Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[Bandit127]

The attachments are fascinating too. I've just posted about some pages of particular interest to the reactor 2 thread. I haven't 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:

http://icanps.go.jp/eng/02Attachment1.pdf

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.

There is a lot more than that in there. A very good read.

Thanks for posting it.

 

[Hiddencamper]

The attachments are fascinating too. I've just posted about some pages of particular interest to the reactor 2 thread. I haven't 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:

http://icanps.go.jp/eng/02Attachment1.pdf

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.

Amazing read using actual data.

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.

 

[SteveElbows]

It was certainly a breath of fresh air compared to most of the reports we had to put up with for so long. I look forward to reading the rest of it, it was a bit too long to read properly in one go to say the least!

I should point out the site it came from in case anyone is interested in reading other documents that went with it:

http://icanps.go.jp/eng/final-report.html

If I combine it with the other final report that I've just been reading, which tends to focus on some different things, then I finally feel like I've got almost as much data, analysis and narrative as I could reasonably hope for until such a time as they are better able to ascertain detail of damage, fuel location etc.

http://warp.da.ndl.go.jp/info:ndljp...nt/uploads/2012/08/NAIIC_Eng_Chapter2_web.pdf

(From http://warp.da.ndl.go.jp/info:ndljp/pid/3856371/naiic.go.jp/en/report/index.html )

Again just to highlight a few areas of interest to me, leaving out reactor 2 which I'm discussing in its own thread:

Page 31 seems to be suggesting this reports authors required a core-concrete interaction to generate sufficient quantities of hydrogen to explain the explosions at reactor buildings 3 & 4.

Pages 90-93 looks at whether the operation of SRVs at reactor 1 depressurised that RPV, or whether pipe damage due to the earthquake was responsible.

In some ways this report doesn't feel quite up to the same standard as the other one, and especially the above highlights may be controversial. But the way in which it looks at such issues, and its broader attempt to construct a narrative of the sequence of events at the reactors in a slightly different manner to the other reports, gives it some worth in my eyes, just not on its own. I highly recommend that anyone frustrated by failures of previous reports to at least mention possible remelts etc after the first stages of disaster at each reactor, eg dates such as 16th and 21st March, or failures to construct a readable narrative that focuses on important details rather than seem to willfully obscure, could do a lot worse than at least skim these documents.

 

[tsutsuji]

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_121126_02-e.pdf Since the area surrounding the [PCV Gas Control System] duct in Unit 3 Reactor Building is high radiation area (Max.approx. 1Sv.h), the inspection will be performed by a robot with a camera attached. The inspection is scheduled on November 27 (and 28), 2012 (...) New Type Robot Name: FRIGO-MA.

http://www.tepco.co.jp/en/press/corp-com/release/2012/1223342_1870.html a TEPCO employee found that Unit 3 reactor injection water amount had increased from 5.8m3/h (as of 10:00 AM) to 7.0m3/h at 11:00 AM today [26 November] during the regular data check. (...) the cause of the increase in the reactor injection water amount was identified to be a worker unintentionally touching the handle to operate the flow rate adjustment valve.

 

[tsutsuji]

http://www3.nhk.or.jp/news/genpatsu-fukushima/20121129/2325_taishinsei.html Tepco made another round of inspections (the 3rd one) concerning unit 4's earthquake resistance. The maximum inclination value on the western wall was 4.4 cm against a 13 m height, which is nearly the same as in the previous inspection.

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_121129_01-e.pdf Results of the Third Soundness Inspection of Unit 4 Reactor Building at Fukushima Daiichi Nuclear Power Station

http://www3.nhk.or.jp/news/genpatsu-fukushima/20121130/index.html The teleconference videos covering the helicopters spraying water over unit 3 on 17 March 2011 and the discussions on 30 March, 4 April, etc. leading to the decision to release contaminated water into the sea without prior explanations given to national or international concerned parties have been made available to journalists. Other videos covering the last two weeks up to 11 April 2011 are to be made available by January 2013.

 

[SteveElbows]

Here is an english article about the latest teleconference video releases, including some bad comedy when it came to trying to get the fire department to respond to fire at reactor 4 building. Judging by other articles and the timeline of events, I think there is a mistake in the article and when they say March 15th they actually mean March 16th.

http://green.blogs.nytimes.com/2012/11/30/new-view-from-inside-fukushima-chaos-and-uncertainty/?smid=tw-share

The robot investigation of reactor 3 PCV gas duct also involved quite a detailed survey of the equipment hatch area. Radiation levels around the rails showed readings considerably higher than last time in places, although I do not know if this reflects fresh contamination as opposed to a difference in measuring equipment etc.

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_121128_02-e.pdf

eg at height of 0.4m at location 2, 1740mSv/h this time as opposed to 800 mSv/h last time. And at floor surface at location 1, 4780 mSv/h this time as opposed to 1300 mSv/h last time.

Some of the videos of the reactor 3 PCV gas line inspection also show the equipment hatch area again, with the gap clearly visible and also a look inside the cupboard that houses the equipment that enables the plug to move on the rails. I don't think it shows anything new of particular note though.

http://photo.tepco.co.jp/en/date/2012/201211-e/121128-01e.html

 

[SteveElbows]

Another teleconference story, this time about manpower shortages, exhaustion and radiation exposure:

http://ajw.asahi.com/article/0311disaster/fukushima/AJ201212010043

“My people have been working day and night for eight straight days,” Masao Yoshida barked at officials of Tokyo Electric Power Co.’s head office in Tokyo during a teleconference on March 18, 2011. “And they’ve been going to the site a number of times. They pour water, make checks and add oil periodically. I cannot make them be exposed to even more radiation.”

TEPCO, the operator of the plant, allowed journalists on Nov. 30 to view the video footage of its in-house teleconference following the disaster.

Like earlier footage released by the utility, the latest clips underscored the chaos and confusion at the plant and TEPCO headquarters after the Great East Japan Earthquake and tsunami caused the triple meltdown.

“All workers are approaching 200 (millisieverts) in exposure or have even topped 200,” Yoshida said. “I cannot tell them to go and connect wires under high radiation.”

Yoshida had asked for an increase in manpower since the accident began. His frustrations over TEPCO’s lack of progress in providing additional support boiled over in the teleconference with the head office.

“If we do the work under a plan with no feasibility, it will end in failure. We cannot do it unless we have thorough help,” he said.

 

[tsutsuji]

http://www3.nhk.or.jp/news/genpatsu-fukushima/20121203/index.html Unit 4 fuel removal will be quicker than previously announced. Fuel removal will start in November (instead of December) 2012, and be completed by December 2014 (instead of 2015), Tepco announced. This new plan is made possible by "increasing the number" of "steel containers for removed fuel", which makes the work more efficient.

 

[SteveElbows]

I guess you mean 2013 rather than 2012?

 

[tsutsuji]

I guess you mean 2013 rather than 2012?

oops yes I meant 2013. I am sorry for the mistake.

By the way, the latest mid-long term meeting was held on 3 December 2012 and I hope I can find the headlines and pdf presentations on the Meti website soon.

 

[tsutsuji]

http://www.tepco.co.jp/nu/fukushima-np/roadmap/images/m121203_08-j.pdf page 7/20 : Tepco plans to close unit 2's blowout panel by next March. A report on that plan was sent to the NRA on 30 November. [I can't find any press release about that report on the NRA website.]

 

[Tepconium-311]

OT:
Please take opportunity to vote for tsutsuji on this https://www.physicsforums.com/showthread.php?t=656505.
Thanks!

P.S.:
You also could vote for Jim Hardy. But, I believe that Old Jim probably will be okay with tsutsuji being elected...

 

[tsutsuji]

http://www.tepco.co.jp/index-j.html At 17:18 on 7 December an intensity 4 [JMA scale] earthquake occurred on the Hamadori region (the coastal region) of Fukushima prefecture.

Fukushima Daiichi : concerning all monitoring post values, units 1,2,3,4,5,6 plant parameters, reactor water injection facilities, accumulated water transportation facilities, water treatment equipments, no abnormality was found. Personnel injury was not reported. The largest acceleration was the one measured at unit 6 with 26.2 gal (horizontal direction).Fukushima Daini : maximum value 26.0 gal (vertical direction).

http://www.jiji.com/jc/c?g=soc_30&k=2012120700686 A 1 m high tsunami was measured at Ishinomaki (Miyagi prefecture) at 18:02 on 7 December 2012. The workers at Fukushima Daiichi have taken shelter in elevated places away from the sea.

 

[jim hardy]

Thanks Tepconium... indeed that's so.

 

[tsutsuji]

The 12th mid & long term meeting was held on 3 December 2012: http://www.meti.go.jp/earthquake/nuclear/20121203_02.html

1) Previous related topics:

12th meeting English roadmap http://www.tepco.co.jp/en/nu/fukushima-np/roadmap/images/m121203-e.pdf

The 11th meeting (22 October 2012) https://www.physicsforums.com/showpost.php?p=4127659&postcount=13788

11th meeting English roadmap : http://www.tepco.co.jp/en/nu/fukushima-np/roadmap/images/t121022_01-e.pdf and http://www.tepco.co.jp/en/nu/fukushima-np/roadmap/images/m121022-e.pdf

The 10th meeting (24 September 2012) https://www.physicsforums.com/showpost.php?p=4096335&postcount=13735

The 9th meeting (27 August 2012) https://www.physicsforums.com/showpost.php?p=4051034&postcount=13635

The 8th meeting (30 July 2012) https://www.physicsforums.com/showpost.php?p=4020743&postcount=13588

The 7th meeting (25 June 2012) https://www.physicsforums.com/showpost.php?p=3979794&postcount=13512

The 6th meeting (25 May 2012) : https://www.physicsforums.com/showpost.php?p=3933442&postcount=13399

The 5th meeting (23 April 2012) : https://www.physicsforums.com/showpost.php?p=3881074&postcount=12979

The 4th meeting (28 March 2012) : https://www.physicsforums.com/showpost.php?p=3838108&postcount=12764

The 3rd meeting (27 February 2012) was translated into English on Tepco's website : http://www.tepco.co.jp/en/nu/fukushima-np/roadmap/conference-e.html

2) Translation:

3 December 2012 government-Tokyo Electric mid and long term response committee, steering committee (11th meeting)

http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02a.pdf Agenda
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02b.pdf Participants

Document 1
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02c.pdf Abstract of the proceedings of 11th steering committee meeting

Document 2: Plant status
Document 2-1: Plant status
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02d.pdf Plant parameters
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02e.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/nuclear/pdf/121203/121203_02f.pdf Schedule
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02g.pdf Condensate Storage Tank (CST) water injection (into reactor) system installation work : scope and schedule revisions
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02h.pdf Results of nitrogen injection into unit 1 suppression chamber
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02j.pdf Results of checking the status of unit 3 PCV gas management system ducts
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02k.pdf Change of pressure-resistant hoses into polyethylene ones

3-2 Treatment of accumulated water
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02m.pdf Schedule
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02n.pdf Ground water bypass implementation status
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02p.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/nuclear/pdf/121203/121203_02q.pdf Schedule
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02r.pdf Countermeasures to reduce harbour seawater concentrations (November)
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02s.pdf Reduction of harbour seawater concentrations (survey plan)
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02t.pdf Silt fence replacement work in front of unit 3 screen chamber
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02u.pdf Results of evaluation of additional releases from reactor buildings

3-4 Improvement of working conditions
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02v.pdf Schedule
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02w.pdf Fiscal 2012 heatstroke prevention countermeasure implementation status
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02x.pdf Infectious disease prevention and contagion prevention countermeasures
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02y.pdf Questionnaire survey on the actual labour conditions
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02z.pdf Entrance and departure management facilities completion schedule change

3-5 Countermeasures for spent fuels pools
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02aa.pdf Schedule
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02bb.pdf Spent fuel pool countermeasure schedule
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02cc.pdf Debris removal work, reactor building top part, unit 3
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02dd.pdf Debris removal work, reactor building top part, unit 4
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02ee.pdf Schedule of fuel removal from unit 4 spent fuel pool
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02ff.pdf Outline of cover structure for unit 3 fuel removal
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02gg.pdf Results of periodical inspection for the purpose of checking the soundness of unit 4 reactor building
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02hh.pdf Unit 1 operation floor re-inspection results

3-6 Preparations for fuel debris removal
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02jj.pdf Schedule
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02kk.pdf Plan to inspect the surroundings of unit 2 vent pipe lower parts

3-7 Treatment and disposal of radioactive waste
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02mm.pdf Schedule
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02nn.pdf Debris, cut down trees management status
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02pp.pdf progress status of temporary storage by means of covering with soil

Document 4
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02qq.pdf Program decided within the implementation plan specified by the Special Nuclear Power Facility status

Document 5
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02rr.pdf Mid and long term roadmap progress status (abstract)

Document 6
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02ss.pdf Mid and long term roadmap progress status and future problems

Document 7
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02tt.pdf Mid and long term roadmap seminar (to be held in Fukushima City on 19 December 2012)

3 December 2012 government-Tokyo Electric mid and long term response committee, technical development progress headquarters (11th meeting) ( http://www.meti.go.jp/earthquake/nuclear/20121203_03.html )

http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_03a.pdf Agenda

Document 1
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_03b.pdf Abstract of proceedings of 10th meeting (draft)

Document 2-1
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_03c.pdf Fiscal 2013 research and development plan (draft)
Document 2-2
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_03d.pdf Fiscal 2013 executive plan of research and development toward decommissionning of nuclear energy facilities (draft)

Document 3
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_03e.pdf Practical use of national and international knowledge in accident progression analysis (OECD-NEA BSAF project)

Document 4
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_03f.pdf Initiative toward the determination of the research and development plan for treatment and disposal of radioactive waste (draft)

Document 5
http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_03g.pdf Invitation to the Fukushima workshop on machinery and equipments, etc. toward the decommissionning (draft) (to be held in Fukushima City on 19 December 2012)

 

[tsutsuji]

The first one of the eight unit 2 vent pipe lower part inspections has been completed by the quadrupedal walking robot (robot picture is available on http://www.meti.go.jp/earthquake/nuclear/pdf/121203/121203_02kk.pdf page 3 (2/6)) :

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_121211_01-e.pdf Results of Investigation on the Lower Part of Unit 2 Vent Pipe at Fukushima Daiichi Nuclear Power Station (English)

 

[SpunkyMonkey]

Here's a slide presentation on the explosions of Units 1 and 3 by the Japan Nuclear Energy Safety Organization, presented on September 17, 2012 at the IAEA General Conference:

http://www.aec.go.jp/jicst/NC/sitemap/pdf/P-4.pdf

They opine that the Unit 3 explosion propagated upwards from a hydrogen release on the 1st floor. Apparently the force of the explosion increased significantly over time, doing very little damage to lower floors but growing so strong that by the time it reached the 5th floor it annihilated that top floor.

The slide presentation says:

Major Assumptions:

• In Unit 1, Hydrogen of 400 kg was released to
the top floor (5F) of reactor building (R/B) and
ignited there.

• In Unit 3, Hydrogen of 1000kg was released to
the first floor (1F) of R/B and ignited there.

 

[zapperzero]

They opine that the Unit 3 explosion propagated upwards from a hydrogen release on the 1st floor. Apparently the force of the explosion increased significantly over time, doing very little damage to lower floors but growing so strong that by the time it reached the 5th floor it annihilated that top floor.

So, they are contending that hydrogen escaped via the equipment hatch, diffused into the entire building, then ignited somehow there, on the bottom floor and managed to only blow out the roof and top floor?

No. There would be crushed piping, debris and such at all levels.

EDIT: in unrelated news I am quite pleased with myself, as their estimate of H2 quantities agrees with my own BOE calcs :D

 

[tsutsuji]

http://www3.nhk.or.jp/news/genpatsu-fukushima/20121220/index.html On 20 December 2012, the 7 m long, 470 kg heavy steel beam that had fallen into unit 3 SFP in September was lifted out of the pool. Tepco says that the beam was caught with other debris, and was possibly bearing consequences on the debris removal work. The debris removal work was planned to be completed by March 2013, but it is feared that the beam falling event might have caused a delay from the schedule.

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_121220_02-e.pdf Debris Removal from the Upper Part of Unit 3 Reactor Building at Fukushima Daiichi Nuclear Power Station: Removal of the Steel Beam Which Fell into the Pool

 

[tsutsuji]

http://www.tepco.co.jp/nu/fukushima-np/roadmap/conference-j.html The 13th mid-long term meeting was held on 25 December 2012 [but the pdf presentations are not available at http://www.meti.go.jp/earthquake/nuclear/decommissioning.html yet]

http://www.tepco.co.jp/nu/fukushima-np/roadmap/images/m121225_05-j.pdf There is something new about the plan to use the TIP guide tubes for installing alternative thermometers in unit 2. Some work for this was started on 20 December. There is a plan to inject nitrogen into unit 2 suppression chamber like they did at unit 1. There is a High Integrity Container (HIC) falling test. There is some more about the plan to close unit 2's blowout panel. There is something on unit 3's debris removal work.

 

[zapperzero]

http://www.japantimes.co.jp/text/nn20130101a3.html

The CMRT, consisting of 33 scientists and engineers, arrived at Yokota Air Base on March 16 from Nellis Air Force Base in Las Vegas and initiated test flights within 12 hours of arriving, according to an NNSA senior official. The CMRT conducted the first round of AMS operations from March 17 to 19, using two U.S. military aircraft.

The AMS flight operations over Fukushima were conducted around 100 times totaling 525 flight hours until the CMRT left Japan on May 28, 2011, an NNSA official said.

It would be really nice if some US citizen could do a FOIA request for those flight records and the test data... I am pretty sure that there are/were reporters lurking in this thread. Perhaps we would then learn more about the timing of radioactive releases.

 

[Azby]

http://www.japantimes.co.jp/text/nn20130101a3.html



It would be really nice if some US citizen could do a FOIA request for those flight records and the test data... I am pretty sure that there are/were reporters lurking in this thread. Perhaps we would then learn more about the timing of radioactive releases.

I'm not a reporter, but I've looked at the NNSA data available here:

http://www.nnsaresponsedata.net/

There's a lot there, maybe what you're looking for. It requires a registration, but that took only about 2 hour to turn around.

 

[zapperzero]

http://www.tepco.co.jp/en/news/libr...8209002&bclid=347242463002&bctid=400972619002

 

[Joffan]

http://www.tepco.co.jp/en/news/libr...8209002&bclid=347242463002&bctid=400972619002

Why on Earth did Tepco post that - it shows absolutely nothing.

The other videos on that page are interesting though.

 

[Astronuc]

http://www.tepco.co.jp/en/news/libr...8209002&bclid=347242463002&bctid=400972619002

I didn't see much of interest in the video, since the water is rather murky.

Better images are available here - http://www.world-nuclear-news.org/RS_Continuing_cleanup_of_Fukushima_pool_0302131.html

 

[zapperzero]

Better images are available

Actually I was trying to post a video of a Unit 1 walkthrough... don't know what happened to the link.
EDIT: third one down on the right side, same page. Can't be bothered to figure how to link directly to it... I'll put it on Mega or something later.

LATER EDIT:
here it is

 

[turi]

That's the tepco link you were looking for:
http://photo.tepco.co.jp/en/date/2013/201302-e/130207-01e.html

Quite intriguing video from October 18, 2011. Quite a bit of noise. My limited Japanese knowledge picked up things like "xyz milli" presumably being the current mSv/h (or possibly the accumulated dose in mSv, I didn't pay enough attention to the numbers), readings from sensors ("kochira zero desu": "This one is zero"), things like "daijoubu desu ne" (good, ain't it) and "ikimashou, ikimashou" (let's go, let's go) when the radiation alert goes off (I think it goes off because they have reached a preliminarily set maximum accumulated dose as it goes of at a place where they have been before).

Can anyone with more knowledge of Japanese and the daichi reactors shed some light on what they were inspecting up there in unit 1?

 

[zapperzero]

That's the tepco link you were looking for:

no, it is not. that's a much older video

 

[turi]

no, it is not. that's a much older video

Hm, it the same as the one you've uploaded to mega and has been released on February 6 this year.

There's now also a video been released yesterday from the same place but recorded in November 2012. Much better video quality. They even look at some of the same instruments.
http://photo.tepco.co.jp/en/date/2013/201302-e/130215-01e.html

 

[zapperzero]

Hm, it the same as the one you've uploaded to mega and has been released on February 6 this year.

Okay. I stand corrected. Thanks for the further link.

 

[LabratSR]

Will Davis over at Atomic Power Review has updated his site to include a section on the Fukushima accident.

http://atomicpowerreview.blogspot.com/p/fukushima-daiichi-accident-reports.html



One report that caught my eye was the one from Sandia National Labs, which I don't remember seeing before. Apologies if it has been posted here previously.

http://energy.sandia.gov/wp/wp-content/gallery/uploads/Fukushima_SAND2012-6173.pdf

 

[zapperzero]

Will Davis over at Atomic Power Review has updated his site to include a section on the Fukushima accident.

http://atomicpowerreview.blogspot.com/p/fukushima-daiichi-accident-reports.html



One report that caught my eye was the one from Sandia National Labs, which I don't remember seeing before. Apologies if it has been posted here previously.

http://energy.sandia.gov/wp/wp-content/gallery/uploads/Fukushima_SAND2012-6173.pdf

The conclusions are highly suspect, imho. How can anyone say that a model is accurate when the actual sequence of events remains unknown?

 

[NUCENG]

The conclusions are highly suspect, imho. How can anyone say that a model is accurate when the actual sequence of events remains unknown?

If you read the Abstract of the Sandia report you will find that the model was developed to validate the MELCOR code and its ability to investigate a severe reactor accident. The results were not presented as a final analysis or truth of what actually happened. As you point out there are many things we don't know about the exact timeline, but the process of scientific inquiry does not require us to know everything to at least try to begin learning what happened. If we knew everything already we wouldn't need to model the accidents.

The models tell us what might have happened. Data from the model can be used to focus investigation where the results don't match the reality. It can be used to at least estimate the conditions to be encountered during cleanup. If they find new data the models can be updated and help refine the story. This will be ongoing for years.

Maybe this will help. The Wright Brothers built an airplane with rudimentary scientific inputs. Today's Aeronautical Engineers have far superior knowledge of why airplanes can fly. And the old story is that all that scientific modelling tells us that a bumblebee shouldn't be able to fly. Luckily, bumblebees can't read.

 

[zapperzero]

If you read the Abstract of the Sandia report you will find that the model was developed to validate the MELCOR code and its ability to investigate a severe reactor accident. The results were not presented as a final analysis or truth of what actually happened. As you point out there are many things we don't know about the exact timeline, but the process of scientific inquiry does not require us to know everything to at least try to begin learning what happened. If we knew everything already we wouldn't need to model the accidents.

The paper goes on to conclude that MELCOR is one hell of a code and the model as built is an excellent model, because after tweaking the input data some of the simulation results start to resemble plant readings. This is not very good science, I think.

Overall, these results increase confidence in the MELCOR code; establish confidence in the
Fukushima reactor models and spent fuel pool model; and demonstrate that the code and models
are valid for their intended use. They also add more evidence to the existing body of results that,
when taken has a whole, build confidence in the validity of the MELCOR code.

Also, I think we'd still need to model the accidents; I believe that the most important use of models is not forensic, but predictive.

In other, unrelated news the word "radiolysis" is conspicuously absent from this document...

 

[turi]

In other, unrelated news the word "radiolysis" is conspicuously absent from this document...

Do you have any indication that radiolysis would be a significant source of hydrogen compared to zirconium, steel and B₄C steam oxidation? Those three sources are modeled in the analysis.