Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[MadderDoc]

[PLAIN]http://i.min.us/im7mIU.jpg[/QUOTE]

Part of the fhm from unit 3 may after initial service deck impact have rebounded, or slid off the deck, to land further down in the building which is annexed to the north face of the reactor building. See attachment with a top view with a arrow pointing to the spot, and a ground shot photo, looking up to the penetrated wall. About in the same area at groundlevel can be seen several smaller machine parts, perhaps of fhm3 origin.

Btw, interesting how the water spraying for cooling and 'firework' has had the effect of washing off a lot of dust since March 20th, revealing more clearly in video and photo what is in that big NW corner pile of debris.

http://www.gyldengrisgaard.dk/fuku_docs/perhaps_also_fhm3part_here.jpg

[URL]http://www.gyldengrisgaard.dk/fuku_docs/perhaps_also_fhm3part_here_groundshot.png[/URL]

 

[shogun338]

Part of the fhm from unit 3 may after initial service deck impact have rebounded, or slid off the deck, to land further down in the building which is annexed to the north face of the reactor building. See attachment with a top view with a arrow pointing to the spot, and a ground shot photo, looking up to the penetrated wall. About in the same area at groundlevel can be seen several smaller machine parts, perhaps of fhm3 origin.

Btw, interesting how the water spraying for cooling and 'firework' has had the effect of washing off a lot of dust since March 20th, revealing more clearly in video and photo what is in that big NW corner pile of debris.

http://www.gyldengrisgaard.dk/fuku_docs/perhaps_also_fhm3part_here.jpg

I have been looking at that corner on Unit 3 for awhile now . In some of the videos it almost looks like a dome . The is something large there .

 

[Sirius (b)]

The image Fred is showing looks like the lid of the RPV, you may want to compare it against early thermal imagery. ;)

 

[Joe Neubarth]

Thats the last thing they need is for another plant to have cooling failure . Two out of three external power lines to the Onagawa nuclear power plant, 75 miles northeast of Fukushima and near the epicenter of Thursday's temblor, have been damaged, causing power loss. The plant, operated by Tohoku Electric Power, has been shut down since the March 11 quake and has been relying on external power to cool the reactors. Japan’s Atomic Energy Agency said the two lost power lines were not being used for cooling when tonight’s earthquake hit.
http://www.csmonitor.com/World/Asia...sunami-warning-lifted-but-Fukushima-evacuated

They still have their emergency diesel generators as back up for each reactor.

 

[|Fred]

lid is color coded yellow <=100% certain
green is color for FHM and crane <=100% certain
pink is color code for (hydraulic stuff) <= guessing

 

[Sirius (b)]

They still have their emergency diesel generators as back up for each reactor.

Indeed, but how long is the fuel going to last, batteries next? With destroyed electric grid in several prefectures (downed pylons, blown transformers) they are in a race against time with Higashidori NPP, possibly Onagawa's SNPs (reactors in cold shutdown as of March 11th).

lid is color coded yellow <=100% certain
green is color for FHM and crane <=100% certain
pink is color code for (hydraulic stuff) <= guessing

Pink is the guard railing around SNF & equipment pools. PCV dome could be inside turbine building of Unit 3, or it could be in the ocean.

 

[shogun338]

Indeed, but how long is the fuel going to last, batteries next? With destroyed electric grid in several prefectures (downed pylons, blown transformers) they are in a race against time with Higashidori NPP, possibly Onagawa's SNPs (reactors in cold shutdown as of March 11th).



Pink is the guard railing around SNF & equipment pools. PCV dome could be inside turbine building of Unit 3, or it could be in the ocean.

Thats what I was thinking about fuel running out . I think the guard rails around the spent fuel pools are covered in a green fabric or plastic . If you look in Unit 4 where there pumping water you can still see part of it below the FHM . The pic posted of it before the accident also shows green covered rails .

 

[Giordano]

I'm intersted in the amount of radioactive material leaked into the sea.

My attempt to estimate the ocean pollution of Cs-137 from the leak that was fixed the day before yesterday:

2 l/s -> 3600 m3 in three weeks.

Concentration of Cs-137 is assumed to be 1.8 MBq/cm3

Which gives 6.5 PBq of Cs-137 from one leak!

(Chernobyl totally released 85 PBq of Cs-137 in aerosol form according to Wikipedia)

Is my estimate reasonable? Can anyone make a better one?

Regarding the assumption of Cs-137 concentration:
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110405e30.pdf
http://www.tepco.co.jp/en/press/corp-com/release/11040506-e.html

 

[Borek]

2 l/s -> 3600 m3 in three weeks.

Concentration of Cs-137 is assumed to be 1.8 MBq/cm3

Which gives 6.5 PBq of Cs-137 from one leak!

You are assuming constant contamination all the time.

 

[|Fred]

Giordano this may help

French scientists simulate how the radioactivity dilutes into the Pacific Ocean : http://sirocco.omp.obs-mip.fr/outils/Symphonie/Produits/Japan/SymphoniePreviJapan.htm
See also the simulation after 72 days on page 8/9 of http://www.irsn.fr/FR/Actualites_pr...ident-Fukushima-sur-milieu-marin_04042011.pdf

 

[Sirius (b)]

Thats what I was thinking about fuel running out . I think the guard rails around the spent fuel pools are covered in a green fabric or plastic . If you look in Unit 4 where there pumping water you can still see part of it below the FHM . The pic posted of it before the accident also shows green covered rails .

Then the paint has peeled off during the steam build up/explosion from SNP of number 4. And yes, those are fuel assemblies (what's left of them) that can be seen from the footage with the camera strapped to the concrete pump.

I'll check my archive to bring you the construction of Fukushima Daichi during the 1970s - blast from the past.

Fuel Assemblies in use at these reactors are not silvery grey, but black in colour.
Added: http://www.youtube.com/watch?v=cTshYXmN1AY&feature=mfu_in_order&list=UL at mark 1:10.

Unit 4, March 20th. What's your guess as to the temperatures we might be seeing here?

 

[Giordano]

You are assuming constant contamination all the time.

Yes I am assuming the leak was going on since they filled everything with water, you think that is a poorly made assumption?

They discovered the leak maybe a week ago, but don't you think it's been going on for a long time?

And the concentration I assume was even higher in the beginning rather than from the time the sample was made that I used. Maybe my estiamate qualifies as a lower boundary!?

 

[Giordano]

Giordano this may help

Thank you for response.

SCIROCCO writes:

"We are not able to prescribe in our model realistic scenarios as we do not know how much radionuclides have been rejected, when they have been rejected and how they behave once they reach the sea. That is why we do not claim that our simulations are able to provide a quantification of radioactivity in the sea."

I don't think they make assumptions of quantities!?

The second document has this interesting piece of information concerning "normal" levels of Cs-137 in Japanese waters:
"A titre de comparaison, avant l’accident de Fukushima, les niveaux de concentration
en césium 137 dans l’eau de mer du littoral japonais étaient de quelques mBq/L (1 à 3 mBq/L) et l’iode 131 n’était pas détecté."

 

[Borek]

Yes I am assuming the leak was going on since the filled everything with water, you think that is poorly assumed?

They discovered the leak maybe a week ago, but don't you think it's been going on for a long time?

And the concentration I assume was even higher in the beginning rather than from the time the sample was made that I used.

I am not judging your assumptions, I am naming them. Intuition tells me you can be wrong by orders of magnitude - each direction, although overestimate seems more likely.

I doubt such a high radioactivity leak could go unnoticed for long, so my bet is that leak was there earlier, but it was detected when radioactivity got higher - which could suggest radioactivity wasn't that high initially.

But it is way too speculative for my liking.

 

[shogun338]

Then the paint has peeled off during the steam build up/explosion from SNP of number 4. And yes, those are fuel assemblies (what's left of them) that can be seen from the footage with the camera strapped to the concrete pump.

I'll check my archive to bring you the construction of Fukushima Daichi during the 1970s - blast from the past.

Fuel Assemblies in use at these reactors are not silvery grey, but black in colour.
Added: http://www.youtube.com/watch?v=cTshYXmN1AY&feature=mfu_in_order&list=UL at mark 1:10.

See pics of reactor room and spent fuel pool in post #2650 . Where did you get the fuel assemblies are black ?

 

[Sirius (b)]

See pics of reactor room and spent fuel pool in post #2650 . Where did you get the fuel assemblies are black ?

https://www.physicsforums.com/showpost.php?p=3230265&postcount=2889

Point 1 - several 'intact' assemblies, 200 mm across. Refer to thermal image in my post above.

Added: On the question of the colour of the housing for the pellets - http://www.youtube.com/watch?v=cTshYXmN1AY&feature=mfu_in_order&list=UL at mark 1:10.

 

[heckler73]

Yes I am assuming the leak was going on since they filled everything with water, you think that is a poorly made assumption?

What is the function for your analysis? I am assuming concentration of outflow water will go down exponentially (from whatever event is the source).
Your analysis assumes linear concentration over time, it seems.
Is there any information on the actual source(s) of the contamination?
Where, When, How, etc...

ref: JAIF Trends for Seawater Radiation
http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1302167890P.pdf

 

[Giordano]

I am not judging your assumptions, I am naming them. Intuition tells me you can be wrong by orders of magnitude - each direction, although overestimate seems more likely.

I doubt such a high radioactivity leak could go unnoticed for long, so my bet is that leak was there earlier, but it was detected when radioactivity got higher - which could suggest radioactivity wasn't that high initially.

But it is way too speculative for my liking.

I agree it is speculative and an error by orders magnitude is possible.

I was trying to get some numbers to the quite common statement that it is better to pollute the sea rather than the atmosphere/land.

 

[rmattila]

Adding to my previous speculation on whether the cooling water injected actually goes into the core as desired:

does anybody have an idea whether it would be possible to inject water into the core through the control rod drive mechanism pipes in the BWR3/4 reactors? In the ASEA BWR:s, there is a constant rinse flow of the order of 10 kg/s during operation in order to keep crud away from the drive mechanisms, and in case of emergency, this route could in principle be used to drive water into the core from below. I've heard that in some new BWR designs this injection route is considered as a possible diverse system for the high pressure core injection.

 

[MJRacer]

Re Unit 3 explosion

Assuming that the objects that seem to have been lifted to great heights (>500m?) may have been roof tiles (as others have also surmised), how is it possible aerodynamically given air resistance? Looking at videos of the explosion, it looked to me like they might have been surfing on top of a ball or sphere of very hot gas that was rapidly rising, until they fell off one by one.

How hot would such a sphere have to be? At this website (http://tornado.sfsu.edu/geosciences/classes/m201/buoyancy/CAPE_Procedure.html), I found a relatively simple formula for calculating the acceleration of a parcel of air based on differences in temperature. The formula is a=(T_ap - T_e)/T_e*g, where T_ap is the temperature of the air parcel and T_e was about 16°C or 289.15 K at 11:00AM on 3/15(??) and g is the acceleration of gravity.

By looking at the video of the explosion (<iframe title="YouTube video player" width="640" height="390" src="http://www.youtube.com/embed/Q-9ax_X_PQ4" frameborder="0" allowfullscreen></iframe>), I estimated the initial acceleration of the sphere of gas AFTER the initial expansion somewhat at ground level to be about 50m/sec^2 using the vent towers for scale (~100m tall). T_a then would be about <b>1500°C</b> for a sphere about 50m to 100m in diameter AFTER the initial expansion. This very high temperature raises the question of whether a hydrogen explosion alone could have cause this. Maybe somebody else can look at this.

Should the possibility that a criticality event may have happened in SFP 3 then be considered? Such a criticality probably would have lasted only a few millliseconds, but it may have flashed a good bit of the remaining water in the pool to cause the initial expansion. A hydrogen explosion may have also taken place and, perhaps, the shock wave from the hydrogen explosion may have helped create the criticality in the first place. Again, just surmises.

If such an event did take place, it would have dispersed or partially dispersed the contents of SFP 3 outside the pool, thus explaining the very hot stuff that was bulldozed over between units 3 and 4 and finds elsewhere on the premises. It would also explain the video showing the cloud of debris rising as if shot out of a cannon. Also, it would explain how the RPV and the PCV could have remained fairly intact, because the reinforced concrete walls of the SFP would have shielded them. However, every other part of the building that was pneumatically connected to the SFP would have suffered severe damage.

Finally, this is all a maybe. Just food for thought.

 

[Giordano]

What is the function for your analysis? I am assuming concentration of outflow water will go down exponentially (from whatever event is the source).
Your analysis assumes linear concentration over time, it seems.
Is there any information on the actual source(s) of the contamination?
Where, When, How, etc...

ref: JAIF Trends for Seawater Radiation
http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1302167890P.pdf

Thank you for answering.

I'm not quite sure I understand you.

My purpose was to try to get a feeling (a lower boundary perhaps) for how much radioactive material had reached the ocean and how big volume of water that is need to dilute it to normal levels. I used the leak in front of unit 2 becuase I thought I had some numbers that were useful. Also Cs-137 has quite a long half-time so the environmental impact can be significant, which is the reason why I focused on that nuclide.

Yes, I assumed linear conc over time, it's the best I managed, based on the facts I had.

I didn't think so much of the specific event. But I did look at this document: http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110327e15.pdf
It measures the conc of Cs-137 in the water under the turbine building under unit 2, a week earlier to a bit higher levels.

Thank you for the doc. I had actually missed that one but I have been wathching here:
http://www.mext.go.jp/english/radioactivity_level/detail/1304192.htm

Would you like to make an estimation?

 

[Borek]

T_a then would be about <b>1500°C</b> for a sphere about 50m to 100m in diameter AFTER the initial expansion. This very high temperature raises the question of whether a hydrogen explosion alone could have cause this.

No problems here - adiabatic flame temperature for air/hydrogen mixture is well over 2000 °C.

That said, I don't like the rest of your analysis - equation you refer to is used for buoyant force, that's not the case here.

 

[PietKuip]

I'm intersted in the amount of radioactive material leaked into the sea.

My attempt to estimate the ocean pollution of Cs-137 from the leak that was fixed the day before yesterday:

2 l/s -> 3600 m3 in three weeks.

Concentration of Cs-137 is assumed to be 1.8 MBq/cm3

Which gives 6.5 PBq of Cs-137 from one leak!

(Chernobyl totally released 85 PBq of Cs-137 in aerosol form according to Wikipedia)

Is my estimate reasonable? Can anyone make a better one?

Regarding the assumption of Cs-137 concentration:
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110405e30.pdf
http://www.tepco.co.jp/en/press/corp-com/release/11040506-e.html

Good work. I had been looking for a pair of such numbers: flow and activity of the same water.

 

[shogun338]

https://www.physicsforums.com/showpost.php?p=3230265&postcount=2889

Point 1 - several 'intact' assemblies, 200 mm across. Refer to thermal image in my post above.

Added: On the question of the colour of the housing for the pellets - http://www.youtube.com/watch?v=cTshYXmN1AY&feature=mfu_in_order&list=UL at mark 1:10.

4 is pointing to the rail that surrounds the spent fuel pool . The smaller rods could be older spent fuel rods that have cooled for years so not to hot . The large grey mass looks like something that has melted . The FHM is has collapsed on top of spent fuel pool and crushed some of the railing around the spent fuel pool .

 

[Sirius (b)]

Racer,

The height of the gas vent towers is 130 metres. There 3 are distinct pieces of debris seen emerging from the vertical dust cloud, they could be either: FHM, PCV dome, concrete DW plug, reactor lid itself. The SFP is not the cause of the explosion, there may have been hydrogen in the secondary containment (reactor room), but the trigger was the thermal explosion inside the RPV - cold water coming into contact with 3/4 melted core, which, possibly fell down to the bottom of the RPV, triggering the steam release via the most likely route - bolted top. While the torus may have been destroyed in the event, I would worry about fuel from the core and SFP of Unit 3.

Concrete was pulverised in the detonation, that is steel debris flying sky-high to 500 metres+, with the cloud reaching up-to 1 km, or more.

P.S. What pressure was reported for Unit 3 D/W, RPV prior to the explosion? The core had already melted to some percentage before then, otherwise you can't have the observed events.

4 is pointing to the rail that surrounds the spent fuel pool . The smaller rods could be older spent fuel rods that have cooled for years so not to hot . The large grey mass looks like something that has melted . The FHM is has collapsed on top of spent fuel pool and crushed some of the railing around the spent fuel pool .

Yes. Whatever was the cause of the damages seen to Unit 4 building, it blew a hole 8 metres in diameter South to North through it, around the level the fuel assemblies would be stored at.

If anyone is interested in latest thermal imagery of the plant, PM me and I'll get them sourced and uploaded.

 

[RealWing]

Adding to my previous speculation on whether the cooling water injected actually goes into the core as desired:

does anybody have an idea whether it would be possible to inject water into the core through the control rod drive mechanism pipes in the BWR3/4 reactors? In the ASEA BWR:s, there is a constant rinse flow of the order of 10 kg/s during operation in order to keep crud away from the drive mechanisms, and in case of emergency, this route could in principle be used to drive water into the core from below. I've heard that in some new BWR designs this injection route is considered as a possible diverse system for the high pressure core injection.

Injection via the CRD's is one of the routes that the NRC was recommending

"4. CRD injection is desired for cooling directly to the core and for cooling material on
bottom of vessel"

 

[Borek]

Which gives 6.5 PBq of Cs-137 from one leak!

"A titre de comparaison, avant l’accident de Fukushima, les niveaux de concentration en césium 137 dans l’eau de mer du littoral japonais étaient de quelques mBq/L (1 à 3 mBq/L) et l’iode 131 n’était pas détecté."

I was trying to get some numbers to the quite common statement that it is better to pollute the sea rather than the atmosphere/land.

The volume of the Pacific Ocean is around 600 million cubic km.

Full dilution gives 0.01m Bq/L (unless I miscounted zeros, too many of them) - 300 times less than the background. Sure, full dilution is unrealistic.

 

[cola]

I'm intersted in the amount of radioactive material leaked into the sea.

My attempt to estimate the ocean pollution of Cs-137 from the leak that was fixed the day before yesterday:

2 l/s -> 3600 m3 in three weeks.

Concentration of Cs-137 is assumed to be 1.8 MBq/cm3

Which gives 6.5 PBq of Cs-137 from one leak!

(Chernobyl totally released 85 PBq of Cs-137 in aerosol form according to Wikipedia)

Is my estimate reasonable? Can anyone make a better one?

Regarding the assumption of Cs-137 concentration:
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110405e30.pdf
http://www.tepco.co.jp/en/press/corp-com/release/11040506-e.html

hello. i can't give you any hard numbers, but Robert Peter Gale who coordinated the medical relief efforts for victims of the Chernobyl disaster and who is in J-Village, where all the international experts in fukushima berate, writes in german spiegel magazine that so far in fukushima 10% of the chernobyl-amount of iodine-131 and caesium-137 have leaked.
he also writes that he doesn't expect many deaths from this and that smoking is more dangerous for manchild than this etc. though.
forgive my bad english, i often get probs with the syntax when building too long sentences.

 

[Jorge Stolfi]

Sorry, I may not be able to update my plots of Fukushima Daiichi vars until next tuesday.
(However the scripts and files are availabe at the site, if anyone cares...)
http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/plots/cur/

 

[tadjik]

Where do you find the source material ?
I have this link in english http://www.nisa.meti.go.jp/english/ , but the information are 2 days old.

hello. i can't give you any hard numbers, but Robert Peter Gale who coordinated the medical relief efforts for victims of the Chernobyl disaster and who is in J-Village, where all the international experts in fukushima berate, writes in german spiegel magazine that so far in fukushima 10% of the chernobyl-amount of iodine-131 and caesium-137 have leaked.
he also writes that he doesn't expect many deaths from this and that smoking is more dangerous for manchild than this etc. though.
forgive my bad english, i often get probs with the syntax when building too long sentences.

Maybe ... anyway, there will be, on the long run, chronic exposure to caesium for the area inhabitants. Even at low levels, this could have an effect on health (read somewhere that it has an effect on foetus formation although the effect on adults is not so strong).