a direct cycle – the primary circuit runs all through the turbine hall, condensers systems, and back.


@Cyril R

The hyperbola is yours, not mine. I would suggest that you are in violation of the comment policy regarding civility.
Satire is not considered in-civility.


> the interview with Evan Douple

Exactly. That NPR web page on the science is doing a very good job presenting the risk assessments, explaining how _low_ the risks are.

It’s refreshing to see a site discussing the science and free the ranting from “either side” of “the debate” — no sides, no debate. Just the facts as best we can figure them out.


Ted Nation, if you don’t want hyperbola response, try posting something new.
Steady up Cyril – this is how things get inflamed. I have appended a note to Ted’s comment.


Hyperbole is attitude; hyperbola is trajectory.

Thanks bks for the link. I wonder how long the government and utility have known that little fact.

Everything we thought was based on the notion that the plant survived the quake. Sounds like they’ve known for a while that wasn’t the case.

No wonder the other old plants are being looked at so carefully, the event apparently proved their weakness rather than their strength as we’d been thinking for the past month — if that report is correct.


READ the cite before posting your disbelief.


Amazing flurry of news stories now.

“… “Without the injection of water [by fire trucks], a more disastrous event could have ensued,” said Mr. Matsumoto.

Tepco also released its analysis of a hydrogen explosion that occurred at unit No. 4, despite the fact that the unit was in maintenance and that nuclear fuel stored in the storage pool was largely intact.

According to Tepco, hyrogen produced in the overheating of the reactor core at unit 3 flowed through a gas-treatment line and entered unit No. 4 because of a breakdown of valves. Hydrogen leaked from ducts in the second, third and fourth floors of the reactor building at unit No. 4 and ignited a massive explosion. …”

15 May 2011 Last updated at 08:46 ET

“Japanese engineers have abandoned their latest attempt to stabilise a stricken reactor at the Fukushima nuclear plant….”
Japan left with no choice but to widen nuke evacuation zone
May 16, 2011 1:12AM


I wonder how stable the foundations of the reactor buildings can be, with all the water that’s been poured through them that’s disappeared into the ground. They say there’s an impermeable layer some distance below the plant. Either the water’s pooling on top of that, or running off at that level along whatever slope that impermeable layer takes it.

They must be planning or doing some drilling to try to locate and maybe pump out the contaminated groundwater– but they won’t likely get to that until they get the buildings pumped out so they can go in and try to deal with the reactor cores.

Let’s hope the foundations of the reactor buildings are very, very stable even when they’re sitting in mud. Liquefaction from another quake or settling would be very bad news.


I’m finding bits of what was apparently a long press conference; has anyone seen a transcript of the whole session anywhere?

Another bit:

“TOKYO (Kyodo) — Data taken at the Fukushima Daiichi nuclear power plant on the night of March 11 showing a high level of radiation at a reactor building suggest the possibility that key facilities there may have been damaged by the quake itself …. a utility source said Saturday.

The revelation may call for a review of preparedness against quakes at various nuclear power stations … as they have [been] assuming that reactor facilities at the plant were unscathed by trembling.

On March 11 …. Workers entered the No. 1 reactor building in the night to assess damage to the reactor but a few seconds later their dosimeter’s alarm was triggered, according to the sources at Tokyo Electric Power Co. The building was believed to be filled with steam with high radiation dose, prompting the workers to evacuate….
… a result suggesting a large amount of radioactive materials from nuclear fuel in the reactor was already released [by containment failure; cooling failure but an intact pressure vessel] is thought to require a much longer time before such building is filled with steam.

“A source at TEPCO admitted the possibility of key facilities having been compromised before the tsunami waves, saying, “The quake’s trembling may have caused damage to the pressure vessel or pipes.””

My guess — the large scale evacuation we’ve seen happened because this was known, but the facts had been kept from the public for “reassurance” while evacuating. Just my guess. Words above in square brackets are mine, trying to clarify the very muddy language found in the translations.


Hank Roberts, on 16 May 2011 at 3:57 AM said:

Let’s hope the foundations of the reactor buildings are very, very stable even when they’re sitting in mud. Liquefaction from another quake or settling would be very bad news.

According to my limited knowledge of geology as a resident of a subduction zone, liquefaction is associated with specific soil types.

University of Washington Article on soils susceptible to liquefaction -

“… a significant level of soil “liquefaction” that has surprised researchers with its widespread severity, a new analysis shows.
The findings also raise questions about whether existing building codes and engineering technologies are adequately accounting for this phenomenon …”

The soil wasn’t saturated at the time of the earthquake. Is it now, after water has been pumped into the area? I dunno. Any soil that’s saturated behaves very differently than the same soil when dry. It’s very rare for this kind of artificial flood to soak a large site; when that happens, it causes problems.

It’s the silence about this that bothers me. Surely someone there has tried a test well and figured out where the water is going and how wet how much of the site has become.

But egad, they knew the first day that they had more radiation in the building than could be explained by the ‘venting steam’ story that’s been spun out until yesterday, and now we know that the claim given for all this time was “reassuring” but false.

Maybe reassurance is all we’re going to get.

Remember this?


Re: Core totally demolished at Fukushima Daiichi No. 1
Will Davis has a good summary of the latest TEPCO releases. Will notes that even though it appears there was quake damage to RPV and PCV, that the tsunami remains the root cause of TEPCO’s troubles with unit 1 – because of the SBO station blackout.

It isn’t clear what the new TEPCO strategy will be. It is clear that all of the injected water is exiting as contaminated water into the building and soils.


(deleted personal opinion on motives)
The headline writers are getting more caustic.

This one’s about Unit 3:

” TEPCO concealed radiation data before explosion at No. 3 reactor 2011/05/14

Tokyo Electric Power Co. concealed data showing spikes in radiation levels at the Fukushima No. 1 nuclear power plant in March, one day before a hydrogen explosion injured seven workers.

The Asahi Shimbun obtained a 100-page internal TEPCO report containing minute-to-minute data on radiation levels at the plant as well as pressure and water levels inside the No. 3 reactor from March 11 to April 30.

The data has never been released by the company that operates the stricken plant.

The unpublished information shows that at 1:17 p.m. on March 13, 300 millisieverts of radiation per hour was detected inside a double-entry door at the No. 3 reactor building. At 2:31 p.m., the radiation level was measured at 300 millisieverts or higher per hour to the north of the door. …”


Anybody know the plumbing of the sewage systems in Japan? Old US systems mixed stormwater and septic together, but those have mostly been replaced by separate systems to keep toxics washed off streets and roofs out of the septic sewers (except during big storms).

I ask because I’m wondering how the fallout got into the sewage systems– I’m guessing they have the old combined system and the radioactivity is from rainfall going into sewer systems.

“Sewage plants in Fukushima perplexed over how to dispose of highly radioactive sludge – Mainichi, May13”

Source of the story is:

I found it here:


“… They washed with special shampoo at the nuclear crisis operations center about 20 kilometers away from the plant. However, three of them were unable to completely decontaminate themselves. They tried again at a TEPCO facility but failed to completely remove radioactive substances from their bodies. TEPCO subsequently issued a certificate specifying the areas of their bodies contaminated with radioactive material, and they returned to work….

TEPCO said the certificate specifying the areas of workers’ bodies contaminated is issued if high levels of radiation are detected during screening, but claimed that such workers are completely decontaminated before returning to work.”

Kan Says Timetable to Resolve Nuclear Crisis Hasn’t Changed
By Yuji Okada and Takashi Hirokawa – May 15, 2011 8:59 PM PT
“… yesterday Tepco confirmed the No. 1 fuel assembly melted within 16 hours of the disaster.

The cores of reactors 2 and 3 may also have melted by the same amount, Junichi Matsumoto, a general manager at Tepco, said today. The company will make an announcement on the status of the two reactors later, he said, without giving a timeframe….

“In terms of achieving cold-shutdown status within six to nine months, I believe we should be able to proceed without changing the timeframe,” Kan said today in parliament. “Tokyo Electric will announce a revision to its road map tomorrow and the government will also issue its view on how to go forward with the plan.” “


sorry, I failed to repeat the full cite; what you deleted was attributed to the source fully cited in the immediately previous note– immediately above.

I didn’t realize you’d deleted it til today.

I’ll duplicate the full cites from now on when I put quotes into separate posts.

Seems to me nobody else here is following events at Fukushima, so I’ll quit commenting til Barry starts a fresh thread and updates his own discussion.


What I really want to know, with the weekend’s talk of full-core disruption/meltdown at reactor #1, is why the hell there was that stupid “70% damage becomes 55% ” story two weeks earlier. Did I miss something in translation?


@Hank Roberts

Seems to me nobody else here is following events at Fukushima, so I’ll quit commenting til Barry starts a fresh thread and updates his own discussion.

Hank I’m following Fukushima, including all your comments — which have said what needed to be said, so I’ve had nothing to add.
I had same question. A possible explanation of the difference is the first access to #1 control room. John Timmer at Ars Technica summarized the latest TEPCO release yesterday, covering much of the same ground as Will Davis (that I linked yesterday). But also including some info that was new to me:

The new analysis was enabled by the recent installation of air purifiers that let personnel reenter the reactor control room for the first time. Once inside, they were able to recalibrate some of the instruments that have been monitoring the reactor core; the revised numbers have enabled TEPCO to better understand what happened in the wake of the tsunami.

Timmer also linked the new TEPCO slide deck. That presentation is worth a careful read. Note the “Temperatures around RPV” chart at the end with diagram of sensor locations.
The bottom line from TEPCO is
1. RPV cooling water leak is likely
2. RPV significant bottom damage unlikely (inferred from temp/pressure data)
3. The corium on bottom of RPV “considered to be sufficiently cooled inside the RPV”
Not discussed are the leak(s) from the PCV, where the contaminated water is going, and what they are going to do next. In particular how are they going to achieve recirculation cooling?


I’ll do a fresh open thread on Fukushima, with a brief summary of current conditions, tomorrow. Thanks to those who’ve otherwise been using this thread for its intended purpose, and continue to post updates. Just be aware that a few have not got through moderation, because of their excessive use of “OMG, this new finding is catastrophic, the authorities ought to be hung, drawn and quartered” type language. Please, stick to the facts, folks.


Could we have a new Philosophical OT too – I have noticed several comments on different threads that are OT in this regard and they probably need a “new home”.


Did you erase those earlier posts becuause providing a link to the source in one post, then saying “from the previously cited source” is unacceptable?

It would help to understand why you’re deleting direct quotes from identified sources reachable by a click on a link.

You want the full cite in every post, not in the prior post? Is that the idea?
As Barry has explained, commenters are not supposed to slip in a quick one-liner accompanied by a link or reference. More detailed comment that shows you have read and understood all the suggested links and your own evaluation, not just slabs of quotes from the articles, is required. Otherwise it is just like a news-feed. In one instance I deleted a comment that looked to be outside these criteria, but I realised after that it was a link that you had inadvertently left out of a previous comment so that was an addition to your previous longer post. Sorry for my mistake there. Re-post the link and I will append it to your relevant (remind me of the time of that posting)comment.


Always easier commenting on problems in hindsight.

One of the significant issues seems to be the inability to have good data on status of reactors post ‘problem’.

I am hopeful that later models of reactors incorporate temperature and pressure sensors and radiometers that are resistant/survivable post calamity. In this instance the exposure of fuel rods would always have resulted in hydrogen explosion. Design for that

The complete exposure of fuel rods seems to have occurred within a very short time and the cascade of events including explosions was projected. The subsequent actions over the next month showed that the information data gathering systems were not up to expectations (especially those of the public).

Lessons learnt seem to be shut down or take off stream >50% of nuclear reactors in japan – I hope that they are okay, but more importantly that useful modifications can be put in place. It is not enough to ensure that each recator will survive the next calamity. It is imperative that each facility can be MANAGED post calamity.


forgive me if this was covered previously but I have not been able to locate any comments indicating such… assuming damage to #1 is factual and there are holes in the bottom of the RPV and there is damage to the containment, allowing water pumped into the reactor to leak out, what good is it to recirculate the water? don’t they have to plug the leaks as well?


I believe TEPCO has now admitted that operators on #1 turned off the ECCS after the quake due to low pressure, which may have exacerbated the issue when the Tsunami hit… several hours it was apparently down.
Schla – please remember that on BNC you are required to submit references to support your “beliefs” that are quoted as facts.. Please do so in future comments or risk them being deleted as per BNC Comments Policy.


schla, on 18 May 2011 at 5:41 AM said:

allowing water pumped into the reactor to leak out, what good is it to recirculate the water? don’t they have to plug the leaks as well?

In laymans terms-
Instead of a cold bath, the fuel is getting more of a cold shower and rather then the water being pumped out via the designated drain line it’s being leaked out by via an unexpected hole in the tub into the basement.

At some point they will need to plug the leaks in the containment vessel.

A ‘closed loop’ system is preferable in order to minimize the quantity of radioactive water.


@harrywr2, thanks for the link. In the 17 May TEPCO Progress Status

Click to access 110517e2.pdf

I see for the first time the plan to reuse the contaminated water leaking into the turbine building — which should address my concern that they would be overwhelmed by the volume of contaminated leakage. On this issue they say:

Issue 1. Reactors: revision of prioritized countermeasures due to the coolant leakage

・ Entered into R/B in Unit1 after improving work environment. Confirmed status of R/B and calibrated instrumentations (reactor water level, etc.)

・ As a result, it turned out that the coolant leakage from PCV occurred in Unit 1 as well as in Unit 2. There will be the same risk in Unit 3.

・ Accordingly, as a major countermeasures to achieve “cold shutdown” in Step 2, revision was made to prioritize “establishment of circulating injection cooling (please refer to the figure in upper right)” over flooding operation (flooding the PCV up to the top of active fuel). In circulating injection cooling, contaminated water accumulated in buildings is reused to be injected into the PCV after being processed.


I like David’s point that the key monitoring instruments need to be as robust as possible to allow for accurate data collection during and after an event. That’s an upgrade well worth considering.

I couldn’t disagree more that “Lessons learnt seem to be shut down or take off stream >50% of nuclear reactors in japan”… this would be an overreaction and just make a bad situation worse.


This daily updates from TEPCO is also worth reading. TEPCO refutes, with rather convincing evidence in my opinion, a former researcher’s claim that the Unit 3 had another meltdown 10 days later which caused molten fuel leakages out of the PV. This has been widely reported in the papers.

In the Asahi Shimbun article titled “Report suggests second meltdown at reactor at Fukushima plant”, it is reported that Unit 3 might have melted twice. TEPCO’s position is shown below:

“A second meltdown likely occurred in the No. 3 reactor at the Fukushima No. 1 nuclear power plant, a scenario that could hinder the current strategy to end the crisis, a scientist said.
In that meltdown, 10 days after the March 11 Great East Japan Earthquake, the fuel may have leaked to the surrounding containment vessel, according to a report by Fumiya Tanabe, a former senior researcher at what was then the government-affiliated Japan Atomic Energy Research Institute. “

(TEPCO’s comment)
– As for the status of the reactor core around March 21, even though water injection was not sufficient, we do not believe additional large amount of radioactive materials were released into the PCV from damaged fuels based on the fact that indication of CAMS in the drywell had been decreasing during this period.
– On May 24, we have reported reactor core status in the “Analysis and evaluation of the operation record and accident record of Fukushima Daiichi Nuclear Power Station at the time of Tohoku-Chihou-Taiheiyou-Oki-Earthquake “. In this report, assuming the reactor water level was not maintained, the analysis showed that the RPV was damaged although part of fuel remained in the vessel.
– The result of the analysis and plant parameters indicated majority of the reactor core was damaged and moved downward from its original position but we believe most of the fuel is under stable cooling.

“Between 1 a.m. and 3 a.m. on March 21, the pressure within the pressure vessel of the No. 3 reactor core increased sharply to about 110 atmospheres, likely caused by an explosion within the pressure vessel due to a lack of cooling of the fuel. That was probably the start of the second meltdown, Tanabe said.”

(TEPCO’s comment)
– In our plant parameter release as of 5:00 on March 21, as we described “at 3:58 reactor pressure indicator switched from B to A due to malfunction of the pressure indicator”, we do not think the pressure increase to 110 atmospheres was actual pressure response.

“As for the sudden pressure increase, Tanabe points to the possibility that the clump of melted fuel in the pressure vessel may have fallen apart due to a lack of cooling. The magma-like substance with high temperatures may have leaked out of the vessel and emitted large amounts of steam when it came in contact with water. “
(TEPCO’s comment)
– If “clump of melted fuel ・・・ leaked out of the vessel ・・・” was correct, very large increase of radiation level in the PCV is expected. However, we do not see any such increase from the drywell CAMS data. The CAMS data shows decrease during this period.

(Full article)

TEPCO Washington Office: 202-457-0790
Kenji Matsuo, Director and General Manager
Ikuo Nishimura, Deputy General Manager,
Masayuki Yamamoto, Manager, Nuclear Power Programs


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