Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[|Fred]

some one mentioned looking to see if other group of reflexion came up with different ideas..
I found this one http://forum.atominfo.ru/index.php?showtopic=575 It's in Russian.. could not make much of it .. but I don't think they conjectured anything like aou Fuel Handling Machine bullet. (speaking of witch we can identify above SFP roof debrit on the ground between unit 3 and 4.

Now my small visit to the Russian board concurred that the blueprint I found on a patent site match Fukushima plant .. as they were able to get the file.. 69Megapixel ... I'll just link you to the scaled down version 2mo 17Mega pixel
http://min.us/mvbsHCv

 

[Jorge Stolfi]

In here http://www.google.co.uk/url?sa=t&so...g=AFQjCNHvmvjzUQY_apDXEqIqcmenR6gKzA&cad=rja"

It says that the spent fuel pools are at about half capacity, however, that is only after "Re-racking" looking at dates though that does appear to be before number 4 was emptied.

Thanks, that is it. I understand that spent fuel was unevenly distributed through the 6 reactors; IIRC #4 had the largest stock. Moreover (IIRC) reactor #4, besides the fuel load removed from the RPV, also had a shipment of fresh fuel.

 

[tadjik]

One gets very little - but one does get hydrogen. Some of the hydrogen produced diffuses into the Zircaloy cladding. At < 300 C, the reaction is very slow. One can do a calculation of how much hydrogen is produced from a reaction of Zr => ZrO2 of thickness ~20-100 microns over the area of the fuel or 400 or 548 assemblies.

Also, if the fuel ruptures, then there is a Zr-linear of 75 microns thickness (which could produce about 200 microns oxide) that can react with water/steam to produce hydrgoen. How much hydrogen generated depends on how many of the cladding tubes and channels oxidized on the outer surface, and how many cladding tubes ruptured in which the liner heavily corroded/oxidized.

Apparently, whatever phenomena increases pressure in reactor 1, it seems progressive.
http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/plots/v6/plot-un1-full.png
Any hope this could just be some H2O vapor ?

And (if the question has not been raised yet) : 7 atm is a very high pressure, I thought the desin was for 4 atm ... why inject nitrogen under such circumstances ?

 

[georgiworld]

Very interesting! and to quote in part the referenced article:

"The possibility of another hydrogen explosion like those that ripped through reactors 1 and 3 early in the crisis, spreading high levels of radiation into the air, was "extremely low," he said.

But TEPCO suspected that the outside casing of the reactor vessel was damaged, said the official.

"Under these conditions, if we continue cooling the reactors with water, the hydrogen leaking from the reactor vessel to the containment vessel could accumulate and could reach a point where it could explode," he added."

and I again refer to my analysis at post #2936
https://www.physicsforums.com/showpost.php?p=3230713&postcount=2936

and my opinion of where damage to the reactor pressure vessel damage from lateral acceleration exceeding design parameters might be likely to occur (X marks the spot)

http://i306.photobucket.com/albums/nn270/tcups/Screenshot2011-04-05at100427AM.png

just saying . . .

And here is further confirmation of your hypothesis. Nice job.
http://english.kyodonews.jp/news/2011/04/83613.html

 

[Astronuc]

Apparently, whatever phenomena increases pressure in reactor 1, it seems progressive.
http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/plots/v6/plot-un1-full.png
Any hope this could just be some H2O vapor ?

And (if the question has not been raised yet) : 7 atm is a very high pressure, I thought the desin was for 4 atm ... why inject nitrogen under such circumstances ?

Pressure would increase if the temperature of the gas increased. Nitrogen is there to provide for an inert, non-combustible environment. Of course, if there is a leak, then the nitrogen leaks as well.

Well, the design pressure is greater than 4 atm, but the operating limit would be specified at 4 atm to ensure that the containment had sufficient margin to failure. Theoretically, the concrete the steel liner should hold to about 7 atm, although the concrete might start cracking (leaking).

Leak-before-break is a typical approach to designing containment systems.

 

[TCups]

And here is further confirmation of your hypothesis. Nice job.
http://english.kyodonews.jp/news/2011/04/83613.html

Well, it sounds like both news stories arise from reporting of the same conference, so it isn't independent "confirmation". And while it is interesting to think it may be something like what actually happened, I might characterize what was reported as "evidence for" rather than "confirmation of" the earlier hypothesis.

 

[tadjik]

Pressure would increase if the temperature of the gas increased. Nitrogen is there to provide for an inert, non-combustible environment. Of course, if there is a leak, then the nitrogen leaks as well.

Well, the design pressure is greater than 4 atm, but the operating limit would be specified at 4 atm to ensure that the containment had sufficient margin to failure. Theoretically, the concrete the steel liner should hold to about 7 atm, although the concrete might start cracking (leaking).

Leak-before-break is a typical approach to designing containment systems.

OK, I understand for nitrogen. Thanks.

But the source gives temperature slowly going down; of course, they can think the data are wrong but it seems to me the 2 measures are "coherent" both in time and between them.
On the other hand, it does not exclude increase elsewhere in the system, of course.

 

[|Fred]

http://english.kyodonews.jp/news/2011/04/83613.html

=> in which way to you find it confirms anything?

edit: which

 

[georgiworld]

http://english.kyodonews.jp/news/2011/04/83613.html

=> in witch way to you find it confirms anything?

I may be mistaken in reading between the lines but as I read the article the managers of the disaster are attempting to prevent a repeat of what happened in Reactor3

According to the article "Nishiyama said past hydrogen explosions have likely occurred due to hydrogen accumulation caused by the reaction of melted fuel rods' zirconium with steam from the coolant water".

It also states that
"The utility has been pouring massive amounts of water into the reactors and their spent nuclear fuel pools as a stopgap measure to cool them down. But the measure is causing ''side effects,'' such as the detection of contaminated water in various parts of the nuclear complex and some leakage into the sea."

TCups points out "That big old steel reactor vessel sets on a pedestal like a long, skinny boiled egg. It is made of heavy steel, and it is full of water and one of the densest things I know of -- uranium.

Furthermore he states

"If the lateral acceleration forces exceed the design parameters, the pressure vessel risks becoming the upside down clanger in a giant bell shaking at about a 9 on the Richter scale."

The key vulnerable structure if that happens is the high pressure steam outlet pipe. If that cracks or leaks, then you have high pressure steam and shortly thereafter, hydrogen in the primary containment"

 

[Astronuc]

One can find there assessment reported in the NY Times here:

http://djysrv.blogspot.com/2011/04/nrc-threat-assessment-of-fukushima.html

 

[Giordano]

Apparently, whatever phenomena increases pressure in reactor 1, it seems progressive.
http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/plots/v6/plot-un1-full.png
Any hope this could just be some H2O vapor ?

And (if the question has not been raised yet) : 7 atm is a very high pressure, I thought the desin was for 4 atm ... why inject nitrogen under such circumstances ?

Hope this is not a stupid comment...

7 atm, isn't that the reading inside of the RPV!? And I thought the operating pressure in the RPV is something like 10 times that!?

 

[|Fred]

Thank you.
ps: I'm i the only one with the google doc linked in the article displaying upside down?

 

[Astronuc]

Hope this is not a stupid comment...

7 atm, isn't that the reading inside of the RPV!? And I thought the operating pressure in the RPV is something like 10 times that!?

If there is ample communication between the RPV and containment, then the pressure is more or less equal. The RPV is designed to handle much higher pressures (operational ~ 72 atm, but should withstand much higher) than containment (~ operating limit of 4 atm). The RPV is afterall a 'pressure vessel', and containment is only a low pressure container.

 

[Astronuc]

Thank you.
ps: I'm i the only one with the google doc linked in the article displaying upside down?

No - it's copied upside. Just print or flip the pages 180 degrees.

 

[razzz]

Firework Colorants

 

[Giordano]

Has anyone seen an estimate of how much total radioactive material has leaked (or still is leaking!?) or been dumped into the sea? I suppose most interesting is the amount of Cs-137.

Maybe someone here would like to maka a personal estimate?

The ocean is vast but not infinite...

 

[bytepirate]

new http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110406e23.pdf"

a lot of te-129m, but *no* te-129.

any explanation for that?

 

[Giordano]

http://www.tepco.co.jp/en/press/corp-com/release/11040613-e.html
"Injection of nitrogen to reactor containment vessel of Fukushima Daiichi Nuclear Power Station Unit 1"

(with schematics)

 

[Astronuc]

Has anyone seen an estimate of how much total radioactive material has leaked (or still is leaking!?) or been dumped into the sea? I suppose most interesting is the amount of Cs-137.

Maybe someone here would like to maka a personal estimate?

The ocean is vast but not infinite...

It's difficult to say at this point, because the source term (how much fuel has failed) is not well known. And there are 4 units with various degrees of damage.


As for fuel release, it would be useful to find out if there are any detections of:
Nd isotopes, and Ce¹⁴⁴, Zr⁹⁵, Ru¹⁰³, Ru¹⁰⁶, Ba¹⁴⁰, Eu¹⁵⁴ in addition to the volatile Cs isotopes, which are gamma emitters. Other than the Cs which can easily get out of the fuel because of low melting temperatures and solubility, the others are harder to get out and therefore their presence in the environment would support loss of fuel from damaged/breached fuel rods.

 

[Astronuc]

new http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110406e23.pdf"

a lot of te-129m, but *no* te-129.

any explanation for that?

I expect it is because they are doing gamma spectroscopy to identify elements. Te-129m decays to Te-129 by gamma emission, which is easily detectable. Te-129 is a beta emitter, with lower energies of 540 keV (89%), 350 keV (9%), and others.
Ref: http://www.nndc.bnl.gov/chart/decaysearchdirect.jsp?nuc=129TE&unc=nds

Sb-129 beta decays to Te-129m/Te-129.
http://www.nndc.bnl.gov/chart/decaysearchdirect.jsp?nuc=129SB&unc=nds

 

[razzz]

Encapsulation? I can understand attempted purging using nitrogen but encapsulation due to leaks would have to be a continuous inputting, for months. Of course, what the hell do I know.

 

[jensjakob]

Meltdown?
"The fuel rods remain nearly half exposed as the coolant water inside the reactor has not yet risen high enough"
http://www3.nhk.or.jp/daily/english/07_01.html

 

[PietKuip]

new http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110406e23.pdf"

a lot of te-129m, but *no* te-129.

any explanation for that?

But another new weird one: Be-7 at 32 kBq/kg.
http://nucleardata.nuclear.lu.se/nucleardata/toi/nuclide.asp?iZA=040007

I would not trust that result. Natural levels in soil can be a picocurie/cm3 (37 Bq/liter), produced by cosmic radiation.

 

[ian_scotland]

I found this one http://forum.atominfo.ru/index.php?showtopic=575 It's in Russian.. could not make much of it .. but I don't think they conjectured anything like aou Fuel Handling Machine bullet. (speaking of witch we can identify above SFP roof debrit on the ground between unit 3 and 4.

Now my small visit to the Russian board concurred that the blueprint I found on a patent site match Fukushima plant ..

Yahoo Babel Fish will translate the text from Russian to English quite well if you paste in the http address.

(I've only read a few of their threads, but someone there states that only Fuku 1 is if GE mk1 design and Fuku 2,3 and 4 are of GE mk2 design. Here on PF its been established that all Fuku units are of GE mk1, correct?)

 

[bytepirate]

I expect it is because they are doing gamma spectroscopy to identify elements. Te-129m decays to Te-129 by gamma emission, which is easily detectable. Te-129 is a beta emitter, with lower energies of 540 keV (89%), 350 keV (9%), and others.

thanks for the explanation.
this means, that if SR-90 would be present, it would not show up. right?

 

[Atomfritz]

Now my small visit to the Russian board concurred that the blueprint I found on a patent site match Fukushima plant .. as they were able to get the file.. 69Megapixel ... I'll just link you to the scaled down version 2mo 17Mega pixel
http://min.us/mvbsHCv

Thank you!
I was looking for such a blueprint for long time.
It is very helpful identifying the crap lying around in the damaged reactor buildings.

thanks for the explanation.
this means, that if SR-90 would be present, it would not show up. right?

Some elements spread better by air than water because of insolubility. Afaik Sr belongs to them, like Pu. Both also have in common that most of the emissions fall down in the near vicinty, little of it travels long distances. But, long term spreading eventually occurs through erosion and wind.

http://www.tepco.co.jp/en/press/corp-com/release/11040613-e.html
"Injection of nitrogen to reactor containment vessel of Fukushima Daiichi Nuclear Power Station Unit 1"

Thanks, the text explains the negative pressures observed in the reactors with production of hydrogen.
I fear that there will be worrying hydrogen bubbles in the containment for long time, as the schematic does not show where the hydrogen should be vented off.
And they must also take care of not blowing the vacuum breakers...

... atmosphere susceptible to reach combustible limit...

Cherry blossoms fireworks?

 

[AntonL]

Meltdown?
"The fuel rods remain nearly half exposed as the coolant water inside the reactor has not yet risen high enough"
http://www3.nhk.or.jp/daily/english/07_01.html

explanation to water level -1600 to -2300 which is -62 to -88inches
which is well above active fuel level according to diagram below
(interesting it corresponds to an outlet port of the reactor vessel)

core is exposed at 158" = -4013

http://min.us/mvbjpP8/gallery.zip"

 

[denislaurent]

I apologize for a newbee question, but could somebody clarify what is behind Minimum Debris Retention Injection Rate (MDRIR) from NRC report ?

 

[AntonL]

some one mentioned looking to see if other group of reflexion came up with different ideas..
I found this one http://forum.atominfo.ru/index.php?showtopic=575 It's in Russian.. could not make much of it .. but I don't think they conjectured anything like aou Fuel Handling Machine bullet. (speaking of witch we can identify above SFP roof debrit on the ground between unit 3 and 4.

Now my small visit to the Russian board concurred that the blueprint I found on a patent site match Fukushima plant .. as they were able to get the file.. 69Megapixel ... I'll just link you to the scaled down version 2mo 17Mega pixel
http://min.us/mvbsHCv

Could be the print for unit 1

Unit 2,3,4 as well as unit 5 re improved Mark1 1100MW design and
Unit 6 is a Mark 2
[PLAIN]http://k.min.us/imBdts.JPG

 

[Atomfritz]

explanation to water level -1600 to -2300 which is -62 to -88inches
which is well above active fuel level according to diagram below
(interesting it corresponds to an outlet port of the reactor vessel)

core is exposed at 158" = -4013

http://min.us/mvbjpP8/gallery.zip"

The schematic shows the active core is 150" tall. This is almost 4 meters.

If "half covered" means a water level of 1600-2300mm (equivalent to mentioned 62-88"), then could this mean that Tepco counts "water level" from top of active zone down?

And, this and the melting of the upper core in mind, could this mean that in fact most of the fuel is now underwater, in form of a melt cake as it happened in TMI?

A melt cake lying on the RPV floor?
Well insulating its liquid, convecting violently hot corium by a fragile ceramic crust from the water?
And so creating the imminent danger of steam explosion if the crust cracks and tons of liquid corium and water get in touch?
Or softening, eroding and bulging the steel RPV until failure point is reached?
Maybe already corium already began dripping/flowing thru control rod borings into the containment vessel causing this mysterious pressure increase observed?

What happens if this mass breaks through the RPV floor?

Remember, in TMI the RPV cracked and almost broke at a hot spot, as you can verify impressive photo on page 30 on this interesting presentation: http://www.tec-sim.de/images/stories/severe-accident-phenomenology.pdf (Very interesting link, I think i found it about 1000 posts earlier in this thread)

 

[razzz]

I'll give you some what ifs...I live near a shipyard (worked there once for a month) and the noise(s) on that Unit 3's launch soundtrack (even though I can't confirm it to be the matching soundtrack), before the flash and after the fallout, has the same sounds that emanate from a shipyard. I guarantee that a shipyard has metal structures make dwarf this nuclear contraption...with that in mind, first sounds on video are after our pressure capsule has/is venting to oversize metal doughnut echoing inside metal voids, water flashing to steam taking place, more venting then a explosion (probably hydrogen) releases any captured water bound nuke particles in the doughnut to air which gets caught in the updraft. Flash in video doesn't necessarily have to be an explosion, could be a burn. More water to steam flashing until water source is exhausted (take that both ways, up and sideways through constrictions). Finally last metallic sounds (lack of a better description) on video is either the crane beam landing or vessel and torus interacting or both. When I mention red cloud, I think you know what I mean. Our capsule survives but resembles a sieve, flight time unknown.

http://www.youtube.com/watch?v=nw2Aw3komgc"

Thanks for the tolerance.

 

[PietKuip]

explanation to water level -1600 to -2300 which is -62 to -88inches
which is well above active fuel level according to diagram below
(interesting it corresponds to an outlet port of the reactor vessel)

Yes. The RST assessment believes that recirculation pump seals may have failed.

 

[RealWing]

explanation to water level -1600 to -2300 which is -62 to -88inches
which is well above active fuel level according to diagram below
(interesting it corresponds to an outlet port of the reactor vessel)

core is exposed at 158" = -4013

http://min.us/mvbjpP8/gallery.zip"

Based on footnote 2 for RPV water level in the status updates: http://www.nisa.meti.go.jp/english/files/en20110404-5-1.pdf
it seems to indicate that the zero reference is at the top of the fuel strings and thus anything negative means exposed fuel elements?

 

[Astronuc]

Yahoo Babel Fish will translate the text from Russian to English quite well if you paste in the http address.

(I've only read a few of their threads, but someone there states that only Fuku 1 is if GE mk1 design and Fuku 2,3 and 4 are of GE mk2 design. Here on PF its been established that all Fuku units are of GE mk1, correct?)

FK-I Units 1-5 are MK I containment, but FK-I Unit 6 is Mk II.

Unit 1 is a BWR/3, Units 2-5 are BWR/4 and Unit 6 is a BWR/5.

 

[Astronuc]

I apologize for a newbee question, but could somebody clarify what is behind Minimum Debris Retention Injection Rate (MDRIR) from NRC report ?

I believe that MDRIR is the minimum flow rate to keep the bottom plenum of the RPV flooded such that any core debris does not melt the RPV shell. I'll try to confirm that.