|Oct23-12, 04:36 AM||#13788|
Japan Earthquake: nuclear plants
The 11th mid & long term meeting was held on 22 October 2012: http://www.meti.go.jp/earthquake/nuc...121022_01.html
1) Previous related topics:
The 10th meeting (24 September 2012) http://www.physicsforums.com/showpos...ostcount=13735
The 9th meeting (27 August 2012) http://www.physicsforums.com/showpos...ostcount=13635
The 8th meeting (30 July 2012) http://www.physicsforums.com/showpos...ostcount=13588
The 7th meeting (25 June 2012) http://www.physicsforums.com/showpos...ostcount=13512
The 6th meeting (25 May 2012) : http://www.physicsforums.com/showpos...ostcount=13399
The 5th meeting (23 April 2012) : http://www.physicsforums.com/showpos...ostcount=12979
The 4th meeting (28 March 2012) : http://www.physicsforums.com/showpos...ostcount=12764
The 3rd meeting (27 February 2012) was translated into English on Tepco's website : http://www.tepco.co.jp/en/nu/fukushi...ference-e.html
22 October 2012 government-Tokyo Electric mid and long term response committee, steering committee (11th meeting)
http://www.meti.go.jp/earthquake/nuc...121022_01c.pdf Abstract of the proceedings of 10th steering committee meeting
Document 2: Plant status
Document 2-1: Plant status
http://www.meti.go.jp/earthquake/nuc...121022_01d.pdf Plant parameters
http://www.meti.go.jp/earthquake/nuc...121022_01e.pdf Accumulated water storage status
Document 3 Study and execution of each special plan
3-1 Cooling by closed loop water injection
http://www.meti.go.jp/earthquake/nuc...121022_01g.pdf Unit 2 alternative thermometer installation
http://www.meti.go.jp/earthquake/nuc...121022_01h.pdf Unit 1 PCV internal survey results
http://www.meti.go.jp/earthquake/nuc...121022_01j.pdf Nitrogen injection into Unit 1 suppression chamber
http://www.meti.go.jp/earthquake/nuc...121022_01k.pdf Completion of unit 4 SFP salt removal
3-2 Treatment of accumulated water
http://www.meti.go.jp/earthquake/nuc...121022_01n.pdf Responses toward the start of the multinuclide removal facility (ALPS)'s hot test
3-3 Countermeasures to reduce environmental radiations
http://www.meti.go.jp/earthquake/nuc...121022_01q.pdf Mid and long term implementation policies for plant premises decontamination
http://www.meti.go.jp/earthquake/nuc...121022_01r.pdf Radiation dose reduction in front of Fukushima Daiichi NPP's seismic-isolated building
http://www.meti.go.jp/earthquake/nuc...121022_01s.pdf Results of evaluation of additional releases from reactor buildings
3-4 Improvement of working conditions
3-5 Countermeasures for spent fuels pools
http://www.meti.go.jp/earthquake/nuc...121022_01v.pdf Debris removal work, reactor building top part, unit 3
http://www.meti.go.jp/earthquake/nuc...121022_01w.pdf Debris removal work, reactor building top part, unit 4
http://www.meti.go.jp/earthquake/nuc...121022_01x.pdf Plans to survey unit 1's operating floor again
http://www.meti.go.jp/earthquake/nuc...121022_01y.pdf Results of preliminary underwater survey (survey No. 3) into unit 3 spent fuel pool for the purpose of inside pool debris removal
3-6 Preparations for fuel debris removal
3-7 Treatment and disposal of radioactive waste
http://www.meti.go.jp/earthquake/nuc...21022_01bb.pdf Debris, cut down trees management status
http://www.meti.go.jp/earthquake/nuc...21022_01cc.pdf Cut down trees (branches, leaves, roots) temperature monitoring status
http://www.meti.go.jp/earthquake/nuc...21022_01dd.pdf Installation of cut down tree temporary storage vessels
http://www.meti.go.jp/earthquake/nuc...21022_01ee.pdf roadmap progress (abstract)
22 October 2012 government-Tokyo Electric mid and long term response committee, technical development progress headquarters (10th meeting) ( http://www.meti.go.jp/earthquake/nuc...121022_02.html )
http://www.meti.go.jp/earthquake/nuc...121022_02b.pdf Committee member list
http://www.meti.go.jp/earthquake/nuc...121022_02c.pdf Abstract of proceedings of 9th meeting (draft)
http://www.meti.go.jp/earthquake/nuc...121022_02d.pdf Outline of progress status of grasping in-reactor status by upgrading accident progression analysis tools
http://www.meti.go.jp/earthquake/nuc...121022_02e.pdf Progress status of "development of management and disposal techniques for the secondary waste generated by contaminated water treatment" and ""development of management and disposal techniques radioactive waste"
http://www.meti.go.jp/earthquake/nuc...121022_02f.pdf Outline of progress status of "building material accounting methods for fuel debris"
http://www.meti.go.jp/earthquake/nuc...121022_02g.pdf Progress status of "development of criticality management techniques for fuel debris"
|Oct26-12, 04:12 AM||#13789|
http://www3.nhk.or.jp/news/genpatsu-...025/index.html On 24 October, Tepco inspected the top part of unit 1's reactor building using a balloon (diameter 2 m, height 3 m ). It was confirmed that although there are concrete debris, etc, the overhead crane and the fuel handling machine have not fallen. The radiation measured near the 2nd floor was 150 mSv/hour, and the one near the 5th floor was 85 mSv/hour. Tepco had tried to do this survey in August, but failed as the balloon hit some debris. This time they used a smaller diameter balloon, and were able to inspect the top part of the building for the first time.
http://www.tepco.co.jp/en/nu/fukushi...21024_02-e.pdf Results of Reinvestigation of Unit 1 Operation Floor at Fukushima Daiichi Nuclear Power Station (24 October 2012)
http://www.tepco.co.jp/en/nu/fukushi...20808_02-e.pdf 8 August 2012 balloon mission
[question: would it not have been easier to install one camera or two on the top beams of the cover/tent structure ? Or to put cameras on the crane that was used to build the cover structure ? (http://photo.tepco.co.jp/en/date/201...11008-02e.html : Installation Work of Roof Panels for Reactor Building Covers at Unit 1, Oct 08, 2011)]
|Oct27-12, 06:16 AM||#13790|
However because the roof of Unit 1 collapsed somewhat like a blanket over the whole refuelling floor the view was limited from overhead.
Having said that, there was some earlier crane video that showed much of what has been obtained on this latest balloon effort. I can't find the clip on the TEPCO site but here is a link.
Video , U1, west side, FL5 Crane - Timestamped May 16 2011 (and yes, photobucket isnt very good for video :( )
Then there is this crane video from Oct 2011 which shows how limited the view was from above.
Situation of Upper Part of Unit 1 Reactor Building, Fukushima Daiichi Nuclear Power Station - Oct 08 2011
Also, thankyou again for your reports.
|Oct28-12, 06:33 AM||#13791|
hindsight is 20/20 I guess and TEPCO's self-enforced lack of curiosity is infinite
|Oct30-12, 09:16 AM||#13792|
|Oct30-12, 12:06 PM||#13793|
It is Tepco's own idea. You can see green color cameras on the diagram on the last page at http://www.tepco.co.jp/en/press/corp.../110624e15.pdf
I wonder what happened to those cameras.
http://www3.nhk.or.jp/news/genpatsu-...030/index.html The investigation launched after the "pocket dosimeter in lead cover" problem revealed additional problems. Investigating the cases where both dosimeters [sounding like each worker always carries two of them?] had a difference higher than 25%, at least 20 cases of inappropriate radiation exposure management were revealed. They found 3 data input mistakes, 6 inappropriate management cases like the worker carries his dosimeter when he is off duty, and 11 cases where the lower of the two dosimeter values had been reported [sounding like the rule is to report the highest one]. However, no intentional misreporting was found. The ministry of labour and health instructed Tepco and 37 subcontractors to take recurrence prevention countermeasures.
|Nov7-12, 04:03 AM||#13794|
Asahi has a couple of stories in English:
http://ajw.asahi.com/article/0311dis...AJ201210140034 "A day wasted"
http://ajw.asahi.com/article/0311dis...imgIX=0&page=2 "Have we got batteries?"
http://ajw.asahi.com/article/0311dis...imgIX=0&page=3 "Radiation rises"
http://ajw.asahi.com/article/0311dis...imgIX=0&page=4 "Yoshida overburdened"
http://ajw.asahi.com/article/0311dis...AJ201211030052 "Tepco admits 4th worker exposed to radiation in early days of disaster"
NHK has a set of stories questioning whether Tepco can keep a sufficient workforce to perform the decommissioning:
http://www3.nhk.or.jp/news/genpatsu-...10_taiguu.html An increasing number of workers resign because remuneration is worsening. At the start, I received 230,000 per month, and just before I resigned, I had only 180,000 and had to pay for lunch, a worker who resigned says. Another one who came from Kansai had 250,000 that decreased to 200,000 and he was asked to leave the company-paid ryokan where he was staying.
http://www3.nhk.or.jp/news/genpatsu-...105/index.html It was found by journalist investigation/interviews that the number of registered workers is 8000 instead of the 24,000 figure presented by Tepco. At present, 3000 workers are working on a given day. Tepco estimates it needs 11,700 workers for this year. Tepco asserted that it can secure this number, based on the fact that 24,000 workers have registered. Actually this figure is the number of workers who registered since the accident. Since then, 16,000 have cancelled their registration, and as of last month, only 8000 workers were registered.
http://www3.nhk.or.jp/news/genpatsu-...106/index.html Fukushima prefecture asked Tepco whether it can secure enough workforce. Tepco said "as the needed workforce per month is 6000, 8000 registered workers is enough".
|Nov11-12, 06:44 AM||#13795|
Part of the reason that US concerns about the fuel pool lagged behind the established reality is quite visible in the transcripts that were published a long time ago. Their man on the ground in Japan had formed an opinion of the situation, and as is often the case with humans he had trouble abandoning this position when contradictory facts started to emerge. He saw the state of the building and freaked out, and he was unconvinced by the first footage the Japanese obtained which they believed showed water in the pool. It didnt help that he was tired, and the Japanese refusal to give him a copy of footage to watch at his leisure probably made him suspicious.
Personally I think that as soon as the helicopter flight decided to dump water on reactor 3 pool rather than reactor 4 pool, we had clear signs of what the people with the best information at the time thought was the priority.
Given that people didnt instantly catch on to the idea that the reactor well was full of water and the pool gate may have failed, and that they hadnt figured out why reactor 4 building exploded, its not really surprising that the worst scenarios for reactor 4 pool seemed credible in the early days.
|Nov18-12, 04:41 PM||#13796|
http://www3.nhk.or.jp/news/genpatsu-...117/index.html The NHK journalists tried to check again radiation doses. When they found something strange ("unnatural") in the radiation data from Fukushima Daini, 12 km South of the accidented plant, they asked Tepco for clarification, and the existence of until now undisclosed data was revealed. These undisclosed data cover a period from 15 March to 3 April 2011. They include the following March 16 data : the until then 20 microsievert/h radiation jumped to 80 microsievert/h at around 09:40 and 87.7 microsievert/h 10 minutes later. About one hour sooner, at around 8:30 white smoke had risen from the Fukushima Daiichi unit 3 reactor building, and the relationship between the smoke and the radiation peak at Fukushima Daini is being questioned. Kado Shinichiro of Tokyo University says: "For analysis, it is highly regrettable that unreleased data come out one year and 8 months after the accident. It is necessary to check the data, including the relationship between the peak and the white smoke at unit 3". Tepco says "we are investigating why the data were not released. We'll study a release of these data as the investigation progresses".
http://www.tepco.co.jp/nu/fukushima-...21114_01-j.pdf Tepco submitted to the NRA a change in the "mid-term safety principles"-based operational plan report. Unit 3's future cover structure is shown on diagrams.
|Nov19-12, 03:05 AM||#13797|
|Nov20-12, 12:27 PM||#13798|
http://www3.nhk.or.jp/news/genpatsu-...1755_date.html The data had been collected by hand, and they [including the unreleased ones?] had been reported to the government [NISA, I guess]. The released data were showing only every 10 minutes for one hour every three hours, instead of every 10 minutes. The missing data have been added on Tepco's website on 19 November 2012.
http://www.tepco.co.jp/nu/fukushima-...21119_02-j.pdf Tepco's explanation about the missing Fukushima Daini radiation data.
http://www.tepco.co.jp/en/nu/monitoring/11031602a.pdf English version for 16 March 2011 [the unreleased data are still missing : there is a gap between 09:00 and 11:10]
http://www.tepco.co.jp/cc/press/betu...es/110316d.pdf Japanese version for 16 March 2011 [the new completed version, I guess] [including the 80.0 and 87.7 microsievert/h figures at 09:40 and 09:50, Monitoring post MP-4]
|Nov20-12, 05:09 PM||#13799|
I wonder if we can get documentation for this. Wikipedia says, " Chinook helicopters were preparing to pour water on Unit 3, where white fumes rising from the building was believed to be water boiling away from the fuel rod cooling pond on the top floor of the reactor building, and on Unit 4 where the cooling pool was also short of water." But the two sources given are dead.
Probably somebody remembered that unit 4 was full of water and therefore less an imminent danger compared to the unit 3 pool, where they also did not know about water leaks.
|Nov22-12, 12:08 PM||#13800|
Obviously when looking at this we have to take into account wind direction. I have started looking through data for the period after the 16th, to see if there are any other spikes which those articles dont mention.
Firstly I suggest looking at data for the 15th, because there are plenty of high readings at Daini then too, and the wind was blowing from the north during many initial hours of this period. It is a shame the data only starts on the 15th, we could really do with some values from 9PM on the 14th onwards to see how these values may have grown in the first place, eg in relation to events occurring at reactor 2, or even earlier for reactor 3.
Increases on March 21st which are quite notable from 8:10 to 8:30am
Increases on March 22nd peaking around 14:20.
There were a couple of other times values temporarily rose in March but they were less significant numbers so I havent bothered to highlight them here.
|Nov22-12, 06:21 PM||#13801|
I've been looking back at some investigation reports that may not have been translated very quickly after they were first published. I was looking for details of interest to me that I dont remember being published in other reports we talked about here.
Page 61, in talking about possible leakage paths, notes that steam was seen escaping from a region of the upper part of damaged reactor 1 building that could be the concrete plugs above the vessel head. Its nice to see this mentioned, as it was infuriating that we saw this kind of thing on early video footage but there was no comment about it at the time. Sadly I dont think they make the same comments about reactor 3.
Around that part of the document they also mention a manhole that is built into the containment vessel head.
Page 68, when looking at possible sources of ignition for the hydrogen in the reactor 1 building, they note that shortly before the explosion, there are logs which suggest that electric power had just been restored to the boric injection system.
Various parts of this report are also rather good at pointing out how wrong some of the data used by the accident models for assessing things like fuel melt & RPV damage might be.
Page 75, they talk about time period where containment damage at reactor 2 may have already started to happen. The period they mention is from 13:45 to 18:10.
|Nov22-12, 07:39 PM||#13802|
The attachments are fascinating too. I've just posted about some pages of particular interest to the reactor 2 thread. I havent had time to read the stuff dealing with reactor 3 yet but here are a couple of highlights in regards reactor 1 and this document:
Pages 53-56 looks at the MAAP & MELCOR analysis and frankly discusses a number of large problems with the analysis these models offered.
Pages 64-67 discusses radiation increases around 21:25 on March 14th and the possibility that this wasnt just down to reactor 2 or even reactor 3, but also further damage occurring at reactor 1.
|Nov25-12, 12:26 PM||#13803|
Thanks for posting it.
|Nov25-12, 04:50 PM||#13804|
What's interesting is the unit 3 RCIC appears to had its mechanical trip latch fail. The trip latch, we often call it "the coathanger", seems kinda flimsy. You can see it in http://www.genassis.com/APSAFWPumpTerryTurbine.jpg this picture. It's the long thin bar going from the trip and throttle valve to the main body of the unit shaft and has a spring attached to it. The trip and throttle valve (on the left) has mechanical and electrical (solenoid) trip mechanisms. Most BWRs don't use the electrical trip during normal operation, and instead opt to close the steam supply valve instead, as the supply valve does not need an operator to manually reset it, while the trip and throttle valve requires a manual reset to lift the valve off its seat.
If the mechanical latch was what failed then the failure mode needs to be determined and confirmed as terry turbines (used for RCIC/HPCI/Aux feed) are used in a LARGE number of LWRs in the US and world.
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