Fukushima Japan Earthquake: nuclear plants Fukushima part 2

[zapperzero]

Sounds like bits of roofing.

 

[Sotan]

http://www.tepco.co.jp/nu/fukushima-np/handouts/2014/images/handouts_140214_04-j.pdf
(in Japanese)

It's a report on the results of checks performed in the building of Reactor 3, after removing the debris.
Many interesting photos.
One important finding is that the massive concrete shield plug that covers the PCV (made of 3 slabs of concrete stacked one atop the other, each 600 mm thick) appears to have a big "dent", the surface is pushed in, about 300 mm. Most likely caused by the fall of the ceiling crane (it had a big heavy trolley right in that area). They don't seem much alarmed by this, though, as it probably didn't cause important damage to the PCV and the situation seems to be stable now.

 

[Hiddencamper]

http://www.tepco.co.jp/nu/fukushima-np/handouts/2014/images/handouts_140214_04-j.pdf
(in Japanese)

It's a report on the results of checks performed in the building of Reactor 3, after removing the debris.
Many interesting photos.
One important finding is that the massive concrete shield plug that covers the PCV (made of 3 slabs of concrete stacked one atop the other, each 600 mm thick) appears to have a big "dent", the surface is pushed in, about 300 mm. Most likely caused by the fall of the ceiling crane (it had a big heavy trolley right in that area). They don't seem much alarmed by this, though, as it probably didn't cause important damage to the PCV and the situation seems to be stable now.

Inside the reactor cavity, there is a reactor vessel head. On top of that is the PCV head. And on top of that is the shield plugs. I think the shield plugs did part of their job of protecting the PCV head, which is likely the most vulnerable point of the PCV.

 

[LabratSR]

An interesting twist to the filtered vent debate.

http://ex-skf.blogspot.com/2014/02/tepco-tells-governor-of-niigata-that.html

 

[Sean Thornock]

Meltdown: What Really Happened at Fukushima?

The authors have spoken to several workers at the plant who recite the same story: Serious damage to piping and at least one of the reactors before the tsunami hit. All have requested anonymity because they are still working at the plant or are connected with TEPCO. One worker, a maintenance engineer in his late twenties who was at the Fukushima complex on March 11, recalls hissing and leaking pipes. “I personally saw pipes that came apart and I assume that there were many more that had been broken throughout the plant. There’s no doubt that the earthquake did a lot of damage inside the plant," he said. "There were definitely leaking pipes, but we don’t know which pipes – that has to be investigated. I also saw that part of the wall of the turbine building for Unit 1 had come away. That crack might have affected the reactor.”

A second worker, a technician in his late 30s, who was also on site at the time of the earthquake, narrated what happened. “It felt like the earthquake hit in two waves, the first impact was so intense you could see the building shaking, the pipes buckling, and within minutes, I saw pipes bursting. Some fell off the wall. Others snapped. I was pretty sure that some of the oxygen tanks stored on site had exploded but I didn’t see for myself. Someone yelled that we all needed to evacuate and I was good with that. But I was severely alarmed because as I was leaving I was told and I could see that several pipes had cracked open, including what I believe were cold water supply pipes. That would mean that coolant couldn’t get to the reactor core. If you can’t sufficiently get the coolant to the core, it melts down. You don’t have to have to be a nuclear scientist to figure that out.”

Before the dawn on March 12, the water levels at the reactor began to plummet and the radiation began rising. Meltdown was taking place. The TEPCO Press release issued on March 12 just past 4am stated, “the pressure within the containment vessel is high but stable.” There was a note buried in the release that many people missed. “The emergency water circulation system was cooling the steam within the core; it has ceased to function.”

Oddly enough, while TEPCO later insisted that the cause of the meltdown was the tsunami knocking out emergency power systems, at the 7:47 p.m. TEPCO press conference the same day, the spokesman in response to questions from the press about the cooling systems stated that the emergency water circulation equipment and reactor core isolation time cooling systems would work even without electricity.

http://www.thewire.com/global/2011/07/meltdown-what-really-happened-fukushima/39541/

 

[Rive]

stuff

That article is from mid-2011.
This part of the events were discussed loooooong time ago, in the previous section of this topic.

 

[Sean Thornock]

The Geology of Fukushima

At a time when everyone is wondering where the coriums of the crippled Fukushima Daiichi nuclear plant may be, it is interesting to know the nature of the terrain where they could possibly be hiding. Although all documents used to write this article are readily available, most are in Japanese and this explains that to date knowledge of the geology of Fukushima is fragmented. Based on the geological survey that was conducted prior to building the plant, as well as on results of seismic testing and recent research related to drilling, this article will attempt to give an updated picture of the nature of the substratum of the nuclear plant, which may help to predict possible developments in the currently unfolding disaster.

http://www.fukushima-blog.com/article-the-geology-of-fukushima-88575278.html

 

[Sean Thornock]

I'm wondering also how they can clear the 50 tons of steel, refueling mast and cement out of the #3 fuel pool. Could these fuel racks still be intact ? I wonder how this can be done.

http://www.iaea.org/newscenter/focus/fukushima/statusreport270412.pdf

 

[LabratSR]

Meltdown: What Really Happened at Fukushima?
http://www.thewire.com/global/2011/07/meltdown-what-really-happened-fukushima/39541/

You may be interested to read the conclusion in this report. Look under Earthquake Damge, page 17

http://warp.da.ndl.go.jp/info:ndljp...ent/uploads/2012/09/NAIIC_report_lo_res10.pdf


The full report may be found here.

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

 

[nikkkom]

I'm wondering also how they can clear the 50 tons of steel, refueling mast and cement out of the #3 fuel pool. Could these fuel racks still be intact ? I wonder how this can be done.

They will use the novel technique of "pulling debris piece by piece out of the water". What did you expect?

 

[Sean Thornock]

Feb. 17, 2014: Co-60 - 750 Bq/L ( Wells No. 1-6 )

http://www.tepco.co.jp/nu/fukushima-np/f1/smp/2014/images/2tb-east_14021801-j.pdf

 

[Rive]

I heard that can't even get robots near this area.

I'm afraid it's simply not true. They've sent robots even much worse areas and doing their jobs as scheduled by remotes, robots and: personally too.

The top of the U3 was cleaned up with remote controlled machinery. That cleanup was performed unexpectedly well. The pool of U3 will be emptied by the same machinery.

 

[Sean Thornock]

I'm afraid it's simply not true. They've sent robots even much worse areas and doing their jobs as scheduled by remotes, robots and: personally too.

The top of the U3 was cleaned up with remote controlled machinery. That cleanup was performed unexpectedly well. The pool of U3 will be emptied by the same machinery.

I thought those fuel rods were delicate & the radiation levels at unit three are off the charts. Much different then taking wreckage from the roof. The #3 sfp is in very bad shape.

BWR/6 Fuel Assemblies & Control Rod Module ( these can't handle 50 tons without sever damage )

http://www.nucleartourist.com/images/bwrfuel1.jpg


What do you think about the fault / sandstone below the corium kinda makes it hard to stop the 600 tons of water flowing toward the ocean every day, no ?

 

[Sean Thornock]

And what about Cobalt-60 ? Or last weeks Cesium-137 54,000 Bq / Liter / Or the new revised Strontium-90 5 million Bq / Liter per recent well reading.

After 3 years the readings are quickening not slowing.

 

[jim hardy]

Well, you might peruse that reference Labrat posted, and study the old thread to see where we've been.

Questions are welcome but crazy assertions and articles from the tabloid press are, well, just not helpful.

Judge your sources. Isaac Asimov wrote at length about his "Built In Doubter" which makes him question all assertions that aren't backed up by supporting facts. And always cross check.

For example, that claim about fuel elements and 50 tons:
How then can fuel pools be stacked two layers deep?
What about the steel from which the fuel racks are made?

I think a fuel bundle might well support 50 tons in compression, especially if the racks prevent buckling.

So ask what you don't know, don't assert it as if it were fact - that way you'll be perceived as not so confrontational and annoying.



old jim

 

[SteveElbows]

What you may need to keep in mind is that this is a physics forum. As such there is a low tolerance towards various forms of discussion about Fukushima that veer to far away from the scientific method.

As I understand it there was more slack given to the main Fukushima thread than would often be the case, in terms of moderation etc, because at the time it was a fast-evolving situation with many unknowns and much room to speculate without unscientifically ignoring well-established facts. Over time more has been learnt, and certain things ruled out as possibilities, but since it will be very many years till certain important details may be discovered, and some may remain permanently out of reach, I expect some slack is still granted. Especially as poor communication and obfuscation from various official sources at various times, combined with bouts of ineptitude, has eroded faith in certain aspects of the official picture.

But with that said, people who consistently struggled to accept any evidence that contradicted their worst-case assumptions about Fukushima and the things that could yet go wrong on site, eventually ran into problems here. Not too many so far if memory serves me correctly, but it would be a shame to have any more, especially now that some years have passed with rarely anything more dramatic than water leaks. What you might find here is that many people already rank Fukushima as a very major series of nuclear disasters, and consider the clean-up operation, in so much as it will prove to be possible, is fraught with complications and not without risks. And that they don't need to inject a fresh sense of immediacy into the view of Fukushima in 2014 in order to appreciate the scale of the problems and the issues.

It is certainly true that the removal of spent fuel from the reactor 3 pool has a number of complications compared to the operation at reactor 4. Far more debris had & has still to be removed, and the radiation levels in the vicinity do require remote operations at this stage which makes the operation far more clunky. Plenty of things could impede progress at some point, but the progress that has been achieved to date, however slowly, is still going to be recognised here.

 

[Hiddencamper]

I'm pretty sure spent fuel pools need to be capable of surviving cask and other load drop accidents as part of their design criteria. So this really precludes major fuel or rack damage even with load drops in the pools. If major fuel damage had occurred it would be very easy to detect though a water sample of the pool. I wouldn't be surprised if they busted some bundles, but I'm not expecting anything that would be of major interest. I'll see if I can find anything. My plant uses similar spent fuel racks to the ones at Fukushima.

As for timelines, IAEA released a report that said Fukushima would be around 30-40 years. It was a final decommissioning timeline put together with TEPCO and the Japanese regulator with a lot of international help. I have the actual report on my thumb drive at work, I'll try to remember to post the link to it.

 

[Hiddencamper]

And what about Cobalt-60 ? Or last weeks Cesium-137 54,000 Bq / Liter / Or the new revised Strontium-90 5 million Bq / Liter per recent well reading.

After 3 years the readings are quickening not slowing.

Do not take the fact that higher numbers are being detected as an increased problem. A large amount of radioactive material has relocated from where it is supposed to be, and it is going to be moving slowly out from the areas around the plant. That doesn't mean it's getting worse, that just means stuff that got relocated by the accident is now starting to become detectable (it's moving), and the fact that it is moving isn't unexpected. What we didnt know is how quickly it would be moving.

The focus for everyone, shouldn't be on the "omg they found a high measurement" and more on how they are progressing with their efforts to stop the leaks, which will then reduce those measurements.

The reactors are shut down. No new radioactive material is being created. A lot of radioactive material is being relocated, and most of it is going into filters, but some of it is getting out, and that's going to happen until they reach a point where they no longer need to cool/shield the core material on site. Everyone on this site has known this for quite a while now, so no need to try and stir the pot.

If you don't understand radiation or nuclear technology, there are many people here who are more than willing to answer questions, but please be respectful of the fact that the people here have been following the accident since it happened, reading all sorts of official and unofficial reports, and have a very good understanding of it. I personally was involved with some of the earlier US industry response to Fukushima, and there are others who have a lot of nuclear industry knowledge here from a theoretical and/or practical perspective. We know pretty well what the magnitude is and what its going to take to clean it up, so trying to tell us its "zomg so bad" is just going to anger some people, because it detracts from any form of meaningful discussion about the event findings and cleanup progress.

tl;dr, don't detract from meaningful discussion and we will all be happy to discuss with you, teach what we know, or point you in the direction of data/documents. Otherwise please consider finding another site to post on. Thanks!

 

[Hiddencamper]

I thought those fuel rods were delicate & the radiation levels at unit three are off the charts. Much different then taking wreckage from the roof. The #3 sfp is in very bad shape.

BWR/6 Fuel Assemblies & Control Rod Module ( these can't handle 50 tons without sever damage )

http://www.nucleartourist.com/images/bwrfuel1.jpg


What do you think about the fault / sandstone below the corium kinda makes it hard to stop the 600 tons of water flowing toward the ocean every day, no ?

Before you make a claim that a BWR/6 fuel bundle can't support 50 tons, ask the question of what they can support. I work at a BWR and if I get a chance I can probably look up the structural load capacity of the fuel racks. I don't work in the same building as our engineering library anymore so I don't get a chance to pull stuff as often, but I'll see what I can do.

What I can tell you right now, is that the spent fuel racks are required to handle load drops in the pool as part of their seismic/structural safety requirements. The racks are Seismic category I and safety class 2, so I'm doubtful a large load would affect them given the large surface area to work with. But at the same time, WE HAVE A CALCULATION FOR THAT. Those calculations exist. So before you make an assertion, ask someone what they know.

 

[Hiddencamper]

Meltdown: What Really Happened at Fukushima?

The authors have spoken to several workers at the plant who recite the same story: Serious damage to piping and at least one of the reactors before the tsunami hit. All have requested anonymity because they are still working at the plant or are connected with TEPCO. One worker, a maintenance engineer in his late twenties who was at the Fukushima complex on March 11, recalls hissing and leaking pipes. “I personally saw pipes that came apart and I assume that there were many more that had been broken throughout the plant. There’s no doubt that the earthquake did a lot of damage inside the plant," he said. "There were definitely leaking pipes, but we don’t know which pipes – that has to be investigated. I also saw that part of the wall of the turbine building for Unit 1 had come away. That crack might have affected the reactor.”

A second worker, a technician in his late 30s, who was also on site at the time of the earthquake, narrated what happened. “It felt like the earthquake hit in two waves, the first impact was so intense you could see the building shaking, the pipes buckling, and within minutes, I saw pipes bursting. Some fell off the wall. Others snapped. I was pretty sure that some of the oxygen tanks stored on site had exploded but I didn’t see for myself. Someone yelled that we all needed to evacuate and I was good with that. But I was severely alarmed because as I was leaving I was told and I could see that several pipes had cracked open, including what I believe were cold water supply pipes. That would mean that coolant couldn’t get to the reactor core. If you can’t sufficiently get the coolant to the core, it melts down. You don’t have to have to be a nuclear scientist to figure that out.”

Before the dawn on March 12, the water levels at the reactor began to plummet and the radiation began rising. Meltdown was taking place. The TEPCO Press release issued on March 12 just past 4am stated, “the pressure within the containment vessel is high but stable.” There was a note buried in the release that many people missed. “The emergency water circulation system was cooling the steam within the core; it has ceased to function.”

Oddly enough, while TEPCO later insisted that the cause of the meltdown was the tsunami knocking out emergency power systems, at the 7:47 p.m. TEPCO press conference the same day, the spokesman in response to questions from the press about the cooling systems stated that the emergency water circulation equipment and reactor core isolation time cooling systems would work even without electricity.

http://www.thewire.com/global/2011/07/meltdown-what-really-happened-fukushima/39541/

Sorry I'm chain posting responses but there is too much bull this guy is posting.

With regards to "busted pipes",

Check out this link

http://www.tepco.co.jp/en/press/corp-com/release/betu13_e/images/131213e0101.pdf

Page 7

"Drawing surveys, eyewitness accounts, plant data, and other information have made it clear that the water flowing into the 4th floor of the nuclear reactor building unit 1 flowed in via a duct in the spent fuel pool".

This makes sense physically. The water level in the pools is maintained with scuppers and skimmers. Directly above these is a set of ducts used to draw vacuum above the pool to limit offgas of radioactive isotopes. During the earthquake a significant amount of water would have sloshed into this ductwork. The ductwork has sections designed for water to break/pass through, because it was envisioned that human error could overfill the pools and they didnt want water to inundate the entire reactor building HVAC system.

To add to this, any busted pipes in the reactor building that had safety significance would have either been in the ECCS cubicles or inside the containment. The containment is inerted with nitrogen, so no humans were in there. The ECCS cubicles were likely off limits due to flood waters preventing entry through the water tight doors.

There are reports of potential damage to feedwater. Feedwater is NOT a safety system. With the power grid offline, feedwater was incapable of functioning in the first place (Feedwater is not powered by emergency generators in BWRs). So the reports that broken pipes meant water couldn't get into the core combined with the physical layout of the plant of cooling pipes meant that the only pipes which they COULD have been talking about were the non-safety, non-functioning feedwater system.

If you have any questions about the ECCS network of BWR series plants or the design criteria, let me know and I will answer them. If you answer with some bs web link, assertion, or whatever, expect to get BS back in return.

 

[Sean Thornock]

I'll let the article stand on its merit. It has more information regarding TEPCO issues in the past regarding those pipes in question. Workers said they seen busted pipes in an article a few months after the disaster. Many of the assertions regarding safety issues are searchable.

What about the rubber seals on the SFP doors that inflate with air. Those will not hold air without power. ( fuel pool gate between pool & reactor. Powered by electricity off grid not diesel backups or batteries. ( Hatch/Georgia 1986 lost 141,000 gallons in a few hours time because of this same issue. )

I'd like to talk about the Cobalt-60, Manganese-54 ( neutron activation radionuclide / product ) & the large Cesium levels ( wells 1-6 ) pointing toward sfp criticality.

 

[Sean Thornock]

So in #4 with a hot core load, suspect door seals, indeed, projections are possible.

Decay heat projections SFP all levels, funny thing is the worst spot / water height low-mid level point on rods, it stops water / air circulation.

Operational Safety of Spent Nuclear Fuel Argonne

http://www-ns.iaea.org/downloads/ni/embarking/argonne_workshop_2010/Braun/L.6.2%20Braun%20Operational%20Safety%20of%20Spent%20Nuclear%20Fuel.pdf

 

[jim hardy]

Decay heat projections SFP all levels, funny thing is the worst spot / water height low-mid level point on rods, it stops water / air circulation.

well duu-uhh, - that's why you keep the pool filled.

and why the bottom of door is above top of fuel.

 

[nikkkom]

I heard that can't even get robots near this area. TEPCO announced record cesium & today cobalt-60 readings in the test wells.

?! The readings around the shield plug were published already, IIRC they are at or below 300 mSv/h. That's ~30 R/h in "old" units. That's nowhere near enough to incapacitate a robot.

 

[nikkkom]

I thought those fuel rods were delicate & the radiation levels at unit three are off the charts.

What is "off the charts"? Engineering is done with numbers, otherwise it's handwaving.

 

[jadair1]

What is "off the charts"? Engineering is done with numbers, otherwise it's handwaving.

I believe the "off the charts" referred to may be the 100,000 Sv/hr postulated from the 10 Sv/hr detected in helicopters 100 M above reactor #3 I believe it was.

Not sure how accurate this report was as I'm working with a faulty memory and a link I accessed on ENENEWS, not the most credible of sources, but no less credible than the BS TEPCO puts out.

If indeed the report was accurate and the math was correct is this a credible number, it seems high to me?

If there was a complete loss of containment and a full blown meltdown of a nuclear core would the readings be that high at the surface of the melting core and would that correspond to 10 Sv/hr at 100 M?

 

[Sean Thornock]

well duu-uhh, - that's why you keep the pool filled.

and why the bottom of door is above top of fuel.

#4 pool ect.

Ummm, Jim, this means the water, five feet above the tops of the bundles boiled off, as you can see they would in the Argonne pdf, as the steam had shown us for weeks above all pools in fact. Without power. Those air drops of water did nothing.

So let's dive into the numbers, facts, does anybody want to speak to the larger concerns regarding the criticality signatures / neutron activated ( cobalt-60, Manganese-54 ) in the wells 1-6 or the seals on the spent fuel pools not receiving air.

 

[Sean Thornock]

What is "off the charts"? Engineering is done with numbers, otherwise it's handwaving.

This is true. I thought everyone was aware of the #3 readings.

" The JSDF helicopters that dropped water on the Fukushima Daiichi reactors and spent fuel pools in the days after March 11 were outfitted with the types of radiation shields used in hospital x-ray rooms. Nisho says that this was akin to “putting on a lead helmet in order to protect yourself from radiation from space”. The planners, he argues, did not even understand the difference between airborne radiation from a nuclear accident and radiation used in the controlled environment of hospital treatment. " -

Measures must also be taken to gauge different types of exposure (i.e. alpha rays from plutonium and beta rays from strontium).

http://japanfocus.org/events/view/100

Containment monitor reading: 10,000,000 R/hr [100,00 Sv/hr] (unconfirmed), tried to replicate the reported high radiation levels at site gate and computed and reported 375 R/hr [3.75 Sv/hr] from helicopter at 100 meters above spent fuel pools.

http://pbadupws.nrc.gov/docs/ML1328/ML13284A040.pdf

 

[Hiddencamper]

I'll let the article stand on its merit. It has more information regarding TEPCO issues in the past regarding those pipes in question. Workers said they seen busted pipes in an article a few months after the disaster. Many of the assertions regarding safety issues are searchable.

What about the rubber seals on the SFP doors that inflate with air. Those will not hold air without power. ( fuel pool gate between pool & reactor. Powered by electricity off grid not diesel backups or batteries. ( Hatch/Georgia 1986 lost 141,000 gallons in a few hours time because of this same issue. )

I'd like to talk about the Cobalt-60, Manganese-54 ( neutron activation radionuclide / product ) & the large Cesium levels ( wells 1-6 ) pointing toward sfp criticality.

Basically you are choosing to accept a poorly translated worker account that contains no details or information from 2011 over an official report from an investigation into the things which were difficult to explain which was released at the end of 2013.

Or in other words, your opinion and belief over science.

As for spent fuel pool gates, do you honestly believe they just left the pools without gates and did nothing for the past 3 years? Seriously? Apparently you don't realize the Mark I BWR design for spent fuel pools is such that even with a total gate failure, water will not uncover the fuel (the bottom of the gate is above the top of fuel). Additionally, there is no evidence a total gate failure happened.

This is not a place for FUD. Can we please have an admin ban this guy. These tactics he is using are social engineering and are not conducive to the discussions about Fukushima. This guy posts no technical details and is beyond frustrating to even look at. This isn't reddit. We shouldn't be having these types of people being misleading and disrupting.

 

[Sean Thornock]

As for spent fuel pool gates, do you honestly believe they just left the pools without gates and did nothing for the past 3 years? Seriously? Apparently you don't realize the Mark I BWR design for spent fuel pools is such that even with a total gate failure, water will not uncover the fuel (the bottom of the gate is above the top of fuel). Additionally, there is no evidence a total gate failure happened.

No sir, the doors seal shut by inflatable air that fills a rubber gasket sealing the doors.

When you have loss of power, no air, then no water.

And you can say " it's poorly translated " because it contains information you do not like. Is it that crazy for someone to say they seen broken pipes after a huge earthquake. Again, all the reports within the article regarding TEPCO safety history regarding Unit #1 are searchable, and true.