Fukushima Japan Earthquake: nuclear plants Fukushima part 2

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A magnitude-5.3 earthquake struck Fukushima, Japan, prompting concerns due to its proximity to the damaged nuclear power plant from the 2011 disaster. The U.S. Geological Survey reported the quake occurred at a depth of about 13 miles, but no tsunami warning was issued. Discussions in the forum highlighted ongoing issues with tank leaks at the plant, with TEPCO discovering loosened bolts and corrosion, complicating monitoring efforts. There are plans for fuel removal from Unit 4, but similar structures will be needed for Units 1 and 3 to ensure safe decontamination. The forum also addressed the need for improved groundwater management and the establishment of a specialist team to tackle contamination risks.
  • #61
Rive said:
The time limit could be extended with some special clothing (check some Chernobyl vids).
For lead the half-value thickness for 2 MeV gamma radiation is 1.4 cm. That's one heavy suit... And it makes you probably working half as fast than working without it, eliminating its usefulness.
 
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  • #62
more practical to use a protective shield of lead.
Given that the source of dot.
Similar protection (much lightly built) were seen in the photo of Fukushima Unit 4.
on the north side.
 
  • #66
a.ua. said:
etudiant


However there is nothing stopping just open the door to the containment and send the robot.

The Soviet Union used a toy, a toy tank, (the price 10 $ ).
2 years after ...
Then they saw "shining" to 100 Sv:smile:

however is meaningless walk there now.
you just need to stop the leak.

The issue is getting into containment requires using large gantry cranes to lift the massive shield plugs in front of the containment hatches, then breaching 2 airlocks, which, when breached, will contaminate the **** out of the reactor building and provide a pathway for a lot of shine. What also makes it challenging is the subpile room is not at the same elevation as the entry hatches, and requires some vertical maneuvering which would be challenging for a robot. I'm not positive if Mark Is have a separate hatch going into the subpile room undervessel, but I have seen hatches like that before.

At Chernobyl, they had no containment, so it was a matter of drilling through spots then running the toy tank in. But I'm sure you saw the video, those guys were less than stellar about limiting their exposure and would do what they could to hide it. Now a days, with digital dosimeters, you can't even do that unless you are doing something to blatently shield your dosimeter.

Without an understanding of the physical layout of the BWR containment system its hard to understand why you can't just send a robot on. As someone who was in a BWR drywell chamber within the last week, you pretty much need scaffold to get anywhere important. The only areas you can easily access are the reactor recirculation pumps, and usually there is a permanent ladder up to the SRV/MSIV mezz
 
  • #69
I was poking around the Oak Ridge website and stumbled across this interesting report that was released in April.

Fukushima Daiichi – A Case Study for BWR Instrumentation and Control Systems Performance during a Severe Accident

http://info.ornl.gov/sites/publications/Files/Pub42256.pdf
 
  • #71
LabratSR said:
I was poking around the Oak Ridge website and stumbled across this interesting report that was released in April.

Fukushima Daiichi – A Case Study for BWR Instrumentation and Control Systems Performance during a Severe Accident

http://info.ornl.gov/sites/publications/Files/Pub42256.pdf

Basically, most instrumentation was useless as soon as power went out. Nobody ever accounted for such a possibility.
 
  • #72
nikkkom said:
Basically, most instrumentation was useless as soon as power went out. Nobody ever accounted for such a possibility.

That is the problem, Tepco looked at the possibility of a major earthquake and resulting tsunami but did nothing to protect the plant from them.

They knew they were vulnerable but did nothing as it would have cost too much.
 
  • #73
nikkkom said:
Basically, most instrumentation was useless as soon as power went out. Nobody ever accounted for such a possibility.

As detailed in the report, Preface pages xi - xiii, Some data was certainly being recorded after the power loss.

"Operators were dispatched to hazardous areas of the plants’ reactor buildings to obtain
instrument readings and to control systems because of lack of power to main control rooms."
 
  • #74
jadair1 said:
That is the problem, Tepco looked at the possibility of a major earthquake and resulting tsunami but did nothing to protect the plant from them.

They knew they were vulnerable but did nothing as it would have cost too much.

You're being kind compared to these guys. I suggest the html, version 1 and 2 over the download versions

Executive Summary

http://warp.da.ndl.go.jp/info:ndljp/pid/3856371/naiic.go.jp/en/report/

"Our report catalogues a multitude of errors and willful negligence that left the Fukushima plant unprepared for the events of March 11. And it examines serious deficiencies in the response to the accident by TEPCO, regulators and the government.

For all the extensive detail it provides, what this report cannot fully convey – especially to a global audience – is the mindset that supported the negligence behind this disaster."
 
  • #75
jadair1 said:
That is the problem, Tepco looked at the possibility of a major earthquake and resulting tsunami but did nothing to protect the plant from them.

They knew they were vulnerable but did nothing as it would have cost too much.

The $64 billion question now is how to stop this sort of management failure from happening.
If we can't stop it, then nuclear power generation has no future.
 
  • #76
From the report WANO "Lessons learned from the accident at the Fukushima Daiichi nuclear power plant":

TEPCO conducted training on severe accidents for executives using computer learning tools . Although the teaching materials covered a wide range of problems , it lacked certain details that might contribute to the development of a critical approach to the assessment of critical parameters, including awareness of the limited control of the instrument in an emergency . For example, in teaching materials no information about the concept of a surge in the capillaries of instruments measuring the level in the reactor vessel , which leads to a false notion of a higher level in the reactor , as opposed to the lower - the real one. Relying on computer training programs, which are organized with a fairly low frequency , management contributes to the appearance of vulnerability in the preservation of knowledge and depth of understanding.
 
  • #77
nikkkom said:
The $64 billion question now is how to stop this sort of management failure from happening.
If we can't stop it, then nuclear power generation has no future.

As the astronomical cost of the Fukushima disaster becomes clearer, it should gradually dawn on everyone associated with the nuclear enterprise that belt and suspenders prevention is very economical indeed. Filtered venting, dry fuel storage and such are just more band aids.
The industry needs to embrace ultra safe designs, aiming at set and forget operations as the key parameter. Unfortunately, none of the current fleet of reactors come close to that ideal. That suggests a very large opportunity for innovation left unexploited.
 
  • #78
Preliminary Summary Report

The Follow-up IAEA International Mission on remediation of large contaminated areas off-site the Fukushima Daiichi

http://www.iaea.org/newscenter/focus/fukushima/remediation-report-211013.pdf
 
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  • #79
TEPCO plans a new ‘freeze’ mission in underground tunnels at Fukushima Daiichi

http://enformable.com/2013/10/tepco-plans-new-freeze-mission-underground-tunnels-fukushima-daiichi/NHK link with video

http://www3.nhk.or.jp/nhkworld/english/news/20131022_32.html
 
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  • #80
I've been trying to find this report for months.

S.R. Greene was one of the original members of the BWR Severe Accident study group at Oak Ridge and this is a post Fukushima report.

THE CANARY, THE OSTRICH, AND THE BLACK SWAN: AN HISTORICAL
PERSPECTIVE ON OUR UNDERSTANDING OF BWR SEVERE ACCIDENTS
AND THEIR MITIGATION

http://media.wix.com/ugd/903593_97ef117ecbca067e9d76cd699e3be5dc.pdf
 
  • #81
A lot of the recent posts belong not here but rather in the "political thread".

This thread is part two of a thread discussing the physics and science behind the continuing events there.

Please relegate the finger pointing to the proper thread that is linked below so we can keep this thread on topic.

https://www.physicsforums.com/showthread.php?t=486089
 
  • #82
etudiant said:
As the astronomical cost of the Fukushima disaster becomes clearer, it should gradually dawn on everyone associated with the nuclear enterprise that belt and suspenders prevention is very economical indeed. Filtered venting, dry fuel storage and such are just more band aids.

However, current design continue to operate, and while I do want to see new reactor designs to be better, I'm more concerned that even "band-aids" as you say aren't implemented fast enough.

For example. It's been 2.5 years since Fukushima. Still no filtered vents on US reactors?!
 
  • #83
nikkkom said:
However, current design continue to operate, and while I do want to see new reactor designs to be better, I'm more concerned that even "band-aids" as you say aren't implemented fast enough.

For example. It's been 2.5 years since Fukushima. Still no filtered vents on US reactors?!

That reminds me of a post by Sherrell Greene (see report above) on his blog about hardened vents. Note he doesn't take a position for or against.

http://www.sustainableenergytoday.blogspot.com/2013/03/post-79-to-vent-or-not-to-vent-that-is.html
 
  • #84
LabratSR said:
That reminds me of a post by Sherrell Greene (see report above) on his blog about hardened vents. Note he doesn't take a position for or against.

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

> Industry's position on the hardened vents can be summarized as, ..."We need to understand all the implications of the FLEX strategy before we require the plants to spend buckets of money installing hardened filtered vents."

Which is cow's excrements. "Buckets of money" in this case - adding a filter on the vent line - refers to 5-20 million dollars per reactor unit (NRC study).

Considering that filtered venting at Fukushima would drastically reduce off-site contamination (make it ~100 times less), and considering that most other countries already had filtered vents installed even BEFORE Fukushima, spending such a small sum is a complete no-brainer.
 
  • #85
nikkkom said:
Considering that filtered venting at Fukushima would drastically reduce off-site contamination (make it ~100 times less)

I have trouble believing that was the case at Fukushima, due to the large amount of contamination that came from containment failure rather than venting. Most obviously from reactor 2 where no venting appears to have taken place successfully, but also due to containment failures at the other reactors too.
 
  • #86
SteveElbows said:
I have trouble believing that was the case at Fukushima, due to the large amount of contamination that came from containment failure rather than venting. Most obviously from reactor 2 where no venting appears to have taken place successfully, but also due to containment failures at the other reactors too.

Imagine that: more than one thing went wrong at Fuku. *Including* the shocking lack of personnel training what to do in a SBO, vent or not to vent, and how to initiate venting.
 
  • #88
LabratSR said:
I'm seeing a tremendous amount of drama and outright hysteria on the internet about the upcoming removal of spent fuel from Unit 4. Here is TEPCO's release.


http://photo.tepco.co.jp/library/131030_02e/131030_01-e.pdf

This seems like a well laid out plan, with reasonable provisions for expected glitches.

Afaik, TEPCO has been categorical that there was no fire in the reactor 4 SFP, based on the absence of any alkaline signature in the SFP water as would have been inevitable if the zirconium cladding had burned. So the main challenges here are debris and rack deformation, which the clean up is prepared for.
Obviously it will be much more challenging to do the same unloading in the other 3 reactors, because of the much worse contamination. Still, if TEPCO executes well on the number 4 SFP, I think some of the Fukushima concerns will abate, simply because the frantic hype has been so overblown.
 
  • #89
  • #90
This is the filter which TEPCO installs right now at Kashiwazaki-Kariwa's vent lines.
Claimed to be capable of capturing 99,9% of contaminants.
Doesn't look too complicated or huge, right?
 

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