Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[rowmag]

Here is the link http://www.ustream.tv/recorded/14641270 I welcome translation insight
if it has been said it was there, I expect more today

Just listened to a bit at the beginning, but as Jim Lagerfeld summarized, the water level is unmeasurably low in the pressure vessel, and below the original bottom of the fuel. There must be some cooling going on, though, or the pressure vessel temperatures would be higher than they are.

As for the containment vessel, they can measure pressures there, but not water levels (pressure gauges are not meant for that job), and do not know what the water level in there is. As for where all the water that has been pumped in has gone, they don't know. There may possibly be a leak into the Unit 1 building.

Sound quality is bad, but I don't think I heard a clear statement that there is no water in the containment vessel, just that they don't know what the water level is. Did anybody else catch a clearer statement on that?

 

[elektrownik]

Can low water level can be connected to radiation spike and sensor faliture in unit 1 ? Some days ago sensor jump to 80Sv/ and then die (or they don't give data because it is too bad)

 

[AntonL]

1- if what used to be the core in N°1 has totally relocated at the bottom of the RPV, how can all the parameters given by TEPCO be interpreted? Total BS?

2- the same question applies to the 2 other reactors (2 and 3): are this parameters relevant to assess the situation or can it be considered like for N°1 as total BS? Then i have to admit that one of the "proofs" that N°3 reactor was still there in a "close to normal shape" is clearly weakened because of this revelation...

It may be BS and if it is then Tepco will become the laughing stock of the world and the question should then be asked if that disqualifies them to operate any nuclear plant, however:

1- Even if the core is not fully submerged it is continually being sprayed by water, is this enough to keep the core intact and stopping it collapsing into a pool of rubble. So part core collapse is feasible I think.

2- reactor 3 is more problematic, its bottom temperatures are around 150 degrees C with no indication of dropping even if water spraying has increased.

 

[PietKuip]

Just listened to a bit at the beginning, but as Jim Lagerfeld summarized, the water level is unmeasurably low in the pressure vessel, and below the original bottom of the fuel. There must be some cooling going on, though, or the pressure vessel temperatures would be higher than they are.

Cooling has been by spraying, by a flow. It has always been clear that water was disappearing.

Michio Ishikawa was right: http://ex-skf.blogspot.com/2011/04/fukushima-i-nuke-plant-ishikawa-of-jnti.html

 

[rowmag]

また、外側の格納容器にもほとんど水がたまっていないことが、政府関係者への取材で分かりました。原子炉に水を入れる作業は続いていますが、水は格納容器の外に漏れている可能性が高いということです。

Literal translation:

Also, it was found through an interview with the government officials that outside of the containment vessel there is almost no water.

Although the process of injecting water to the reactor is continuing, it is a high possibility that the water is leaking to outside the containment vessel.

They use the word 格納容器 "containment vessel" which doesn't make sense. I would have thought they should have used 圧力容器 "pressure vessel".

The containment vessel is what surrounds the pressure vessel. So they are saying that according to the government official, there is also almost no water in the containment vessel, which is on the outside of the pressure vessel. They will keep pouring water in, but there is a possibility that water may also be leaking out of the containment vessel.

 

[htf]

Anyway, this 'no water' scenario is not consistent with any other data available (temperature, radiation, pressure) so I think that this one (two) instrument(s) gone mad and not all the others.

When I look at the history of this accident and the TEPCO announcements there is only one conclusion that I can draw:

TEPCO has no idea about the state of the reactors. All reported data is questionable. The worst scenario is the most likely!

I don't know whether they were just extremely optimistic and did not want to face the truth or they knew better but knowingly reported misleading data.

It won't surprise me if they will report in a few weeks the the RPVs have holes and that the melted cores have escaped from the RPVs.

 

[AntonL]

Can low water level can be connected to radiation spike and sensor faliture in unit 1 ? Some days ago sensor jump to 80Sv/ and then die (or they don't give data because it is too bad)

some days ago it was 8th April, Cams peaked to over 180Sv/h before falling and then discarded. That same day was also a temperature peak see https://www.physicsforums.com/showpost.php?p=3291622&postcount=6305"

 

[|Fred]

I've overlay and added some labeled

I do believe that we can see an original steel structure between A and B
It is my perception the "arc" aka green path between A and B is not a deformed formely mention AB steel structure.
But my main point of attention is in the bottom view , I've highlighted white metalic structure, perspective might be a bit hard to see from this angle but the right picture might help you

[AD] and [BC] are part of the double layered East West metallic structure the double layer is Pink on top blue at the bottom with some reinforcement in white between the Two layer
[AD] and [BC] are link by dual layer cross bars

I think that the pictures show that [BC] is twisted and is falling abruptly to the pool, I also think that there are remains of the cross bars covering . I do not believe that the damage we see could have been cause by a circular exiting object . I do believe that some of the damage to the crossbar was done by the [BC] structure . I do not know what cause the [BC] structure to twist / break /wall , might have been by an interaction between FHM and its Crane


[PLAIN]http://i.min.us/ikY3PY.jpg

 

[GJBRKS]

It may be BS and if it is then Tepco will become the laughing stock of the world and the question should then be asked if that disqualifies them to operate any nuclear plant, ...
.

Wouldn't then this be a perfect setup for dismantling the company known as TEPCO ?

Could this be part of the information war ?

If you can't control the situation , control the flow of information ?

Create confusion ?

Because this news amounts to the equivalent of several stun- tear - flash -and smokebombs combined ...

ESPECIALLY if they backtrack on this data ...

If not then I wonder about the state of ALL the other readings ...

 

[zapperzero]

I think the questions to be focused on in the case of reactor 1 are not "where is the water and where is it going" but rather "where is the corium and how hot is it" if we are to get a reasonable picture of what happens next.

"How can it be directed to where it would do the least amount of harm" seems also to be worthwhile question, but not for us, for those fighting this battle.

I for one am not optimistic, given that instrumentation on the bottom of the RPV has failed a long time ago. April 8? Who knew a meltdown could be so slow?

 

[elektrownik]

Unit 3 is 283C now and increasing...
Also 2nd unit 3 sensor jump from 156 to 203C

 

[PietKuip]

I think the questions to be focused on in the case of reactor 1 are not "where is the water and where is it going" but rather "where is the corium and how hot is it" if we are to get a reasonable picture of what happens next.

The water must have leached an enormous amount of radioactive isotopes from the fuel, so its path is also interesting. And if the outflow is in the bottom, the current could also have carried pieces of corium with it.

 

[|Fred]

i see that "moderate" members start to be upset by what they discover weeks after weeks... Stay scientific and have a rational approach of things as much as possible, this understandable desire would be, as things will developped, undermined by the fact that the infos, on which we base most of our efforts and reflexions.
So my point is: how can people like us think of being able to do a good or even satisfactory scientific work based on sources that are in fact so unreliable and weak? I have my own answer from the beginning (time will prove if I was wrong or right) but I let people here meditating about this...

I do not think that a rational approach is undermined by weak data. As I use to be told geometry is the art of thinking out of false drawing. The idea not to make the theory fit the data. Does the actual adjustment, makes more sens ? Explain a gray area in the formally postulated hypothesis leading to and other hypothesis or does it makes thicken the plot ?
I think better usually comes from decisions based on reasoning (although the reasoning might be wrong) rather than on a 50/50 bet.

 

[GJBRKS]

Unit 3 is 283C now and increasing...
Also 2nd unit 3 sensor jump from 156 to 203C

Could you please provide links to your source when announcing these data ? (As there are 13 temp readings per unit)http://www.tepco.co.jp/nu/fukushima-np/f1/images/032_1F3_05121300.pdf

 

[zapperzero]

The water must have leached an enormous amount of radioactive isotopes from the fuel, so its path is also interesting. And if the outflow is in the bottom, the current could also have carried pieces of corium with it.

I could not care less. The sea is where the fishes and a couple dozen discarded nuclear reactors live (I'm not talking only subs, the Russians dumped massive amounts of effluent from their plutonium separation plants into the sea). Plankton won't die from a few pCi/l more, the whales could use a 60-year moratorium on fishing. We live on land. A big fire or steam explosion means China gets a sizeable dose, while Japan gets cut in half.

Corium flowing into that lagoon? Meh. Think corium coating 80% of the world's chip foundries.

 

[AntonL]

Can low water level can be connected to radiation spike and sensor faliture in unit 1 ? Some days ago sensor jump to 80Sv/ and then die (or they don't give data because it is too bad)

some days ago it was 8th April, Cams peaked to over 180Sv/h before falling and then discarded. That same day was also a temperature peak see https://www.physicsforums.com/showpost.php?p=3291622&postcount=6305"

Evidence of Earthquake Susceptibility of the Reactors


Evidence 1
On 7th April there was a reported 7.1 (some say 7.4) north of Fukushima that also shook Tokyo. http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/usc0002ksa.php
[PLAIN]http://k.min.us/ilcuMS.JPG

and look what happened to the CAMS reading from 30 to 100 to 187
[PLAIN]http://k.min.us/ikY1Ys.jpg
Now with all the information we have today leak sprung in the reactor vessel releasing very radioactive water.

Evidence 2
On May 1^st, 11.48AM A 4.8 earthquake struck 9.5km from Fuskushima NPP
http://neic.usgs.gov/neis/bulletin/neic_kjal.html
[PLAIN]http://k.min.us/ikXLzM.JPG

after that the temperature in the reactor 3 rose, something changed!
[PLAIN]http://k.min.us/ilcVfi.JPG

I believe two earthquake events and two changes from the steady state reactor parameters is proof enough to make the statement that the damaged Fukushima reactors are susceptible to Earth quakes, and is a very worrying thought for trying to get fukushima under control.

Edit: After Borek's comment https://www.physicsforums.com/showpost.php?p=3297660&postcount=6831"

 

[clancy688]

Unit 1 remains a mystery for me. During the last few hours, some questions popped up...

Here's the NHK news regarding the Unit 1 water leak: http://www3.nhk.or.jp/daily/english/12_23.html

On Thursday morning, it was found that the water level was more than one meter below the bottom of the fuel rods, suggesting a large volume of water is leaking into the containment vessel.

The utility company also believes that the water is leaking from the containment vessel into the reactor building. This is because the estimated volume of water inside the containment vessel appears to be less than what leaked into it from the reactor.

Tokyo Electric says temperatures at the bottom of the reactor are between 100 and 120 degrees Celsius, suggesting that the fuel has fallen and is being cooled in the water below.

The utility says it does not believe the fuel has completely melted and spilled through the bottom of the reactor. It adds that instead, the fuel appears to be being cooled inside the reactor.

I didn't thought about it first, but that means that not only the water level sensor is malfunctioning, but another sensor as well - the pressure sensor.
Stolfis Plots ( http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/plots/cur/plot-un1-full.png ) were showing contant water levels and rising pressure for Unit 1.
Now we've learned that Unit 1 is leaking, both RPV and containment. If there's a leak, the RPV pressure will very unlikely rise significantly over atmosphere level.

A user raised doubts that the whole molten core could relocate in the bottom of the pressure vessel. I have no idea how big (in m³) the area 1m below the bottom end of the fuel rods is, and I also have no idea how much space (in m³ again) the whole core in corium form needs. It would be nice if someone, who has the needed numbers, could calculate this.
Even if there would be enough space for a fully molten core, it would be impossible to cool it down. The water could only reach the corium's surface, not the hot core.

Moreover, TEPCO stated that the bottom of the RPV is only slightly over 100 degree °C hot. But if the core's really relocated to the bottom, there's nothing between the hot corium and the steel. And then it's only 100 degrees hot? I can't believe that.

Since today we know that the RPV and the containment are breached. Water's disappeared and TEPCO doesn't know where it went. Perhaps the Houdini Unit 3 is getting acquaintance. If it went to the sides, TEPCO would have discovered it, as with the water leaks from Units 2 and 3.
So in my opinion, that leaves the only direction where TEPCO has no eyes - down.
What, if part of Unit 1s fuel got uncovered and melted, dropping to the bottom and compromising the RPVs integrity. It burned a hole into the RPV, which's now leaking. Water is escaping and the overall water level is sinking, more fuel is uncovered and melts as well. But those parts are not settling down at the bottom of the RPV, but washed out with the water flow - since there is always water supply from above.
Parts of this fuel gather at some point in the containment and burn another hole in the bottom, sinking through the basement and into the ground. Now the water can escape into the ground as well.

There's also a probability of sudden fuel cladding failure. The fuel was uncovered for a certain amount of time, but did not melt. But the zircalloy was very severely damaged. It's highly oxidated and unstable. Everything seems fine, water flow is resumed. Then, a violent afterquake hits, shaking all assemblies.
This sudden stress could result in rupturing and breaking of the cladding, releasing the fuel pellets to the ground. And if that happens in enough places, it could trigger a chain reaction (mechanical, not nuclear... ^^;), leading to a similar outcome as described above. I don't find them anymore, but sometime during the last weeks I saw assessments of Mark I containments and BWR pressure vessels during accidents. They stated that the RPV would likely be breached by corium in less than one hour.

 

[PietKuip]

Evidence of Earthquake Susceptibility of the ReactorsEvidence 1
On 7th April there was a reported 7.1 (some say 7.4) north of Fukushima that also shook Tokyo. http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/usc0002ksa.php

and look what happened to the CAMS reading from 30 to 100 to 180
[PLAIN]http://k.min.us/ikY1Ys.jpg
Now with all the information we have today leak sprung in the reactor vessel releasing very radioactive water.

Interesting analysis. And that "100.0" reading, was not that a code for "off scale"?

 

[elektrownik]

I also think that core is in drywell science radiation jump in drywell...

 

[artax]

Sorry... simple question but what does CAMS stand for?

 

[MadderDoc]

Find attached my assessment of the state of the roof structure of unit 3, after the explosion.

Based on visual inspection of photos, each field in a 16x24 matrix covering the entire roof structure was assessed to one of five categories of damage, see legend. The method used gives the assessment a resolution of about 1.5 meter.

Fragments found on the roof of unit 3 were assessed, as were fragments of the roof structure locatable to the south and the east side of the building. Due to poor photo coverage and their inter-mixture with other debris fragments which ended to the north of the building could not be inspected. Those parts of the structure from the N end and from the SE corner which could not be inspected were assessed based on plausibility, judging from visually inspected close-by or bordering fields.

 

[jlduh]

Just wanted to remember everyone that Tepco just recalculated 2 weeks ago the amount of fuel damaged in the cores:

http://www.powermag.com/POWERnews/3678.html

For Unit 1 it was revised from 70% to 55%...

All this gave the impression of precision and control of what was going on, isn't it?

Now it's 100%. Finally, we could call it a "50/50 bet" , after all. With much "scientific" (maybe pseudo?) reasoning though.

Which credit should we give to the numbers for the other units, now?

 

[PietKuip]

Just wanted to remember everyone that Tepco just recalculated 2 weeks ago the amount of fuel damaged in the cores:

http://www.powermag.com/POWERnews/3678.html

For Unit 1 it was revised from 70% to 55%...

Indeed. Based on the CAMS readings (Containment Atmospheric Monitoring System). But Michio Ishikawa never believed it.

 

[artax]

Thanks Piet, have these images been discussed, particularly the ones of the surveying helicopter at the bottom?

http://cryptome.org/eyeball/daiichi-npp14/daiichi-photos14.htm

 

[htf]

Moreover, TEPCO stated that the bottom of the RPV is only slightly over 100 degree °C hot. But if the core's really relocated to the bottom, there's nothing between the hot corium and the steel. And then it's only 100 degrees hot? I can't believe that.

If the temperature readings are correct then the corium is not at that location. This would be my conclusion. So, where is the core?

 

[AntonL]

Unit 1 remains a mystery for me. During the last few hours, some questions popped up...


I don't find them anymore, but sometime during the last weeks I saw assessments of Mark I containments and BWR pressure vessels during accidents. They stated that the RPV would likely be breached by corium in less than one hour.

Correction - All units remain a mystery.

Lets just get the facts straight, http://k.min.us/ikop60.JPG" that 200GJ of energy is required for a melt a large civil core we can then calculate using the formulas provided that the time for melt through is using Po=1380MW
0 minutes after shut down - 4hours
01 hours after shut down - 5 hours
02 days after shut down - 11 hours
30 days after shut down - 26 hours
60 days after shut down - 36 hours

So it is very unlikely that the core has melted completely and is digging itself to the centre of the earth. We can forget that.

Reactors 2 and 3 Po=2380MW and the times will be proportionally less.

EDIT: as per Clancy688 https://www.physicsforums.com/showpost.php?p=3297899&postcount=6855"

 

[PietKuip]

Thanks Piet, have these images been discussed, particularly the ones of the surveying helicopter at the bottom?

http://cryptome.org/eyeball/daiichi-npp14/daiichi-photos14.htm

The Ministry of Defense has released the thermal images taken by the helicopter in April.

I have not seen any data about radiation levels from those helicopter flights. Anyway, that was at a height of 3000 meters if I remember correctly. They did not have equipment to do any gamma imaging.

 

[AntonL]

Thanks Piet, have these images been discussed, particularly the ones of the surveying helicopter at the bottom?

http://cryptome.org/eyeball/daiichi-npp14/daiichi-photos14.htm

Wearing lead suit to protect body and testicles is a good precaution, but surely they should also wear helmets to protect the most vital organ - the brain

 

[SteveElbows]

Regarding earthquakes, perhaps have to be slightly cautious about stuff that changed at reactor 1 around April 7th because they started injecting nitrogen a day earlier. I find it quite plausible that earthquakes can change things though, not ruling it out, just want to consider other factors too.

I think the April 11th earthquake is the one TEPCO tend to mention in reactor history, but that's because it knocked out power to the site for a while.

 

[MadderDoc]

Now we've learned that Unit 1 is leaking, both RPV and containment. If there's a leak, the RPV pressure will very unlikely rise significantly over atmosphere level.<..>

Yes that's a mystery. Both RPV pressure meters give readings considerably above atmospheric, and both meters appear to be 'alive', picking up an upward trend, rather than just static.

<..>TEPCO stated that the bottom of the RPV is only slightly over 100 degree °C hot. But if the core's really relocated to the bottom, there's nothing between the hot corium and the steel. And then it's only 100 degrees hot? I can't believe that.

If that's the temperature at the outside of the vessel (I believe it is), and the readings from the drywell pressure/temperature are valid, it may not be entirely incredible. Readings show the drywell to be at close to atmospheric pressure, and below 100 deg. C. This would be consistent with liquid water interfacing with the bottom outside of the reactor vessel, in which case that could not get much above 100 C.