Japan Earthquake: nuclear plants

LabratSR

Highest radiation found at Fukushima No.1 reactor

http://www3.nhk.or.jp/daily/english/20120628_01.html

MadderDoc

After all those months, with reams of stories told potentially elevating the information level of journalists and the lay public ...still to the NHK writer of this piece -- inside or outside the reactor, a pressure vessel, a containment, or a suppression chamber -- are all just one porridge.

Even as regards the most interesting angle apparently to the writer -- the alleged record breaking radiation, there appears to be no memory of any previous potential record-holder (although in reporting of record breaking the dethroned party and the previous record traditionally get a mention). Has the measured >10,000 mSv/hr at the vent/SGTS pipe to the Unit1+2 exhaust stack last July been forgotten?

MadderDoc

Much of the unit3 debris removal has gone on at ground level, and around the building in a rather big radius -- the Unit 3 explosion was a very littering event indeed.

Comparing this June 18th 2012 photo, with this September 15th 2011 photo it can be seen that quite some progress has been made as regards getting close to the building proper as well as apparently establishing a foothold, a heavy duty elevated working platform at the east wall of the upper floors. I'd expect some of the equipment used currently at unit 4 will be relocated to unit 3 in time.

Rive

http://photo.tepco.co.jp/en/date/201...20627_01e.html
http://www.tepco.co.jp/en/nu/fukushi...20627_02-e.pdf

- Isn't that radiation a bit high compared to the water drawn from the T/B basement for decontamination?
- Why is the radiation decreases underwater?

elektrownik

The water blocks radiation so it is suggest that the radiation source is somewhere out of the water

Rive

As it was suggested elsewhere maybe it's the torus.

If the torus itself is watertight and the cooling water escapes where the torus connected to the DW then the water inside the torus might be there from the very first days -> much more heavily contaminated than the water drawn from the T/B basements.

Tepconium-311

Why then radiation increases strongly when approaching water?
Doesn't this indicate water surface emitting high radiation?

Sadly shielding obstacles like walking girders aren't shown in Tepco presentation chapter 3 to help explain radiation measurements. They are only indicated in chapter 2.
If torus is watertight, wouldn't radiation increase less sharply when approaching water surface?

Any expert ready to comment?

NUCENG

Time, distance and shielding are the watchwords for assessing radiation doses.

Distance: If the water is contaminated, approaching it would result in increasing radiation. If the trus is the source and you are getting clo=ser to it as you approach the water, the same applies.

Shielding: As you get closer to the water you may be going into an area with less shielding. The torus itself is partly above the water level. Any contamination in the atmosphere of the torus or deposited on the structures inside the torus has only the thin shell of the torus as shielding. Core debris inside the containment may be creating radiation streams near the vents between the containment and torus.

Time: has any pumping operation been done which could have stirred up contamination? Does the radiation level change over time (other than decay) showing priods of increase and decrease?

If there is information on the makeup of the radiation (by isotope) or much more detailed geometry information you may start to chip away at this problem. Good luck.

Tepconium-311

Dear NUCENG, thank you for reply!

If I understand you correctly, published Tepco data only reveals high radioactivity in torus room, but not where it is from.
Your explanation sounds really convincing that there is something dangerous in torus, torus vents or nearby.

But, another thing I don't understand yet.
Somebody mentioned (iirc) that torus room of unit 1 is above groundwater level.
If this is correct, then this cannot be groundwater.

Can there be other paths for cooling water to reach basements than via leak in torus?
Because, if torus is watertight, how can there be so much radioactive water in reactor and turbine buildings' basements??

Sounds contradictory to me.
So, in other words, is there any real chance that torus is _not_ damaged?

r-j

What kind of radiation are they measuring?

SteveElbows

Regarding the reactor 1 torus room, is it fair to say that we should be considering some corium blowdown into the torus room as a possibility here? High radiation readings and TEPCOs typically understated comments about 'sediment' tempt me to wander in that direction, especially given the smaller physical size of reactor 1 containment and the length of time it went without water injection.

SteveElbows

At least one study of mark 1 containment failure mentions the blowdown that I was just talking about. I wil try to find the study, but in a nutshell this process does not have to involve the torus itself being damaged. Rather core material that is splattered across the floor of containment eats away at the steel wall near to where it meets the steel floor, and gets into the space between the concrete and the large pipes (downcomers?) that connect containment to torus. This offers a pathways whereby core material can get into the torus room, without having to pass through the torus itself. This would also open up a pathway through which water injected into containment later on could get to the torus room.

There may be some technical inaccuracies in this description but its the best I can offer without having the report to hand.

Of course I do not mean to suggest that we now have anything like solid proof that this happened, just that we should consider it as a possibility given the survey.

SteveElbows

Having now watched the video and seen how much material they disturbed with the probes, I would like to retract by comment about the sediment.

tsutsuji

The 7th mid long term meeting was held on 25 June: http://www.meti.go.jp/earthquake/nuc...120625_02.html

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

25 June 2012 government-Tokyo Electric mid and long term response committee, steering committee (7th meeting)

http://www.meti.go.jp/earthquake/nuc...120625_02a.pdf Agenda
http://www.meti.go.jp/earthquake/nuc...120625_02b.pdf Participants

Document 1
http://www.meti.go.jp/earthquake/nuc...120625_02c.pdf Abstract of the proceedings of 6th steering committee meeting

Document 2: Plant status
Document 2-1: Plant status
http://www.meti.go.jp/earthquake/nuc...120625_02d.pdf Plant parameters
http://www.meti.go.jp/earthquake/nuc...120625_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/nuc...120625_02f.pdf Schedule
http://www.meti.go.jp/earthquake/nuc...120625_02g.pdf Unit 2 alternative thermometers installation progress status

3-2 Treatment of accumulated water
http://www.meti.go.jp/earthquake/nuc...120625_02h.pdf Schedule
http://www.meti.go.jp/earthquake/nuc...120625_02j.pdf Status of multinuclide removal facility (ALPS) qualification test and installation works, and characteristics of waste objects
http://www.meti.go.jp/earthquake/nuc...120625_02k.pdf Subdrain purification test report
http://www.meti.go.jp/earthquake/nuc...120625_02m.pdf Progress status of construction of underground water storage tanks
http://www.meti.go.jp/earthquake/nuc...120625_02n.pdf Progress status of ground water bypass study

3-3 Countermeasures to reduce environmental radiations
http://www.meti.go.jp/earthquake/nuc...120625_02p.pdf Schedule
http://www.meti.go.jp/earthquake/nuc...120625_02q.pdf Management of debris, cut down trees, generated by the response to the accident
http://www.meti.go.jp/earthquake/nuc...120625_02r.pdf Countermeasures against fire of cut down trees (branches, leaves and roots) during the summer season, and future plans.
http://www.meti.go.jp/earthquake/nuc...120625_02s.pdf Suitability tests of decontamination techniques within plant premises
http://www.meti.go.jp/earthquake/nuc...120625_02t.pdf Consequences on water quality of the covering of the sea floor in the harbour (as of June)
http://www.meti.go.jp/earthquake/nuc...120625_02u.pdf Results of evaluation of additional releases from reactor building's primary containment vessels
http://www.meti.go.jp/earthquake/nuc...120625_02v.pdf Results of yearly radiation exposure at the plant premises boundary (as of June)

3-4 Improvement of working conditions
http://www.meti.go.jp/earthquake/nuc...120625_02w.pdf Schedule

3-5 Countermeasures for spent fuels pools
http://www.meti.go.jp/earthquake/nuc...120625_02x.pdf Schedule
http://www.meti.go.jp/earthquake/nuc...120625_02y.pdf Debris removal work, reactor building top part, unit 3
http://www.meti.go.jp/earthquake/nuc...120625_02z.pdf Debris removal work, reactor building top part, unit 4
http://www.meti.go.jp/earthquake/nuc...20625_02aa.pdf Results of seismic safety study taking into consideration local outer wall bulging at Fukushima Daiichi unit 4 reactor building
http://www.meti.go.jp/earthquake/nuc...20625_02bb.pdf Performance of preliminary underwater surveys (2nd and 3rd ones) in spent fuel pool for the purpose of removing debris at unit 3.
http://www.meti.go.jp/earthquake/nuc...20625_02cc.pdf Performance of dry cask temporary storage facility construction work
http://www.meti.go.jp/earthquake/nuc...20625_02dd.pdf Results of survey inside Fukushima Daiichi unit 2 reactor building (3rd ～ 5th floors)

3-6 Preparations for fuel debris removal
http://www.meti.go.jp/earthquake/nuc...20625_02ee.pdf Schedule
http://www.meti.go.jp/earthquake/nuc...20625_02ff.pdf Performance of survey into unit 1's torus room

3-7 treatment and disposal of radioactive waste
http://www.meti.go.jp/earthquake/nuc...20625_02gg.pdf Schedule
http://www.meti.go.jp/earthquake/nuc...20625_02hh.pdf Status of contaminated water analysis
http://www.meti.go.jp/earthquake/nuc...20625_02jj.pdf Collection of samples to analyse debris and cut down trees

Document 4
http://www.meti.go.jp/earthquake/nuc...20625_02kk.pdf roadmap progress (abstract)

Document 5
http://www.meti.go.jp/earthquake/nuc...20625_02mm.pdf Violations of safety regulations reflected in the first fiscal 2011 safety inspection at Fukushima Daiichi nuclear power plant (additional instructions)

25 June 2012 government-Tokyo Electric mid and long term response committee, technical development progress headquarters (7th meeting) (http://www.meti.go.jp/earthquake/nuc...120625_01.html )

http://www.meti.go.jp/earthquake/nuc...120625_01a.pdf Agenda

Document 1
http://www.meti.go.jp/earthquake/nuc...120625_01b.pdf Abstract of the proceedings of 6th meeting

Document 2
http://www.meti.go.jp/earthquake/nuc...120625_01c.pdf Decided projects for the global radiation reduction plan

Document 3
http://www.meti.go.jp/earthquake/nuc...120625_01d.pdf Securing education and human resources as seen from the mid and long term perspective

Document 4
http://www.meti.go.jp/earthquake/nuc...120625_01e.pdf Organization of the "Fukushima Workshop" (provisional name) on development of machinery and equipments etc. toward the decommissioning of Tokyo Electric Power Company (K.K.) Fukushima Daiichi nuclear power plant

clancy688

Here you go:

http://www.osti.gov/bridge/servlets/...Hq/5835351.pdf

zapperzero

Does anyone know what is the current status of PCV equipment hatches in Unit 4?

Furthermore, were they supposed to be open, or closed, at the time of the accident?

tsutsuji

Translation:

1/4

2/4

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