Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[clancy688]

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.

Here you go:

http://www.osti.gov/bridge/servlets/purl/5835351-nR29Hq/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]

The 7th mid long term meeting was held on 25 June:

3-5 Countermeasures for spent fuels pools
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02bb.pdf Performance of preliminary underwater surveys (2nd and 3rd ones) in spent fuel pool for the purpose of removing debris at unit 3.

Translation:

1/4

2/4

 

[tsutsuji]

Translation:

3/4

4/4

 

[jim hardy]

in this document linked above (thanks again Tsutsuji )
http://www.meti.go.jp/earthquake/nuc...120625_02y.pdf

there's two red circles on bottom left photo.
800 % is about all the expansion it'll stand, and i don't see what is significant there.
Except that a lot of debris has been cleared.

is there anything I'm missing by my inability to read the captions ?

old jim

 

[SteveElbows]

No you aren't missing anything, debris removal is all its about. In this case they finally dealt with the roof debris that's been dangling down there, having previously cleared away rather large quantities of debris & broken buildings from the area below.

Since I was asking about progress at this reactor the other day, I am very grateful for the translation above which gives us a sense of timescale, as well as these new images.

 

[SteveElbows]

Here you go:

http://www.osti.gov/bridge/servlets/purl/5835351-nR29Hq/5835351.pdf

Thanks very much, that's the one, not sure if there are any others.

Anyway I guess we aren't going to learn much more about this for a long time, and there is little else that I can use right now to build on any theories in this regard. I suppose alternative possibilities are core material washing down into S/C or torus room later, or something related to wet venting.

The next thing we might learn about reactor 1 is the state of the TIP room, and updated measurements of previously inspected southern parts of the first floor, as they are due to do the robot thing there on wednesday according to this handout:

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120703_01-e.pdf

 

[tsutsuji]

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

3-2 Treatment of accumulated water
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02n.pdf Progress status of ground water bypass study

This document was already translated into English by Tepco in http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120618_05-e.pdf pages 4/17 to 8/17 (only the date is different [25 June instead of 18 June])

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

3-2 Treatment of accumulated water
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02k.pdf Subdrain purification test report

Most of this document was already translated into English by Tepco in http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120618_05-e.pdf pages 12/17 to 17/17:

http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02k.pdf 2/7 content similar with http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120618_05-e.pdf 14/17 "Complete the pumping test" was achieved on 15 June for unit 1 and 19 June for unit 2.
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02k.pdf 3/7 translated in http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120618_05-e.pdf 15/17
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02k.pdf 4/7 translated in http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120618_05-e.pdf 13/17
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02k.pdf 5/7 content similar with http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120618_05-e.pdf 14/17
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02k.pdf 6/7 translated in http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120618_05-e.pdf 12/17
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02k.pdf 7/7 translated in http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120618_05-e.pdf 17/17

 

[Azby]

The English-language executive summary of The Fukushima Nuclear Accident Independent Investigation Commission was just released a few minutes ago. You can download it from here:

http://naiic.go.jp/en/

 

[SteveElbows]

The English-language executive summary of The Fukushima Nuclear Accident Independent Investigation Commission was just released a few minutes ago. You can download it from here:

http://naiic.go.jp/en/

Thanks. Of particular relevance to the discussion of technical matters is the following from page 31:

The government-run investigation committee’s interim report, NISA’s “Technical Findings,” and specifically TEPCO’s interim report, all concluded that the loss of emergency AC power—that definitely impacted the progression of the accident— “was caused by the flooding from the tsunami.” TEPCO’s report says the first wave of the tsunami reached the site at 15:27 and the second at 15:35. However, these are the times when the wave gauge set 1.5km offshore detected the waves, not the times of when the tsunami hit the plant. This suggests that at least the loss of emergency power supply A at Unit 1 might not have been caused by flooding. Based on this, some basic questions need to be logically explained before making a final determination that flooding was the cause of the station blackout.

4. Several TEPCO vendor workers who were working on the fourth floor of the nuclear reactor building at Unit 1 at the time of the earthquake witnessed a water leak on the same floor, which houses two large tanks for the isolation condenser (IC) and the pip- ing for IC. The Commission believes that this was not due to water sloshing out of the spent fuel pool on the fifth floor. However, since we cannot go inside the facility and perform an on-site inspection, the source of the water remains unconfirmed.

5. The isolation condensers (A and B2 systems) of Unit 1 were shut down automatically at 14:52, but the operator of Unit 1 manually stopped both IC systems 11 minutes lat- er. TEPCO has consistently maintained that the explanation for the manual suspen- sion was that “it was judged that the per-hour reactor coolant temperature excursion rate could not be kept within 55 degrees (Celsius), which is the benchmark provided by the operational manual.” The government-led investigation report, as well as the government’s report to IAEA, states the same reason. However, according to several workers involved in the manual suspension of IC who responded to our investiga- tion, they stopped IC to check whether coolant was leaking from IC and other pipes because the reactor pressure was falling rapidly. While the operator’s explanations are reasonable and appropriate, TEPCO’s explanation is irrational.

6. There is no evidence that the safety relief (SR) valve was opened at Unit 1, though this should have taken place in the case of an accident. (Such records are available for Units 2 and 3.) We found that the sound of the SR valve opening for Unit 2 was heard at the Central Control Room and at Unit 2, but no one working at Unit 1 heard the sound of the Unit 1 SR valve opening. It is therefore a possibility that the SR valve might not have worked in Unit 1. In this case, a minor LOCA caused by the seismic motion could have taken place in Unit 1.

 

[tsutsuji]

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

3-1 Cooling by closed loop water injection
http://www.meti.go.jp/earthquake/nuclear/pdf/120625/120625_02g.pdf Unit 2 alternative thermometers installation progress status

1) Previous related topics:

1 March 2012 report ( https://www.physicsforums.com/showpost.php?p=3795578&postcount=12465 part 1, https://www.physicsforums.com/showpost.php?p=3796935&postcount=12485 part 2, https://www.physicsforums.com/showpost.php?p=3799356&postcount=12492 part 3)

28 March 2012 government-Tokyo Electric mid and long term response committee, steering committee (4th meeting)

http://www.meti.go.jp/earthquake/nuclear/pdf/120328_02f.pdf page 7 is about the revision of priorities for installation of alternative thermometers. The high radiation routes are cancelled. What is left is Jet Pump system B X-40C/D in area B with priority 1, SLC differential pressure sensor X-51 in area C with priority 2, and TIP in area D as priority (1) with a note. The note says: "there is a possibility that the TIP guide tubes are surviving in the outer surroundings of the core (see page 8). →If undamaged TIP guide tubes are left, they can be promoted to priority 1." The figure in the left part of page 8 shows a yellow area where surviving TIP tubes are believed to exist.

23 April 2012 report: https://www.physicsforums.com/showthread.php?p=3939578#post3939578 (insertion and freezing mock-ups)

28 May 2012 government-Tokyo Electric mid and long term response committee, steering committee (6th meeting): https://www.physicsforums.com/showt...ighlight=alternative+thermometers#post3941037 Results of the surveys on location concerning the environment improvement for the purpose of installing alternative thermometers in unit 2's RPV

01 June 2012 videos:

http://photo.tepco.co.jp/en/date/2012/201206-e/120601_02e.html "Decontamination around the truck bay door at Unit 2, Fukushima Daiichi NPS" (released on 1 June 2012)

http://photo.tepco.co.jp/en/date/2012/201206-e/120601_01e.html "Mock-up test to check the insertability of the alternative thermometer at Unit 2" (released on 1 June 2012)

2) Translation:

01/12

02/12

03/12

 

[tsutsuji]

Translation:

04/12

05/12

06/12

 

[tsutsuji]

Translation:

07/12

08/12

09/12

 

[tsutsuji]

Translation:

10/12

11/12

12/12

 

[elektrownik]

Unit 4 top is almost clean now:

 

[SteveElbows]

Your image link isn't working for me but you can see the image here, and click it to see a higher resolution version:

http://enformable.com/2012/07/photo-of-the-week-fukushima-daiichi-reactor-4-building-debris-removal/

The removable concrete cap sections are visible in their storage positions under the yellow containment cap and to the south of it.

Some of the groundwork preparing the foundations for the fuel removal structure are partially visible south of the building.

 

[zapperzero]

http://fukushima-diary.com/2012/07/...y+(Fukushima+Diary)&utm_content=Google+Reader

Can someone confirm this?

 

[a.ua.]

Analyses of core melt and re-melt in the Fukushima Daiichi nuclear reactors
http://www.tandfonline.com/doi/full/10.1080/18811248.2011.636537

 

[elektrownik]

Analyses of core melt and re-melt in the Fukushima Daiichi nuclear reactors
http://www.tandfonline.com/doi/full/10.1080/18811248.2011.636537

"Re-melting of core materials: 21 March 01:25 21–25 March"
and
"This still from film footage released by Tokyo Electric Power Co. shows black smoke billowing from the crippled Fukushima I nuclear power plant in northeastern Japan, March 22."
from:
http://www.csmonitor.com/USA/2011/0...What-s-in-the-smoke-emerging-from-Fukushima-I

 

[SteveElbows]

Analyses of core melt and re-melt in the Fukushima Daiichi nuclear reactors
http://www.tandfonline.com/doi/full/10.1080/18811248.2011.636537

Thats a rather interesting study.

To look at something other than the later core remelt possibilities for a moment, I am rather interested in the reports suggestion that unlike reactors 1 & 3, the initial core melting at reactor 2 didn't result in a runaway zirconium-steam reaction, due to a lack of steam generation in the core.

This would certainly be an interesting alternative explanation as to why there was no hydrogen explosion at reactor 2. But I haven't quite got my head around the reasons this report thinks such a reaction did not occur. Could someone take a look at the report and attempt to explain this to me?

Many thanks.

 

[elektrownik]

Thats a rather interesting study.

To look at something other than the later core remelt possibilities for a moment, I am rather interested in the reports suggestion that unlike reactors 1 & 3, the initial core melting at reactor 2 didn't result in a runaway zirconium-steam reaction, due to a lack of steam generation in the core.

This would certainly be an interesting alternative explanation as to why there was no hydrogen explosion at reactor 2. But I haven't quite got my head around the reasons this report thinks such a reaction did not occur. Could someone take a look at the report and attempt to explain this to me?

Many thanks.

Look at this part "3.3.1. Core boil-off process and meltdown into lower plenum"

 

[tsutsuji]

Analyses of core melt and re-melt in the Fukushima Daiichi nuclear reactors
http://www.tandfonline.com/doi/full/10.1080/18811248.2011.636537

Tanabe's core remelting theories were first mentioned on Physics Forum on https://www.physicsforums.com/showpost.php?p=3443421&postcount=10864 (August 2011)

This was before Tepco revised its flow rate data for unit 3 http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_110909_06-e.pdf (September 2011). See https://www.physicsforums.com/showpost.php?p=3494451&postcount=11193

I wonder why http://www.tandfonline.com/doi/full/10.1080/18811248.2011.636537 published in January 2012 is still using the older data in its "Figure 19:Injection water flow rate in comparison with MDHRFR in 1F-3".

 

[elektrownik]

Tanabe's core remelting theories were first mentioned on Physics
I wonder why http://www.tandfonline.com/doi/full/10.1080/18811248.2011.636537 published in January 2012 is still using the older data in its "Figure 19:Injection water flow rate in comparison with MDHRFR in 1F-3".

But it use also some other data (temp and pressure).

 

[MadderDoc]

Tanabe's core remelting theories were first mentioned on Physics Forum on https://www.physicsforums.com/showpost.php?p=3443421&postcount=10864 (August 2011)

This was before Tepco revised its flow rate data for unit 3 http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_110909_06-e.pdf (September 2011). See https://www.physicsforums.com/showpost.php?p=3494451&postcount=11193

I wonder why http://www.tandfonline.com/doi/full/10.1080/18811248.2011.636537 published in January 2012 is still using the older data in its "Figure 19:Injection water flow rate in comparison with MDHRFR in 1F-3".

Perhaps due to the close timing collision between Tepco's publishing of revised flow estimates, and the finalising of this particular article; it was received on 11 August 2011 and the final version was accepted for publication on 16 September 2011.

 

[MadderDoc]

Tsunami photo sequence released June 9th

A photo sequence of the March 11th tsunami hitting Daiichi, recent released at:
http://photo.tepco.co.jp/date/2012/201207-j/120709_01j.html

 

[SteveElbows]

The following is a version of the recent helicopter footage. Can see how far they have progressed with platform to east and south of reactor 3 at a few moments in the footage.



Sorry I couldn't find the original version of this video.

 

[MadderDoc]

The following is a version of the recent helicopter footage. Can see how far they have progressed with platform to east and south of reactor 3 at a few moments in the footage.



Sorry I couldn't find the original version of this video.

Thank you, Steve. I think I've found the progenitor of that version, it is a published snippet of a video taken by a Kyodo News helicopter on July 5th 2012:
http://www.youtube.com/watch?v=-FgXPX5iYC4&feature=plcp

 

[tsutsuji]

A photo sequence of the March 11th tsunami hitting Daiichi, recent released at:
http://photo.tepco.co.jp/date/2012/201207-j/120709_01j.html

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120710/index.html Tepco released 33 new pictures of the tsunami in response to the Diet investigation commission pointing out the existence of unreleased pictures. The picture were taken by a contractor company employee who was within the plant premises. Among the pictures taken before the tsunami arrival, one can see the white spray of the rising wave while it approaches, and a tanker seeking refuge by getting out of the port. The pictures taken after the tsunami arrival show the violent muddy stream, a large container being carried away by the stream and these pictures let one know again about the violence of the tsunami. Then, we see employees who had taken refuge on a roof who are worryingly looking at the stream. Tepco had released 17 Fukushima Daiichi tsunami pictures in May 2011, but the present pictures had not been released until the Diet investigation commission pointed them out. Tepco said:"Among the taken pictures, we selected for public release those that are the easiest for understanding how the tsunami came. We would like to apologize for the insufficient points in provision of information".

http://www3.nhk.or.jp/news/genpatsu-fukushima/20120706/index.html The Diet's investigation commission report contains up to now unreleased transcripts of plant manager Yoshida's testimony where he says "the line of command was a mess" and contains his criticism of the interference by the Prime Minister's Office. Yoshida said: "If the Main Office had said "stop" [injecting seawater], that would be debatable, but there was no such instruction at all. A phone call came from supporting role Prime Minister's Office: what is this stop thing? As it is on phone, it is difficult to discuss. The line of command was a mess. I thought that in the end I would decide by my own judgement". [Also quoted by http://www.yomiuri.co.jp/dy/national/T120706003982.htm (English) and http://mainichi.jp/english/english/newsselect/news/20120706p2a00m0na010000c.html (English)]

 

[SteveElbows]

Reactor 3 torus room survey robot, which had sound monitoring equipment to listen for running water, got stuck and hasnt been retrieved. 360 mSv/h measured at side of the northern torus access hatch, 230 mSv/h in location where robot is stuck:

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120712_03-e.pdf

Some photos of upper levels of reactor 3, but quality is poor. Some of the images have some signs of interlacing lines, which suggests to me that its from a video, but no video has been released.

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120711_03-e.pdf

http://photo.tepco.co.jp/en/date/2012/201207-e/120711_02e.html

Images released as part of the announcement of completion of reactor 4 upper level debris removal, but they are all taken from unhelpful angles. Helicopter footage we've already seen was better than this stuff.

http://photo.tepco.co.jp/en/date/2012/201207-e/120711_01e.html

 

[LabratSR]

TEPCO to release footage of video conferences

http://www3.nhk.or.jp/daily/english/20120712_15.html