Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[MadderDoc]

Indeed.

As far as official info about this event, the wording was quite poor and tried to downplay things regarding unit 4, but anyway:

March 14th 04:08 Temperature of pool is 84 degrees C.
March 15th 06:14 It was confirmed that a part of wall in the operation area of Unit 4 was damaged
March 15th 09:38 Fire spotted at unit 4
March 15th 11:00 Fire no longer seen - presume it went out of its own accord

Yes, it is and was confusing. I got the impression that for whatever their reason, after the explosion, recurrent fires were at play in unit 4. A striking change of color and shape of some debris hanging out from a hole at 4th floor in the north wall could be the signature of a fire event in that area at some time between March 15th and March 16th.

<..>
Given the timing of unit 3 explosion, I do not have an alternative explanation for what happened at unit 4. It happened within within minutes of the explosive sound at suppression chamber of unit 2, but I don't see how those events could be related.

Independent events do happen all the time, concurrently, but I think it is worth a thought, if there could be some causal relationsship between events in unit 2 and unit 4, since there is this tight coincidence.Following those big pipes along the turbine buildings might be worth a shot. I can't think of anything else connecting the buildings, which might be able to pump up unit 4 with hydrogen from unit 2.

Given that the temperature of the pool was reported at 84C about 26 hours before the explosive event, I still blame the pool, even if we can't see any obvious damage to fuel (can there be significant damage that is not visible?)

Pass. I feel not, but that could be wrong. After seeing the sfp videos, the Tepco theory of a flush of water from the reactor cavity released by an explosion has still credence. However, what exploded, and from where did it come?

 

[I_P]

Looking at the righthand photo posted by MadderDoc above you can see that the buckled upper wall panels are putting strain on the wall and columns below. If the upper portion of the wall were to collapse and pull down the support columns below perhaps this would put additional strain on the fuel storage pool supporting structure. Maybe this is what the concern with unit 4 stability is...

 

[SteveElbows]

I don't find taking personal swipes at people very useful to the conversation.

Well I am afraid that's the risk you take when you post sloppy information as if it was fact. There is nothing wrong with a bit of speculation, but pretending that such things are certain is not good. I also fear that attempts to make your sources sound great will not count for very much here, it does not make up for poor quality evidence. The onus is on you to provide decent evidence, don't complain if the theory is not taken seriously without such evidence.

We have known for a good while that they worry about unit 4 building & the stability of the pool, this emerged back when TEPCO announced their roadmap to bring the site under control. But the press didnt really talk about it as soon as this plan was announced, it went almost unnoticed, until TEPCO themselves started making comments about having to take it easy with the pool spraying, because they were worried about the weight of the water. But then things got more confusing because as soon as they said that, they went on a multi-day marathon where a huge quantity of water was sprayed into number 4. Then they stopped, did not spray at all between april 28th and may 4th, and then sprayed a very large amount of 270t on the 5th, 180t on the 6th and 120t on the 7th. If the pool was hanging by a thread, or the building was starting to lean badly, if they were absolutely afraid that the pool may collapse at any moment, then I doubt they would have risked putting so much water in in one go.

So yes, its a concern, something horrible could happen, but there's no way this disaster requires sexing up by some people drawing dodgy lines on photos and acting like its conclusive proof of anything.

 

[SteveElbows]

Looking at the righthand photo posted by MadderDoc above you can see that the buckled upper wall panels are putting strain on the wall and columns below. If the upper portion of the wall were to collapse and pull down the support columns below perhaps this would put additional strain on the fuel storage pool supporting structure. Maybe this is what the concern with unit 4 stability is...

That photo is a wall that's on the opposite side of the building to the fuel pool.

Personally I don't know exactly what makes them afraid, except to say that in general the building is in poor condition. Perhaps they are worried by what they see when they look into the hole that is lower down on the south side of the building, or the lower holes on the east side,certainly I assume that there is much detail we cannot see from the few photos we have, and that's part of the reason I don't think we have learned very much from all these hours spent (over)studying photos.

 

[SteveElbows]

Yes, it is and was confusing. I got the impression that for whatever their reason, after the explosion, recurrent fires were at play in unit 4. A striking change of color and shape of some debris hanging out from a hole at 4th floor in the north wall could be the signature of a fire event in that area at some time between March 15th and March 16th.

Yes, there was a further fire reported in a useless way that never properly confirmed it:

The fire at Unit 4 occurred (05:45 March 16th) TEPCO reported that no fire could be confirmed on the ground (06:15 March 16th).

http://www.nisa.meti.go.jp/english/files/en20110317-1.pdf

 

[gmax137]

Apologies if this has already been asked & answered, but I'm wondering if the work in Unit 4 at the time of the earthquake (removing core barrel (??)) involves use of acetylene cutting torches, or other equipment involving tanks of flammable/explosive stuff? Wasn't it cold there in early March? -- maybe the construction crews had propane heaters inside? I can imagine that with the core offloaded, there could be a lot of non-seismic temporary stuff brought in for the work. Stuff prone to damage by the earthquake.

Or how about the turbine-generator cooling hydrogen system - does any of that pass through the reactor building? I wouldn't think so, but I have no experience at BWRs.

Just fishing for off the wall ideas here.

 

[SteveElbows]

I think that they move crane to take video of SFP or/and inside building from new point.

Yes. People said they had seen the crane around unit 4 at night, but as I mentioned in a previous post, times for spraying are published and its rare for these time to be at night. We do not consistently hear about temperatures they have measured in the pool, and have no way to know if they do this more than is mentioned in the press, but its quite probable that they are doing other things using the crane, possibly at night/early morning before sunrise.

 

[MadderDoc]

Looking at the righthand photo posted by MadderDoc above you can see that the buckled upper wall panels are putting strain on the wall and columns below. If the upper portion of the wall were to collapse and pull down the support columns below perhaps this would put additional strain on the fuel storage pool supporting structure. Maybe this is what the concern with unit 4 stability is...

Sorry the nameing of that photo file might've indicated to you that we are looking at the south wall where the fuel pool is. But, the photo is of the north wall.

 

[MadderDoc]

That photo is a wall that's on the opposite side of the building to the fuel pool.

Personally I don't know exactly what makes them afraid, except to say that in general the building is in poor condition. Perhaps they are worried by what they see when they look into the hole that is lower down on the south side of the building, or the lower holes on the east side,certainly I assume that there is much detail we cannot see from the few photos we have, and that's part of the reason I don't think we have learned very much from all these hours spent (over)studying photos.

Who them, they?

Perhaps it is not so much what we have learnt, but what we have unlearnt. Think if all we had were the written reports, no imagery, think of what fancy theories we could come up with, based on the limited evidence, :-) and think how many of those we so readily can sort away and dismiss, based on what we know from photos.

 

[whoswho69]

http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110508e1.pdf
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110508e2.pdf
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110508e3.pdf
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110508e4.pdf
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110508e5.pdf
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110508e6.pdf
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110508e7.pdf
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110508e8.pdf
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110508e9.pdf
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110508e10.pdf
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110508e11.pdf
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110508e12.pdf
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110508e13.pdf

 

[SteveElbows]

Who them, they?

Perhaps it is not so much what we have learnt, but what we have unlearnt. Think if all we had were the written reports, no imagery, think of what fancy theories we could come up with, based on the limited evidence, :-) and think how many of those we so readily can sort away and dismiss, based on what we know from photos.

I am pleased we got something, images soon after the event were more plentiful than I had hoped. There has not been enough new material in last month to satisfy peoples curiosities or give us something to feed off, so attempts to come up with something new have become somewhat desperate in recent weeks.

Anyway it sounds like if everything has gone according to plan, workers have entered reactor 1 through the doors that were opened on Sunday:

Tokyo Electric Power Co. said the doors of the No. 1 reactor building connecting it to the adjacent turbine building at the crisis-hit Fukushima Daiichi nuclear power plant were opened Sunday, paving the way for the utility to proceed with efforts to stabilize the damaged reactor.

The move came after the government's Nuclear and Industrial Safety Agency gave the go-ahead, saying it has assessed that opening the double-entry doors at the troubled facility would not have adverse impact on the environment.

Tokyo Electric, also known as TEPCO, said it plans to have workers go inside the reactor building at around 4 a.m. Monday to measure the levels of radioactivity inside.

http://english.kyodonews.jp/news/2011/05/89826.html

 

[SteveElbows]

According to a press report, 'demolition robots' made by this company are going to be used at Fukushima:

http://www.brokk.com/

http://www.yomiuri.co.jp/dy/national/T110508002670.htm

[URL]http://krafttelerobotics.com/industries/nuclear/images/180r_large.jpg[/URL]

 

[SteveElbows]

Two of the links in that strange post of many links are actually interesting. Strontium 89 & 90 results, found in soil and sea (none detected in air).

Sea: http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110508e5.pdf

Soil: http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110508e7.pdf

 

[Caniche]

I'm sure all those nice vids are of Fukushima SFP 4 . But you know what they say, seen one spent fuel pool,seen them all
And what a stroke of luck that none of those blasted rsj's or roof panels or concrete panels ended up in the pool,neat

 

[Caniche]

Tepco -"Units 4-6 ,outage due to regular inspection ." Well it's not a complete lie,but hmm

 

[Astronuc]

I think I got it:
Under normal conditions enriched boric acid H₃BO₃ probably is -even at its much higher price and limited availability- the boron compound of choice in a nuclear power plant: highest concentration B-10, lowest concentration of accompanying elements (only O and H) and high purity due to its multi-step synthesis. And indeed therefore less high-grade NaOH or other base is needed for pH-adjustment.
I assume the purity requirements of the cooling water are very stringent. If the water after refueling/maintenance has to be made boron-free again by ion-exchange, smaller quantities are advantageous, even if the materials are more expensive.

Boric acid is NOT normally used in a BWR - certainly not in the primary system - and not in the spent fuel pool. The spent fuel structure contains boron in boral or boraflex.

Soluble boron in a BWR is introduced only in the case of emergency.

Soluble boron is used routinely in PWRs, and some used enriched boric acid. Some fuel design use enriched boron in ZrB₂ coating on fuel pellets in some fraction of fuel rods.

 

[ernal_student]

And what a stroke of luck that none of those blasted rsj's or roof panels or concrete panels ended up in the pool

With due respect, I have been asking myself, too. I am only a lay person, so all I can do is ask.
I have seen the images of the destroyed roofs on 3 reactors, and if I remember correctly someone had written in this forum that the pools are normally uncovered or just have a plastic cover.
How is it possible that only a few small items have fallen into a pool in a building that has exploded? In one case, did not a machine fall into a pool (I think that had been written in this forum)? There are only very few pictures that have been shown, it seems. How can one trust the information?

 

[MiceAndMen]

The technicians at the plant are citing the instabilities of the structure as a whole as causing worry about the SFP stability. From what I was told by a reliable source in the media is that this is a considerable worry, getting some sort of reinforcement under the SFP is a priority. This was before the building began leaning over.

Hi Nancy, glad you registered and started posting here. To my mind you're somewhat of a celebrity since you're the only one publicly named so far by the Japanese nuclear industry on their "internet enemies list". If it was me, I would wear that proudly as a badge of honor. I've been critical of some of your analyses on your website, but nevertheless am still glad you decided to join the conversations here. More data is always good and you seem to have some sources. Bringing more info to light will be good going forward in light of the reduced flow of photos coming out of Japan.

Considering the culture of Japanese business I think it's not unusual that some of your sources want to remain anonymous. Anonymous sources of information, however, will generate a fair amount of pushback here. Until their information can be corroborated by other sources they will not be given much weight.

With that said, I also don't think too much can be read into the "leaning tower of Fukushima" evidence presented thus far. The structural integrity of the unit 4 reactor building is a concern considering all the spent fuel in its pool, absolutely, but I don't think grainy long-distance pictures can be relied upon for proof. If the remaining concrete structure on the south side of building 4 came crashing down, taking the SFP with it, that would certainly be a very bad thing. But as of right now I just don't see it happening. It would be nice right about now if we could get a new set of high-res photos taken of the buildings at the Dai-ichi plant. Unfortunately I don't see that happening in the near future, either.

 

[MiceAndMen]

In one case, did not a machine fall into a pool (I think that had been written in this forum)? There are only very few pictures that have been shown, it seems. How can one trust the information?

I think you are referring to the Fuel Handling Machine from Unit 3. It was speculated here for a long time that it had been blown up into the air and landed near the northwest corner of its building. Later on there were photos (from the T-Hawk drone?) that showed it partially in the Unit 3 SFP. The FHM from Unit 4 is still standing and visible in many photos.

If they showed pictures of the Unit 3 SFP and it looked as clean as those from Unit 4 then I think a whole lot of people would jump on the TEPCO conspiracy bandwagon, but what we've seen from the Unit 4 SFP videos isn't all that surprising IMO.

 

[ernal_student]

I think you are referring to the Fuel Handling Machine from Unit 3. It was speculated here for a long time that it had been blown up into the air and landed near the northwest corner of its building. Later on there were photos (from the T-Hawk drone?) that showed it partially in the Unit 3 SFP. The FHM from Unit 4 is still standing and visible in many photos.

If they showed pictures of the Unit 3 SFP and it looked as clean as those from Unit 4 then I think a whole lot of people would jump on the TEPCO conspiracy bandwagon, but what we've seen from the Unit 4 SFP videos isn't all that surprising IMO.

I understand. So I have confused reactor 3 and reactor 4, sorry.

 

[ranchorelexo]

New temps for reactor 3.

http://www.tepco.co.jp/nu/fukushima-np/f1/images/032_1F3_05090600.pdf

 

[Jorge Stolfi]

Yes. We appear to have seen enough fuel racks to hold the recorded number of assemblies in the pool. Here is a rough lineout of the stacking in the pool, as much as can be gleaned from the two released videos.

How do you get the distance to the back wall? Could there be a wider gap there?

I cannot make out the far edge of the racks (beyond the fallen stair). Shouldn't there be a broader metal "lip" all around the rack (as there is on the near side)? Perhaps there is some large dark piece of debris over the fuel, just beyond the stairs?

Is the water in that part of the pool murkier than the rest (as if there were more bubbles there)? Or is it just that things are farther away in that direction?

 

[coolin'_down]

Thank you all for so much for this site and for all the information. I'm not a scientist but I've been listening to the briefings given by Tepco and NISA trying to keep track of the situations at Fukushima NPP. Though the situation is still very worrying and the many crude approaches taken by Tepco is surprising, I had never been alarmed enough to warrant posting in this site. To get to the point. Tepco just annouced that they will be putting Hydrazine into the spent fuel pool (I think in #1) to counter corrosion, but I read on wikipedia that Hydrazine is also used as rocket fuel! Is Hydrozine usually used in NPP?

 

[Jorge Stolfi]

And what a stroke of luck that none of those blasted rsj's or roof panels or concrete panels ended up in the pool,neat

In unit 4 the fuel-handling machine was parked over the spent-fuel pool when the explosion happened. Perhaps it caught most of the roof debris that would have otherwise fallen into the pool.

There is a video taken by a T-Hawk that peeks into one of the service floor "new windows" on the East side of Unit 4, looking at the yellow drywell cap parked near the opposite wall. Given the extension of the damage to walls and roof, there seems to be surprisingly little concrete rubble on the service floor.

The wall panels were blasted outwards, so it is no wonder that none is to be found inside. As for the roof,
someone suggestde that it may have been lifted by the explosion largely as a single unbroken sheet, which then fell down diagonally over the north end of the building, slicing through the northernmost row of roof girders and contributing to the damage of the north wall.

 

[rowmag]

Here's what Google Translate gives for the headers

Let me make a stab at improving a little on Google Translate (corrections welcome):

1. Temperature of Water Nozzle N4B
2. RPV base head (upper part)
3. RPV body flange
4.Temperature of lower part of pressure vessel
5. RPV stud-bolt temperature
6. RPV body flange (temperature of lower part)
7. Relief safety valve 2-71D Leakage
8. Relief safety valve 2-71F Leakage
9. Main steam isolation valve 2-86A Leak-off
10. D/W HVH return temperature
11. RPV bellows seal
12. S/C Pool water temperature A
13. S/C Pool water temperature B

 

[MiceAndMen]

In unit 4 the fuel-handling machine was parked over the spent-fuel pool when the explosion happened. Perhaps it caught most of the roof debris that would have otherwise fallen into the pool.

There is a video taken by a T-Hawk that peeks into one of the service floor "new windows" on the East side of Unit 4, looking at the yellow drywell cap parked near the opposite wall. Given the extension of the damage to walls and roof, there seems to be surprisingly little concrete rubble on the service floor.

The wall panels were blasted outwards, so it is no wonder that none is to be found inside. As for the roof,
someone suggestde that it may have been lifted by the explosion largely as a single unbroken sheet, which then fell down diagonally over the north end of the building, slicing through the northernmost row of roof girders and contributing to the damage of the north wall.

In the underwater SFP video, I think the metal staircase is from the fuel handling machine. It looks like a complete set of stairs with a handrail, not like it was separated from something else. The vertical distance seems to be appropriate for accessing some parts of the FHM.

 

[Jorge Stolfi]

Here is a rough lineout of the stacking in the pool, as much as can be gleaned from the two released videos.

The "round thing" may be an enclosure within the SFP that holds a fuel transportation cask while loading and unloading. That would be another version of the square concrete enclosure visible in the far left corner of the SFP in the photo of an unidentified japanese reactor (Unit #5?) attached.

Some blueprints/drawings (said to fit Unit #1) show a separate "cask-loading pool" between the equipment pool and the elevator shaft. Presumably in Units #2--#4 that separate pool was replaced by a smaller enclosure within the SFP.

 

[Jorge Stolfi]

Yes. We appear to have seen enough fuel racks to hold the recorded number of assemblies in the pool. Here is a rough lineout of the stacking in the pool, as much as can be gleaned from the two released videos.

Your sketch shows 30*(7+7+12+12+10)+40 = 1480 slots for fuel assemblies; perhaps there are another 60 in the blind corner at right. On the other hand, some slots seem to be empty.

Yet a previous post claims that there were (548 in-use + 1331 spent + 202 new) = 2081 assemblies in the pool. If that number is correct, then we are missing 500 to 600 assemblies. Seems a bit too much for roundoff error...

 

[ernal_student]

named so far by the Japanese nuclear industry on their "internet enemies list".

Where can one see such a list (of one person?)

 

[MadderDoc]

Your sketch shows 30*(7+7+12+12+10)+40 = 1480 slots for fuel assemblies; perhaps there are another 60 in the blind corner at right. On the other hand, some slots seem to be empty.

Yet a previous post claims that there were (548 in-use + 1331 spent + 202 new) = 2081 assemblies in the pool. If that number is correct, then we are missing 500 to 600 assemblies. Seems a bit too much for roundoff error...

Yes indeed. I was going with the figure 1331 assemblies in storage, by March 2011, according to this source.
http://progressivelever.com/2011/03/22/more-on-spent-fuel-pools-at-fukushima/

 

[yakiniku]

New temps for reactor 3.

http://www.tepco.co.jp/nu/fukushima-np/f1/images/032_1F3_05090600.pdf

Do we have corresponding information regarding the pressures and radiation levels in reactor 3?

Would someone be able to comment at what temperature would things become a concern? The values look high but what is considered 'okay', 'normal' or 'abnormal'?

 

[AntonL]

Your sketch shows 30*(7+7+12+12+10)+40 = 1480 slots for fuel assemblies; perhaps there are another 60 in the blind corner at right. On the other hand, some slots seem to be empty.

Yet a previous post claims that there were (548 in-use + 1331 spent + 202 new) = 2081 assemblies in the pool. If that number is correct, then we are missing 500 to 600 assemblies. Seems a bit too much for roundoff error...

it is 1331+202 = 1533 fuel rods
548 in use is included in 1331

 

[Jorge Stolfi]

Yes indeed. I was going with the figure 1331 assemblies in storage, by March 2011, according to this source.
http://progressivelever.com/2011/03/22/more-on-spent-fuel-pools-at-fukushima/

OK, so the 1331 figure includes both in-use and spent. But what about the new assemblies? Several sources give "1331 + 204 new = 1535", e.g.

http://www.ken-zo.com/wp-content/uploads/METI Japan-challenges_full.pdf

It is quite possible that they got it wrong too. But google finds >20,000 hits for Fukushima Daiichi 1535...

 

[MiceAndMen]

Where can one see such a list (of one person?)

A Japanese news story from 27 April says TEPCO doesn't like what Nancy has on her website.
http://www.asahi.com/english/TKY201104260122.html

This is like Sony trying to blame the Anonymous hackers for their own incompetence. Sony was running unpatched web servers without a firewall. Solution? Blame someone else.
http://www.reuters.com/article/2011/05/04/sony-idUSN0422224820110504
http://consumerist.com/2011/05/secu...re-was-obsolete-months-before-psn-breach.html

If Nancy made TEPCO angry then she must be doing something right. That's why I support what she's trying to do on her website even though I disagree with a lot of her analysis and conclusions. I hope she sticks around here as we all try to learn from each other and piece together what has happened, and what is happening at the Dai-ichi plant.

 

[fluutekies]

it is 1331+202 = 1533 fuel rods
548 in use is included in 1331

That are my figures:

1331 used + 204 unused = 1535 assemblies in SFP4

http://www.iaea.org/newscenter/news/tsunamiupdate01.html
[Fukushima Nuclear Accident Update (22 March 2011, 18:00 UTC)]