Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[Gary7]

First time poster. Lurker of just the past few days. Apologies in advance if I run aground of the rules. I am not a physicist. I am a long-time resident of Tokyo. I speak and read Japanese. Many, many thanks to the contributors of this site, and to the moderators, as there are very few sites with as many knowledgeable comments as I have found at PhysicsForums. I have been following the Fairewinds site for some time and am generally impressed, but I was disappointed when they picked up started promoting the "Reactor #4 is Leaning" story that has been circulating around the blogosphere. I am still trying to understand the possibilities of recriticality and so I am quite interested in the discussions I have read here. Having said that, I have only one thing to add to the discussion this morning, and that is the radiation readings from inside reactor unit #1. This comes from today's Tokyo Shimbun. For those who are familiar with BWR Mark 1, it may help decipher which part of the RPV or drywell that is leaking. The translations are mine. The original is at the site below. The view is from the top, looking down at the reactor building (RPV is the circle in the center).
http://www.tokyo-np.co.jp/article/national/news/CK2011051502000040.html

 

[westfield]

snip >What you wrote about mono/stereo is interesting. I guess plotting the difference between L/R channels should show that's really the case - I would expect it to be flat for mono and not-flat for stereo (plus minus compression artifacts).

Indeed, I considered summing the channels , both in and out of phase to investigate further but the samples make it so obviously wrong I didn't bother delving into it any deeper.

Personally I despise how news services dramatise the news nowadays with video and audio special fx amongst other techniques. Bad news doesn't need to be made to appear worse just for ratings.

 

[AntonL]

So, the reactors may not have survived the initial earthquake!

Data taken at the Fukushima Daiichi nuclear power plant on the night of March 11 showing a high level of radiation at a reactor building suggest the possibility that key facilities there may have been damaged by the quake itself that day rather than tsunami-caused power loss that failed the reactor's cooling function, a utility source said Saturday.

complete article here: http://english.kyodonews.jp/news/2011/05/91126.html

"a utility source said Saturday" is this a further Tepco leak but of a kind we need.

 

[AntonL]

Tokyo Electric Rules Out Future Criticality at No. 1 Reactor

Is there any scientific evidence to support above statement?
http://jen.jiji.com/jc/eng?g=eco&k=2011051400003

 

[default.user]

Tokyo Electric Rules Out Future Criticality at No. 1 Reactor

Is there any scientific evidence to support above statement?
http://jen.jiji.com/jc/eng?g=eco&k=2011051400003

It was already reported in March that Technicium99m was found.
In one German media is thus based on criticality.
Often the argument of the rapidly declining decay heat is given. Normally, should have reassured the nuclei after two months of cooling.
Nevertheless, the temperature in the reactors.
For me, the rise in temperature is an indication of criticality and thus increasing or constant temperature, despite cooling.
Perhaps the corium has formed a skin. The corium is washed with water from the outside. The boron in the water can not flush the corium. Thus its effect is irrelevant.

Sorry my bad english.

Kind regards

http://www.taz.de/1/archiv/print-ar...sort=sw&dig=2011/03/29/a0082&cHash=96559c9d6c

 

[AntonL]

They injecting 14,5m³/h to unit 3 now but temperatures going up not down...

In April water injection was a steady 6m3
4 May increased to 9m³ in response to rising temperature
13 May increased 60 12m³
14 May increased to 15,5m³

However no rise in water level, actually a fall in the last couple of days if water level meters can be trusted after Unit 1 experience. More worrying, is that temperatures in the bottom of reactor are not coming down, I suspect we have the same situation as in Unit 1 but a bit more serious due to the higher temperatures in lower reactor that are not coming down. (2-brown and 4-red as bold lines)

The RPV top body flange (3) and stud bolt (5) temperature sensors are up and down like a yo-yo. However, other temperatures have suddenly shown a steady dramatic rising trend.

I am waiting for the Tepco announcements regarding the state of Unit 3, I think that the core is also in the bottom of the reactor and in a more serious state and Tepco is much concerned as they are injecting huge volumes of water, with no apparent effect, which will be a near-future and costly disposal problem for them. Also they doubled their logging rate, http://www.tepco.co.jp/nu/fukushima-np/f1/images/032_1F3_05150600.pdf

[PLAIN]http://k.min.us/in6LVe.JPG
http://i.min.us/ilcM2M.jpg"

 

[MiceAndMen]

Personally I despise how news services dramatise the news nowadays with video and audio special fx amongst other techniques. Bad news doesn't need to be made to appear worse just for ratings.

Can someone please refresh my memory and say who first posted the Unit 3 boom-boom-boom explosion video? Was it a news network or some random youtube user? I have a very short list of "news media" outlets that I do not trust based on verifiable failures to report the news accurately. I would like to know if that list needs updating. At one time I respected the journalistic profession but those days are long gone (starting around the time Rupert Murdoch arrived on the scene).

Who was responsible for the Youtube posting (that first included the bogus soundtrack) of the explosion at unit 3?

 

[AntonL]

http://www3.nhk.or.jp/daily/english/15_04.html

The company had planned to fill the containment vessel with water and set up a cooling system. But it now says that it will study a plan to circulate water directly from the basement, through a decontamination filter and heat exchanger, and then back into the reactor.

Will this also be the solution for units 2 and 3?

 

[razzz]

Can someone please refresh my memory and say who first posted the Unit 3 boom-boom-boom explosion video? Was it a news network or some random youtube user? I have a very short list of "news media" outlets that I do not trust based on verifiable failures to report the news accurately. I would like to know if that list needs updating. At one time I respected the journalistic profession but those days are long gone (starting around the time Rupert Murdoch arrived on the scene).

Who was responsible for the Youtube posting (that first included the bogus soundtrack) of the explosion at unit 3?

I linked to a video with the audio imbedded, don't know if I was the first. Not sure where I found it when chasing links at the time but clicking on the below link has notations on the video attributing to where it came from, not sure if it is correct or not.

http://sinais2012.blogspot.com/2011/03/fukushima-i-nuclear-power-plant-reactor.html"

I downloaded the video and if you paste the name in a search engine box it will turn up everywhere as a lot of sites used it. Can't say if it was the original name or not.

Fukushima I Nuclear Power Plant Reactor 3 explosion on March

Attached is the Information imbedded in the video.

In the beginning I was more interested in the redness coloring of the plume clouds and noted the audio was out of sync and later posted I couldn't confirm the audio track belonged to the video after posters were skeptical of the sound track as it was shown without audio when first aired, at least that what some comments said about the video. I thought it might be the correct sound but not that important.

 

[elektrownik]

http://www3.nhk.or.jp/daily/english/15_04.html


Will this also be the solution for units 2 and 3?

No ? In unit 1 they inject 10 000 t of water, but they found only 3000 t, so this mean that water is leaking from reactor building... it would be great solution, but with leaks not, (unit 2 is also leaking).

 

[liamdavis]

With respect to the unit 3 reactor pressure vessel. If water were below the fuel, and a significant quantity of corium dropped into it, the volume of steam generated could exceed the capacity of the relief valves and leaks to discharge it. On a graph, a sharp high spike over a short time span would represent this. While this inadequate pressure venting was taking place more water would be able to super heat under the increasing pressure. When catastrophic failure finally occurred water would flash to steam. Modern boilers rarely explode not just because of relief valves but because the controls remove the heat being applied and thus the volume of steam to be vented. That could not be done in this case.

Grist for the mill.
liam

 

[AntonL]

No ? In unit 1 they inject 10 000 t of water, but they found only 3000 t, so this mean that water is leaking from reactor building... it would be great solution, but with leaks not, (unit 2 is also leaking).

No other way round they can account 7000 in PCV and 3000T missing, assumed in the basement and partly leaked to environment.

Basement Half Filled with Water http://jen.jiji.com/jc/eng?g=eco&k=2011051400367

Tokyo Electric Power Co. found Saturday that the basement of a reactor building at its crippled Fukushima No. 1 nuclear power station is half filled with radioactive water. The radioactive water at the plant's No. 1 reactor is likely to have leaked from the containment vessel to the basement of the building that houses the vessel, the plant operator said

However, by reducing basement water level, leakage to environment is reduced.

And I take any bet that 3 is leaking too!

 

[westfield]

Can someone please refresh my memory and say who first posted the Unit 3 boom-boom-boom explosion video? Was it a news network or some random youtube user? I have a very short list of "news media" outlets that I do not trust based on verifiable failures to report the news accurately. I would like to know if that list needs updating. At one time I respected the journalistic profession but those days are long gone (starting around the time Rupert Murdoch arrived on the scene).

Who was responsible for the Youtube posting (that first included the bogus soundtrack) of the explosion at unit 3?

I doubt there is a version of the video with the soundtrack in question that doesn't include a SKY or Channel 9 (Australia) watermark. It sounds more like a SKY presenter. Both love to tart the news up.
But who knows where it originated, this is at least a direct copy of the original, if not the source -

http://video.au.msn.com/watch/video/9raw-hydrogen-explosion-at-nuclear-plant/xy3zbug"
(you may have to sit through an advert unfortunately)

Then here on youtube with the Ch 9 watermark again. (wow, over 2 million views of that clip)
http://www.youtube.com/watch?v=T_N-wNFSGyQ"

NTV who apparently took the footage seem only to show it with a big graphic over the explosion, wt? - http://www.youtube.com/watch?v=vMCa-Zo_ZEU"

 

[PietKuip]

Tokyo Electric Rules Out Future Criticality at No. 1 Reactor

Is there any scientific evidence to support above statement?
http://jen.jiji.com/jc/eng?g=eco&k=2011051400003

This quote is certainly true:

"A lack of water makes it more difficult for criticality, or a self-sustained nuclear fission chain reaction, to happen, the officials said."

 

[zapperzero]

So, the reactors may not have survived the initial earthquake!
complete article here: http://english.kyodonews.jp/news/2011/05/91126.html
"a utility source said Saturday" is this a further Tepco leak but of a kind we need.

I hate being right about this kind of thing. I'm betting on the RHR. Any takers?

 

[razzz]

Better that they leak until the lava flows cool down or the Units would be drowning in radioactive water, the whole site could be unapproachable by humans.

http://en.wikipedia.org/wiki/Corium_%28nuclear_reactor%29"

It's bad enough that they are hundreds of tons of poison masses but it would help if they spread out in the lower containment aka the basemat.

 

[MadderDoc]

<..>
Attached is the Information imbedded in the video.
<..>

? How can the video of the explosion have been
'Encoded UTC 2011-03-13 03:13:11'
'Tagged UTC 2011-03-13 03:13:11'

the explosion at unit 3 was at UTC 2011-03-14 02:01, wasn't it?

 

[MiceAndMen]

I doubt there is a version of the video with the soundtrack in question that doesn't include a SKY or Channel 9 (Australia) watermark. It sounds more like a SKY presenter. Both love to tart the news up.
But who knows where it originated, this is at least a direct copy of the original, if not the source -

http://video.au.msn.com/watch/video/9raw-hydrogen-explosion-at-nuclear-plant/xy3zbug"
(you may have to sit through an advert unfortunately)

Then here on youtube with the Ch 9 watermark again. (wow, over 2 million views of that clip)
http://www.youtube.com/watch?v=T_N-wNFSGyQ"

NTV who apparently took the footage seem only to show it with a big graphic over the explosion, wt? - http://www.youtube.com/watch?v=vMCa-Zo_ZEU"

Thanks westfield, I will do a little more research and see what I can dig up. Appreciate the links.

Just to put my last post in context, my beef is with whatever news organization thought it was OK to add a phony soundtrack to a newsworthy video clip in order to increase viewership ratings (and therefore profits). It's all too common that news organizations routinely put profits uber alles. And my list of trusted news sources is smaller than untrusted list. For those here who took the video sountrack as authentic, I have no problem with that either, even though I suspected it was fake from day 1. Not everyone has experience in looking for the telltale signs of a fake, and to the untrained eyes and ears it was probably very convnicing.

 

[razzz]

? How can the video of the explosion have been
'Encoded UTC 2011-03-13 03:13:11'
'Tagged UTC 2011-03-13 03:13:11'

the explosion at unit 3 was at UTC 2011-03-14 02:01, wasn't it?

Time zone difference when/where tagging??

 

[MadderDoc]

I doubt there is a version of the video with the soundtrack in question that doesn't include a SKY or Channel 9 (Australia) watermark. It sounds more like a SKY presenter. Both love to tart the news up.

Only one of the videos I picked up shortly after the event, had any traces of sound, and that was a video I picked up from BBC. Oh yes, it has a SKY news logo overlayed. There is only a brief bit of sound right at the start, then it fades over to the British presenter: "This was perhaps expected -- certainly feared..."

 

[MadderDoc]

Time zone difference when/where tagging??

The time is given as UTC time. UTC time is very much equal to GMT, it should be the same in whatever which time zone you may be. Assuming the encoding/tagging computer time setting had a minus one day offset error would move the encoding time from 22h48m before the event (impossible), to 1h12m after the event (possible, maybe plausible).

 

[elektrownik]

reactor 3 water level going down (-1950 -2300), temperature up, and they injecting 15,5m3/h now...

 

[NUCENG]

NUCENG, thanks for your detailed answers. So, from what you wrote it seems most likely to me that they brought the core shroud in through the refueling tunnel/entrace. It seems to involve fewer complications to use the existing building features than to construct new openings in the building. Also, no such round hole in the roof can be seen in unit 4. Further, a square hole would probably have been easier to cut into the roof than a round one.

Follow-up question (just curious): Do we know what was the status of the core shroud replacement in unit 4?

Also, NUCENG, with all your inside knowledge, would you mind commenting on my question about why the SFPs in these type of BWRs are apparently not covered with concrete shield plugs during normal operation, which I had already brought up twice in this thread, but no one has picked up on it yet?

Just followup. I haven't found any discussions of covering spent fuel pools. So the following points are just ideas that may be involved.

1. If they were covered at Fukushima it may have made it harder to add water to the spent fuel pools.
   
2. Spent fuels are warm due to decay heat. There would be a hot moist environment below a cover. That could accelerate corrosion or degradation of concrete.
   
3. Covering the pools may increase the demand on fuel pool cooling systems by preventing evaporation cooling at the surface of the pool. It also might result in faster heatup following a loss of Fuel pool cooling.
5. Concrete covers would be heavy loads and would have to be put on and taken off frequently. That could be a higher risk to the spent fuel that a seismic event.
6. Covering pools could allow gas buildup under the cover.
7. Currently fuel pool level is easily visible. Failure of level instrumentation while the pool is covered could be a problem.

I haven't found any discussion of design basis that would require a cover. The exclusion of debris and dirt is handled by loose parts programs, skimmers, and filtration on pool water. Obviously, if the roof caves in these systems aren't up to that task.

 

[Rive]

Just followup. I haven't found any discussions of covering spent fuel pools.

Some NPPs has separate pools to receive fuel casks. These pools are connected with the main pool by channels, as it can be seen on the general BWR GE MK1 drawing. I've checked this SFP-covering thing through my NPP-pictures collection, and these additional pools looks missing on some pictures, even if that NPP has such pools.

Of course it's possible that I made some mistakes during collecting the pictures, but maybe it worth to consider if these covers belongs to the additional pools.

 

[swl]

reactor 3 water level going down (-1950 -2300), temperature up, and they injecting 15,5m3/h now...

Sounds bad. What was the source of data?

 

[jlduh]

Just followup. I haven't found any discussions of covering spent fuel pools. So the following points are just ideas that may be involved.

1. If they were covered at Fukushima it may have made it harder to add water to the spent fuel pools.
   
2. Spent fuels are warm due to decay heat. There would be a hot moist environment below a cover. That could accelerate corrosion or degradation of concrete.
   
3. Covering the pools may increase the demand on fuel pool cooling systems by preventing evaporation cooling at the surface of the pool. It also might result in faster heatup following a loss of Fuel pool cooling.
5. Concrete covers would be heavy loads and would have to be put on and taken off frequently. That could be a higher risk to the spent fuel that a seismic event.
6. Covering pools could allow gas buildup under the cover.
7. Currently fuel pool level is easily visible. Failure of level instrumentation while the pool is covered could be a problem.

I haven't found any discussion of design basis that would require a cover. The exclusion of debris and dirt is handled by loose parts programs, skimmers, and filtration on pool water. Obviously, if the roof caves in these systems aren't up to that task.

An article on this subject of sabotage or terrorism and SFPs:

http://belfercenter.ksg.harvard.edu/publication/364/radiological_terrorism.html

 

[NUCENG]

Some NPPs has separate pools to receive fuel casks. These pools are connected with the main pool by channels, as it can be seen on the general BWR GE MK1 drawing. I've checked this SFP-covering thing through my NPP-pictures collection, and these additional pools looks missing on some pictures, even if that NPP has such pools.

Of course it's possible that I made some mistakes during collecting the pictures, but maybe it worth to consider if these covers belongs to the additional pools.

I have not seen any covered spent fuel pools in the plants I have visited, toured, or worked at. Nor have I found reguatory mentions of covered pools in US or International websites. There may be such pools, I just found nothing definitive, so I tried to think of reasons why covering a pool might be problematic - thus my list in the previous post.

The OP pdObq was asking a question that he had apparently asked before without response. I think he assumed a cover might have protected the fuel in the pools at Fukushimafrom the debris from the explosions. It is a legitimate question that deserves an answer. I'm hoping my post may trigger some discussion about whether covering fuel pools would be a good idea based on what happened at Fukushima.

 

[Rive]

...

Maybe I made a mistake - I thought that this thread is the followup of the SFP coverings found on some equipment weight/movement list. What I intended to say is that maybe those covers belongs to the additional (cask receive) pools and channels, because on some pictures they are visible, but they looks missing or covered on some other pictures.

Sorry for the confusion.

 

[Samy24]

Because of the rising temperatures they may fear criticality in unit 3.

At 2:33 pm on May 15, we started injecting boric acid through the fire
extinction system.

http://www.tepco.co.jp/en/press/corp-com/release/11051503-e.html"

 

[NUCENG]

It was already reported in March that Technicium99m was found.
In one German media is thus based on criticality.
Often the argument of the rapidly declining decay heat is given. Normally, should have reassured the nuclei after two months of cooling.
Nevertheless, the temperature in the reactors.
For me, the rise in temperature is an indication of criticality and thus increasing or constant temperature, despite cooling.
Perhaps the corium has formed a skin. The corium is washed with water from the outside. The boron in the water can not flush the corium. Thus its effect is irrelevant.

Sorry my bad english.

Kind regards

http://www.taz.de/1/archiv/print-ar...sort=sw&dig=2011/03/29/a0082&cHash=96559c9d6c

I hope I understand your question. Tc-99m has a half life of only 6 hours and was still being measured in late March. You are asking if that would support a conclusion that the reactor had gone recritical. Tc99m is also being produced by a decay chain of other fission products from Rb99 to Sr99 to Y99 to Zr99 to Nb99 to Mo99 to Tc99m and Tc99 due to beta decay. It also has inputs from beta, neutron decays of Rb100, Sr100, and Y100. Most of these parent isotopes have half lives in seconds or fractions of seconds and are gone in about 30 minutes. However Mo99 has a 66 hour half life and will continue producing measureable Tc99m for about 30 days post-shutdown. So only measureable Tc99m or increases in sampes after the middle of April would need to be investigated seriously for evidence of criticality.

Rising temperatures may be due to poor cooling, and don't need criticality to happen. If the corium does have a skin and water is only cooling the skin the corium deeper in the pile would not have an effective moderator to permit thermal fission. Boron in water outside the skin would continue to absorb neutrons preventing them from being reflected back into the corium. So although there may be a lot of uranium in the corium mass it may still be lacking in thermal neutrons for fission.