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Nuclear Open Thread

Fukushima Technical Discussion Open Thread

It was suggested in a comment — and I agree — that the previous open threads on the Fukushima Daiichi Nuclear Accident were becoming difficult to read, because they are such a mixture of technical details and philosophical discourse. That is, it’s generally a bad idea to cater to two different audiences in one comment thread. So, I will split them up.

Please restrict all discussion here to technical information, analysis, criticisms and questions on FD — no philosophising or excursions into whether nuclear power is ‘good’ or ‘bad’ or the implications of FD for the future of nuclear power (except for new technical developments, e.g. safety standards), etc. You may impart your deep wisdom on how the world should work on the other open thread I’m about to open.

Besides the above guidelines, the other rules of the Open Threads on BNC apply. Read here for details.

To kick off discussion, below is the latest FEPC status report (I’ll update this as new reports come in). You will also be interested in:

— JAIF Updates #35 and #36

NISA Major Parameters 0600 March 29

NISA Summary Conditions 0600 March 29

—————-

  • Radiation Levels
    • At 11:45PM (JST) on March 28, TEPCO announced that plutonium 238, 239 and 240 were detected in the soil sampled on March 21st and 22nd at five spots in Fukushima Daiichi Nuclear Power Station. Concentration of detected plutonium 238, 239 and 240 are the same level of the fallout observed in Japan at the atmospheric nuclear tests in the past and poses no major impact on human health.
    • At 6:30PM on March 29, radiation level at main gate (approximately 3,281 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 177 micro Sv/hour.
    • At 6:30PM on March 29, radiation level at west gate (approximately 3,609 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 120.2 micro Sv/hour.
    • Measurement results of environmental radioactivity level around Fukushima Nuclear Power Station announced at 7:00PM on March 29 are shown in the attached PDF file. English version is available at: http://www.mext.go.jp/english/radioactivity_level/detail/1304082.htm
    • 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
    • At 1:00PM on March 29, pressure inside the reactor core: 0.371MPa.
    • At 1:00PM on March 29, water level inside the reactor core: 1.65 meters below the top of the fuel rods.
    • At 1:00PM on March 29, pressure inside the primary containment vessel: 0.265MPaabs.
    • At 1:00PM on March 29, the temperature of the reactor vessel measured at the water supply nozzle: 570.9 degrees Fahrenheit
    • As of 3:00PM on March 29, transferring the water found at the turbine building to the condenser continues.
    • As of 4:00PM on March 29, the injection of freshwater into the reactor core continues.
  • Fukushima Daiichi Unit 2 reactor
    • At 1:00PM on March 29, the temperature of the spent fuel pool: 114.8 degrees Fahrenheit.
    • At 1:00PM on March 29, pressure inside the reactor core: -0.025MPa.
    • At 1:00PM on March 29, water level inside the reactor core: 1.5 meters below the top of the fuel rods.
    • At 1:00PM on March 29, pressure inside the primary containment vessel: 0.1MPaabs.
    • As of 4:00PM on March 29, the injection of freshwater into the reactor core continues.
    • As of 7:00PM on March 29, approximately 96 tons of water in total has been injected into the spent fuel storage pool.
  • Fukushima Daiichi Unit 3 reactor
    • At 12:00PM on March 29, pressure inside the reactor core: 0.029MPa.
    • At 12:00PM on March 29, water level inside the reactor core: 1.85 meters below the top of the fuel rods.
    • At 12:00PM on March 29, pressure inside the primary containment vessel: 0.1075MPaabs.
    • At 2:17PM on March 29, TEPCO began to shoot freshwater aimed at the spent fuel pool, with a specialized vehicle normally used for pumping concrete, until 6:18PM (approximately 100 tons in total).
    • As of 4:00PM on March 29, the injection of freshwater into the reactor core continues.
    • As of 7:00PM on March 29, approximately 4,697 tons of water in total has been shot to the spent fuel storage pool.
  • Fukushima Daiichi Unit 4 reactor
    • At 11:50AM on March 29, lighting was restored in the Central Control Room.
    • As of 7:00PM on March 29, approximately 960 tons of water in total has been shot to the spent fuel storage pool.
  • Fukushima Daiichi Unit 5 reactor
    • At 2:00PM on March 29, the temperature of the spent fuel pool: 101.5 degrees Fahrenheit.
  • Fukushima Daiichi Unit 6 reactor
    • At 2:00PM on March 29, the temperature of the spent fuel pool: 70.7 degrees Fahrenheit.
  • Fukushima Daiichi Common Spent Fuel Pool
    • At 3:10PM on March 28, the temperature of the spent fuel pool: 95 degrees Fahrenheit.
    • As of 7:00PM on March 29, approximately 130 tons of water in total has been injected to the spent fuel storage pool.

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.

368 replies on “Fukushima Technical Discussion Open Thread”

nuclear toxicity

The previous post only sought to make the point that cancer rates are set to rise – even though we are tackling non-nuclear causes – smoking, UV radiation, carcinogenic chemicals etc.

However, it is not possible to avoid this issue. Iit is possible to see this demonstrated in the distribution of iodine 131 from nuclear testing.

See: http://en.wikipedia.org/wiki/File:US_fallout_exposure.png

I regard these amounts of iodine, in the context of its production, is properly described as toxicity.

I regard iodine 131 as a toxin.

Whether this leads to morbidity is a separate matter, and whether this then leads to mortality is another separate matter. These two issues will be resolved only after the Fukushima nukes have been stabilised.

The only reason why food and water is being tested is that hot isotopes are inherently toxic.

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MODERATOR
A reminder of the topics/subjects you should be posting on this thread:

“Please restrict all discussion here to technical information, analysis, criticisms and questions on FD — no philosophising or excursions into whether nuclear power is ‘good’ or ‘bad’ or the implications of FD for the future of nuclear power (except for new technical developments, e.g. safety standards), etc. You may impart your deep wisdom on how the world should work on the Philosophical Open Thread.”

When a comment is posted on to the wrong thread it causes a cascade of answering comments on the wrong thread – which means that your message will be lost to those reading the Philosophical OT thread.It seems, mainly, to be the technical experts who are wrongly posting on the Philosophical OT.
I am looking in to a way to move these comments to the right thread but in the meantime I will have to start deleting off-topic comments (as per BNC rules)and asking you to re-post.
Please try harder to post your comment on the appropriate thread.

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Note to MODERATOR : This is a reply to the discussion that was started in the “philosophical” section.

I said :
“At some point highest Transuranics (Americium, Curium) prevent safe running of the reactor.”

Barry Replied

“That is not correct. The equilibrium concentration of Am and Cm in pyroprocessed metal fuel (after multiple recycles) is in the order of a few percent, with more than sufficient delayed neutrons to keep the reactor stable. This is not theory, it is proven engineering based on extensive fuel testing at Argonne West in the late 1980s.”

My source was the last edition of Stacey’s “Nuclear Reactor Physics” where he says
“Based on the studies to date, it is the preponderance of informed opinion that sub-critical operation will be required in at least some of the reactors in the international “fleet” in order to fully achieve the closed fuel cycle.”
As it is the basic book for a lot of freshly minted nuclear engineers, you may want to discuss that assertion with him.

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Charles, that does not apply to metal fuel that has been electrorefined — I presume they are talking about experience with oxide fuel. My data is straight from the horses mouth, i.e. the key fuel conditioning facility folks at INL (formerly Argonne West)

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@Rational Debate,

I just wanted to thank you for the posts with links you’ve been posting.

Thanks for the thanks!

And thanks for the thumbs-up on that video linked by KBMAN. Your review moves that video up our watch-queue. We live on our yacht, currently in Hobart. Australian internet is bandwidth-capped, especially if like us at the RYCT, access is via a WiFi hotspot at the yacht club. We buy the max-monthly allocation – even so we have to carefully ration all content. We put video links in a “queue” so when we stop for a coffee at Zums cafe we can download. Worse, in the last ~10 days Youtube has defeated downloads, so we are reduced to snuggling around the iPad to watch streaming video at Zum.

I hoped that Will David/Atomic Power Review would prove to be a reliable source. I’m not so sure now – I think his “double breaches” speculation has been defeated by emerging facts. I’m referring to his assertion:

TEPCO, NISA and the Japanese Government now clearly (…) also associate the volumetric flow rate of injection water to the reactor cores as being roughly directly transferable to the trenches.

What is your take on the KBMAN analysis?

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@ Barry,

The passage I quoted in Professor Stacey’s book comes right after the description of the IFR reactor and pyro process, so I would be surprised that he didn’t take it into account.
A possible explanation of this divergence of opinion could be that thermal fission and/or long delays for reprocessing yield different distributions of minor actinides, that are less favorable in terms of reactivity control than irradiated fuel coming straight from an IFR.
In such case, an IFR “starting from scratch” pure U5 or Pu9 could have an infinite reprocessing ability, but an IFR starting from reprocessed old PWR spent fuel (Including Am, Np and Cm) would be more troublesome.
This is just an hypothesis though. I recon you are closer from the horse’s mouth than I am.

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Thank you very much Barry for your attention,

While you are asking references to the “Argonne folks”, can you ask if “IFR in Submarine” is something that has been studied somewhere ? After all, the first submarine reactor in the “USS Seawolf” was Na based, and a submarine containing an automated power plant could be entirely pressurized with Argon (no Pun intended), even in the turbine room.
That could potentially settle all the problems related to tsunami, earthquake, loss of access to coolant or penetrating device (plane or bomb).

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@ Jan,

Darn it Jan, I don’t know what the deal is with their readings – skimpy as they are. That was a good catch on your part, and sorry to be so slow on it.

As you note, at one point the ratio Te-129/129m is 13529. But it varies all the way down to 0.79. 4 of the ratio’s are in the 1.xx neighborhood.

Of course I’d expect the ratio to change since we’re not creating more 129m directly… but clearly it ought to be a progression in terms of the ratio for any given day. This is all over the map.

I still can’t go for a re-criticality scenario, because other isotopes that would be expected aren’t being reported. Even if a reactor was critical, it looks like it would be producing Te-129m, not 129 – although it also looks as if Sb-129 may come into play depending on release route.

I’ve been trying a little bit to find relatively current BWR source terms online and not having a lot of luck. Did find NRC’s Rascal program which lists source terms but I’m not sure if they’re the most current… They initially set Te-129 = Te-129m (.63)

So darned if I know what the deal is with the TEPCO monitoring analyses, Jan. Plus what I/we really need to do is look at the full set they’re saying they’ve detected and compare it to the source terms for various conditions (e.g., cladding failure v. core melt v. melt thru RPV) and see what appears reasonable. It’s the overall pattern that should tell us far more than looking at individual isotopes. Even so, clearly there are some things that are just off, and don’t seem to make much sense on the face of it.

Folks here may find the NRC RASCAL information interesting reading anyhow:

http://docs.google.com/viewer?a=v&q=cache:_fNaM6-ZGpUJ:www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1887/sr1887.pdf+BWR+%22source+term%22+radioisotopes+te-129&hl=en&gl=us&pid=bl&srcid=ADGEESi5iptXVepDojHytE7kmjwt2JprlsbANcYite0Wck-t7YaE4QZVVjpP7aIsT3k08144ORr5LVtUSDKKrkEryOVqmkBgBJpJA7LjXcQoflo5Hv6FAxLSVJ6k3Hy_kYM6SeVa566y&sig=AHIEtbQhLWbBDEiBnkX8aSta1KNDi4WK_A

A few other online bits that folks may find interesting:

Accident Source Terms for Light-Water Nuclear Power Plants (NUREG-1465) http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1465/

SOARCA slide show briefing http://www.google.com/url?sa=t&source=web&cd=3&sqi=2&ved=0CCAQFjAC&url=http%3A%2F%2Fwww.nrc.gov%2Fpublic-involve%2Fconference-symposia%2Fric%2Fslides%2Fgauntt-soarca.ppt&rct=j&q=Soarca%20%22offsite%20release%22&ei=-SqUTY2GEMHG0QGc6MztCw&usg=AFQjCNGEABwOFNnHLX9Nlh4V-Tp68JdRPg&cad=rja

Another SOARCA briefing: http://www.google.com/url?sa=t&source=web&cd=6&sqi=2&ved=0CDYQFjAF&url=http%3A%2F%2Fsacre.web.psi.ch%2FISAMM2009%2FISAMM09%2FPresentations%2FSession%25204(35%2C11%2C14%2C26%2C27)%2FPaper%25204.4(26)Thinkler.pdf&rct=j&q=Soarca%20%22offsite%20release%22&ei=-SqUTY2GEMHG0QGc6MztCw&usg=AFQjCNE8-Ozh5R2s6tzXdjAwC5WsYnXL-Q&cad=rja

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@Ken F:

RPV or containment? they are two different items, obviously. I thought the idea was that the meltdown may have breached the RPV but not the containment… and I believe the containment is actually steel with concrete around it if you believe what you see in the attached photo from a similar reactor in process of construction…

that containment clearly is without concrete…

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apologies for the multiple posts, my point in the previous post was that breach of RPV does not necessarily = breach of containment…

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Perhaps this has been mentioned before, but during the “is-there-or-is-there-not-water-in-the-storage-pools” period, did anyone think to overfly the reactors at night and look for the tell-tale glow of Cherenkov radiation?

Would the energies involved in a dry pool be high enough to generate Cherenkov Radiation in air, or would it just happen if there was water?

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@Steve Darden: I liek the info on nuclear tourist’s web site, but I am not certain it is completely factually accurate? there are two covers, one for containment and a second for the RPV. it appears the one they are showing as being for the RPV is actually for the containment?

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@BerGonella

thanks for the pictures. you can clearly see either the containment or RPV lid in the corner of #4 (round yellow thing). can’t really see much else though. it seems that the crane in #1 is clearly off to one side, which is why the roof did not drop all the way down to the refueling floor on the one side. it is clear though that the steam rising from #4 was from the SFP. it is also interesting (as point out in other threads) how it was that the explosion in 4 did so much damage to the entire structure surrounding the containment…

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michael r. james, on 30 March 2011 at 11:46 PM said:

Why did Dai-ni escape apparently scot free?

I haven’t been here for awhile and so I am making my way through comments, so I apologise if this has been dealt with. I have mentioned this before, but one of the reasons or maybe the main reason Dai-ni escaped the problems of Dai-ichi is that it never lost outside power. No loss of power, no problem with maintaining cooling. They lost their backup power and/or sea pumps. Three reactors there have been rated as INES 3. Not sure it should be that high, but that may be because of their loss of backup power. This was 2 weeks ago that I last mentioned it. I can go find the links, if anyone is interested. Now a non-problem, but will be important in a full analysis of the situation and how it might have been worse.

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One interesting point of speculation on the explosions, perhaps already mentioned, is that the lighter construction over the refueling floor for reactor building #1 may have resulted in less serious damage – because it blew out in a way that limited damage to the rest of the building. Certainly, recalling the video, there was a visible upward pressure pulse from that explosion that, confined by a heavier structure, might have caused something more like reactor building #3’s damage.

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Best I can tell the last progress report we have (http://www.slideshare.net/iaea/summary-of-reactor-status-30-march-2011-1430-utc) shows that the RPV/core is being cooled by “injection of fresh water via mobile electric pump and backup diesel generator”.

One would think that TEPCO is still trying to get one of the cooling loops going. Based on the info presented here:

Click to access 03.pdf

it might be the DHRS (decay heat recovery system) or perhaps just the simple recirculation loop.

Has anyone heard anything about the status of the effort to get these cooling loops up?? It’s been almost 2 days since the last report.

Thx,
GSB

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@ George Bower

They’re having trouble, George, because some of the equipment, pumps, electrical items that have to be checked or repaired are in the turbine building basement or the trenches. So they’ve got to get the highly contaminated water out before they can make much more progress – or figure out and construct a work around if that’s possible.

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Thx Rational Debate,

You’d think we would get a status on the activity of getting the radioactive water out of the cooling buildings…. but I guess they are waiting for (processing???) equip or tankage or both from someone (the French)??

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schla, on 31 March 2011 at 1:46 AM said:

is technology that exists that can “clean” (filter? forgive my layman’s terms) the water so it is not so “dangerous?

Hank Roberts, on 31 March 2011 at 2:26 AM said:

Routinely done.
http://www.google.com/search?q=nuclear+power+filter+ion+exchange+clean

While ion exchange resins are routinely used to reduce the circulating small amounts of fission products and activated reactor materials, this is far from routine levels of radioactive material, plus the cooling water is now salt water, not very pure water, so I don’t think ion exchange resins are going to be useful. An overwhelming amount of ions present mostly from the salt water. Evaporation with filtering then burial, maybe. Not sure how practical that is either. Dilution in the ocean is the most tempting option. Not very politically desirable, but may be the best of the options and is already going on to some extent.

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re post by:George Bower, on 1 April 2011 at 6:44 AM

Hi George,

You can find bits of updates if you check the various agencies reporting status. Pain in the rear, I know. But there’s TEPCO, NISA, JAIC for official sources, and then I hit NHK news & world nuclear news too (seems like I’m forgetting one or more).

The rest of this is a bit off the cuff…. Basically tho there are quite a few different drains, sumps, tanks for hold-up (delay & decay) tanks for storage, transfer tanks, etc. Each is associated to varying degrees with various types of waste water at nuclear power sites such as laundry, equipment drains, floor drains (& drains can be from areas where there’s no contamination, or areas where there is, so those are mostly separate) radwaste treatment systems etc.

So it sounds like they’re checking what might be reasonable to use, then how much space is available, and where there’s not enough space, where some can be made by transferring lower activity wastes into other tanks/hold up locations and so on.

Then before doing the transfers, they’ve got to decide how – thru existing lines or if they have to rig something…. and either way, before they can transfer they’ll have to check integrity of connections, piping, etc.

Finally, they have to actually do the transfers, which considering that power is still a problem probably means a good bit of work too, quite possibly including having to set up new transfer lines or connect somehow to a pump that works/has power, like a fire pumper truck.

So something that sounds like it ought to be fairly quick and straightforward probably actually requires a good bit of time and effort.

I wonder how much the tsunami may have been able to back up some of these systems, forcing water in thru the discharge lines or flooding drains from the surface outside the buildings… or flooding from building drains that were support buildings and got washed away by the tsunami. I don’t know all of the systems well enough to know if chances of that were very little, or fairly large. Obviously there would be valves on lines that led into more contaminated streams that would for the most part prevent this, but its the more pedestrian lines and drains – and the temporary storage tanks that might be associated with those that I wonder about. Just can’t help but suspect that with a tsunami, they may find they’ve got sea water places they never expected.

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The one backup that survived was the battery backup. What are these things that can take a quake and a tsunami and keep going ? I want some of these for data centers. All i got is a big pile of lead-acid batteries.

sidd

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Thx Rational,

Not sure what piece of equipment they used to inject salt water into the reactors (weeks ago). Perhaps it was a fire truck.

At any rate it took someone w/ an in depth knowledge of how this plant works in order to figure out where to actually hook up the hoses. A standard worker bee would only have the training to know what button to push or what back up systems were available but not where to hook up a fire hose.

If you look here:

Click to access 03.pdf


on page 14 you can see valves to isolate the main steam line and main feedwater line. Perhaps there is some very large “T” fitting at that location where they could tap into the reactor.

The details of all this would be fascinating!!

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@William Fairholm:

I tend to agree with you, and does “filtering” the water just mean you are trading contaminated filter media for clean (er) water? might be easier to dispose of?

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@sidd:

I believe the battery backup used was NiCad? they looked a lot like NiCad batteries I have seen. did that save the day from the tsunami? I doubt it. I am willing to bet the only reason they survived is because the battery banks were in a room either higher than the height of the tsunami or sealed from the effect of same…

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@ Barry and Moderators:
The Blog is pumping with information and posts, and each thread someone subscribes to generates hundreds of emails.

Is it time to use a forum? There’s a forum that just ‘plugs in’ to wordpress called Simplepress.

http://simple-press.com/

Articles could then be posted on the WordPress blog, and then a Forum discussion started in reply to each article.

Having a forum would also kill the need for “Open Threads” as people could log in and choose the forum for renewables, for example, and ask questions about renewables there.

What do you think?
MODERATOR
Barry advised : Makes it very difficult to control/moderate discussion.

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@ Schla, William, anyone else re treating the water – there are quite a few different ways, all depending on just what it is you’re trying to do. Many are used routinely at nuclear power plants.

Nothing is routine about the current situation, of course, especially with the sea water as an added complication. At least, I’m not aware of situations where they’ve needed to treat highly radioactive sea water – tho that doesn’t mean it hasn’t either occurred or been studied, that’s for sure.

Anyhow, centrifuges can be used to pull out solids and particulates (espc. heavy particulates), ion exchange has already been mentioned and there are different types, cation, anion, and mixed beds, evaporative methods, demineralizers, hold-up tanks (e.g., you store it temporarily to allow short lived radionuclides to decay), filtration, gas stripping, electrodialysis, reverse osmosis, and so on.

Various combinations can be used too of course, all as needed or appropriate. It will be very interesting to hear what they wind up using.

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Yeh, I kind of liked the idea of using one of the out-of-work oil tankers to capture all the outflow. But I gather they don’t have a deepwater dock there, or one of the navies would have sailed alongside and provided support/power/water long since, and that didn’t happen.

Too bad. A tanker could sail the stuff well out to sea, and even offer accomodations for vacationers. Rename it the _Hormesis_ ….

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@ Hank
excellent thinking as I would guess the big holdup now is getting the turbine room drained and the pumps fixed so an automated cooling loop can be started.
GSB

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@Hank Roberts, on 1 April 2011 at 10:30 AM said:

But I gather they don’t have a deepwater dock there, or one of the navies would have sailed alongside and provided support/power/water long since

There should be two barges there by now.
http://mdn.mainichi.jp/mdnnews/news/20110326p2a00m0na004000c.html

As far as using the barges as a ‘waste’ vessel it’s unfortunately illegal to deliberately dispose of radioactive waste in the ocean.

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> tanker
Yeah, I wasn’t thinking of using a tanker to dump, but to hold and clean the water. Filters get disposed of in waste facilities. Once cleaned, if really cleaned, a tanker-load of water could be brought back and used to refill emergency tanks at reactors, or even parked. Double-hull design would be about as safe as anything else available, and hold far more than the barges delivering fresh water:
“The 50-meter-long barges can each store about 1,100 tons of fresh water….” (from the link above)

Of course parking something like this right at the coast would be a mistake if _another_ tsunami happens; offshore a ways would do better.

http://www.seanews.com.tr/article/TURSHIP/TANKERS/47071/Tankers-Markets-Middle-East/
“Middle East Supertanker Surplus Unchanged as Ship Demand Slows”
Friday, 31.Dec.2010, 00:29 (GMT+2)

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re post by: George Bower, on 1 April 2011 at 6:44 AM

Don’t get me wrong George – I agree with you and would dearly love to be able to get a lot more details and updates too!!!

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re post by: sidd, on 1 April 2011 at 8:55 AM said:

The one backup that survived was the battery backup. What are these things that can take a quake and a tsunami and keep going ? I want some of these for data centers. All i got is a big pile of lead-acid batteries.

I don’t know either Sidd, but if you find out, I’d be interested in knowing – especially how portable they are or aren’t.

I will say, however, that very often it seems that something commonly used or well known in one industry or discipline is often not known in another where it could be most useful. Things have gotten so specialized and the mass of knowledge so large, that some/a lot gets missed where it could be really useful.

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Cross posted (my bad) on the Fukushima Philosophical Discussion Open Thread (as that’s where I found RD’s comment)

@Rational Debate re post by: EL, and “Neutron beam observed 13 times at crippled Fukushima nuke plant”

I think you might be following “kbman”. If so, you may have already seen his remarks last night – way at the bottom of the comments on his …Update 3/30… Are you guys on the same page?

Ferenc almost lost me by citing the neutron beam story as his reason for pursuing this. That story has for some time now been recognized as a case of poor translation. There is a very specific meaning to the term “neutron beam” and to make the measurements to establish that one existed would have required an apparatus specifically designed to detect it. What most have come to accept as the likely physical reality of the story is that when they said a neutron beam what they really meant were locations with high neutron counts.

Then when he made calculations of the Chlorine inside unit 1 by saying that they began injecting seawater on the March 23rd, that’s when I stopped reading. They started the seawater injections at unit 1 in the early hours of the incident, the evening of March 12th. Any point he was trying to make with his calculations was invalid at that point.

I’d also love to see a link for the story about melted fuel in the unit 1 reactor building. Melted fuel in the reactor building? I find that very hard to believe. Enough to cause isolated uncontrolled nuclear chain reactions? I find that very, very hard to believe. I say this because it takes a significant amount of fuel to create criticality, especially given that U-235 is generally only on the order of 5% of the uranium present. I don’t question that you’ve read this, I just would like to review the source material.

I believe it is possible that busted fuel has made its way into the relatively pure water of the Balance-of-Plant components – the turbines, condensers, heat exhangers and feedwater system. Once there I believe that there may be the possibility for some local subcritical fission given the absence of neutron absorbers and the presence of the water moderator. I think it stretches the bounds of reason to believe that enough has accumulated in a small region to make local criticality a possibility.

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re post by: Hank Roberts, on 1 April 2011 at 10:30 AM said:

…and even offer accomodations for vacationers. Rename it the _Hormesis_ ….

ROFLMAO!! Add it to the list with the existing ‘health spa’s’ of mines and some hot springs that way! They could even make it a non-profit, with all proceeds going to help Japan humanitarian aid.

On a more serious note, is it decided that they’re going to use barges? I suppose that’s why they’re going for barges, much smaller draft? Or are they just bringing in fresh water at this point?

Speaking of which, I don’t get it – they’re already using fresh water, so where have they been getting it from? It seems a bit hard to believe that bringing it in by barge would be quicker or easier than getting it elsewhere, but perhaps that’s an indication of how badly the local infrastructure is torn up…

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re post by: Hank Roberts, on 1 April 2011 at 11:43 AM said:

…Of course parking something like this right at the coast would be a mistake if _another_ tsunami happens; offshore a ways would do better.

Yeah, I keep getting periodic flashes of little horrible mental heebie-jeebies over the worry that they may get a really huge aftershock still. Every day that goes bay without one makes it less likely but still… supposedly its fairly common to get an aftershock that is one order of magnitude smaller than the original within a few days… which would be an 8.0. Like they REALLY need something that size, along and probably another tsunami to deal with. Talk about a horror nightmare.

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re post by: Steve Darden, on 1 April 2011 at 12:15 PM

Steve, I was trying to go find the post in question so I could be sure I knew what you were referring to, but I’m having trouble finding it. I searched for El or neutron beam on the philosophical discussion page, but didn’t find either. I’m probably messing up somehow, and sorry to ask this, but could you copy the link to the comment, or the comment header with the date?

Also, you had asked me for my opinion on the KBMAN article, and I’d put it off a little wanting to look at a couple of issues more closely and give you a little more detailed review. In general, however, what he’s saying sounds reasonable to me, albeit with perhaps a few relatively minor errors. Keep in mind tho that I’m not a nuke eng. specializing in core design or even a plant systems engineer – so it’s entirely possible that I could miss some factor or another that would totally change the results of a review on KBMAN’s article.

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@ Steve Darden – oh, and the ‘pipe to nowhere’ that I’d mentioned on the video? After seeing the high res. photos to compare to, it’s clear that the pipe is to the stack. Also the debris on the hillside that I’d mentioned? Now after seeing those high res. photos also, I’m thinking that may be from the explosion rather than tsunami, but I can’t tell for sure. No question those explosions blew building bits and debris all over the place.

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Now that professor Lahey has made his judgment that part of a core has melted through the steel container, 5 obvious questions arise;

1) what else flowed through the breech – water?

2) would a Leidenfrost effect prevent water cooling of molten core?

3) Is the real hope, more that the thermal mass of concrete will absorb enough heat from the melt to finally reduce its progress?

4) what is the melt point of concrete relative to the temperature of melting core?

5) is Lahey, right or wrong?

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I’ve been having a bit of a read of Physics for Radiation Protection by James E. Martin today. It’s an extremely good health physics reference book, and a good reference book covering the fundamentals of nuclear physics and nuclear engineering, too.

Extremely useful reading material if you’re interested in understanding, interpreting or talking about the situation in a technical, scientifically literate fashion.

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@Chris Warren

5) Lahey is wrong.

See D/W CAMS

R1 37.7 Sv/hr R2 39.6 Sv/hr R3 26.8 Sv/hr

If you don’t understand, maybe you can get Lahey to help you.

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Leo Hansen, on 1 April 2011 at 3:27 PM said:

Your link does not work.

There is no source.

I am having difficulty corroborating your post.

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D/W CAMS is not a link. D/W is a location and CAMS is an instrument. It is not a problem of corroboration, its whether the elevator makes it to the top floor

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re post by: Leo Hansen, on 1 April 2011 at 3:27 PM said:

I agree with Leo. Not only D/W CAMS, but also the RPV bottom temperatures.

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re post by: George Bower, on 1 April 2011 at 9:02 AM said:

Not sure what piece of equipment they used to inject salt water into the reactors (weeks ago). Perhaps it was a fire truck.

Pretty sure it was, but thru different lines into the core (e.g., not the same route in used at all three reactors)

At any rate it took someone w/ an in depth knowledge of how this plant works in order to figure out where to actually hook up the hoses. A standard worker bee would only have the training to know what button to push or what back up systems were available but not where to hook up a fire hose.

Or a combination. You’d probably be surprised at the general level of training and competence that way.

valves to isolate the main steam line and main feedwater line. Perhaps there is some very large “T” fitting at that location where they could tap into the reactor.

What they’ll probably use is whatever line they’re already tapped into. :0) Theoretically speaking, I suspect main steam would be the last place they’d want to go. Too large, too much risk if anything goes wrong, high rad levels, etc. They’d go for systems like Residual Heat Removal (RHR) or Reactor Core Isolation Cooling (RCIC) or the low pressure ECCS lines before trying main steam.

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Barry – Re Prof Lahey – I’ve read the Guardian article quoting him. I’ve looked for and not found any direct material from him about a R-2 RPV melthru (partial or otherwise) and any assesment of facts that support that..

Until we can find direct material from Prof Lahey, then I think he may have been mis-quoted or mis-understood.

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RD – The NISA site has been saying for days on all 3 reactors eg R2 ” Injecting fresh water via the Fire
Extinguish Line.
Flow rate of injected water :150ℓ/min”

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@ Jan & others interested in rad analysis, here we go – more analysis errors discovered. Sigh.

Fukushima plant groundwater likely contaminated despite data error

TOKYO, April 1, Kyodo

Groundwater at the crippled Fukushima Daiichi nuclear power plant is highly likely to be contaminated with radioactive materials, even though its operator Tokyo Electric Power Co. is reviewing its analysis released late Thursday due to erroneous calculations, the government’s nuclear safety agency said Friday.

The Nuclear and Industrial Safety Agency said some of the analysis data on the groundwater presented by the utility known as TEPCO cannot be trusted due to the errors, casting doubts on the finding that the concentration of radioactive iodine in the water was 10,000 times the legal limit….

…Earlier in the week, the utility corrected its analysis of radiation levels in water accumulating in the basement of the No. 2 reactor’s turbine building.

The agency said the density readings of radioactive substances in groundwater samples taken on Tuesday and Wednesday from around the No. 1 reactor’s turbine building may be revised downward, as TEPCO’s evaluation programs for materials such as tellurium, molybdenum and zirconium were found to have errors.

But it said the firm’s analysis programs for radioactive iodine were confirmed to be correct. (continued online w/ primarily other stuff) http://english.kyodonews.jp/news/2011/04/82524.html

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@ Barry – thanks, I’ll go take a read!

@ Leo – thanks Leo. The TEPCO report today just says thru feedwater system for U1, and doesn’t specify for 2 & 3.

@ George – they must have been listening to you – TEPCO’s report today has a few more details on the various work that’s been done going along. Still not a lot, but a little more anyhow. Also, while I’d read several reports that had said they were pumping the high level turbine basement floor puddle to condensate tanks, which is why I’d replied to you that way – but now reports now sure make it sound as if it was to condensers, rather than tank. Sorry about that. You’ll see that if you go take a look at the last TEPCO report today: http://www.tepco.co.jp/en/press/corp-com/release/11040102-e.html

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I noted that the temperature sensor in the bottom of the #2 PV died between 8:30 and 15:30 (from the NISA site). That is another indication of potential containment failure of the PV. Strangely, the last reading was 87.7 degrees Celsius. Not really the melting temperature of steel…

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@RD

Thanks for the very useful links.
I’ve heard at night at NHK that the measurements of Te-129 are some errors. They said that the Tepco will issue the corrections. So apparently I’m not only one who noticed the strange values and ratios.
Funny thing is that in the brand new measurement from the underground water there is again strange Te-129/Te-129 ratio, so I’m not sure if it is also error or what.

Click to access 110331t.pdf


and now they’ve even the Tc-99m rising.
(compared to last measurement http://www.tepco.co.jp/cc/press/betu11_j/images/110330n.pdf)
Looks like the plant is now a real laboratory of strange happenings either in measuring or in reality ;)

I think that to asses what is going on from the complex ratios was why I posted the links to the whole datasheets in the post further above. But I think it would be quite a guess job when we even can’t be sure if the measurements are correct at least like right order of magnitude.

I also don’t find it much likely there is a possibility of recriticality, there is not much anything as a signature of criticality I think. I think Sb-129 could be a likely route, but they don’t measure it, so I don’t know. What I would think the various possible strange transmutations could be a result of complex mutual irradiation in the fancy mix in the leaked 20TBq/m3 underground water sediments possibly also with materials not normally present in the fuel or reactor + the fish they apparently pumped into the cores :)) + the tsunami disgorged crabs, shells and seaflowers. But I’m not knowledgeable enough to dig in this, so I leave it for the experts on sea fauna and flora vs melting core products. (sarcasm)

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Someone emailed me today with the figures below saying they came from Tepco, but I can’t find any mention of them on Tepco’s website (not in English anyway). The figures show staff numbers at Daiichi and Daini, and the numbers of workers who have been exposed. Can anyone find the original material?

Fukushima-Daiichi (staff in plants + office)

Total :370

TEPCO :319

Contractors: 51

-Fukushima-Daini site (plants+office)

Total :626

TEPCO :562

Contractors: 64

– Workers exposed dose

>100mSv :Total :21

TEPCO :18

Contractors :3

>200mSv :Total :0

TEPCO :0

Contractors :0

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@RD 5:46 PM Here is the NISA site that says the injection is thru the fire extingsh line:

Click to access en20110401-1-3.pdf

@RD 5:51 PM re Lahey The blog you reference gets it’s info from an IEES Spectrum article:
http://spectrum.ieee.org/tech-talk/energy/nuclear/nuclear-engineer-says-theres-evidence-fuel-melted-through-reactor-pressure-vessel

The article quotes Lahey but Lahey did not write this himself.

“This morning, Lahey elaborated on his analysis for IEEE Spectrum, which he said had been accurately reported by The Guardian, but misinterpreted by some. (A careless read of the article suggests a new meltdown at the plant, rather an analysis of what probably occurred early on in the crisis.)

Lahey says his analysis was based on the data sources seen by him and colleagues around the world, but that the information has been inconsistent and changes hourly.

However, his best take is that “all cores have melted, and it appears as though Unit 2 has melted through.”

His conclusion about reactor No. 2 comes largely from the amount of radiation in the water found there and the chemical contents of that water.”

===================================

The March 29th Guardian article quoted Lahey as saying: “”The indications we have, from the reactor to radiation readings and the materials they are seeing, suggest that the core has melted through the bottom of the pressure vessel in unit two, and at least some of it is down on the floor of the drywell,” Lahey said. “I hope I am wrong, but that is certainly what the evidence is pointing towards.”

===============================
So Lahey has no more information than what we have and is basing his conclusion of a R2 RPV at least partial meltthru into the drywell only on the high radioactivity of Unit 2 turbine bdlg water.

Many of us, including Barry Brook disagree with his RPV melthru conclusion. I believe that he may be right that there is partial melting of the cores.

To me, the R1 R2 and R3 drywell continuous air monitoring system (D/W CAMS) radioactivity measurements are essentially the same. If there’s corium in R2 D/W, then it’s there in R1 and R3 also. The D/W CAMS measurements can be found at the referenced NISA site.

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Question 1:

If (hypothetical) there is a leak in the torus (that could have been caused by the hydrogen explosion in #2), Where would the water end up?? (Turbine building??)

Is there any instrumentation that would indicate if the torus is leaking.

Question 2)

Where is all the makeup water going that they keep pumping into the PV. (Mostly to steam??) (This question was asked before by another poster but I did not see an answer)

Thx,
GSB

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George, hope you get an answer.

Also a question. I was informed that everything would be fine because the reactors had been shut down and it was only a matter of days before they were cool and safe. Why are they frantically working on these. US France and Japan. Why a anti-radiation cloth and why resin. I thought that radiation was not that harmful. I am still not understanding.

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The NISA data shows the RPV pressure in reactors 2 and 3 to be less than atmospheric(partial vacuum).
How can that be?

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@Rational Debate, on 1 April 2011 at 12:58 PM

Steve, I was trying to go find the post in question so I could be sure I knew what you were referring to, but I’m having trouble finding it. I searched for El or neutron beam

My bad, by reference I was trying to refer to posts by both EL and Rational Debate and the re-criticality issue. It would be impossible to search up your specific post from that reference. This is another example where a forum-style area could really enhance BNC (but that of course means effort).

Like many “loss of control” worries that have been raised, re-criticality seems to be receding.

Sorry to be so slow in reply.

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OK, let me be more precise about the temperature indicator failure.

compare http://www.nisa.meti.go.jp/english/files/en20110331-1-2.pdf (bottom PV temp 87.7)

and

http://www.nisa.meti.go.jp/english/files/en20110331-2-2.pdf (bottom PV temp “Indicator failure”)

mean while in http://www.nisa.meti.go.jp/english/files/en20110401-1-2.pdf

you can read about the operations of reactor #2 :

“29th 16:30~18:25 Switched to the temporary motor‐driven
pump injecting fresh water to SFP.
30th 9:25~23:50 Confirmed malfunction of the temporary
motor‐driven pump injecting fresh water to SFP(9:45). Switched to the injection using the fire pump Truck, but suspended as cracks were confirmed in the hose. (12:47, 13:10) Resumed injection of fresh water(19:05)”

It could have stayed a long time without cooling, which may explain the indicator failure.

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@Jeff Toms 11:09

The NISA site for March 30 gives RPV pressure readings in R2 and R3 from -0.018 to -0.09 MPa g and 0.02 MPa g. The g means gauge readings relative to atmospheric pressure, a zero being ordinary air pressure. A MPa, mega Pascal is 145 psi or 9.86 atmos. Normal pressure readings with these gauges are ~7 MPa g when the reactors are operating and the design amounts of steam is being generated.

So these RPV pressure readings are from -0.18 to -0.89 atmos (below outside air press) and +0.18 atmos.

I believe it is unlikely the containment vessels are under vacuum. It is more likely that all the stress, explosions and cycling these pressure gauges have undergone, that they are no longer accurate. They are inaccurate and all that can be gleaned is that the reactor pressures are near atmospheric.

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There has been some talk of radioactivity in the turbine buildings at Fukushima, but I’m curious about that. Where would the radioactivity come from?

Sure, the working fluid would contain some N-16 and N-13 but they’re very short lived and would decay very rapidly following reactor shutdown.

The main steam isolation valves would have been closed very early on, during the initial earthquake SCRAM or when offsite power was lost.

Therefore, any longer-lived fission products would not escape from the damaged nuclear fuel into the turbine building.

Anybody have any ideas? Are these reports of significant radioactivity in the turbine building accurate?

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@Luke Weston
“There has been some talk of radioactivity in the turbine buildings at Fukushima, but I’m curious about that. Where would the radioactivity come from?”

According to izotope signature it most probably came from the compromised Pressure Suppression Chamber (http://blogs-images.forbes.com/christopherhelman/files/2011/03/nuke-ge-mark.jpg – the ring at the bottom) at No2. It is so radioactive, because the reactor pressure vessel was vented through the water. see http://energyfromthorium.com/pps/FukushimaDaiichiAREVA.pps

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Just want to repost my question from yesterday.

If (hypothetical) there is a leak in the torus (that could have been caused by the hydrogen explosion in #2), Where would the water end up?? (Turbine building??)

Is there any instrumentation that would indicate if the torus is leaking.

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@ Geroge Bower
It is almost sure the torus is breached looking at the signatures of the water found in the underground trench. Although now they say at NHK they also found the leak from it leading to the sea through a cable tunnel, so if the’ll not seal it the water will end in the pond below the plant, which is not completely separated from the ocean by dam.
for idea: http://tumetuestumefaisdubien.sweb.cz/pond.jpg
The instrumentation which indicates the breach is the pressure meter of the containment which indicates atmospheric pressure.

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It would be good to know the flow rate of the leak. I suppose they could calculate it knowing the water makeup into the reactor rate minus what is going off in steam.

The leakage rate would allow them to size their tankage and processing equipment.

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Question; Is reactor 3 the 800 pound gorilla? I’m reading JAIF and expert reports, namely on the RPV status, radioactive water, and the estimated fuel melt of reactor cores in 1 (70%) and 2 (30%), but there is less reporting on the status of reactor 3. We don’t have the same degree of updates on the core, RPV, or SPF of reactor 3. Mainly we have vague terms like damaged, or stable. Does this concern any of the experts here? Yes or no, please explain why?

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“It would be good to know the flow rate of the leak. I suppose they could calculate it knowing the water makeup into the reactor rate minus what is going off in steam.”
There must not be a leak from the reactor. It is from the water signature very possible it is just the radioactive water from the torus, which was created when the reactor was vented. I doesn’t necesarily imply the reactor pressure vessel is breached.inside the containment, because it would need most probably the completely melted without any water in the reactor pressure vessel- which if we can believe the reports is not the case and in such case it would be not the complete LOss of COolant accident. which the BWR Mark I severe accident mitigation strategies assessment
http://www.iaea.org/inis/collection/NCLCollectionStore/_Public/24/072/24072657.pdf describes – which would be bad in case also the pressure suppression chamber is breached. Because the containment can’t be flooded to cool the RPV. So hopefully the reports are true and theres not complete core meltdown at No2 and there is the RPV flooded and no large water leaks on its bottom where the control rods canals are.

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Thx Jan,

Looks like from the mornings TEPCO progress report they are going to try to trace back to the source of the leak in R2. Perhaps they can get a handle on the leakage rate and level of radioactivity from R2 today.

Quote from TEPCO:

after checking the condition,
we began to stop water shutoff and are injecting polymer today(April 3rd).
Tonight, they will depart from Tokyo and will start the work with survey
of the site conditions tomorrow morning April 3. There is a connection
point between the tunnel of unit 2 and this shaft. It was assumed that a
puddle of water in the turbine building of unit 2, out flowed through
this connection point and spilled into the sea from the crack of the
shaft. Therefore, we will investigate out flowed route to the shaft and
implement the water analysis by taking samples in the shaft near the
spilling point to the sea. In addition, from April 2nd, we will implement
sampling at 15km offshore Fukushima Daiichi and Fukushima Daini Nuclear
Power Stations and will evaluate these samples comprehensively.

Also, there is a schematic of how they are moving radioactive waste water from tank to tank on the NISA site. However, I don’t have enough knowledge in order to fully understand it.

Click to access en20110403-3-2.pdf

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> radiation rate … in the torus
Uneducated guess, in normal operation without damage to the fuel, it’d be comparable to that in the turbine, about which Wikipedia says:

http://en.wikipedia.org/wiki/Boiling_water_reactor
“… shielding and access control around the steam turbine are required during normal operations due to the radiation levels arising from the steam entering directly from the reactor core. This is a moderately minor concern, as most of the radiation flux is due to Nitrogen-16, which has a half-life measured in seconds, allowing the turbine chamber to be entered into within minutes of shutdown.”

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Interview quoting one of the workers who has been in the plant: http://mdn.mainichi.jp/mdnnews/news/20110402p2a00m0na016000c.html

“… He said that because of the earthquake there were many holes on the plant premises, with water collected in them. With their vision hampered by their gasmasks, the workers could not always see where they were walking, and several workers fell into the holes. The situation was such that it took two days to finish work that normally would have taken only three to four hours, he said….”

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Pictures of the control rooms do not seem to indicate any working instrumentation. Can somebody tell me how has TEPCO provided the reactor pressure , temperature and well radiation data?

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From an Australian perspective, the stress at Fukushima shows up a dependence on copious supplies of water, which is particularly scarce inland from the Australian coast.
.
We could do a lot better with engineering designs that dumped the waste heat using air or thermal radiation instead of evaporating water.
.
This is not as radical as it may seem at first glance. Once-through gas turbines use air as their working fluid and dump their waste heat directly into the atmosphere. The cycle could be emulated with nuclear replacing the combustion zone.
.
A crucial difference would be that in a failsafe breakdown, an un-manned plant must passively convect decay heat into the immediate air.
.
If that limits the size of the power plant to 50 MW or less, perhaps that is so much the better for a country whose industries are so dispersed.
.
An immediate implication would be that the power plants could go to wherever the industry is, instead of the industries going to the grid.

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@ Roger Clifton:

Water Consumption

Dry cooling technologies are very high power usuers, to drive the fans, they make quite a lot of noise and they take up a lot of space, as well as costing money.

So, wet or dry cooling is not simply a decision based on whether there is a good local water source.

I understand that this is doubly true for dry hot rock geothermal, because there is water lost underground as well as via cooling… heaps of it.

The investigation has to be done on a case by case basis and the numbers crunched.

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Martin Burkle asked about radiation levels around a torus during normal plant operations. My understanding is that it would be in the 10 to 50 mRem per hour range with hotspots around 100 to 150 mRem per hour.
MODERATOR
Jeff – Please supply refs to support your understanding . This is required by BNC commemts policy. In future, you comment may be deleted if not substantiated.

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“The Dai-ni plants do not have the same problem because the AC power was not lost.”
There is still a lesson to be learned. Why was the power not lost?”
1. Why was the switch room not flooded? Maybe the plants are higher or the wave not has high. Maybe the plants are of a newer design and have water tight doors. Maybe something else.
2. Was the local grid supply the same type as Dai-ichi? Maybe the power came from a newer underground power line. Maybe the power poles were of a different design. Maybe something else.
3. Were the emergency generators lost? Are the emergency generators repaired now?
A lesson learned can be because something worked as well as when something does not work.

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I see that the 750 MW Kogan Ck Qld air cooled coal fired power station will get an intermittent 44 MW solar boost
http://www.csenergy.com.au/content-(50)-renewable-energy.htm
On an annual basis it looks like the extra output will be small compared to coal. It is additional to coal, not instead of. It’s less CO2 growth than otherwise, not a reduction from pre-existing levels or negative growth.

If these projects make little or no difference to baseline emissions I wonder if they are essentially a greenwash. A photo-op for politicians. 10% or 20% baseline CO2 cuts would be more impressive.

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John Newlands, on 4 April 2011 at 8:40 AM — Assuming a 21% CF for that location, the average boost is 0.21×44 = 9.24 MW, providing a whole 1.23% elimination of otherwise additional CO2 emissions from that site.

A modest energy efficiency program can easily do at least as well; Kansasians eliminated an impressive 5% of demand over the past 20+ months.

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Risk Analysis

Could it be that absolutely no-one in Australia has any capacity for properly undertaking a modern risk analysis of nuclear?

The is NO record of any copy of ISBN:9780791831403 in Trove, and it is prohibitively expensive to purchase.

So is all the understanding of LERF risk based on heresay?

The situation seems similar to terrorism risk, and aircraft collision risk.

All heresay, and vague references that do not deliver what they promise.

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Roger – people are fairly scarce inland from the Australian coast too, as I understand it. So on the basis that you want the power where the people are, it doesn’t matter much if the power stations need to be on the coast.

For a distributed population, though, your point about generating power in useful sized modules is good, and one or two of the the B&W mPower 125MW reactors might be great for Darwin, for example.

—————–

On a technical question unrelated to Fukushima – would it be reasonable to compare the total global radiation exposure for medical purposes, for a year, to the total radiation exposure due to Chernobyl? This is not an easy calculation to get a hold of, but I get the impression that the two are not wildly different.

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Risk Analysis

The same happens with the earlier version of PRA standard:

ISBN:0791827453

It seems clear that there has been no competant, rigorous, and corroborated risk analysis by any of our[ ad hom deleted] nuclear proponents.

Could it be they have been relying totally on hearsay from America, plus dashings of poetic concepts that do not represent the experiences of real life?

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Chet, on 4 April 2011 at 7:36 AM said:

Pictures of the control rooms do not seem to indicate any working instrumentation. Can somebody tell me how has TEPCO provided the reactor pressure , temperature and well radiation data?

—-

Can you supply dated photos that prove this?

If true, I’d also like to know the answer.

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Sufficiently safe

So how have our [ad hom deleted] nuclear proponents objectively assessed the safety of reactors against aircraft strike if:

APP-GW-GLR-126, “AP1000 Nuclear Island Response to Aircraft Impact,” Westinghouse
Electric Company LLC.

is not available in Australia????

Is their entire understanding hearsay from Westinghouse?

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@ Chris Warren:

Could it be they have been relying totally on hearsay from America

What’s wrong with using US data and experience? Do you doubt the professionalism of the NRC?

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Finrod, on 4 April 2011 at 11:26 AM said:

What’s wrong with using US data and experience? Do you doubt the professionalism of the NRC?

Depends on the evidence?

How did the NRC professionals use the experience of the Sep 11 plane impact into the wall of the Pentagon as data and experience, for other strategic reinforced concrete 0.9m concrete shells spanning 40metre voids?

I doubt they did this?

So it would appear that NRC risk analysis for thin concrete shells on modern nuclear plants is likely uninformed by US data and experience.

I also doubt that Westinghouse used the US data and experience in revising its own documents.

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@ Chris Warren

What is your issue with the US risk analyses proponents might be “relying on”? Studies estimate a core damage frequency of 2*10^-5, or one in 50,000 reactor years. N.B. that this does not imply significant radiological release or “disaster”.

Experiential data still shows that nuclear energy production is the safest form of energy production, globally.

I strongly urge you to put the risks of nuclear energy production into context with the much greater risks of unmitigated climate change.

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My suggestion was for small nukes running a hot-air cycle, water-free, like a gas turbine. However other commentators suggested steam-cycle plants can be made much less thirsty.

@John Newlands pointed out a quite large air-cooled (coal fired steam) power station, Kogan, at 750 MW, which uses only 10% water of conventionally cooled plants.

@John Bennetts says air-cooling takes up lots of space (so what, out bush?) and fans consume much power. If the fans are required to reduce the area used, then perhaps use more piping and more area?

@Joffan says “people are fairly scarce inland”. Indeed, more than 80 per cent of Australians live within 100 kilometres of the coast .

However the remaining 20% of Australians amount to 4.4 million, hardly negligible. With the city average of about 1 kW per capita, that is already 4.4 GW of demand. Yet rural industries such as mining will consume a lot more than 1 kW per worker. A quite ordinary mine site will consume 10 MW, mainly in the processing of its ore.

The Toshiba 4S can be installed with an output as low as 10 MW, however its Alaskan installation assumes plenty of water to cool the condenser. That size of reactor we need to be cooled by air.

If more power is available, it is an option to the mine owner to increase the value density of the product to reduce transport costs. Gove once sought 1 GW(th) of gas just to produce alumina. With more power, they might electrolyse the alumina and produce the metal on site. As might Weipa , or Pinjarra .

Kalgoorlie, Mt Isa, Broken Hill, Weipa seem like candidates for air-cooled nukes.

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Tom Keen, on 4 April 2011 at 12:56 PM said:

[deleted incorrect assertion]
Using your figure, this means that when there are 10,000 reactors (arguably at 2060) core damage has a frequency of 1 in 5 years.

The LERF (cited previously) – which does imply significant radiological release, is at or below 10^-5 if US standards apply.

This is large radiological release freq. of one every 10 years – after 2060.

[deleted unsustantiated opinion]
MODERATOR
Chris – I went back and looked at the comment by Tom Keen in case I had missed any failure to give refs. I really don’t know what you are getting at as the links are in Tom’s comment.

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Aircraft Collision

[deleted unsubstantiated opinion}
However no-one has posted any details of the breaking point of a 40 metres shell of reinforced concrete 0.9 metres thick.

If a 5 tonne engine hits this shell at 500 km/hr (140 m/sec) we can apply force-impulse theory.

Assume that a solid engine imparts its impact in the time taken to travel 1 metre (7 thousandths second), then

F = M dv/dt

is 5000 X 140/.007

This is 10 Mega Newtons.

10 space shuttle engines at take-off !!!!!!

see: MegaNewtons

Depending on the resistance of concrete shells to large hammer blows, even a bowling ball at terminal velocity could damage such a structure.

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@ moderators:

Why are the ridiculous, snide posts of Chris Warren permitted to stand?
MODERATOR
Finrod – I can only moderate according to BNC commenting policy. I have edited some of Chris Warren’s comments. Please point out any other comments (or parts thereof) where you see a violation or a technical point which is not substantiated.

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@ Chris Warren

You have posted assertion without evidence or any source.

This is plainly untrue.

I provided a hyperlink to an EPRI white paper which (bottom of page 3) reports the estimated core damage frequency I quoted. References are given at the bottom. I also provided a hyperlink to a paper which indicates that nuclear energy production has a lower death rate per TWh than any other energy source.

The only statement I did not support with a reference was “much greater risks of unmitigated climate change“, which, on a climate change blog, I thought would go without saying.

What is insufficient about this?

However, you did make this assertion without evidence:

Nuclear energy production only APPEARS safer because the risk is distributed on a dramatically different timescale.

I stand by my statement that nuclear energy production is the safest form of current energy production. And it appears to be getting safer (again, see the EPRI paper). And once we move toward some Generation IV technologies, we can all sleep even more soundly.

You never answered my question: What is your issue with using US risk analyses?
MODERATOR
Chris Warren’s violations of the comments policy have been edited.

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Chris Warren,

Go to google scholar and search for “nuclear power” and “aircraft”. The risks aren’t that high.

Another EPRI study available here, goes through, in detail, the results of some computer model simulations of a Boeing 767-400 collision. The conclusion?
The study determined that the structures that house reactor fuel are robust and protect the fuel from impacts of large commercial aircraft.

Frankly I think your last post was just spreading FUD.

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Tom Keen, on 4 April 2011 at 3:50 PM said:

I am not sure what you are trying to say with the EPRI paper. It is very similar to most other sources.

The assumptions it uses:

engine weight 9,500 lb
speed 350 mph

are equivalent to mine, although I used a slower speed 310 mph – for reasons the EPRI paper also mentions (the size of the target).

AP1000 concrete shell is 0.9 m thick. Much thinner than EPRI’s model – 14%.

The EPRI paper is not a “study”, and in fact says the details are not available “because of security considerations”.

So we can only ask the question – can a reinforced concrete shell spanning 40 metres withstand a hammer-blow of 100 mega-newtons.

When you look at the magnitude of this force at:

MegaNewtons

it appears not.

I do not have any problem with using your 2*10^-5 In fact I halved it.

But the residual issue is how practical and relevant is this to the nuclear roll-outs occurring or proposed for other States.

Your statement at 12:56 was:

Experiential data still shows that nuclear energy production is the safest form of energy production,

After I pointed out the fallacy in this (in capital letters) your statement at 3:16 morphed into:

that nuclear energy production is the safest form of current energy production.

Your insertion of “current” validates my concerns.

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Did we ever get any more news about that chlorine-38 that was reported (and sodium-24 that wasn’t) in the water sampled in one of the reactor basements?

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chris warren, on 4 April 2011 at 5:17 PM said:

So we can only ask the question – can a reinforced concrete shell spanning 40 metres withstand a hammer-blow of 100 mega-newtons.

If I might use a simple analogy.

50 years ago automobile bumpers could withstand a 30 MPH impact with a tree. Allthe energy ended up being transferred to the occupant. The car survived, the occupant didn’t. Today’s bumpers won’t survive a 5 MPH impact with a tree. The survival rate of the occupant is substantially higher as much of the force of the accident is absorbed by the bumper.

The shield building serves the same function for a nuclear reactor that a bumper on an automobile does. The question becomes whether or not a shield building that deforms and suffers damage from a high impact event does a better job of protecting the containment building and more importantly, the core.

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