Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[shogun338]

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

 

[intric8]

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.

 

[intric8]

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.

 

[shogun338]

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

 

[shogun338]

Due to the Tohoku-Taiheiyou-Oki Earthquake which occurred on March 11th
2011, TEPCO's facilities including our nuclear power stations have been
severely damaged. We deeply apologize for the anxiety and inconvenience
caused. http://www.tepco.co.jp/en/press/corp-com/release/11040901-e.html

 

[NUCENG]

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.

 

[flyingblind]

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"

 

[tsutsuji]

A map of contaminated areas in Fukushima prefecture is available on page 6 of http://www.irsn.fr/FR/Actualites_pr...s/IRSN_Residents-Japon_Bulletin2_08042011.pdf

 

[|Fred]

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.

 

[Taxidermista]

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?

 

[michael200]

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.

 

[ceebs]

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.

 

[Astronuc]

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.

 

[ceebs]

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?

 

[tsutsuji]

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."

 

[Astronuc]

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.

 

[ceebs]

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?

 

[Astronuc]

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.

 

[Joe Neubarth]

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.

 

[michael200]

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.

 

[ceebs]

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"

 

[Krikkosnack]

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/

 

[tsutsuji]

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

 

[michael200]

in same link: http://www.dailymail.co.uk/news/art...ukushima-nuclear-plant.html?ito=feeds-newsxml

Picture of Tsunami impact at fukushima 1 site.

 

[Krikkosnack]

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

 

[michael200]

oops

http://www.jnes.go.jp/seismic-symposium10/presentationdata/3_sessionB.html

 

[Krikkosnack]

latest photos...
http://cryptome.org/eyeball/daiichi-npp5/daiichi-photos5.htm

 

[AntonL]

also http://www3.nhk.or.jp/daily/english/09_30.html extracted from http://www.meti.go.jp/press/2011/04/20110409007/20110409007-3.pdf
turbine buildings submerged in 4-5 meter water on seaward side
[PLAIN]http://k.min.us/ikGIkI.JPG
[PLAIN]http://k.min.us/ikGSPw.JPG

 

[AntonL]

Basement flooding in the solid waste volume reduction building
water height = about 13/16 wellington boot size 6.5

[PLAIN]http://k.min.us/ikLtOi.JPG

more here: http://www.meti.go.jp/press/2011/04/20110409001/20110409001-5.pdf

 

[AntonL]

water quality at No 2 inlet where the leak was

[PLAIN]http://k.min.us/imOSaY.JPG

 

[robinson]

latest photos...
http://cryptome.org/eyeball/daiichi-npp5/daiichi-photos5.htm

The set of two photos of the tsunami hitting is for the Fukushima Dai-ni nuclear power plant.

 

[clancy688]

I have a question regarding Iodine-131...

http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110328e12.pdf

http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110409e7.pdf

Those two pdfs are showing "results of nuclide analyses of radioactive materials in the air" (at Fukushima Daiichi).

But from March 26th until now, Iodine-131 concentrations basically stayed at the same level. And I don't understand why. Iodine-131 decays after 8 days, so the numbers should have halfed. Since the scale is logarithmic it's hard to see... or I could be imagining things. But it's still odd.
And it's been nearly one month since the accident (= stop of nuclear fission), so the Iodine left should be well below 10%, So why don't the numbers change? And why are there still such high Iodine concentrations in the water in the reactor buildings?

 

[elektrownik]

I have a question regarding Iodine-131...

http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110328e12.pdf

http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110409e7.pdf

Those two pdfs are showing "results of nuclide analyses of radioactive materials in the air" (at Fukushima Daiichi).

But from March 26th until now, Iodine-131 concentrations basically stayed at the same level. And I don't understand why. Iodine-131 decays after 8 days, so the numbers should have halfed. Since the scale is logarithmic it's hard to see... or I could be imagining things. But it's still odd.
And it's been nearly one month since the accident (= stop of nuclear fission), so the Iodine left should be well below 10%, So why don't the numbers change? And why are there still such high Iodine concentrations in the water in the reactor buildings?

Yes, many peoples is thinking about this problem, some suggests that there could be recricitality in reactor 1

 

[AntonL]

I have a question regarding Iodine-131...

http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110328e12.pdf

http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110409e7.pdf

Those two pdfs are showing "results of nuclide analyses of radioactive materials in the air" (at Fukushima Daiichi).

But from March 26th until now, Iodine-131 concentrations basically stayed at the same level. And I don't understand why. Iodine-131 decays after 8 days, so the numbers should have halfed. Since the scale is logarithmic it's hard to see... or I could be imagining things. But it's still odd.
And it's been nearly one month since the accident (= stop of nuclear fission), so the Iodine left should be well below 10%, So why don't the numbers change? And why are there still such high Iodine concentrations in the water in the reactor buildings?

Yes, many peoples is thinking about this problem, some suggests that there could be recricitality in reactor 1

according to the pressure readings of Reactor 1 it is contained, however reactor 2 and 3 there seem to be breaches. Seawater analysis from reactor 2 leak also showed high Iodine levels larger than Cesium. Draw your own conclusions.

 

[elektrownik]

according to the pressure readings of Reactor 1 it is contained, however reactor 2 and 3 there seem to be breaches. Seawater analysis from reactor 2 leak also showed high Iodine levels larger than Cesium. Draw your own conclusions.

Yes, there is also problem with 2&3, but 1 is most unstable (temperature and radiation fluctuations). Drywell radiation sensor is big unknown, it die after 32>100>68, I don't know what this mean, also temperature is still very hight.