Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[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."

 

[jim hardy]

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

I thought he adequately backed his statement.

The fuel is so dilute in U-235 and Pu-239 isotopes (the only ones that undergo the chain reaction) that it is imperative for the bundles to be immersed in water for criticality to occur.

Do you know what is "enrichment" ? (hint - un-dilution)

Do you know how un-dilute reactor fuel is?
Do you know how un-dilute Little Boy was?

 

[tsutsuji]

Interesting comment on the water flow:


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

best, gnasch

He says "Unit #2’s torus room is dry" but this is wrong. Unit 2 torus room water level is OP 3270 (mm) , which is a little below mid-basement (OP 4000). The water surface is seen in the stairs on the picture on http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120607_02-e.pdf page 2/5 (water level measurements are provided on page 5/5).

He says "all the observed water levels are below penetrations through the walls" but Tepco provided the following diagram showing the penetrations are at 0.3 m and 3.1 m above torus room bottom, which are lower than the 3.8 m water level :

Diagram from my translation at https://www.physicsforums.com/showthread.php?p=3840717#post3840717

 

[a.ua.]

However, in the reactor building 4 is also standing water in the torus room.
Why?

 

[NUCENG]

Diagram from my translation at https://www.physicsforums.com/showthread.php?p=3840717#post3840717

Tsutsuji, I've been missing something important until you reposted that link.

The drawing shows a pipe penetration directly from the torus room to the turbinge building basement. Further it shows a sleeve around the pipe which is not water tight, much less air tight.

In US BWR3 and BWR4 plants such a configuration would seem to degrade secondary containment and the ability to create a negative pressure in the reactor building with the SBGT system. Is there any information about what system is aassociated with those penetrations? Is this a Japanese design difference or am I misremembering the US plant design (OTD)?

Only thing I can think of is that these penetrations were originally sealed and failed during the accident. Does anyone else with US BWR experience know what those penetrations could be? I don't remember any lessons learned about this.

 

[Hiddencamper]

Tsutsuji, I've been missing something important until you reposted that link.

The drawing shows a pipe penetration directly from the torus room to the turbinge building basement. Further it shows a sleeve around the pipe which is not water tight, much less air tight.

In US BWR3 and BWR4 plants such a configuration would seem to degrade secondary containment and the ability to create a negative pressure in the reactor building with the SBGT system. Is there any information about what system is aassociated with those penetrations? Is this a Japanese design difference or am I misremembering the US plant design (OTD)?

Only thing I can think of is that these penetrations were originally sealed and failed during the accident. Does anyone else with US BWR experience know what those penetrations could be? I don't remember any lessons learned about this.

Could it be a penetration for the condensate storage system to fill/drain the torus? Or something else related (CST line to RCIC/HPCI?). I know the older plant designs tend to have their CST feed both RCIC/HPCI and act as a condensate overflow tank. I'm not sure though, my experience with Mark Is is limited.

 

[zapperzero]

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"

looking at the chart, the change started on about the 8th or 9th
so, no, at least on the face of it

 

[tsutsuji]

I found the following document dated 16 December 2012. I don't know if it hast been posted in this forum yet. It's in English :

Severe Accident Analyses of Fukushima-Daiichi Units 1 to 3
Harutaka Hoshi and Masashi Hirano, Japan Nuclear Energy Safety Organization (JNES)
Masashi Iijima and Toshimitsu Homma, Japan Atomic Energy Agency (JAEA)
Side Event “Updated activities about TEPCO’s Fukushima Dai-ichi NPS accident” At Fukushima Ministerial Conference on Nuclear Safety on 16 December 2012

http://www.nsr.go.jp/english/data/dai-ichi_NPS_handouts2.pdf

pages 18 and 19 show "Detonation analysis with AUTODYN" for the unit 1 and unit 3 hydrogen explosions.

 

[LabratSR]

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

Awhile back I was looking at this handout from TEPCO on the new fuel handling building for Unit 4 and looking at the graphic on the left, it "appears" that they are cantilevering the new structure over the Unit 4 reactor building. To me, this could explain the apparent "overbuilding" of the structure. I also believe this could be a statement about their confidence in the structural integrity of the remnants of Unit 4.

http://www.tepco.co.jp/en/nu/fukushima-np/handouts/2013/images/handouts_130313_01-e.pdf

Or I could just be making too much out of the graphic.

 

[NUCENG]

looking at the chart, the change started on about the 8th or 9th
so, no, at least on the face of it

I agree, the temperature began to increase. earlier. but the dates of adjustments in flow are consistent with beginning to cool it back down and then reducing flow after the cooldown returned to the previous value. The beginning or the heatup on the 8th or 9th could be the start of the flow fluctuation they describe on the status report on the 15th. I can't immediately explain why only a few of the sensors responded, but it does match the timing of two physical changes in flow rates.

Of course, sleeping dragons are much more fanciful.

 

[zapperzero]

Of course, sleeping dragons are much more fanciful.

aren't they, though?

But you see, the entire thing reminds me of what doctors call symptomatic treatment
which is generally good at keeping people alive, not so much at curing them. I worry about reactivity. I worry about corium flows. I worry about new cracks in the piping. TEPCO is seemingly unconcerned and just dumps more water in when the "patient" gets too hot.

 

[tsutsuji]

Only thing I can think of is that these penetrations were originally sealed and failed during the accident.

I think you are correct.

I have not found anything like a blueprint showing the detailed structure of those penetrations, but here is what I found :

On the Hitachi-GE website, a robot specification dated 9 November 2012 :

2.1.1 Objectives of the equipment and general system
(1) The first objective of the equipment to be developed consists of checking for any leaks from
the penetration areas of the wall surfaces of the torus rooms and triangular corners in the
basement of the nuclear reactor building.
(2) The second objective of the equipment to be developed consists of monitoring the remotely
operated vehicle underwater that is used to visually inspect the torus rooms and triangular
corners in the basement of the nuclear reactor building.

http://www.hitachi-hgne.co.jp/download/2012/20121109_28-e.pdf page 1/7 (English)

On the NRA website, a document distributed at the 7th meeting, dated 29 March 2013 of the Special atomic facility monitoring and assessment study group meeting :

http://www.nsr.go.jp/committee/yuushikisya/tokutei_kanshi/data/0006_04.pdf page 20/36 (translation)

 

[tsutsuji]

NRA Special atomic facility monitoring and assessment study group, 7th meeting, 29 March 2013 (http://www.nsr.go.jp/committee/yuushikisya/tokutei_kanshi/20130329.html )

http://www.nsr.go.jp/committee/yuushikisya/tokutei_kanshi/data/0007_99.pdf Agenda
http://www.nsr.go.jp/committee/yuushikisya/tokutei_kanshi/data/0007_01.pdf Equipment stop due to blackout at Tepco Fuksuhima Daiichi NPP
http://www.nsr.go.jp/committee/yuushikisya/tokutei_kanshi/data/0007_02.pdf Units 1 to 4 internal electric power source blackout incident (Tepco)
http://www.nsr.go.jp/committee/yuushikisya/tokutei_kanshi/data/0007_03.pdf Reply to comments on unit 4 SFP fuel removal safety (Tepco)
http://www.nsr.go.jp/committee/yuushikisya/tokutei_kanshi/data/0007_04.pdf Status of verifications concerning unit 4 SFP fuel removal (draft)
http://www.nsr.go.jp/committee/yuushikisya/tokutei_kanshi/data/0007_05.pdf Radiation assessment in plant premises surroundings (Tepco)
http://www.nsr.go.jp/committee/yuushikisya/tokutei_kanshi/data/0007_06.pdf Observations about unit 1 torus room radiation measurement results (Tepco)
http://www.nsr.go.jp/committee/yuushikisya/tokutei_kanshi/data/0007_07.pdf Waterproofing countermeasures against ground water seeping in (Tepco)
http://www.nsr.go.jp/committee/yuushikisya/tokutei_kanshi/data/0007_08.pdf Partial revision of "Special atomic facility executive plan" (22 March release) (Tepco)
http://www.nsr.go.jp/committee/yuushikisya/tokutei_kanshi/data/0007_09.pdf Verification status of each remark
http://www.nsr.go.jp/committee/yuushikisya/tokutei_kanshi/data/0007_10.pdf Status of the study group's past deliberations etc. on executive plan

(reference)
http://www.nsr.go.jp/committee/yuushikisya/tokutei_kanshi/data/0007_11.pdf List of measures demanded for Fukushima Daichi NPP in line with the special atomic facility designation [7 November 2012]
https://www.youtube.com/watch?v=xpwa2TCPxts
NRA Special atomic facility monitoring and assessment study group, 7th meeting, 29 March 2013

 

[NUCENG]

aren't they, though?

But you see, the entire thing reminds me of what doctors call symptomatic treatment
which is generally good at keeping people alive, not so much at curing them. I worry about reactivity. I worry about corium flows. I worry about new cracks in the piping. TEPCO is seemingly unconcerned and just dumps more water in when the "patient" gets too hot.

And their alternatives are what? Are there any indications that corium can still be in a molten state after 2 years? Has any radiological evidence of reactivity changes indicated an impending recriticality? They are injecting water through both feedwater and spray piping. Adjustments in these flows seem to demonstrate that at least some of the flow from both paths is getting where it belongs. Operating pressures of piping systems still in use are significantly lower that design conditions. Leaks or additional cracks are possible or even probable due to damage, corrosion, and poor chemistry, but required flows are fairly small and there are additional paths available. Time to respond is in terms of days, not hours as it was in 2011.

You are absolutely justified in your concerns about potential additional problems. Keep watching and questioning.

 

[tsutsuji]

http://www3.nhk.or.jp/news/genpatsu-fukushima/20130404/index.html A little after 05:20 AM on 4 April the multinuclide facility stopped suddenly. As there was no abnormalty or leakage, it was found that an operator had mistakenly pushed a button. The facility was started again one hour later. The problem was not disclosed to national or local governments or mass media until 3 hours after it happened.

http://www3.nhk.or.jp/news/genpatsu-fukushima/20130405/1715_teishi.html Unit 3 SFP cooling stopped at around 2:30 PM on 5 April. An alarm signal was generated on a "power board". Tepco said it plans to restart the system today. Without cooling the pool heats at 0.15°C/hour and it would take 2 weeks without cooling to reach 65°C. There are 566 assemblies in the pool, including 52 fresh fuel ones.

http://www3.nhk.or.jp/news/genpatsu-fukushima/20130405/index.html Unit 3 SFP cooling was restarted at around 5:20 PM.

http://www3.nhk.or.jp/news/genpatsu-fukushima/20130405/1254_hanei.html There was a deliberation on energy and nuclear power at the national diet today. Prime Minister Abe said concerning the accident investigation "Some points that need study are remaining. As the government changed, we want to revise from zero, and resolutely conduct the research of the causes". NRA president Shunichi Tanaka said : "In order to find out if the SBO is due to the earthquake or to the tsunami, one needs to enter the site whose radiation is too high, and our investigation shall include such considerations. The research of causes is an important duty, and as the members in charge of the investigation were selected on March 27, we want to make things clear as quickly as possible".

 

[zapperzero]

And their alternatives are what?
You are absolutely justified in your concerns about potential additional problems. Keep watching and questioning.

Alternatives... I am concerned that the site is still not instrumented properly. We should know most everything by now, or at least all that matters. Water flows, state of piping. Thanks for the encouragement, there is not much I can do from the sidelines, except ask questions.

Are there any indications that corium can still be in a molten state after 2 years?

At one point a few months ago there have been some changes - thermometers failing mostly - that suggested new paths for the water, or corium shifting, or both. We don't know. Just looking at the thermal power that it can still make, there shouldn't be any of it that is still molten though, no? I mean, barring odd situations, such as a hot bubble in a very efficiently insulating ceramic foam or something? When I said "corium flows" I mostly meant in the past - the paths it took are assumed, not known.

Has any radiological evidence of reactivity changes indicated an impending recriticality?

We don't know. There are to my knowledge no neutron detectors anywhere near the reactor buildings. I haven't read any mention of anything like that. The (enormous amount) of assorted metallic debris that has already been removed has not been checked for neutron activation. And so on.

They are injecting water through both feedwater and spray piping. Adjustments in these flows seem to demonstrate that at least some of the flow from both paths is getting where it belongs.

I am not disputing that, evidently there is some water (a lot actually). We don't know how exactly it gets to where it is and we don't really know where it goes when it goes (well, to the sea eventually but...) and so the cooling loop is not really closed. That should be a cause of great concern, due to contamination issues. Yet it somehow isn't.

Operating pressures of piping systems still in use are significantly lower that design conditions.

There's that at least, yes.

Leaks or additional cracks are possible or even probable due to damage, corrosion, and poor chemistry, but required flows are fairly small and there are additional paths available. Time to respond is in terms of days, not hours as it was in 2011.

Small blessings.

I can think of at least one practical reason to FINALLY do a thorough check of the piping system - the water processing/storage facility is overloaded as it is, flows could probably be reduced even further, much further in fact if we (TEPCO really) actually knew where the water is needed and how to get it there.

 

[tsutsuji]

Special atomic facility monitoring and assessment study group, 6th meeting, 8 March 2013 (http://www.nsr.go.jp/committee/yuushikisya/tokutei_kanshi/20130308.html )

http://www.nsr.go.jp/committee/yuushikisya/tokutei_kanshi/data/0006_99.pdf Agenda
http://www.nsr.go.jp/committee/yuushikisya/tokutei_kanshi/data/0006_01.pdf Reply to comments on multinuclide removal facility (Tepco)
http://www.nsr.go.jp/committee/yuushikisya/tokutei_kanshi/data/0006_02.pdf Multinuclide removal facility (line A) hot test evaluation (draft)
http://www.nsr.go.jp/committee/yuushikisya/tokutei_kanshi/data/0006_03.pdf Special atomic facility risk assessment, etc. (reply to comments) (Tepco)
http://www.nsr.go.jp/committee/yuushikisya/tokutei_kanshi/data/0006_04.pdf Mid and long term process toward fuel debris removal (Tepco)
http://www.nsr.go.jp/committee/yuushikisya/tokutei_kanshi/data/0006_05.pdf Radiation assessment in plant premises surroundings (Tepco)
http://www.nsr.go.jp/committee/yuushikisya/tokutei_kanshi/data/0006_06.pdf Structural strength and antiseismic strength of unit 3 cover for fuel removal (reply to comments) (Tepco)
http://www.nsr.go.jp/committee/yuushikisya/tokutei_kanshi/data/0006_07.pdf Verification status of each remark
http://www.nsr.go.jp/committee/yuushikisya/tokutei_kanshi/data/0006_08.pdf Status of the study group's past deliberations etc. on executive plan

(References)
http://www.nsr.go.jp/committee/yuushikisya/tokutei_kanshi/data/0006_09.pdf List of measures demanded for Fukushima Daichi NPP in line with the special atomic facility designation [7 November 2012]
http://www.nsr.go.jp/committee/yuushikisya/tokutei_kanshi/data/0006_10.pdf NRA's awareness of issues
http://www.nsr.go.jp/committee/yuushikisya/tokutei_kanshi/data/0006_11.pdf Opinions raised by outside expert at the last meeting
http://www.nsr.go.jp/committee/yuushikisya/tokutei_kanshi/data/0006_12.pdf Unit 3 cover for fuel removal structural strength and antiseismic strength

https://www.youtube.com/watch?v=Gqg54W9x6j4

 

[zapperzero]

Special atomic facility

What does this mean please? Is it some new classification? A new legal framework?

 

[tsutsuji]

What does this mean please? Is it some new classification? A new legal framework?

Yes. According to http://www.asahi.com/special/10005/TKY201211070747.html Tepco is legally bound under this designation, to submit its operation plan (including reactor monitoring, fuel storage, worker radiation exposure management, etc.) for approval to the NRA.

It sounds like it gives the NRA more power than it has on the other nuclear power plants.

 

[zapperzero]

Yes.
It sounds like it gives the NRA more power than it has on the other nuclear power plants.

Thank you.
This seems reasonable.

 

[tsutsuji]

http://www.tepco.co.jp/cc/press/2013/1226107_5117.html About 6.0X10³ Bq/cm³ was found on 5 April between the outermost sheet and the middle sheet (bentonite sheets) at underground storage tank No 2. Additional water analysis will be performed on 6 April.

http://www.tepco.co.jp/cc/press/2013/1226108_5117.html We are holding an extraordinary press conference about the underground storage tank No 2 at Tepco's main office [in Tokyo], at 01:30 AM, 6 April 2013 (or Fukushima press club room, Fukushima prefecture prefectoral office main building 2nd floor, Fukushima City).

http://www.tepco.co.jp/cc/press/2013/1226111_5117.html At present, underground storage tank No 2 contains 13,000 m³ of water. We plan to transfer 11,500 m³ of water from underground storage tank No 2 to underground water tank No 1 (which is at present empty). 11,500 m³ is the maximum operational volume of underground water tank No 1. As there is no ditch nearby, there is little probability that water flowed to the sea.

http://www.asahi.com/national/update/0406/TKY201304050526.html The underground water tank stores water after it has undergone decontaminating treatment.

http://www3.nhk.or.jp/news/genpatsu-fukushima/20130406/index.html Although cesium has been removed, radioactive strontium remains in the water stored at the underground tank. Strontium was found between the [bentonite] sheets and also very small quantities of strontium were found in the ground outside the tank. Tepco suspects the water is leaking from the underground tank into the ground. As the underground tank is 800 m away from the sea, and as there is no water ditch nearby, Tepco thinks the water has not leaked directly into the sea.

 

[tsutsuji]

What I wrote above contains a mistake. See the top left diagram on http://www.tepco.co.jp/nu/fukushima-np/handouts/2013/images/handouts_130406_03-j.pdf page 4/22. Only the outermost sheet (black) is a bentonite sheet. The other two (red sheets) are HDPE sheets. There is also a layer of concrete (gray) on the inner side. There are also long fiber non woven sheets (dot dash lines) between those sheets.

http://www3.nhk.or.jp/news/genpatsu-fukushima/20130406/index.html Tepco plans to transfer the water into the other underground tank using four pumps with a flow rate of approximately 100 tons/day, so that it will take more than 5 days.

 

[tsutsuji]

http://www.tepco.co.jp/nu/fukushima-np/handouts/2013/images/handouts_130407_03-j.pdf See the diagrams page 4/15 : Tepco thinks that there is a possibility that water leaked through the detector pipe's penetration into the sheets. The leakage point is thought to be located at a high elevation, because no sudden rise of the between-sheets water level was observed. Conversely, a low elevation leakage point would have created a sudden rise, because the water pressure increases with depth.

This explains why Tepco decided to lower the water level in underground tank No. 3 :

Reduce the water level of the underground reservoir No.3 from 95% to less than 80% (by safely
transferring the water to an unused underground reservoir)
...
The water will continue to be stored in the underground reservoirs for the time being
while maintaining the water level at approx. 80% (max.) or less which is the location of the leakage
detection hole on the upper part of the reservoir (which is assumed to be the leakage location).

http://www.tepco.co.jp/en/nu/fukushima-np/handouts/2013/images/handouts_130408_02-e.pdf page 3/4

 

[tsutsuji]

From Asahi : leak could have been detected earlier ; unexpected consequences on the ground water bypass system can be feared:

The company also said April 7 it believes that radioactive water began leaking from the No. 2 tank around March 20.

The company has been monitoring water levels and radioactivity concentrations outside the tank. But only after the leak was detected did TEPCO find that water levels had started falling around March 20.

There were also signs of changes in radioactivity concentrations on March 20, but the company did not notice them until April 3.

[...]

TEPCO planned to pump up groundwater and release it into the sea before it enters the reactor buildings. That plan would be meaningless if the groundwater is already contaminated.

By Shunsuke Kimura http://ajw.asahi.com/article/0311disaster/fukushima/AJ201304080089

http://www3.nhk.or.jp/news/genpatsu-fukushima/20130409/index.html Underground tank No. 1's leak occurred while it was only 55% full, so that the cause is presumed be different from what had been thought earlier for Underground tank No. 2 and No. 3.

 

[turi]

The personnel access lock on floor 1 in reactor 1 seems to have withstood the heat while a penetration nearby has leaked radioactive material (dose rate values are on the last page):

http://www.tepco.co.jp/en/nu/fukushima-np/handouts/2013/images/handouts_130409_10-e.pdf

The access lock looks like it has gotten quite hot:
http://photo.tepco.co.jp/library/130409_01/130409_01.jpg
http://photo.tepco.co.jp/library/130409_01/130409_10.jpg

 

[etudiant]

The concern is that leaking highly radioactive water may gradually contaminate larger areas of the site.
Things are bad enough as is, working in a 50-100mSiv/hr environment would be much worse.
If that is the prospect, TEPCO will surely be forced to ocean dump this contamination.

 

[tsutsuji]

I was hoping Tepco would quickly translate into English the presentation shown by Tepco's president on 10 April about the countermeasures against the underground tank leaks, but at present only the Japanese version is available :

http://www.tepco.co.jp/nu/fukushima-np/handouts/2013/images/handouts_130410_04-j.pdf As you can see on the first page, they plan to move all the water from all underground plastic sheet tanks to on-ground steel tanks : the H2 area tanks, the filtrate water tanks and the G6 area tanks. The green area on page 2/20 is a new area under study where they plan to install even more above ground tanks. The tanks at H8, G3, G4, G5, and G6 (violet) have yet to be installed. The tanks installation plan at G6 is explained on the diagram on page 3/20 which shows in pink the G6 storage capacity gradually increasing over April, May, and June 2013, while the water quantity stored in the underground tanks (in blue) gradually decreases as the water is moved into the above ground tanks. The diagram on page 7/20 explains the plan to pump contaminated water from the detector pipe and put it back into the tank, for the purpose of mitigating (preventing ?) ground water contamination. The map on page 12/20 shows (in violet) the location of the new monitoring holes that will be bored to monitor ground water contamination. The schedule on page 20/20 says the visual inspection of the detector pipe penetration at underground tank No. 2 should be completed on 17 April.

http://ajw.asahi.com/article/0311disaster/fukushima/AJ201304110054 "TEPCO to stop using underground tanks at Fukushima plant"

http://www3.nhk.or.jp/news/genpatsu-fukushima/20130410/index.html 0.11 Bq/cm³ of strontium, etc. was found in a sample of ground water taken on 9 April near underwater tank No. 1. As the salt concentration is stable, it is impossible to judge if this is evidence that the tank is leaking.

The design of those tanks (2 PE sheets, 1 bentonite sheet) had been disclosed by Tepco at the 25 June 2012 mid and long term meeting :

The 7th mid long term meeting was held on 25 June: http://www.meti.go.jp/earthquake/nuclear/20120625_02.html

Document 3 Study and execution of each special plan

3-2 Treatment of accumulated water
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02m.pdf Progress status of construction of underground water storage tanks

 

[tsutsuji]

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

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_01h.pdf Study toward the early implementation of inside-building closed loop and closed loop scaling down

Translation :
01/11

02/11

03/11

 

[tsutsuji]

Translation:

04/11

05/11

06/11

 

[tsutsuji]

Translation:

07/11

08/11

09/11

 

[tsutsuji]

Translation:

10/11

11/11