Japan Earthquake: Nuclear Plants at Fukushima Daiichi

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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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