Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[tsutsuji]

Translation :

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[tsutsuji]

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[tsutsuji]

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[tsutsuji]

http://www3.nhk.or.jp/news/genpatsu-fukushima/20130330/index.html The multinuclide removal facility's test run using real highly contaminated water will begin on 30 March. The facility can remove 62 kinds of radioactive substances. The test run had been planned for last September, but it incurred a 6 month delay caused by a number of problems such as finding that the containers were not strong enough. The NRA approved Tepco's countermeasures last week. At first only the first one of the 3 lines shall be tested. The test is expected to take 4 months. As there are two other lines to test next, there is no prospect that normal operation can start within 2013 as originally planned. Including the groundwater that seeps in, 400 tons of contaminated water are produced everyday at Fukushima Daiichi.

http://www.tepco.co.jp/en/nu/fukushima-np/handouts/2013/images/handouts_130329_01-e.pdf Overview of the Multi-nuclide Removal Equipment (ALPS) at Fukushima Daiichi Nuclear Power Station

 

[turi]

Thanks tsutuji. Nice to have some pictures from reactor one's PCV.
Just shows me again, that I always underestimate the density of lead... 4.2 t of lead just from the 16 penetration end and collar shields. Wow. But "only" 0.37 m³.

 

[LabratSR]

RE: Filtered Vents. I came across this post by Sherrell Greene.

http://www.sustainableenergytoday.blogspot.com/2013/03/post-79-to-vent-or-not-to-vent-that-is.html


Sherrell Greene was a member of the BWR Severe Accident Analysis group at Oak Ridge. A list of his publications can be found here.

http://sustainableenergytoday.blogspot.com/2011/04/post-38-my-professional-publications.html

 

[tsutsuji]

monthly mid & long term report from Tepco, dated 7 March 2013 (246 pages, 11.9MB, Japanese) :

http://www.tepco.co.jp/nu/fukushima-np/roadmap/images/d130307_01-j.pdf

3-1 Cooling by closed loop water injection

37/246 - 46/246 : Results of TIP guide tube soundness verifications for the purpose of unit 2 reactor internal inspection and thermometer installation

A full English translation of that part was made available at : http://www.tepco.co.jp/en/nu/fukushima-np/handouts/2013/images/handouts_130301_03-e.pdf

 

[nikkkom]

Passive filtration is the only enhancement that is not going forward.

You mean, the missing safety feature which could possibly have kept Fukushima from becoming a *major* radiological release is not going to be installed on the US plants?

NRC Commissioners concluded the staff has not justified the safety improvement without going through the rulemaking process.

What does it mean in plain English?

There are additional improvements in power reliability and backup for active filtration (i.e. containment spray).

"Total blackout is impossible, no need to prepare for it"? I think I heard this sort of thing before. March 2011 comes to mind.

 

[tsutsuji]

http://www.nsr.go.jp/disclosure/meeting_operator/NEP/data/20130226_05giji.pdf [26 February 2013 Tepco-NRA meeting] : During the lecture organised on 13 February 2013 by Democratic Party representative Shoichi Kondo (where Tepco was also a participant), former representative Hiroshi Kawauchi requested a study toward the acquisition of Fukushima Daiichi unit 1 process computer system logs. In response, Tepco provides the following explanations :

- System log data acquisition work will start in March 2013, and analysing the logs could take up to one or two months, so that a result can be expected no later than in May or June.
- A business contract between Tepco and the maker Toshiba is necessary for the unit 1 process computer system log acquisition work. The contract is presently being prepared.
- According to Toshiba, apart from the process computer, there is another personal computer dedicated to system log recording and management, and it is possible to acquire the system logs by the restoration of the aforementioned personal computer.
- The onsite radiation is about 15 microsievert/hour

See also http://www.tepco.co.jp/en/nu/fukushima-np/plant-data/f1_1_Setsumei.pdf page 5/13 (published in May 2011) saying that contrary to unit 2 and unit 5, unit 1's "data of process computer (operation data)" are "difficult to obtain".

 

[Hiddencamper]

You mean, the missing safety feature which could possibly have kept Fukushima from becoming a *major* radiological release is not going to be installed on the US plants?



What does it mean in plain English?



"Total blackout is impossible, no need to prepare for it"? I think I heard this sort of thing before. March 2011 comes to mind.

With regards to passive filtration, they are only viable if there is no containment bypass leakage. If the containment is damaged it wouldn't have mattered. As we've seen at Fukushima, the majority of radiological release "appears" to be from unit 2, and unit 2 is the one which may have had a total breach or loss of containment integrity.

Considering this points, the fact that they were unable to break the rupture disk at unit 2, that there was containment leakage and potential pool bypass, a filter would have provided no benefit.

I'm not saying filters are a bad thing in general, but you need to fully understand sequences which a filter may or may not have been a benefit. If Fukushima had portable pumps at all units staged and proper severe accident procedures, they would have likely been able to achieve similar decontamination factors without filters.

Also the US has NOT ruled out filters (i don't know why all these people keep saying that, its completely not true). The NRC commission voted to use the RULEMAKING process to decide vents and decontamination post accident, and also to develop a strong technical basis.

 

[jim hardy]

If Fukushima had portable pumps at all units staged and proper severe accident procedures,

proverbial "ounce of prevention"...

Unfortunately our adversary based legal system has bled into other areas.

Regulators have groups whose job is to play "What If",
Industry has groups whose job is to discredit those what-ifs.
Sometimes it becomes more of a bureaucratic paper shuffling contest than a scientific inquiry.

I have to believe that had Tepco executives been made aware of just what sitting ducks they were they'd have acted to provide that ounce of prevention.
Those recently found historical records of giant tidal waves should have made somebody say "And our diesels are in the basement? Get a submarine hull around that whole electrical room pronto."

Instead they got tossed onto the bureaucratic gaming board.

Delay is the deadliest form of denial. parkinson

Some people think filters are an once of prevention and others a pound of cure..
Indeed it does no good to lock the door after the windows are blown out.
I honestly don't know.
They'll sort it out.

old jim

 

[a.ua.]

Hiddencamper

If the containment is damaged it wouldn't have mattered.

However, the reactor building is a secondary containment.
I will never believe that a small window to spread more radiation than if the building explodes.

 

[turi]

What is the objective of all those visits to the 4th floor of unit 1? This time former diet member Hiroshi Kawauchi (you can recognize him by his name written in katakana on his back) visits the place:
http://photo.tepco.co.jp/en/date/2013/201303-e/130328-01e.html
The two videos are from the same time frame, just from two different camera men.

 

[Hiddencamper]

Hiddencamper


However, the reactor building is a secondary containment.
I will never believe that a small window to spread more radiation than if the building explodes.

Either way, the reason at least one reactor building exploded was because hydrogen likely leaked from the containment penetrations and seals. Once the leak exists, a filter loses a lot of its purpose, because you now have an unfiltered release path. The explosion was just the transmission mechanism for releasing the escaped material to the atmosphere.

 

[tsutsuji]

I am reading the news backwards. Here is the news from 7 March :

http://www3.nhk.or.jp/news/genpatsu-fukushima/20130307/2230_hairo.html [7 March 2013] The new [Shinzo Abe] government installed a new Fukushima Daiichi decommissioning conference whose composition includes Tepco's president and the main nuclear plant makers' presidents. The conference had its first meeting on 7 March and announced that a new mid and long term roadmap would be disclosed in June, with the goal of starting the removal of fuel debris earlier than the within-10-years [from accident] duration announced by the former [Yoshihiko Noda] government. To achieve this, the Economy, Trade and Industry minister Toshimitsu Motegi said they plan to speed up the installation of the organizations/facilities in charge of developing remote controlled robots. In order to prepare the new roadmap, the conference will hear the opinons of Fukushima prefecture and experts.

 

[tsutsuji]

Reading the news further backwards...

http://www3.nhk.or.jp/news/genpatsu-fukushima/20130305/index.html [5 March 2013] The NHK visited Fukushima Daiichi in exclusivity for the first time, whereas in the past, Tepco organised joint visits for journalists from different news organisations visiting in groups. The journalists were allowed for the first time to get out of the bus and walk for about 10 minutes in the surroundings of unit 1 under a 100 microsievert/hour radiation. Some of the fire engine hoses used immediately after the accident, and some tanks displaced by the tsunami are remaining there. 4 cm thick steel plates have been laid on the ground in many places in order to shield the work areas. They passed by bus in the unit 2 and unit 3 area where the radiation is the highest [higher than the 300 microsievert maximum of the dosimeter carried by the journalist], and went to unit 4 to see the construction work of the covering/spent-fuel-removal structure. For the first time a [journalist's] camera was allowed into the water decontamination facility. As there is an air controlling system, the operators don't need to wear masks. They also had a look at the 930 tanks (1000 ton, 11 m high) where the water is stored. A new tank is filled every 2 days or so. That was another glimpse on "the hard way of decommissioning" which is planned to take 40 years.

http://www.dailymotion.com/video/xxz5jk_yyyyyyyyy-yyyyyyyy_news#.UVl9vLJHDGg An 11 minute program interviewing one of the NHK journalists who visited Fukushima Daiichi on 5 March, with a few excerpts from the visit at the plant.

http://www3.nhk.or.jp/news/genpatsu-fukushima/20130301/0025_50sman.html [1 March 2013] a Fukushima Daiichi worker in his 50s died on 27 February. As the diagnosis has not been confirmed, Tepco is unable to indicate the cause of his death.

http://www.tepco.co.jp/en/press/corp-com/release/2013/1225032_5130.html At around 9:20 AM on February 25, at the material storage of cooperative company in Hirono Town, Fukushima Prefecture, a cooperative company worker who was engaged in the preparation for cover installation on Unit 3 Reactor Building reported being sick. The worker was transported to the medical clinic in J-Village. As cardiopulmonary arrest was confirmed at the clinic, an ambulance was called at 9:35 AM. After cardiac massage was performed, the worker's pulse was recovered at 9:54 AM. At 10:10 AM, the worker was transported to Iwaki Kyoritsu Hospital by ambulance. Later, we received an announcement from the main contractor that he was pronounced dead by a doctor at 11:32 PM on February 27.

http://www.tepco.co.jp/en/press/corp-com/release/2013/1225058_5130.html At around 8:50 AM on March 1, a worker driving a dump truck reported being sick near Fureai intersection in Fukushima Daiichi Nuclear Power Station. Upon medical examination at Units 5-6 emergency medical room, judgment was given by a doctor that the worker needs to be transported to a hospital immediately. The worker left Fukushima Daiichi Nuclear Power Station on an emergency transportation vehicle at 9:30 AM and was transferred onto an ambulance at Tomioka Fire Department to be transported to Iwaki Kyoritsu Hospital. At 11:15 AM, the worker arrived at Iwaki Kyoritsu Hospital. As a result of medical examination, it was judged that the worker needs to be hospitalized for a few days to have his condition monitored. No radioactive contamination was found on his body.

http://www3.nhk.or.jp/news/genpatsu-fukushima/20130220/2250_robot.html [20 February 2013] A public presentation organized by the NEDO in Narashino city disclosed the research projects carried out by 6 teams composed of robot makers and universities. One them is a robot with an 8 m long arm which can open a valve in an elevated location. Another one is a cooling suit whose 30 kg heavy equipment is carried by a special mechanism instead of being carried on the worker's shoulders. The aim of these projects is implementation at Fukushima Daiichi. A NEDO official said the robots might start being used as soon as next summer.

http://www.nedo.go.jp/content/100516917.pdf The NEDO's press release (Japanese, 19 pages)

http://www.mhi.co.jp/discover/pickup/giraffe/index.html Super Giraffe (the 8 m long arm robot) (by Mitsubishi Heavy Industries)

Super Giraffe videos :
http://www.mhi.co.jp/discover/pickup/giraffe/movement1.html
http://www.mhi.co.jp/discover/pickup/giraffe/movement2.html
http://www.mhi.co.jp/discover/pickup/giraffe/movement3.html
http://www.mhi.co.jp/discover/pickup/giraffe/movement4.html
http://www.mhi.co.jp/discover/pickup/giraffe/movement5.html end effector module
http://www.mhi.co.jp/discover/pickup/giraffe/movement6.html valve approach
http://www.mhi.co.jp/discover/pickup/giraffe/movement7.html valve opening/closing
approaching and turning the valve

Super Lifter (by Toshiba)

Underwater robot (to be equipped with doppler current meter in order to detect leakage points, and ultrasonic camera) (by Toshiba)

Robot simulator (to train pilots) (by Chiba Institute of Technology)

Contamination mapping technology

"Tsubaki" robot (to be equipped with gamma camera, for the purpose of contamination mapping)

"Sakura" robot (for narrow spaces, to measure radiations and inspect the plant)

Robot suit "HAL" 1/2
Robot suit "HAL" 2/2

I couldn't find videos for the following:
http://www.nedo.go.jp/content/100516917.pdf page 7 (9/19) : a battery charging device for the robots (instead of changing the battery) ;
page 8 (10/19) a robot decontaminating device (to clean up the robots after work) ;
page 9 (11/19) a telecommunication system ;
page 10 (12/19) a human interface system (for operating the robots, with a possibility to make a 360° panorama from 4 cameras, with sensors measuring the distance to the obstacles, etc. One of the goals is to standardize the human interface in order to facilitate operator training)

Unrelated to NEDO :
Dry ice blaster robot (by Toshiba, disclosed on 15 February 2013) "it can clean a 1 m space [1 m² ?] in 20 minutes - we plan to improve it so that it can clean a wider space"

 

[turi]

Today TEPCO has released an overview of the thermometers of units 1, 2 and 3:
http://www.tepco.co.jp/en/press/corp-com/release/2013/1226015_5130.html

 

[tsutsuji]

Today TEPCO has released an overview of the thermometers of units 1, 2 and 3:
http://www.tepco.co.jp/en/press/corp-com/release/2013/1226015_5130.html

The only major difference with the previous monthly report seems to be unit 2's 68 TE-16-114L#1 RPV BELLOWS SEAL AREA now marked as "broken" (red) on page 12/30 whereas it was marked "for reference" (green) last month. The thermometers that are completely OK are the blue ones ("can be used for monitoring"). The black ones are outside the scope of the report (found broken before the accident, or not connected to a cable).

 

[zapperzero]

Y'all need to read this:

http://ex-skf.blogspot.ro/2013/04/now-they-tell-us-only-10-of-water-was.html

Apparently the water injection figures are all wrong, there was some broken piping or something and so between March 20 and March 23 very little water reached reactors 1 and 3.

 

[zapperzero]

Reading the news further backwards...

http://www3.nhk.or.jp/news/genpatsu-fukushima/20130301/0025_50sman.html [1 March 2013] a Fukushima Daiichi worker in his 50s died on 27 February. As the diagnosis has not been confirmed, Tepco is unable to indicate the cause of his death.

http://www.tepco.co.jp/en/press/corp-com/release/2013/1225032_5130.html At around 9:20 AM on February 25, at the material storage of cooperative company in Hirono Town, Fukushima Prefecture, a cooperative company worker who was engaged in the preparation for cover installation on Unit 3 Reactor Building reported being sick. The worker was transported to the medical clinic in J-Village. As cardiopulmonary arrest was confirmed at the clinic, an ambulance was called at 9:35 AM. After cardiac massage was performed, the worker's pulse was recovered at 9:54 AM. At 10:10 AM, the worker was transported to Iwaki Kyoritsu Hospital by ambulance. Later, we received an announcement from the main contractor that he was pronounced dead by a doctor at 11:32 PM on February 27.

http://www.tepco.co.jp/en/press/corp-com/release/2013/1225058_5130.html At around 8:50 AM on March 1, a worker driving a dump truck reported being sick near Fureai intersection in Fukushima Daiichi Nuclear Power Station. Upon medical examination at Units 5-6 emergency medical room, judgment was given by a doctor that the worker needs to be transported to a hospital immediately. The worker left Fukushima Daiichi Nuclear Power Station on an emergency transportation vehicle at 9:30 AM and was transferred onto an ambulance at Tomioka Fire Department to be transported to Iwaki Kyoritsu Hospital. At 11:15 AM, the worker arrived at Iwaki Kyoritsu Hospital. As a result of medical examination, it was judged that the worker needs to be hospitalized for a few days to have his condition monitored. No radioactive contamination was found on his body.

Is it not a bit odd? I mean, this is not your average construction site. One would expect at least blood work to rule out internal contamination.

 

[tsutsuji]

Y'all need to read this:

http://ex-skf.blogspot.ro/2013/04/now-they-tell-us-only-10-of-water-was.html

Apparently the water injection figures are all wrong, there was some broken piping or something and so between March 20 and March 23 very little water reached reactors 1 and 3.

Thanks for the link. It made me discover that ex-skf has more information on the NHK theory about some amount of unit 3's injected water going to the condenser instead of going to the reactor : http://ex-skf.blogspot.com/2013/03/nhk-55-of-water-injected-into-reactor-3.html

 

[tsutsuji]

Fukushima Daiichi decommissioning countermeasure promoting conference, 1st secretariat meeting, 28 March 2013 ( http://www.meti.go.jp/earthquake/nuclear/20130328_01.html )

http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01a.pdf Seating chart
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01b.pdf Agenda
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01c.pdf Participants

Document 1 : Plant status
Document 1-1 : Plant status
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01d.pdf Plant parameters
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01e.pdf Accumulated water storage and treatment status

Document 2 :
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01f.pdf Mid and long term roadmap progression status (abstract)

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/130328/130328_01g.pdf Schedule
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01h.pdf Study toward the early implementation of inside-building closed loop and closed loop scaling down
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01j.pdf Completion of unit 3 fuel pool purification (salt removal)

3-2 Treatment of accumulated water
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01k.pdf Schedule
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01m.pdf Multinuclide removal facility hot test and normal operation schedule
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01n.pdf Ground water bypass progress status
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01p.pdf Additional tank installation semiannual report

3-3 Countermeasures to reduce environmental radiations
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01q.pdf Schedule
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01r.pdf Radiation reduction countermeasure procedure and radiation evaluation results
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01s.pdf Unit 2 blowout panel opening closure and exhaust gas equipment operation adjustment
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01t.pdf Results of evaluation of additional releases from reactor buildings
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01u.pdf Installation of fibrous type adsorbent purification equipment into harbour
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01v.pdf Installation of a specialist study group for the study of harbour seawater radioactive substance reduction

3-4 Improvement of working conditions
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01w.pdf Schedule
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01x.pdf Administrative main building rest area, rest area in front of seismic-isolated building and seismic-isolated building radiation reduction countermeasures

3-5 Countermeasures for spent fuels pools
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01y.pdf Schedule
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01z.pdf Layout map of working areas of units 3 and 4 top part debris removal work and covering work for the purpose of fuel removal
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01aa.pdf Debris removal work, reactor building top part, unit 3
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01bb.pdf Debris removal work, reactor building top part, unit 4
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01cc.pdf Unit 3 spent fuel pool internal survey
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01dd.pdf Steel frame construction work of unit 4 cover for spent fuel removal
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01ee.pdf Inspection report on the first dry storage cask

3-6 Preparations for fuel debris removal
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01ff.pdf Schedule
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01gg.pdf Plan and execution of inspection into reactor building small rooms
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01hh.pdf Unit 2 vent pipe lower part surroundings inspection results
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01jj.pdf Basic experiments on sealing materials for PCV lower part repairs (waterproofing)

3-7 Treatment and disposal of radioactive waste
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01kk.pdf Schedule
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01mm.pdf Debris, cut down trees management status
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01nn.pdf Debris, cut down trees radiation reduction progress status
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01pp.pdf Research and development plans for treatment and disposal of radioactive waste
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01qq.pdf Radioactive waste mid and long term storage plans
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01rr.pdf Radiation analysis of debris, cut down tree samples from plant premises

Document 4
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01ss.pdf Results of the 3rd machinery and equipment Fukushima workshop

Document 5
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01tt.pdf Units 1 to 4 internal electric power source black out incident

Document 6
http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01uu.pdf Mid and long term roadmap and research and development plans revision process

 

[tsutsuji]

http://www.meti.go.jp/earthquake/nuclear/20130402_01.html The second meeting of the Fukushima Daiichi decommissioning countermeasure promoting conference (with Economy, Education ministers, Tepco, Toshiba, Hitachi, JAEA presidents etc.) was held on 2 April. It approved JAEA's plans for the selection of a site to install the "Mockup facility" for the development and testing of remote controlled equipments. 3 sites, named A, B, and C have been preselected. They have to be close from Fukushima Daiichi in order to enable quick transfer of the equipment to the plant and to facilitate personnel training. The site must however be low radiation and close enough to the sea to enable the shipment of equipments by sea, and accessible by large roads or motorways so that the construction work can be done smoothly. A and B are 15 km away from Fukushima Daiichi and C is 25 km away. A and B are 2 km away from Fukushima Daini and C is 10 km away from Fukushima Daini. As those plans have been approved, the next step is a geological study of each site. The Mockup facility is planned to start operating before the end of fiscal 2014.

http://www.kensetsunews.com/?p=8656 [11 March 2013] JAEA plans to install two facilities in Fukushima prefecture : a mockup facility and a radioactive substance analysis and research laboratory. The mockup facility is planned to start operation by the end of fiscal 2014. The research laboratory for melted fuel analysis and treatment is planned to start operation in fiscal 2017.

 

[LabratSR]

Poking around the METI website I stumbled across this page.

http://www.meti.go.jp/english/earthquake/nuclear/decommissioning/20120315_01.html


LOTS of stuff there including these.


Current Situation of Fukushima-Daiichi Nuclear Power Plants and Difficulties in the Defueling Plan
http://www.meti.go.jp/english/earthquake/nuclear/decommissioning/pdf/20120315_01_001.pdf


Fundamental Research Program for Removal of Fuel Debris 1/2
http://www.meti.go.jp/english/earthquake/nuclear/decommissioning/pdf/20120315_01_014.pdf

Fundamental Research Program for Removal of Fuel Debris 2/2
http://www.meti.go.jp/english/earthquake/nuclear/decommissioning/pdf/20120315_01_015.pdf

And there's more.

 

[zapperzero]

http://www.meti.go.jp/earthquake/nuclear/pdf/130328/130328_01d.pdf Plant parameters

Unit 2 chart shows temp spikes in some of the lower sensors (HVH, RPV). Is the dragon stirring in its sleep?

 

[zapperzero]

Current Situation of Fukushima-Daiichi Nuclear Power Plants and Difficulties in the Defueling Plan
http://www.meti.go.jp/english/earthquake/nuclear/decommissioning/pdf/20120315_01_001.pdf

I wonder how optimistic the assumption that the SFPs will remain intact for the duration really is.

 

[gnasch]

where is the leak?

Interesting comment on the water flow:


http://www.hiroshimasyndrome.com/fukushima-commentary.html
entry of 20130327

best, gnasch

 

[ronaldkr]

Interesting comment on the water flow:http://www.hiroshimasyndrome.com/fukushima-commentary.html
entry of 20130327

best, gnasch

That guy is not only a trained NPP operator, but also a trained PR shill. His speciality seems to build straw men to knock them over. When you wold expect temperature data vs. flow -- nothing.
Even TEPCO found it necessary to admit that not all water reached the RPV, so it's not even new.

And physics? "No water equals no criticality", he writes. Tell that to the victims of Little Boy. Oops.

 

[gnasch]

Well - I do not pretend to like or dislike him, but if it is not the containment that is leaking but the pipes, would this not simplify the establishing of a closed circuit for cooling?

Thx, gnasch

 

[NUCENG]

Unit 2 chart shows temp spikes in some of the lower sensors (HVH, RPV). Is the dragon stirring in its sleep?

Possible explanation or contributing factor:

http://www.tepco.co.jp/en/press/corp-com/release/2013/1224790_5130.html

From TEPCO Daily status report:

"-At 12:35 PM on February 15, Unit 2 reactor injection water amount was adjusted as follows since the amount had fluctuated. Feed water system: Increased from approx. 1.8m3/h to approx. 2.0m3/h, Reactor core spray system: Increased from approx. 3.4m3/h to approx. 3.5m3/h."

http://www.tepco.co.jp/en/press/corp-com/release/2013/1224861_5130.html

and after cooling, flow was readjusted on the 20th:

"- During the reliability improvement work to be implemented on Unit 2 feed water system scheduled in March, the reactor water injection from the feed water system is planned to be suspended. In prior to the reliability improvement work implementation, water injection from the feed water system was suspended with all amount injected from the reactor core spray system for the purpose of confirming that there is no significant impact on reactor cooling. At 1:16 PM on February 20, the amount of water injection from the feed water system was decreased from approx. 1.9m3/h to 0m3/h and the amount of injection from the reactor core spray system was increased from approx. 3.4m3/h to approx. 5.5m3/h."