Japan Earthquake: Nuclear Plants at Fukushima Daiichi

In summary: RCIC consists of a series of pumps, valves, and manifolds that allow coolant to be circulated around the reactor pressure vessel in the event of a loss of the main feedwater supply.In summary, the earthquake and tsunami may have caused a loss of coolant at the Fukushima Daiichi NPP, which could lead to a meltdown. The system for cooling the reactor core is designed to kick in in the event of a loss of feedwater, and fortunately this appears not to have happened yet.
  • #5,041
sp2 said:
Anybody see this?

http://www.asahi.com/national/gallery_e/view_photo.html?national-pg/0426/TKY201104260415.jpg

If this is legit, it looks like confirmation of a lot of worst fears.
We're going to end up with a very big exclusion zone --even if they're lucky, and nothing goes horribly wrong in the next year or so (in spite of the fact that neither the Media nor the Markets seem to give a rat's rear.)

Anyone?

Can't say I am surprised. Persistent inland winds haven't even started. Taifun season coming. Doesn't bode well at all.
 
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Engineering news on Phys.org
  • #5,042
AntonL said:
(April 23) To any physicist or engineer it is obvious that SFP4 with an estimated heat load of 2 to 2.4MW is boiling at a rate of about 60-80 tonnes a day - why the bleep tepco cannot say the same, instead they measure the temperature in the furthest corner as close as possible to the wall to show it is 91 degrees and prove that it is not boiling and to state water is lost to evaporation due to the high temperature. I can only think that a boiling radioactive soup is bad PR as it is obvious the amount of contamination carried into the atmosphere is very high. If Tepco really did their job properly then the minimum amount of water would be injected into the pool and have one headache less of what to do with the many tonnes of water spilled every day that needs to stored and decontaminated at high cost. It has been boiling since March the 13th. (https://www.physicsforums.com/showthread.php?p=3244793&highlight=boil#post3244793")

To loose 140 to 200 tonnes of water per day either means that heat load is higher than estimated or the pool has a leak.

(April 27) http://www3.nhk.or.jp/daily/english/27_09.html"
[PLAIN said:
http://www3.nhk.or.jp/daily/english/27_09.html]The[/PLAIN] operator of the troubled Fukushima Daiichi nuclear power plant says water may be leaking from the spent fuel pool of the No. 4 reactor.

We said it earlier

and below confirms my calculation
[URL said:
http://www.asahi.com/national/update/0427/TKY201104270199.html;]Evaporation[/URL] is estimated at 70 tons of fuel a day
 
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  • #5,043
It's really quite surreal.

The Media, the Markets, and the general Populace seem to have decided this is all a minor nuisance.

And to those of us (precious few of us, apparently) who have eyes and a functioning cortex, and can read, the facts on the ground just look worse and worse as each day goes by.

It's like living in a Max Frisch book, or something. Incredible.
 
  • #5,044
sp2 said:
It's really quite surreal.

The Media, the Markets, and the general Populace seem to have decided this is all a minor nuisance.

And to those of us (precious few of us, apparently) who have eyes and a functioning cortex, and can read, the facts on the ground just look worse and worse as each day goes by.

It's like living in a Max Frisch book, or something. Incredible.

That all depends on what you consider a "minor nuisance".

In the grand scale of the whole world, it IS just a minor nuisance. For someone who is injured due to the incident it is a major ordeal.

Just because some people disagree with your outlook doesn't make your view the correct one.
 
  • #5,045
htf said:
If the Japanese had disclosed their all their data there wouldn't be so much speculation.

I have the growing feeling that TEPCO has a lot to hide. It has been explained with cultural differences that TEPCO has rejected any help by foreign expert. Maybe so. But maybe they have to hide some "special industrial secrets" like the extra cooling system for SFP#4 that Jorge Stolfi may have discovered.

The explosions have been discussed here back and forth - I didn't follow this discussion in detail. Are there any estimations how much energy during explosion of unit #3 has been released?

In early posts in this thread and forum there were the calculations of the amount of heat available in the single fuels but that is all Greek to me besides results having to be multiplied by thousands of tons of fuel involved. I read the common spent fuel pond (long term solution because there is nowhere else for storing) is holding more fuel than all the Units 1 thru 6 combined albeit less potent relatively speaking but apparently has avoided any debris hits or water loss.

From http://www.theoildrum.com/node/7706#comment-783191"
Seraph on March 26, 2011 - 2:17pm Permalink | Subthread | Parent | Parent subthread | Comments top


Taking your calculation a little farther.

[A yield of 2.878% would amount to a related fission of 1.31 Kg of uranium 235]

If fuel rods are enriched apprx 3% U235. Then 1.31 Kg U235 becomes apprx 43 Kg of fuel pellets (or apprx 100 lb)

Assume shore current is conservatively 2 mi/hr then the isotopic product of the fuel pellets passing the collection point would have to be replaced 10 times per hour.

This would mean that the fission products of half a ton of fuel pellets/hr (1000 lb/hr) are being swept past that collection point.

That translates into the product of 12 tons of fuel pellets/day flushing into the sea.

*Please excuse the rounding errors - I didn't use a conversion table

To the listing of all the unknowns, the only thing really unknown is the severity of the tragedy.
 
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  • #5,046
sp2 said:
It's really quite surreal. The Media, the Markets, and the general Populace seem to have decided this is all a minor nuisance. And to those of us (precious few of us, apparently) who have eyes and a functioning cortex, and can read, the facts on the ground just look worse and worse as each day goes by. It's like living in a Max Frisch book, or something. Incredible.

I think Asahi is using a NNSA's document released a week ago about. (available a few pages back)it's a year dose, estimate, refer to the document for full details.
Accumulation make radiation dose more dangerous but are somewhat predictable, new event/failure may as well and are less predictable. I prefer a situation getting predictably worse than one unpredictably worse as it has been the case for the past two/three weeks.It is in my opinion easier to manage as far as public safety is concerned.
 
  • #5,047
AntonL said:
Tepco released a new video of taken by T-Hawk on 21.4.2011 flying between the reactors and turbine buildings from unit 1 to unit 4, can be downloaded here http://www.tepco.co.jp/en/news/110311/images/110427_thawk.zip


and new photos released of Site observation by the packbot in the nuclear reactor building of Unit 1
(pictured on April 26, 2011)

Nearby the entrance of SHC pump room
http://www.tepco.co.jp/en/news/110311/images/110427_packbot_1.jpg

Observation of the pressure gauge of the primary containment vessel
http://www.tepco.co.jp/en/news/110311/images/110427_packbot_2.jpg

Check of the leakage from the electrical penetration
http://www.tepco.co.jp/en/news/110311/images/110427_packbot_3.jpg

Check of the leakage from the equipment hatch
http://www.tepco.co.jp/en/news/110311/images/110427_packbot_4.jpg

note the guy at the left he is radiation hardened,
picture released 26.04.2011 of Remote-controlled crawler dump (pictured on April 15, 2011)
http://k.min.us/ilrN2q.JPG
all above and earlier released photos and videos are here http://www.tepco.co.jp/en/news/110311/index-e.html

They're continuing to release material of low value and quality. That T-Hawk video is a joke. They're probably using the T-Hawk everyday and use its IR-camera, too. Getting to see a few more details of the east side of the buildings is okay, but there's not much to see there, really. And it's stuttering. Similarly with these tiny packbot pictures. It's as if they release it so the press has something to show. From media perspective, the released material doesn't differ from previously released material and thus is of low value (in addition to being low quality!). It's as if they want to bore the media into not showing more about Fukushima.

I'd like to see the SFPs up close, same with the inside of #4's service floor, and if they can manage, the drywell lid over #3. They have bots to do that, what's the issue?
 
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  • #5,048
MiceAndMen said:
I remember something similar. Here's a TEPCO press release from 14 March that says they were considering venting hydrogen from Unit 2 through the wall.
http://www.tepco.co.jp/en/press/corp-com/release/11031405-e.html

The only thing I can find right now that says they actually did cut a hole in the wall (on 14 March) is this summary written by David Biello, an associate editor at Scientific American:
http://e360.yale.edu/mobile/feature.msp?id=2385

Biello says, that they removed the panel on March 14th -- Tepco says, that -- in the light of the explosion on the 12th and 14th in unit 1 and 2 -- they considered doing it on March the 14th. Both statements are false.
Photograps taken by Digitalglobe at about noon March 13th clearly shows the panel missing on the building, and its lying at the foot of the east face of the building.
 
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  • #5,049
MadderDoc said:
Biello says, that they removed the panel on March 14th -- Tepco says, that -- in the light of the explosion on the 12th and 14th in unit 1 and 2 -- they considered doing it on March the 14th. Both statements are false.
Photograps taken by Digitalglobe at about noon March 13th clearly shows the panel missing on the building, and its lying at the foot of the east face of the building.

You are, of course, correct. They will say, "We meant another kind of venting through the wall."

Someone should ping Biello about this fact. Especially since this site is part of the Scientific American Partner Network.
 
  • #5,050
sp2 said:
Anybody see this?

http://www.asahi.com/national/gallery_e/view_photo.html?national-pg/0426/TKY201104260415.jpg

If this is legit, it looks like confirmation of a lot of worst fears.

Hm... please don't beat me now, but for me it looks like the contrary. First, half of the 20km zone and over two thirds of the 30km zone are below 20 mSv/a.
And the "hotspot zones" are at a maximum of 100-200 mSv/a. That's not a "death zone" (as depicted in german media) but an "increased cancer disease zone".
That's still bad, but not as worse as I would've thought... recovering of personal items should be possible and there's no haste with an evacuation.

Here are some numbers I found in a german study regarding a catastrophic nuclear accident. There are always two numbers. The first one is a recommendation, the second one is obligatory:

Measures in case of radioactive clouds immeadiatly after the accident:

Stay indoors: 5 mSv / 50 mSv
Evacuation: 100 mSv / 500 mSvRelocation (ground radiation accumulation during one year):

Relocation: 50 mSv / 250 mSvhttp://www.biu-hannover.de/atom/unsicher/teil2.htmSo you could say that the japanese government is playing on the safe side with its evacuations. Which is, of course, not the worst thing they could do.

Just to compare: In Gurapari (Brazil) at the beach you have natural radiation of up to 90 mSv/a, in Ramsar (Iran) at certain hot springs there's a natural radiation of up to 260 mSv/a.

The Fukushima accident could have been much, much worse. Believe it or not, but the japanese have been lucky. Only a tiny fraction of the cores escaped. And only a tiny fraction of this tiny fraction landed on japanese territory, most of it diluted over the pacific.
Imagine what would've happened if we were in the taifun season, as already mentioned before...
No chance to repair anything in those violent winds and the radioactivity would've been distributed all over japan.Btw, has anyone the original map from the ministry of science? Thanks.
 
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  • #5,051
there's some ground activity info here:-

 
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  • #5,052
clancy688 said:
The Fukushima accident could have been much, much worse. Believe it or not, but the japanese have been lucky. Only a tiny fraction of the cores escaped. And only a tiny fraction of this tiny fraction landed on japanese territory, most of it diluted over the pacific.
Imagine what would've happened if we were in the taifun season, as already mentioned before...
I hope they will nevertheless learn their lesson. Considering their history of nuclear accidents I am not too optimistic. But this is up to the Japanese people.
 
  • #5,053
http://www.bloomberg.com/news/2011-04-27/tokyo-water-radiation-falls-to-zero-for-first-time-since-crisis.html

oh dear,..... though they don't really give much away... again!

Yokoso news is a ustream channel, occasionally updating the info they get through various sources.

trys starting at 51 minutes if you have time to listen... don't know if he says anything we don't already know.

http://www.ustream.tv/channel/yokosonews
 
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  • #5,054
TEPCO has revised the estimated fuel damage in the No.1 reactor from 70 percent to 55 percent, saying radiation levels were not correct.

TEPCO also says that it acted inappropriately in excluding fuel damage of less than 5 percent in calculating total damage ratios for the No.2 and No.3 reactors.

As a result, the utility revised upward its estimates of damaged fuel in the No.2 and No.3 reactors by 5 percentage points each to 35 percent and 30 percent respectively.
http://www3.nhk.or.jp/daily/english/27_28.html

:rolleyes: :uhh:

I would have estimated 50-75%. Units 3 and 1, which operated slightly longer, could have greater percentage than Unit 2. Burnup distribution is the unknown here. Unit 1 has 400 assemblies, while Units 2 and 3 have 548 assemblies.
 
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  • #5,055
more interesting would be to know why and how they come to the conclusion that there primary assessment was excessive
 
  • #5,056
|Fred said:
more interesting would be to know why and how they come to the conclusion that there primary assessment was excessive

The previous assessment probably wasn't approved by the management.

Same with the 134I-figures that were declared "impossible".
 
  • #5,057
From one of the site radiation maps, I have assembled the layers beneath, i.e. the plant layout map, at:
http://gyldengrisgaard.dk/fuku_docs/plant/

Using this map, I think I can now point to the position of the two common control rooms, for unit 1+2, and unit 3+4 respectively. (Not unexpectedly, I find them spanning across the junction walls between the matching turbine buildings.)
 
  • #5,058
Astronuc said:
http://www3.nhk.or.jp/daily/english/27_28.html

:rolleyes: :uhh:

I would have estimated 50-75%. Units 3 and 1, which operated slightly longer, could have greater percentage than Unit 2. Burnup distribution is the unknown here. Unit 1 has 400 assemblies, while Units 2 and 3 have 548 assemblies.
what i find somewhat scary is that they don't ever give numbers like 50-75% , never as range. It makes no sense. Plus they always have it very precise. 55% is not really a round number or a ratio, and there is no way they know it to accuracy of 5%.
This is really not a good sign IMO.
 
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  • #5,059
Dmytry said:
what i find somewhat scary is that they don't ever give numbers like 50-75% , never as range. It makes no sense. Plus they always have it very precise. 55% is not really a round number or a ratio, and there is no way they know it to accuracy of 5%.
This is really not a good sign IMO.

That's what I'm saying. They design their output to calm the media and the public. This is managers doing disaster management - for PR.

We really don't know anything other than what we can see in pictures.
 
  • #5,060
MadderDoc said:
From one of the site radiation maps, I have assembled the layers beneath, i.e. the plant layout map, at:
http://gyldengrisgaard.dk/fuku_docs/plant/

Using this map, I think I can now point to the position of the two common control rooms, for unit 1+2, and unit 3+4 respectively. (Not unexpectedly, I find them spanning across the junction walls between the matching turbine buildings.)

Nice map have you got the complete map ? or just the extract you givenT/B turbine building
R/B reactor building
If C/B = control building then there is no common control room for unit 3 and 4 they are just next to each other
remember unit 4 was build after unit 3 and there would be no way that the adjoining walls or even a door be knocked into a working control room.
[PLAIN]http://k.min.us/infM52.JPG
 
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  • #5,061
ascot317 said:
They're continuing to release material of low value and quality. That T-Hawk video is a joke. <..>

Now, now.. Rather enjoy some extra candlelight (however tiny it might be) than curse the darkness :-) I admit, this video stutters distractingly. However, the keyframes are actually pretty good, and they depicture objects we have not had a good view of before, from a so far unseen angle, and with a resolution down to a few centimeters at its best. And , it is _very_ well shot by the operator of the THawk, I must say, I bet he has been on a steep learning slope.

I am actually quite excited by this new video, and thankful to Tepco for making it available. I am not at all through with studying it. Colors of the m1v video from the Tepco website did not make it on my system, but there are perfect coloring flv versions on Youtube and other sites, e.g
 
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  • #5,062
Dmytry said:
what i find somewhat scary is that they don't ever give numbers like 50-75% , never as range. It makes no sense. Plus they always have it very precise. 55% is not really a round number or a ratio, and there is no way they know it to accuracy of 5%.
This is really not a good sign IMO.

they have their formulas and diagrams, put some data in and report the result. not a very scientific approach...

estimation of core-damage:
http://www.iaea.org/ns/tutorials/regcontrol/refs/29generic.pdf

they either don't have reliable data (only the data they released, which are very sparse especially for #1), or they keep the data secret (not very likely).

no matter how i extrapolate the existing data and use the techniques described in the doc above: its always 100% core damage for #1 - of course with a high element of uncertainty...

the correct way to report the result might be: core damage is 50 ±50 % ;-)

i would really like to see their calculations.
 
  • #5,063
Dmytry said:
what i find somewhat scary is that they don't ever give numbers like 50-75% , never as range. It makes no sense. Plus they always have it very precise. 55% is not really a round number or a ratio, and there is no way they know it to accuracy of 5%.
This is really not a good sign IMO.

Wouldn't there be more criticism over a range of 50% to 75%?
 
  • #5,064
AntonL said:
Nice map have you got the complete map ? or just the extract you given

This map shows only the coast-near southern half of of the plant. The inland areas would be on other maps, and so too would the northern part of the plant, where unit 5 and 6 are situated, but of that I have only a few useless blurry fragments.

<..>C/B = control building then there is no common control room for unit 3 and 4 they are just next to each other<..>

That's right, on the drawing, they are. So, to produce the common control rooms they just had to remove a few walls. :-)
 
  • #5,065
MadderDoc said:
Now, now.. Rather enjoy some extra candlelight (however tiny it might be) than curse the darkness :-) I admit, this video stutters distractingly. However, the keyframes are actually pretty good, and they depicture objects we have not had a good view of before, from a so far unseen angle, and with a resolution down to a few centimeters at its best. And , it is _very_ well shot by the operator of the THawk, I must say, I bet he has been on a steep learning slope.

I am actually quite excited by this new video, and thankful to Tepco for making it available. I am not at all through with studying it. Colors of the m1v video from the Tepco website did not make it on my system, but there are perfect coloring flv versions on Youtube and other sites, e.g


Basic operator training for the T-Hawk costs somewhere >100k$ afaik, so that course better pays off.

The trouble I have with these releases is: they hopefully utilize the T-Hawk and the packbots every day. Yet, what the public get to see is, like you say, a candle-light. There should be a whole lot more information available.

I know that how much information should be released during a disaster is controversial. My view on this is: the more the better. Cranks will always make their own theories, no matter how much information gets released (see e.g. the still debated theory of a "nuclear fission explosion" in #3). But with more information available, experts have more leverage. If its not the case, well... more questions, less answers. Cranks will always give answers. The media likes answers better, so the cranks win.

Additionally, withholding information undermines the trustworthiness of a company. The damage is already done, there's no PR battle to be won for Tepco. They can only worsen their position.

I'm working on a merged version of the t-hawk footage (photomerge), but apparently my workstation is running on faulty ram, blegh.
 
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  • #5,066
Trying to make a theory what's happening in the unit 4 (I guess there is now enough information/speculations):

1. Some of the fuel in the SFP may have been damaged:

http://www.world-nuclear-news.org/RS-Most_fuel_in_Fukushima_4_pool_undamaged-1404117.html

2. Because of the damaged fuel there might be radiation in the water:

http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110414e20.pdf

The maximum as mSv/h has been 84 so far, from 6 meters above SFP:

http://search.japantimes.co.jp/cgi-bin/nn20110413x1.html

The radiation level 6 meters above the spent-fuel storage pool at the crippled Fukushima No. 1 nuclear plant was measured at 84 millisieverts per hour Tuesday.

3. The contaminated water may be leaking:

http://www3.nhk.or.jp/daily/english/27_09.html

4. The polluted water may find its way into the turbine building and from there into the basements.

5. The basement contains water from the tsunami.

http://world-nuclear-news.org/RS_Deaths_confirmed_at_Fukushima_Daiichi_0304111.html

Similar basement levels of other reactors on the site have been found to be flooded, possibly by tsunami water flowing through cabling trenches close to the seafront.

http://www.dailymail.co.uk/news/art...-plant-months-control-2-deaths-confirmed.html

They apparently ran into a basement turbine room, which is where they were when the massive wave swept over the plant.

6. The level of water in the basement was just recently +5 m, some of it might be the tsunami waters which is now mixed with the SFP cooling waters:

http://www.asahi.com/english/TKY201104190193.html

Officials of the Nuclear and Industrial Safety Agency (NISA) said April 18 that a pool of water about five meters deep had been found in the basement of the building housing the No. 4 reactor.

7. Another route into the basement might be from the unit 3's turbine building because unit 3's and 4's turbine buildings are connected.

8. Because the tsunami waters have mixed with the cooling waters there is radiation in the basement:

http://www.asahi.com/english/TKY201104190193.html

Radiation levels as high as 100 millisieverts per hour were detected on the water's surface.

9. The contaminated water may infiltrate through the concrete into the sub-drain of unit 4 which as a result would be low-level or middle-level contaminated:

http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110426e15.pdf

And now a question for the real experts: From the recent sub-drain radioactive concentrations we can see that levels are dropping in the sub-drain of unit 4. If this radiation is ultimately coming from the unit 4's SFP (or at least most of it) what does this actually mean? I think it is a good sign?
 
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  • #5,068
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  • #5,069
WhoWee said:
Wouldn't there be more criticism over a range of 50% to 75%?
not from me. I'd rather they give a range than give unrealistically 'accurate' numbers and then change them arbitrarily. It is highly unscientific, and imo bad for disaster mitigation as well, not to know the ranges. In disaster mitigation you have to address the range of possibilities rather than a single number. Same for the safety.
 
  • #5,070
Dmytry said:
what i find somewhat scary is that they don't ever give numbers like 50-75% , never as range. It makes no sense. Plus they always have it very precise. 55% is not really a round number or a ratio, and there is no way they know it to accuracy of 5%.
This is really not a good sign IMO.

The problem is that they have PR guys in charge of...PR.

The guys who actually know what they are doing:
a) are busy, and
b) have no respect for the PR guys, and see it as a waste of time to try to educate them.
 
  • #5,071
MadderDoc said:
I have updated the page at http://gyldengrisgaard.dk/fuku_docs/plant/

It now includes maps of the northern as well as of the southern part of the Daiichi plant.

For those others who, like me, may be somewhat perceptually impaired (and not red-green color blind), here are the roof lines of the reactor buildings and turbine buildings . . .
 

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  • #5,072
Gunderson on the unit 3 explosion.

 
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  • #5,073
Dmytry said:
not from me. I'd rather they give a range than give unrealistically 'accurate' numbers and then change them arbitrarily. It is highly unscientific, and imo bad for disaster mitigation as well, not to know the ranges. In disaster mitigation you have to address the range of possibilities rather than a single number. Same for the safety.

I understand your complaint and think rowmag makes a good point.
 
  • #5,074
Guest Member said:
I'm not sure if this was posted already. Sorry if it was.
Blueprint - http://www.houseoffoust.com/fukushima/blueprint.html

Even if it was it's good to have again... I've gone back to look for things in this thread and it's taken AGES to find!
 
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  • #5,075
TCups said:
For those others who, like me, may be somewhat perceptually impaired (and not red-green color blind), here are the roof lines of the reactor buildings and turbine buildings . . .
Cheers, that's much clearer!
 

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