Japan Earthquake: Nuclear Plants at Fukushima Daiichi

AI Thread Summary
The Fukushima Daiichi nuclear plant is facing significant challenges following the earthquake, with reports indicating that reactor pressure has reached dangerous levels, potentially 2.1 times capacity. TEPCO has lost control of pressure at a second unit, raising concerns about safety and management accountability. The reactor is currently off but continues to produce decay heat, necessitating cooling to prevent a meltdown. There are conflicting reports about an explosion, with indications that it may have originated from a buildup of hydrogen around the containment vessel. The situation remains serious, and TEPCO plans to flood the containment vessel with seawater as a cooling measure.
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  • #3,302
artax said:
I'm interested in the latest thermal imaging of the site, can you get hold of it?

http://www.mod.go.jp/j/approach/defense/saigai/tohokuoki/kanren/230408.pdf
 
  • #3,303
"Still, concerns about the plant remain high. The Nuclear Regulatory Commission speculated Wednesday that some of the core of the No. 2 reactor had flowed from its steel pressure vessel into the bottom of the containment structure. The theory implies more damage at the unit than previously believed.

While a spokeswoman for Tokyo Electric dismissed the analysis, a spokesman for the Nuclear and Industrial Safety Agency of Japan agreed that it was possible that the core had leaked into the larger containment vessel.

The possibility raised new questions. The Nuclear Regulator Commission said that its speculation about the flow of core material out of the reactor vessel would explain high radiation readings in an area underneath, called the drywell.

But some of the radiation readings at Reactors Nos. 1 and 3 over the last week were nearly as high as or higher than the 3,300 rems per hour that the commission said it was trying to explain, so it would appear that the speculation would apply to them as well. At No. 2, extremely radioactive material continues to ooze out of the reactor pressure vessel, and the leak is likely to widen with time, a western nuclear executive asserted.

“It’s a little like pulling a thread out of your tie,” said the executive, who spoke on the condition of anonymity to protect business connections in Japan. “Any breach gets bigger.”

Flashes of extremely intense radioactivity have become a serious problem, he said. Tokyo Electric’s difficulties in providing accurate information on radiation are not a result of software problems, as some Japanese officials have suggested, but stem from damage to measurement instruments caused by radiation, the executive said.

Broken pieces of fuel rods have been found outside of Reactor No. 2, and are now being covered with bulldozers, he said. The pieces may be from rods in the spent-fuel pools that were flung out by hydrogen explosions. "

http://www.nytimes.com/2011/04/09/world/asia/09japan.html?ref=world"
 
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  • #3,304
shogun338 said:
Broken pieces of fuel rods have been found outside of Reactor No. 2, and are now being covered with bulldozers, he said. The pieces may be from rods in the spent-fuel pools that were flung out by hydrogen explosions. Looks like we where right about fuel rods blown out of spent fuel pools .

Astronuc said:
According to whom? Please cite sources when making claims.

[PLAIN]http://k.min.us/ik74PC.JPG
http://www.nytimes.com/2011/04/09/world/asia/09japan.html?_r=2and

[PLAIN]http://k.min.us/imOrOa.JPG
"[URL Report, Official Use Only, Fukushima Assessment, March 26th, 2011
last paragraph page 13[/URL]
 
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  • #3,306
elektrownik said:
http://www.mod.go.jp/j/approach/defense/saigai/tohokuoki/kanren/230408.pdf

The latest thermal imagery, including the window/level scale on the left hand side show the highest temperatures of Bldgs. 1-4.

I believe these are 23C and 33C at Bldg 1, not sure which structures, but presumably the SFP and over the region of the reactor, the 30C hole in the east face of Bldg 2, the 35C SFP 3 and the 46C SFP4, partially obscured by the FHM, complete with tabular data of the temps and daily trends measured at the indicated hot spot (arrow) on the right. Presumably, the measured temperatures could be accurately calibrated against areas of background ambient temperature (and that almost certainly wouldn't be a bucket of liquid nitrogen).

Thanks for posting, electrownik.

PS: for any of those currently experiencing an alternate "dog star" reality, I see nothing hilarious here and see no reason to question |Fred's IQ.

see:
https://www.physicsforums.com/showpost.php?p=3235922&postcount=3309
 
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  • #3,308
NISA has reported some of the 7 April aftershock consequences : http://www.chunichi.co.jp/s/article/2011040990003059.html

According to that article :

Cooling at Onagawa plant's fuel pools was stopped for 1 hour 23 minutes at unit 2, 59 minutes at unit 3, 53 minutes at unit 1.

Cooling at the Higashidori plant's pool was stopped for 26 minutes.

Radiation within Fukushima Daiichi plant's unit 1 containement rose to 100 Sv/h up from the earlier 30 Sv/h, but the validity of the measurement is questioned. Temperature at that unit went up from 223°C to 260°C then later decreased to 246°C.
 
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  • #3,309
I think the vgb doc Its a good collection of most available (unit 1 and 3 have been reported flooded, that's the only detail I could point out after a brief read), thanks ohohoh

AntonL, I have the intuition that the article comes down to the previously mentioned leaked email , with some cheese around.. Could be mistaken of course.
|Fred said:
<click

edit: the more I look into this leaked mail story the more I have the feeling there is a agenda at play, that one could resume as congressman ask NRC information change a could be to a there is in order to make his point.

quoted from http://www.marketwatch.com April 6, 2011, 8:41 p.m

Rep. Ed Markey (D., Mass.), a critic of nuclear power, said in a statement that the NRC believes the core of Unit 2 at the Fukushima plant has "gotten so hot that part of it has probably melted through the reactor pressure vessel." Mr. Markey also said that at least one other reactor core has been severely damaged.

Speaking to reporters Wednesday, Mr. Virgilio said the NRC didn't have evidence that the core at Fukushima's Unit Two had melted through the reactor vessel.

"That's not in the situation report that we have from the team in Japan, and that's as of this morning," he said.

The NRC, he said, believes there was significant fuel damage in three reactors and four spent-fuel pools, "but we don't believe at this point in time that that core has left the vessel.""

Anyhow that's US politic and am clueless on that matter
 
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  • #3,310
TCups said:
PS: for any of those currently experiencing an alternate "dog star" reality, I see nothing hilarious here and see no reason to question |Fred's IQ.

Love hurts (?)
 
  • #3,311
Has the Onagawa plant been given an accident number or rating?
 
  • #3,312
hbjon said:
Has the Onagawa plant been given an accident number or rating?
Unless they have fuel failures, or core or containment failures, there is no accident, and therefore no need for a rating at this time. If they lose power or cooling, but regain it within a specified time limit, it's not reportable as an accident.

http://www.world-nuclear-news.org/RS_New_earthquake_disrupts_grid_power_0704111.html

Diesel generators have replaced grid power at Higashidori nuclear power plant . . . .

Power from the grid through two of three connections was lost at the Onagawa nuclear power plant, where three reactors have been in cold shutdown since 11 March. Cooling systems are still in operation. . . .
As far as I know, Onagawa still has connection to the grid. There EDGs are apparently operational.
 
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  • #3,313
Now, in the light of recent experience at Fukushima, Tepco is proposing to design and install a system of tide barriers with watertight doors at Kashiwazaki Kariwa units 1 to 4. In addition, the company says it has installed facilities on the upland part of the site to provide backup power and water injection to both reactors and spent fuel pools, and taken measures to ensure cooling functions in the event of tsunamis flooding the reactor buildings. http://www.world-nuclear-news.org/RS-Tsunami_countermeasures_for_Kashiwazaki_Kariwa-0804118.html
 
  • #3,314
shogun338 said:
Now, in the light of recent experience at Fukushima, Tepco is proposing to design and install a system of tide barriers with watertight doors at Kashiwazaki Kariwa units 1 to 4. In addition, the company says it has installed facilities on the upland part of the site to provide backup power and water injection to both reactors and spent fuel pools, and taken measures to ensure cooling functions in the event of tsunamis flooding the reactor buildings. http://www.world-nuclear-news.org/RS-Tsunami_countermeasures_for_Kashiwazaki_Kariwa-0804118.html

Will that be sufficient to reassure the Group of Concerned Scientists and Engineers Calling for the Closure of the Kashiwazaki-Kariwa Nuclear Power Plant (　Japanese blog at http://kkheisa.blog117.fc2.com ; Initial 2007 English statement at http://cnic.jp/english/topics/safety/earthquake/kkscientist21aug07.html ) ?
 
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  • #3,315
Astronuc said:
Unless they have fuel failures, or core or containment failures, there is no accident, and therefore no need for a rating at this time. If they lose power or cooling, but regain it within a specified time limit, it's not reportable as an accident.

They might have to signal it as a level-1 incident, no ? Or even as a level-0 anomaly ?
 
  • #3,316
vanesch said:
They might have to signal it as a level-1 incident, no ? Or even as a level-0 anomaly ?

Fukushima Daini reactors 1,2,4 are INES 3...
 
  • #3,317
Proposals made by 16 Japanese experts on nuclear power engineering, nuclear physics and radiology on April 1 : http://search.japantimes.co.jp/cgi-bin/ed20110407a1.html
 
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  • #3,318
tsutsuji said:
NISA has reported some of the 7 April aftershock consequences : http://www.chunichi.co.jp/s/article/2011040990003059.html

According to that article :

...

Radiation within Fukushima Daiichi plant's unit 1 containement rose to 100 Sv/h up from the earlier 30 Sv/h, but the validity of the measurement is questioned. Temperature at that unit went up from 223°C to 260°C then later decreased to 246°C.

I'm part of the newbies brought to this quality conversation by the focus on a rational analysis of this event. I'm just impressed !

Well, if we make the assumption that CAMS reading are trustable for drywell 1, in reactor 1 radiation spikes; this seems to be correlated to temperature. What is the likely cause of radiation spikes with quick decrease, with temperature being correlated, and SPC radiation not increasing ?

Do CAMS only measures gamma radiation ?
 
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  • #3,319
jpquantin said:
I'm part of the newbies brought to this quality conversation by the focus on a rational analysis of this event. I'm just impressed !

Well, if we make the assumption that CAMS reading are trustable for drywell 1, in reactor 1 radiation spikes; this seems to be correlated to temperature. What is the likely cause of radiation spikes with quick decrease, with temperature being correlated, and SPC radiation not increasing ?

Do CAMS only measures gamma radiation ?
According to the article - The Continuous Air Monitoring (CAM) PIPS Detector--Properties and Applications - this particular type of detector detects/counts alpha and beta particles.
http://www.canberra.com/literature/946.asp
http://www.canberra.com/products/509.asp

This one counts beta/gamma -
http://www.canberra.com/products/543.asp

I suspect they use a beta-gamma detector, and it has to be rated for the temperature limit in the containment. That precludes several scintillation detectors. Perhaps they use compensated GM detectors.
 
  • #3,320
shogun338 said:
Now, in the light of recent experience at Fukushima, Tepco is proposing to design and install a system of tide barriers with watertight doors at Kashiwazaki Kariwa units 1 to 4. In addition, the company says it has installed facilities on the upland part of the site to provide backup power and water injection to both reactors and spent fuel pools, and taken measures to ensure cooling functions in the event of tsunamis flooding the reactor buildings. http://www.world-nuclear-news.org/RS-Tsunami_countermeasures_for_Kashiwazaki_Kariwa-0804118.html

One of the problems at the Fukushima nuclear accident is we did not know reactor conditions well after the earthquake and tsunami attack. We think about reactor measuring system again. We have to make the measuring instruments of the very important parts of nuclear plant as dual system. One is for controlling and the other is for emergency situation. The emergency instruments must have it's own battery, and have a wireless communication system to transfer data to outside. If after tsunami attack we knew the plant condition more well, present big nuclear disaster would not happen. We could do proper treatment against the dangerous situation.
 
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  • #3,321
daumphys said:
One of the problems at the Fukushima nuclear accident is we did not know reactor conditions well after the earthquake and tsunami attack. We think about reactor measuring system again. We have to make the measuring instruments of the very important parts of nuclear plant as dual system. One is for controlling and the other is for emergency situation. The emergency instruments must have it's own battery, and have a wireless communication system to transfer data to outside. If after tsunami attack we knew the plant condition more well, present big nuclear disaster would not happen. We could do proper treatment against the dangerous situation.

wireless communication is very difficult in a building like a reactor. It's probably impossible near the RPV.
 
  • #3,322
OFFTOPIC: http://noe.orf.at/stories/509185/" reports that wild hog meat bought in supermarkets has Cesium radiation levels of 1060 Bq/kg (allowed 600Bq/kg). This is a result of the hog's preference in the winter season to forage for a type of truffle (mushroom) which is deep in the ground and as such more likely to be contaminated by Cesium fallout from Tschernobyl of 25 years ago.
 
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  • #3,323
I linked to this way back when...

Contaminated Wild Pig

Wild boar are particularly susceptible to radioactive contamination due to their predilection for chomping on mushrooms and truffles, which are particularly efficient at absorbing radioactivity. Indeed, whereas radioactivity in some vegetation is expected to continue declining, the contamination of some types of mushrooms and truffles will likely remain the same, and may even rise slightly -- even a quarter century after the Chernobyl accident.

From..."[URL Quarter Century after Chernobyl
Radioactive Boar on the Rise in Germany[/URL]
 
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  • #3,324
Latest simulation out of http://db.eurad.uni-koeln.de/prognose/data/alert/ddcs_hem_1h_movtotal_1.gif" presents the high-end possibility of as much as 10Bq (Cs-137) in air within the next few days within my country. Converting this value to absorbed dose, this activity will presumably yield about 2 microsieverts/hr at a distance/depth of 1 cm. If anybody could anyone confirm/clarify this calculation, i would greatly appreciate it as i am a bit perturbed right now. Thank you for this forum. It is such a tremendous resource.
 
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  • #3,325
intric8 said:
Latest simulation out of http://db.eurad.uni-koeln.de/prognose/data/alert/ddcs_hem_1h_movtotal_1.gif" presents the high-end possibility of as much as 10Bq (Cs-137) in air within the next few days within my country. Converting this value to absorbed dose, this activity will presumably yield about 2 microsieverts/hr at a distance/depth of 1 cm. If anybody could anyone confirm/clarify this calculation, i would greatly appreciate it as i am a bit perturbed right now. Thank you for this forum. It is such a tremendous resource.

I can't answer your question, but what country are you in?
 
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  • #3,326
LIKE MOST Japanese men, Katsunobu Sakurai read apocalyptic comic-book stories about the future when he was a boy. He never expected to live through one of those stories.

A common plot sees a modern city reduced overnight to a ghostly husk as fears of nuclear contamination empty it of people. Businesses shut and food, water and petrol run out. Old people left behind begin to die. The city mayor makes a desperate televised appeal for help. Such is real life in Sakurai’s city of Minamisoma.

More than 71,000 people lived here before March 11th. Today there are fewer than 10,000. About 1,470 are dead or missing, the remainder are scattered throughout Japan in more than 300 different locations, “as far as we can tell”, says Sakurai, who took over as mayor in January.

Dangling from his neck are two radiation counters, a reminder that the nightmare that descended on his city last month has yet to end. http://www.irishtimes.com/newspaper/world/2011/0409/1224294302687.html
 
  • #3,327
I'll be in the Philippines until June. Using http://www.radprocalculator.com/Beta.aspx" to calculate the dose. I'm almost positive these values are given in air; also assuming ingestion and so-called bragg peak, an electron at 0.5 cm would efficiently be giving up its full dose at about a 1/2 - 1 cm depth, which could make absorbed dose even higher. 10 Bq of activity in which each electron were to strike the skin would account for a similar absorbed dose, for all practical purposes, though biological effect and organs of interest would differ.

It seems like converting Bq to absorbed dose is very tricky and accurate answers are hard to come by.
 
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  • #3,328
meant to say "an electron in the 0.5 mev range" would efficiently be giving up its full dose at about a 1/2 - 1 cm depth.
 
  • #3,329
Japan expects to stop pumping radioactive water into the sea from a crippled nuclear plant on Saturday, a day after China expressed concern at the action, reflecting growing international unease at the month-long nuclear crisis.
"The emptying out of the relatively low radiation water is expected to finish tomorrow (Saturday)," a Tokyo Electric Power Co (TEPCO) official said late on Friday. http://newsonjapan.com/html/newsdesk/article/88775.php
 
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  • #3,330
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  • #3,331
Astronuc said:
According to the article - The Continuous Air Monitoring (CAM) PIPS Detector--Properties and Applications - this particular type of detector detects/counts alpha and beta particles.
http://www.canberra.com/literature/946.asp
http://www.canberra.com/products/509.asp

This one counts beta/gamma -
http://www.canberra.com/products/543.asp

I suspect they use a beta-gamma detector, and it has to be rated for the temperature limit in the containment. That precludes several scintillation detectors. Perhaps they use compensated GM detectors.

The abreviation CAMS in a BWR may also refer to Containment Atmosphere Monitoring System. This system measures and records H2 and O2 concentrations as well as radiation (if there is power). It is classified as Post-Accident Monitoring Instrumentation and was installed after TMI-2.
 
  • #3,332
NUCENG said:
The abreviation CAMS in a BWR may also refer to Containment Atmosphere Monitoring System. This system measures and records H2 and O2 concentrations as well as radiation (if there is power). It is classified as Post-Accident Monitoring Instrumentation and was installed after TMI-2.
Yup *3 CAMS : Containment Atmospheric Monitoring System http://www.nisa.meti.go.jp/english/files/en20110409-4-3.pdf"
 
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  • #3,334
To be exact it is a map of the annual dosage extrapolated from radiation output measured over 3 days by the (DOE/NNSA) flying thing between the 30 Mars and the 3rd April.
 
  • #3,335
NUCENG said:
The abreviation CAMS in a BWR may also refer to Containment Atmosphere Monitoring System. This system measures and records H2 and O2 concentrations as well as radiation (if there is power). It is classified as Post-Accident Monitoring Instrumentation and was installed after TMI-2.

Has Tepco released H2 and O2 concentrations?
 
  • #3,336
amongst many other things, I'd be curious to know if the japanese also implemented something similar to the USNRC regulatory guide 1.97 for post accident monitoring.
 

Attachments

  • #3,337
http://english.kyodonews.jp/news/2011/04/84251.html"

Companies dispatching workers to Tokyo Electric Power Co.'s crippled Fukushima Daiichi nuclear power plant are refusing to adopt the government-imposed provisional limit on radiation exposure for those workers at the plant, saying it would not be accepted by those at the site, Kyodo News learned Saturday.

The limit was lifted from 100 millisieverts to 250 millisieverts in an announcement made March 15 by the Ministry of Health, Labor and Welfare at the request of the Ministry of Economy, Trade and Industry, which has the Nuclear and Industrial Safety Agency under its wing, and other bodies.

The increase was requested to enable workers to engage in longer hours of assignments and to secure more workers who meet the restriction.

The advisability of the hastily decided limit may be called into question as workers have to handle a wider range of work over an extended period of time. They are now faced with tasks such as removing rubble and disposing of contaminated water in addition to their initial job of restoring the lost power sources at the plant that was crippled by the March 11 quake and tsunami.

The contract companies say they are sticking to the previous limit.
 
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  • #3,338
NUCENG said:
The abreviation CAMS in a BWR may also refer to Containment Atmosphere Monitoring System. This system measures and records H2 and O2 concentrations as well as radiation (if there is power). It is classified as Post-Accident Monitoring Instrumentation and was installed after TMI-2.
That is the context of CAMS. I was looking for the type of radiation detector used in CAMS. I apologize for the confusion.

There is a short statement in the ABWR DCD, page 7.6-17, http://www.nrc.gov/reactors/new-reactors/design-cert/abwr/dcd/tier-2/CH_07/07_06.pdf
Each gamma radiation channel consists of an ion chamber, a log radiation monitor, and a recorder. Each channel has a range of 0.01 Gy/h to 105 Gy/h.

In an older operating plant which uses Mk I containment - "During CAM system operation, containment atmosphere is withdrawn through piping connected to primary containment penetrations for obtaining both a drywell and suppression chamber air sample. Hydrogen and oxygen concentration are measured outside the primary containment (evaluated with the primary containment structure) and the sample returned to the primary containment. The sample withdrawal lines in both cases are heat traced to prevent condensation in the sample lines which would cause measurement inaccuracies. A check valve is installed in the return discharge line for primary containment. In addition, a check valve is installed in each reagent and calibration gas line for primary containment. The containment atmosphere monitoring system consists of oxygen and hydrogen analyzer process instrumentation and various indication and annunciation instruments, primary containment monitoring panels, and gross gamma detector channels (from detector to annunciator and computer points). The system is automatically activated upon the occurrence of a LOCA, or manually by an operator. The system initiates a primary containment group 2 isolation on high radiation."
From - http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1796/sr1796.pdf - see page 246 of 965. In the pdf, search on 'Containment Atmosphere Monitoring System'.

So it appears that the CAM radiation detectors are gamma only.


FYI - Books on Nuclear Safety
http://books.google.com/books?id=wivyuNAvtTEC

This subject may be worthy of it's own thread.
 
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  • #3,339
Astronuc said:
That is the context of CAMS. I was looking for the type of radiation detector used in CAMS. I apologize for the confusion.

There is a short statement in the ABWR DCD, page 7.6-17, http://www.nrc.gov/reactors/new-reactors/design-cert/abwr/dcd/tier-2/CH_07/07_06.pdf


In an older operating plant which uses Mk I containment - "During CAM system operation, containment atmosphere is withdrawn through piping connected to primary containment penetrations for obtaining both a drywell and suppression chamber air sample. Hydrogen and oxygen concentration are measured outside the primary containment (evaluated with the primary containment structure) and the sample returned to the primary containment. The sample withdrawal lines in both cases are heat traced to prevent condensation in the sample lines which would cause measurement inaccuracies. A check valve is installed in the return discharge line for primary containment. In addition, a check valve is installed in each reagent and calibration gas line for primary containment. The containment atmosphere monitoring system consists of oxygen and hydrogen analyzer process instrumentation and various indication and annunciation instruments, primary containment monitoring panels, and gross gamma detector channels (from detector to annunciator and computer points). The system is automatically activated upon the occurrence of a LOCA, or manually by an operator. The system initiates a primary containment group 2 isolation on high radiation."
From - http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1796/sr1796.pdf - see page 246 of 965. In the pdf, search on 'Containment Atmosphere Monitoring System'.

So it appears that the CAM radiation detectors are gamma only.


FYI - Books on Nuclear Safety
http://books.google.com/books?id=wivyuNAvtTEC

This subject may be worthy of it's own thread.

So is there a sensible reading why the reading on drywell of reactor 1 might suddenly jump? and then they appear to have stopped publishing results for the last two reports?
 
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  • #3,340
ceebs said:
http://english.kyodonews.jp/news/2011/04/84251.html" ... The limit was lifted from 100 millisieverts to 250 millisieverts in an announcement made March 15 by the Ministry of Health, Labor and Welfare...

Professor Cham Dallas of the University of Georgia, who is visiting Japan, was interviewed yesterday :

２倍にする科学的根拠はない。作業員を確保するためだろう。よくないことだ。http://www.zakzak.co.jp/society/domestic/news/20110408/dms1104081619027-n1.htm

"There is no scientific ground for making it twice. This should be for protecting workers. It is a bad thing."
 
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  • #3,341
michael200 said:
amongst many other things, I'd be curious to know if the japanese also implemented something similar to the USNRC regulatory guide 1.97 for post accident monitoring.
I would expect so. However, this particular accident is beyond what TEPCO personnel ever expected.

Looking at the literature regarding CAMS, it is an air flow system. What happens when containment is flooded, or there is a persistent high radiation situation above the alarm limit? One of the documents talks about calibrating after an accident, but does that work in the presence of a persistent high-level radation field. A lot of the guidance seem to implicitly assume that an event or accident won't be allowed to get as bad as it has gotten at FK.
 
  • #3,342
So does that imply that the problem at reactor 1 is worse than at the other two? in that the results there seem to be following expected decay curves Even though the major problems such as pressure vessel puncturing are all reported at reactors 2 and 3?
 
  • #3,343
ceebs said:
So does that imply that the problem at reactor 1 is worse than at the other two? in that the results there seem to be following expected decay curves Even though the major problems such as pressure vessel puncturing are all reported at reactors 2 and 3?
It's difficult to say. Each unit has varying degrees of damage. Visibly, we see that Unit 3 secondary containment - the upper metal structure is the most damage - which would mean a larger explosion (ostensibly due to hydrogen detonation) than say Unit 1 and certainly than Units 2 and 4. We don't know if the SFPs are intact or not, and we don't know what pipes or vessels have been cracked/broken. There has been a lot of speculation.

What we cannot know at the moment is the extent of damage in the concrete containments and RPV. From the high radiation fields, we can expect that a lot of fuel has breached, although not necessarily melted.

Other than gamma (or gamma + beta) radiation detection, it's not clear what other techniques, if any, are being used. One technique, inductively couple plasma (ICP) emission can be used to discern particular elements, but does not distquish between isotopes. Then there is ion mass spectroscopy. But the techniques require certain treatment of the samples.
 
  • #3,344
ceebs said:
So does that imply that the problem at reactor 1 is worse than at the other two? in that the results there seem to be following expected decay curves Even though the major problems such as pressure vessel puncturing are all reported at reactors 2 and 3?
Nobody knows for certain. The potential is there for tremendous additional difficulty. The hope is that everything will quiet down and the world can talk of Fukushima in the past tense.
 
  • #3,345
If the drywell is flooded, then probably only thing they can do is attempt to monitor through the post accident sampling system (PASS). Unfortunately, like everything else, there is a need to have some electrical power for this system. Considering the general area dose rates that they are measuring, it may be doubtful that they can access even the PASS system.
However, I'm not sure that the drywell is actually flooded- nor to what level in the containment it is flooded. Another unclear aspect of this entire series of events.
 
  • #3,346
Astronuc said:
From the high radiation fields, we can expect that a lot of fuel has breached, although not necessarily melted.

With the high readings, is it in any way possible to say how much to any degree more than "a lot"
 
  • #3,347
Atlanta (CNN) -- Two of the world's largest concrete pumps will depart the United States later this week as part of the effort to resolve the crisis at Japan's Fukushima Daiichi nuclear power plant, officials said.

Each pump weighs 190,000 pounds and has a boom reach of over 227 feet, and can pump water and concrete at massive rates. They will be loaded aboard enormous Russian cargo jets Friday.
http://www.dailymail.co.uk/news/art...ukushima-nuclear-plant.html?ito=feeds-newsxml

http://edition.cnn.com/2011/WORLD/asiapcf/04/07/japan.concrete.pumps/
 
  • #3,348
Some knowledge on seismic/tsunami safety plant design :

* 1st Kashiwazaki International Symposium on Seismic Safety of Nuclear Installations, November 2010 : http://www.jnes.go.jp/seismic-symposium10/presentationdata/content.html

includes tsunami safety presentations : http://www.jnes.go.jp/seismic-symposium10/presentationdata/3_sessionB.html

includes "Tsunami assessment for nuclear power plants in Japan" M.Takao, TEPCO : http://www.jnes.go.jp/seismic-symposium10/presentationdata/3_sessionB/B-11.pdf

includes Open Seminar "Overview of Tsunami assessment" by A. Yalciner : http://www.jnes.go.jp/seismic-symposium10/presentationdata/Open_Semi/3-1_yalcinerE.pdf (99 pages, 17 Mbyte)

* International Technical Meeting on Seismic Safety of Nuclear Power Plants, Tivoli (Roma) - Italy March 25-26, 2010 : http://www.iter-consult.it/Meetings&Courses/ITM Tivoli/Presentations ITM Tivoli.htm

includes Seismic safety requirements for NPP and experience feedback in Japan (JNES, Japan Nuclear Energy Safety Organization) : http://www.iter-consult.it/Meetings...P and experience feedback in Japan (JNES).pdf by Yoshi Fukushima

* IAEA/JNES/NIED Seminar on Nuclear Disaster & General Disaster Management against Tsunami and Earthquake, Tokyo, December 2007 http://www.jnes.go.jp/pickup/event/tipeez.html (English programme : http://www.jnes.go.jp/content/000015467.pdf )

includes “Safety Assessment and Disaster Management for Tsunami Hazards at Onagawa Nuclear Power Plant”, Y. Matsumoto, (Tohoku Epco, Japan) : http://www.jnes.go.jp/content/000015486.pdf (in Japanese)

includes "IAEA - EBP on Tsunami Safety" by Antonio Godoy : http://www.jnes.go.jp/content/000015488.pdf (in English)

*Japan Society of Civil Engineers "Tsunami Assessment Method for Nuclear Power Plants in Japan" (2002) http://www.jsce.or.jp/committee/ceofnp/Tsunami/eng/JSCE_Tsunami_060519.pdf
 
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the impact on the nuclear power plant...

http://energheia.bambooz.info/index.php?option=com_content&view=article&id=158%3A-tsunami-wave-smashes-into-nuclear-plant&catid=60%3Avideo&Itemid=85&lang=en
 
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