Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[Rive]

nikkom, a mental exercise probably doesn't belong on this thread. But while you're at it why not throw in a loss of gravity accident?

I have a slightly better question to chew on: with all those makeup pipes all around, are they ready for the winter?

What would happen if some water transfer pipes gets blocked by ice? What would happen with the SFPs? With the makeup cooling of the SFPs?

 

[NUCENG]

I have a slightly better question to chew on: with all those makeup pipes all around, are they ready for the winter?

What would happen if some water transfer pipes gets blocked by ice? What would happen with the SFPs? With the makeup cooling of the SFPs?

If you are talking about the hoses and pipes at Fukushima, I would hope that they are providing insulation and heat taping to prevent freezing. If you are talking about the emergency hookups at operating plants, consider that simply draining the external piping can prevent ice plugs, just as most homeowners do with their outdoor yard faucets. Or consider the fire hydrants used in most cities, fires happen in winter, too.

 

[Rive]

If you are talking about the hoses and pipes at Fukushima, I would hope that they are providing insulation and heat taping to prevent freezing.

Of course operating plants can handle a winter - they had some, and they are still operational.

I'm talking about Fukushima, the crippled plants and the equipment there.

Pictures about piping 'in the wild':
http://www.tepco.co.jp/en/news/110311/images/111022_20.jpg
http://www.tepco.co.jp/en/news/110311/images/111022_26.jpg
http://www.tepco.co.jp/en/news/110311/images/111022_08.jpg

From here: http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_111022_02-e.pdf

I have some doubts.

 

[NUCENG]

Of course operating plants can handle a winter - they had some, and they are still operational.

I'm talking about Fukushima, the crippled plants and the equipment there.

Pictures about piping 'in the wild':
http://www.tepco.co.jp/en/news/110311/images/111022_20.jpg
http://www.tepco.co.jp/en/news/110311/images/111022_26.jpg
http://www.tepco.co.jp/en/news/110311/images/111022_08.jpg

From here: http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_111022_02-e.pdf

I have some doubts.

I have doubts as well, but pretty small ones. In the outdoor pictures I see some hoses that probably will need to be insulated and or heated. Components in the buildings and tent shelters can be heated with space heaters. Some piping of chemicals may not be close to freezing (salt water is more susceptible to freezing as salinity is reduced.) Fluids can be heated. If a spent fuel pool has a small layer of ice, the water below probably isn't evaporating, and I doubt that winters could freeze more than 2o feet deep to where the fuel is located in spent fuel pools.

You asked a valid question, but it is not a show stopper.

 

[Rive]

...it is not a show stopper.

The show will go on anyway, but if they are not already prepared then it can turn in some unexpected directions... That's what I'm worried about. And judged by the pictures, they are not thoroughly prepared.

We will see.

 

[Shinjukusam]

I have some doubts.

Well, and bear in mind that I've been to Fukushima in winter, it's not a very cold area.

from the Fukushima international exchange website:http://www.pref.fukushima.jp/kokusai/contents/chiiki/nz/fukushima.html"

Coastal Region
As the region is located at the southern most part of the northeastern region of Japan, it is fairly mild throughout the year. The average temperature for winter wavers between 2-3°C while temperatures rise up to mid 20s in the summer. Mostly dry & sunny winters with little snowfall, while in the summer sandy beaches prove to be the popular summer destination for all.

(although that last line will likely be revised)

 

[zapperzero]

http://cryptome.org/eyeball/daiichi-111211/daiichi-111211.htm
photo-reportage

 

[Rive]

Well, and bear in mind that I've been to Fukushima in winter, it's not a very cold area.

Well, IMHO they should prepare for the worst, for this time - they are already failed with that once, with the tsunami...

 

[NUCENG]

Well, IMHO they should prepare for the worst, for this time - they are already failed with that once, with the tsunami...

As the Boy Scouts say, "Be Prepared!"

But please,Rive, take a deep breath and relax. There are many more threats that warrant your concern more than this. There is much less decay heat to remove today than in March. Even if something did freeze up, there is time margin to restore flow today that they didn't have then. If, and this is a big IF, they haven't already considered winterization, this is not even on the same continent as the failure to design for the tsunami. You raised a valid point, but you lose credibility if you overstate the issue. We don't even know if it has already been addressed or planned.

 

[Rive]

...

If what I said was like an overstatement, then: sorry. You are right, of course even worst case the result will be far from catastrophic.

But I want them to pass this second exam (proper handling of the events is like a second exam for them, IMHO, ?!) so I'm still worried, even if the consequences of a fail are not, nowhere in match with the original accident :-)

We will see.

 

[nikkkom]

nikkom, a mental exercise probably doesn't belong on this thread. But while you're at it why not throw in a loss of gravity accident?

Loss of gravity is (a) implausible and (b) wouldn't matter anyway, since all other human infrastructure would be destroyed by it, not only NPPs.

SBO and EDG failures are plausible failure modes.

 

[nikkkom]

A NPP will suffer meltdowns if confronted with a long and total SBO. And a plane will crash if all engines fail and can't be restarted. That's why you engineer those things the way that this shouldn't happen.

Sorry, but it is not true. Many *existing* NPPs will suffer meltdowns in this case. By now I think we need to mandate that all new NPP must be designed, and most existing NPPs retrofitted with means to prevent that. *Passive* means: EDGs do not count.

Is it even possible to turn ICs on/off and/or vent the containment without electricity? I honestly don't know.

If you mean, "was it possible at F1?" then I am interested in the answer too.

 

[NUCENG]

Loss of gravity is (a) implausible and (b) wouldn't matter anyway, since all other human infrastructure would be destroyed by it, not only NPPs.

SBO and EDG failures are plausible failure modes.

You proposed: "Do a mental exercise: imagine that all EDGs on all NPPs on the planet have vanished into thin air; then cut all power - put all NPPs into extended SBO." and call that plausible?

This is a technical forum. If your intent was simply to state that if an extended SBO could result in another accident, then you are correct. However, for such an event to occur, absent a similar design deficiency as the tsunami at Fukushima is very low risk. For it to occur at every plant on the planet simultaneously is a risk on the same order of probability as loss of gravity.

If you want to make your post topical, please explain how "EDGs vanish into thin air" and "cut all power" is probable at even one other plant unless there is another 1000 year external event. Then please explain why you think lessons learned from this accident won't make another accident even less likely.

I am not questioning your concerns or fears, but at least on this thread, let the anti-nuke hysteria be based on something more credible than your mental exercise appears to be.

 

[rmattila]

Another issue to take into consideration is the separation between "regular" EDGs and specific (usually air-cooled) SBO diesels fitted to some plants to enable certain vital safety functions even if all EDGs are lost. If they have sufficiently diversified power supply lines, they might provide some extra depth against severe accidents in station blackout situations. There seems to be a variety of opinions on how such dedicated SBO diesels should be treated in the post-Fukushima station blackout analyses.

 

[nikkkom]

You proposed: "Do a mental exercise: imagine that all EDGs on all NPPs on the planet have vanished into thin air; then cut all power - put all NPPs into extended SBO." and call that plausible?

This is a technical forum. If your intent was simply to state that if an extended SBO could result in another accident, then you are correct. However, for such an event to occur, absent a similar design deficiency as the tsunami at Fukushima is very low risk. For it to occur at every plant on the planet simultaneously is a risk on the same order of probability as loss of gravity.

The thought experiment wasn't meant to simulate a SBO over entire planet. That is not plausible. It was meant to construct an (implausible) situation in which every currently existing NPP is forced to go through real Fukushima event.

I am saying that I do not believe that almost every plant will survive. IOW: I don't believe in "stupid Japanese are to blame" theory.

 

[nikkkom]

I have a slightly better question to chew on: with all those makeup pipes all around, are they ready for the winter?

What would happen if some water transfer pipes gets blocked by ice? What would happen with the SFPs? With the makeup cooling of the SFPs?

OTOH, in winter uncovered SFPs have naturally better cooling :D

 

[NUCENG]

The thought experiment wasn't meant to simulate a SBO over entire planet. That is not plausible. It was meant to construct an (implausible) situation in which every currently existing NPP is forced to go through real Fukushima event.

I am saying that I do not believe that almost every plant will survive. IOW: I don't believe in "stupid Japanese are to blame" theory.

Neither do I, but the failure of TEPCO to incorporate new information about tsunami threats was a huge mistake that was a root cause of the accident.

It is not enough to come up with a "thought experiment" of extended SBO to condemn nuclear power in general. That "extended SBO" must be plausible and that takes more than imagining EDGs vanishing into thin air and loss of all power.

I reject your "thought experiment" unless you can show that there is a reason to believe the Fukushima scenario is plausible at other plants. This means you must identify a realistic set of external events and internal design vulnerabilities that can cause a similar result. And you must show that the lessons learned from Fukushima cannot or will not mitigate that vulnerability. Finally you must explain why the risks outweigh the benefits of nuclear power generation as those vulnerabilities are addressed.

If that burden can be met for any nuclear plant, then I, too, want that plant shutdown immediately and until until the vulnerabilities are corrected. If even one of these criteria can be met the burden should shift to the operators of the plant to show cause why they should be allowed to continue to operate pending corrective action.

This seems to put a huge burden on the person or organization that opposes nuclear power, but don't bother with the tired complaint that it is up to the nuclear industry to prove that it is safe to operate. "Safe" is an illusion and is not the issue. Nuclear power has risks and every plant that has been licensed has met the regulatory standards to show that the risk is low.

I reject your "thought experiment" because it is intellectually dishonest to apply a standard of 100% safe to nuclear power while tolerating the risks of tobacco, fossil plant emissions, automobiles, and the millions of other activities that do not meet that standard.

 

[LabratSR]

New Video released by TEPCO.

http://youtu.be/Lq_5KI787pI

 

[Luca Bevil]

Neither do I, but the failure of TEPCO to incorporate new information about tsunami threats was a huge mistake that was a root cause of the accident.

It is not enough to come up with a "thought experiment" of extended SBO to condemn nuclear power in general. That "extended SBO" must be plausible and that takes more than imagining EDGs vanishing into thin air and loss of all power.

I reject your "thought experiment" unless you can show that there is a reason to believe the Fukushima scenario is plausible at other plants. This means you must identify a realistic set of external events and internal design vulnerabilities that can cause a similar result. And you must show that the lessons learned from Fukushima cannot or will not mitigate that vulnerability. Finally you must explain why the risks outweigh the benefits of nuclear power generation as those vulnerabilities are addressed.

If that burden can be met for any nuclear plant, then I, too, want that plant shutdown immediately and until until the vulnerabilities are corrected. If even one of these criteria can be met the burden should shift to the operators of the plant to show cause why they should be allowed to continue to operate pending corrective action.

This seems to put a huge burden on the person or organization that opposes nuclear power, but don't bother with the tired complaint that it is up to the nuclear industry to prove that it is safe to operate. "Safe" is an illusion and is not the issue. Nuclear power has risks and every plant that has been licensed has met the regulatory standards to show that the risk is low.

I reject your "thought experiment" because it is intellectually dishonest to apply a standard of 100% safe to nuclear power while tolerating the risks of tobacco, fossil plant emissions, automobiles, and the millions of other activities that do not meet that standard.

Are you excluding from this "burden of proof" the japanese plants that have not been restarted yet, I must suppose ..

While I cannot sware on the EDG, pump protection, anti-tsunami barriers and similar resilience factors for each and every one of them, it does seem to a first rough examination of basic plant topology, levels of rectors above OP, that many share the same basic vulnerabilities than Fukushima daiichi had.

They will be probably upgraded before restarting.

Furthermore, and in this specific pointI suppose you will agree, most if not all US plants do have an unsatisfactory spent fuel disposal management, with overloaded spent fuel ponds, that does expose them to a set of possible risks, terrorist airplane strike, or above design assumptions earthquake shock, being two of the simpest I can think of.
Do we need a burden of proof to require proper disposal of nuclear spent fuel as well ?

 

[Most Curious]

I would agree too much spent fuel is stored at various NPP and that some risk is associated with that storage.

Why is that? Not because of the plants operators but the environmental kooks that have stopped EVERY attempt at building a storage location. How many billion $ was spent on Yucca Mountain before the hand wringers stopped it, thereby creating a MORE SERIOUS problem?

While on a rant, let us also consider the much greater volume of waste (and the wastefulness of calling much of it waste!) because the US does not reprocess spent fuel to recover the useful fissionable material therein.

 

[zapperzero]

While on a rant, [...]

I don't really think this belongs in here. There's a political thread.
https://www.physicsforums.com/showthread.php?t=486089

 

[LabratSR]

PNAS Report on the dispersion of various nuclides

http://www.pnas.org/content/early/2011/11/09/1111724108.full.pdf+html

 

[Astronuc]

Are you excluding from this "burden of proof" the japanese plants that have not been restarted yet, I must suppose ..

While I cannot sware on the EDG, pump protection, anti-tsunami barriers and similar resilience factors for each and every one of them, it does seem to a first rough examination of basic plant topology, levels of rectors above OP, that many share the same basic vulnerabilities than Fukushima daiichi had.

They will be probably upgraded before restarting.

Units 1-4 at Fukushima Daichi will not restart. Units 5 and 6 may restart pending permission of the government.

Any Mk I BWR at the same elevation of FK-I near the ocean is potentially vulnerable IF the EDGs, fuel supply and electrical switch gear are similarly vulnerable. The Mk II units are less vulnerable.

Other units at different locations may be required to adopt site-specific measures before restart, while some older units may be permanently shutdown and decommissioned.

Furthermore, and in this specific point I suppose you will agree, most if not all US plants do have an unsatisfactory spent fuel disposal management, with overloaded spent fuel ponds, that does expose them to a set of possible risks, terrorist airplane strike, or above design assumptions earthquake shock, being two of the simpest I can think of.
Do we need a burden of proof to require proper disposal of nuclear spent fuel as well ?

What is the basis of said assumption. Utilities must have the ability to do a full core offload to the spent fuel pool. Spent (or now called 'used') fuel, after a specified miniumum cooling period, is placed in dry storage at the reactor sites pending receipt by the US government for reprocessing or disposal in a respository.

US BWRs had a number of retrofits that were apparently not applied to FK Daiichi units. In addition, there are design differences at most US BWRs that make them less vulnerable than the FK-I units.

 

[LabratSR]

IAEA Remediation Mission Issues Final Report
http://www.iaea.org/newscenter​/focus/fukushima/final_report1​51111.pdf

 

[nikkkom]

I reject your "thought experiment" unless you can show that there is a reason to believe the Fukushima scenario is plausible at other plants.

Fukushima happened. That is a fact. I am not willing to accept any amount of pseudo-scientific proofs that "extended SBO + all EDGs are dead" scenario is soooo unlikely that we can ignore the possibility. Sorry, I don't buy it. We need to add systems which cover that possibility.

This means you must identify a realistic set of external events and internal design vulnerabilities that can cause a similar result.

No, it's your (meaning: nuclear industry, not you personally) task to convince me that it can't happen. And with me, you won't be able to do that. Maybe younger, more naive people should be target audience for attempts to do so.

If that burden can be met for any nuclear plant, then I, too, want that plant shutdown immediately and until until the vulnerabilities are corrected.

I don't call for immediate shutdowns. I would settle for "fully passive cooling system should be added during next 10 years to every operating plant".

 

[Rive]

Some survey around U3 containment equipment hatch:

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_111116_01-e.pdf

That white stuff around the wet parts looks like salt for me. It's not good if it IS salt.
http://www.tepco.co.jp/tepconews/pressroom/110311/images/111116_03.jpg

 

[clancy688]

Why isn't it good?


In the early stages of the accident, big fire engines were used to spray sea water directly onto the reactors (At Unit 4 for sure, and as far as I know at Unit 3 as well). They wanted to refill the spent fuel pools. So that's where the salt could've come from.

 

[SteveElbows]

Approx 1300 mSv/h detected near the surface of the northern rail is surely the main indicator that should cause concern?

Im not sure if the containment hatches themselves were compromised at some point during the indecent, or if the source of the substances is pipework above the hatch locations. Either way, I think there was some quite active stuff on the floor near the other (south western) hatch, which they previously tried to vacuum, and then placed sheets on the floor to reduce dose to workers.

 

[Luca Bevil]

What is the basis of said assumption. Utilities must have the ability to do a full core offload to the spent fuel pool. Spent (or now called 'used') fuel, after a specified miniumum cooling period, is placed in dry storage at the reactor sites pending receipt by the US government for reprocessing or disposal in a respository.

US BWRs had a number of retrofits that were apparently not applied to FK Daiichi units. In addition, there are design differences at most US BWRs that make them less vulnerable than the FK-I units.

I remember reading far from reinsuring data in several pages in March.

Now I looked up and found for example this page

http://blogs.reuters.com/gregg-easterbrook/2011/03/18/the-danger-of-spent-fuel-rods-and-the-yucca-mountain-project/

or

http://www.commondreams.org/view/2011/03/21-2

of course I woud be happy to read more reinsuring data/evaluations from you if you can point to more reliable information.

 

[NUCENG]

Are you excluding from this "burden of proof" the japanese plants that have not been restarted yet, I must suppose ..

While I cannot sware on the EDG, pump protection, anti-tsunami barriers and similar resilience factors for each and every one of them, it does seem to a first rough examination of basic plant topology, levels of rectors above OP, that many share the same basic vulnerabilities than Fukushima daiichi had.

They will be probably upgraded before restarting.

Furthermore, and in this specific pointI suppose you will agree, most if not all US plants do have an unsatisfactory spent fuel disposal management, with overloaded spent fuel ponds, that does expose them to a set of possible risks, terrorist airplane strike, or above design assumptions earthquake shock, being two of the simpest I can think of.
Do we need a burden of proof to require proper disposal of nuclear spent fuel as well ?

I do not exclude any plant in any country from the basic process of learning from experience. Right now there is a new appreciation for the power of tsunamis in Japan. It is still nearly incomprehensible to me that the nation that gave us the word "tsunami" needed this lesson, but it happened. It proved that a 1000 year event can occur in a 40 or 60 year plant life and that the consequences of that rare event needed to be included in the design. It is clear that the costs of hardening the Fukushima plants against tsunamis would have been a bargain compared to what they are now facing. If utilities operating nuclear plants are slow or ineffective in taking actions, it depends on the regulators to step in and force the action or shut the plant down. This backup also failed in Japan. As a result we have the political backlash that is represented by prefectural governors blocking plant restarts in search of the "100% safe" myth. Italy and Germany have also taken a political decision which is their right and is supported by their citizens.

I do agree that spent nuclear fuel is a major issue in the US. But this issue is a result of political issues overriding technical solutions that were promised by the government and paid for by the nuclear industry, but not delivered. Plants have installed dry cask storage to reduce fuel pool loading. The risks of terrorism and seismic activity are being reviewed. Actions have been taken to upgrade security, and GI-199 was already being finalized into regulatory requirements when the earthquake hit Japan. You may disagree, but the industry, the regulators, and the general public in the US support that process.

 

[NUCENG]

Fukushima happened. That is a fact. I am not willing to accept any amount of pseudo-scientific proofs that "extended SBO + all EDGs are dead" scenario is soooo unlikely that we can ignore the possibility. Sorry, I don't buy it. We need to add systems which cover that possibility.



No, it's your (meaning: nuclear industry, not you personally) task to convince me that it can't happen. And with me, you won't be able to do that. Maybe younger, more naive people should be target audience for attempts to do so.



I don't call for immediate shutdowns. I would settle for "fully passive cooling system should be added during next 10 years to every operating plant".

You are still missing the point, nikkom, your thought experiment jumps to the condition of an extended SBO at every plant because it happened at one plant. I agreed that extended SBOs could cause another accident, but I insist that there be a legitimate path to that condition.

In terms of nuclear power accidents we are worried about very low risk events with high consequences. I am frustrated that the public readily accepts high risk low consequence accidents every day that cumulatvely dwarf the consequences of a nuclear accident. Your thought experiment jumps to the consequences with no consideration of risk.

It is not my (meaning: nuclear industry) task to convince you that "it can't happen." It can happen, but the risk is low and the lessons learned from Fukushima will make it even lower. It IS my task to balance the fuzzy logic and misinformation represented by your thought experiment. I respect your right to disagree with me, but the "younger people" you distrust will remain naive if they only hear your side.

 

[Rive]

Im not sure if the containment hatches themselves were compromised at some point during the indecent, or if the source of the substances is pipework above the hatch locations.

- By the linked PDF document the radiation levels are extreme around only one rail there.
- If the equipment hatch is any similar to http://www.tva.com/news/pix/a_4.jpg" , then there are no pipes so close that a leak would affect only one rail.

IMHO.

(Picture index is here: http://www.tva.com/news/pix/index.htm )

 

[nikkkom]

You are still missing the point, nikkom, your thought experiment jumps to the condition of an extended SBO at every plant because it happened at one plant. I agreed that extended SBOs could cause another accident, but I insist that there be a legitimate path to that condition.

In terms of nuclear power accidents we are worried about very low risk events with high consequences. I am frustrated that the public readily accepts high risk low consequence accidents every day that cumulatvely dwarf the consequences of a nuclear accident.

Why are you frustrated by it? There are no practical ways to get rid of automobile transportation. There are no legal ways to prohibit smoking (for now). Therefore, those activities will continue.

But there are practical way to make nuclear power plants safer. They do exist.

F1 should have been safer wrt the accident conditions which actually were experienced. It's a pity the problems there were not fixed before F1, but it's history now. The question now is, will we (humanity as a whole) at least take action *after* it was empirically shown at F1 that currently nuclear industry isn't as safe as we want it to be?

The "stupid Japanese" theory leads us in the direction where only Japanese NPPs and their personnel will improve their safety systems and training. The rest of the world will need to wait for another wakeup call. I don't like it.

 

[nikkkom]

I do agree that spent nuclear fuel is a major issue in the US.

I thought dry cask storage solves the problem in medium term?
(a) dry casks are rather safe wrt natural disaster or industrial damage and theft
(b) the fuel from dry casks can be reprocessed in the future, it does not deteriorate
(c) the fuel in dry casks becomes less and less radioactive over time - making it less, not more dangerous with time
(d) dry cask storage is not very expensive

Am I missing something?

 

[SteveElbows]

- By the linked PDF document the radiation levels are extreme around only one rail there.
- If the equipment hatch is any similar to http://www.tva.com/news/pix/a_4.jpg" , then there are no pipes so close that a leak would affect only one rail.

IMHO.

(Picture index is here: http://www.tva.com/news/pix/index.htm )

Given that containment hatch/personnel airlock's are one of a number of containment failure points highlighted in studies of containment under severe accident conditions, I certainly do not require pipework to exist in the vicinity in order to explain the contamination in this area. But I can't completely rule it out either, nor can I state that pipework absolutely must be within a certain proximity in order to contaminate only one rail.

An example of the sort of study I refer to is this one http://www.osti.gov/bridge/servlets/purl/6409677-0h1aot/6409677.pdf

 

[SteveElbows]

TEPCO have released a large number of previous unpublished videos, taken over many months.

http://www.tepco.co.jp/en/news/110311/111111-e.html

Has anybody watched many of these videos yet? I've watched just over half of them so far. Main themes of note to me so far are:

Many looks at the upper building of reactor 4, during numerous fuel pool measuring or spraying activities. Get a look at the reactor well in one of them.

A few videos showing workers performing pipework-related activities inside reactor buildings, often having to climb stairs to a higher level.

A video that shows what's going on under the less-collapsed part of reactor 1 buildings roof. When zoomed in some clouds can be seen, I strongly presume we are looking at the fuel pool. They then proceed to study the remains of the roof above this section, and in a later video it appears that they sprayed something through part of this roof, creating a hole (its not labelled as such but seems like this may be how they initially added water to unit 1's fuel pool)

A couple of videos of reactor 3 pool spraying, where the operator spends quite soon time zooming into an area which, if my orientation is correct, is around the area where the fuel pool-to-reactor gate is.

There are lots of other videos but these were not so notable to me.

One particular reactor 4 pool video gives us a much extended view underwater of the pool & its contents. It goes on for many minutes and offers a much clearer and more comprehensive view than the videos of months ago. I am not especially interested in the pool anymore, but it was still an interesting video. The link is below, and underwater stuff starts at around the 10 minutes 40 second mark (or just before half way of the position slider if you can't tell how far throughout he video you are because of the way TEPCO have delivered these videos in web browser).

http://www.tepco.co.jp/en/news/110311/movie_1111/1111_21-e.html

I must admit I was slightly surprised to see what appears to be a fuel bundle on its own, with a slightly bent handle, sitting quite upright but not inside multi-bundle racking like all the other fuel. I do not presume that this has anything to do with the accident, but I'd like to know a little more about it. It is briefly visible towards the end of the video, when the camera has panned to the right of the pool, and then pans downwards after previously looking up at a section of pool wall. Around the 21:25 to 21:29 mark.

 

[NUCENG]

Why are you frustrated by it? There are no practical ways to get rid of automobile transportation. There are no legal ways to prohibit smoking (for now). Therefore, those activities will continue.

But there are practical way to make nuclear power plants safer. They do exist.

F1 should have been safer wrt the accident conditions which actually were experienced. It's a pity the problems there were not fixed before F1, but it's history now. The question now is, will we (humanity as a whole) at least take action *after* it was empirically shown at F1 that currently nuclear industry isn't as safe as we want it to be?

The "stupid Japanese" theory leads us in the direction where only Japanese NPPs and their personnel will improve their safety systems and training. The rest of the world will need to wait for another wakeup call. I don't like it.

First, if I have given you the impression that I oppose taking action based on lessons learned from Fukushima because it is low risk, that is not the case. But the simplistic cookie cutter approach of requiring all plants to retrofit completely passive heat removal systems is not warranted if it can be shown that the combination of active and passive systems already in place are sufficient to meet the risk of internal and external events. Installing and protecting additional AC, DC, or pneumatic power sources to extend operation of existing active systems may suffice.

I do not recommend eliminating automobiles, but I would be less frustrated if more people recognized the daily decisions we make to accept risk in return for the benefiits of our activities. I want the same kind of risk/benefit balance in decision making about nuclear power.

Why do you keep harping about the "stupid Japanese" theory? I have clearly stated that it is nonsense and does not excuse other countries from taking action.

I will give you one more consideration. All of the hype and, in my opinion, misinformation is likely to seriously delay or abort efforts to build new plants that do have passive safety designs. Concerns over global warming are threatening operation of fossil fuel plants. You have seen the impact of the plant shutdowns on the Japanese economy. The end result, to avoid similar impacts on other economies could be to continue to extend operation of the plants with the highest risks.

 

[NUCENG]

I thought dry cask storage solves the problem in medium term?
(a) dry casks are rather safe wrt natural disaster or industrial damage and theft
(b) the fuel from dry casks can be reprocessed in the future, it does not deteriorate
(c) the fuel in dry casks becomes less and less radioactive over time - making it less, not more dangerous with time
(d) dry cask storage is not very expensive

Am I missing something?

Dry cask storage is only necessary because the US government did not meet its commitment for a federal depository.

Right now there are more than 100 temporary storage sites requiring security and protection.

Reprocessing options were discarded in the US nearly 40 years ago and only recently have been discussed again as a serious potential.

As you say, spent fuel becomes less dangerous with time - a LOOOOOONG time. The same can be said for fuel in a pool or in a geological depository.

Finally, dry cask storage ain't cheap.

 

[nikkkom]

Right now there are more than 100 temporary storage sites requiring security and protection.

Are they co-located with NPPs which already require the same?

As you say, spent fuel becomes less dangerous with time - a LOOOOOONG time.

A 90-year old spent fuel is more than 10 times less radioactive than 4-year old one, right? I imagine reprocessing plant designers would like this fact.

 

[westfield]

Has anybody watched many of these videos yet? I've watched just over half of them so far. Main themes of note to me so far are:

Many looks at the upper building of reactor 4, during numerous fuel pool measuring or spraying activities. Get a look at the reactor well in one of them.

<snip>


I must admit I was slightly surprised to see what appears to be a fuel bundle on its own, with a slightly bent handle

< snip.

This one? Appears to be towards the SE corner of the Unit 4 SFP. We've never seen right into this SE corner of the pool perhaps due to the limitations of the camera rig they are using.

I didn't see any of the Unit 4 reactor void, which clip was that?
I saw the camera get as far as looking beyond the FHM down onto the Cask area in the NW corner of the SFP but no further.
Also saw them get the water spray boom very jammed up under the unit 4 main crane, I imagine a change of pants was in order when that sprang free!, appeared to do some minor damage to the camera\thermocouple lowering rig. Short clip http://s1185.photobucket.com/albums/z360/fukuwest/misc/?action=view&current=U4boomsnag.mp4

Some views of the Unit 1 "service shaft", the very bent main crane, the FHM etc which has been hiding under the roof debris -

The unit 3 SFP videos reveal where these earlier images of the U3 SFP came from.

Apr 14th Still Image
http://i1185.photobucket.com/albums/z360/fukuwest/misc/sfp_boom_14Apr110415_1f_4_1.jpg


Apr 18th image from video - Near the NW corner of the U3 SFP
http://i1185.photobucket.com/albums/z360/fukuwest/misc/1312011111712_51_55.jpg (zoomed out, ladder visible in centre of image)
http://i1185.photobucket.com/albums/z360/fukuwest/misc/1382011111715_56_57.jpg (zoomed in)

In that video they seem to be checking the water level of the SFP against the SFP Skimmer outlet as they are adding water - the outlet is a dark rectangle in the wall of the sfp barely visible amongst the steam. The camera operator also zooms in on a large object in the SFP, more towards the eastern side of the pool. It has some characterisics of a FHM but it's not clear enough to see if it is part of the FHM or not. This area is the source of the other previously released SFP image.

 

[NUCENG]

Are they co-located with NPPs which already require the same?



A 90-year old spent fuel is more than 10 times less radioactive than 4-year old one, right? I imagine reprocessing plant designers would like this fact.

Not all spent fuel storage is at active plants, some are at decommissioned sites that have storage licenses. When you talk about 90 years, does that mean you expect plant license extensions that long? Obviously, if we can't eventually move this stuff offsite, the answer to your question will eventually be NO!

If your number is correct and spent fuel after 90 years is only 10% of the radiation levels of 4 year old fuel, I have to paraphrase a previous comment of mine, "10% of a big number is still a big number." I would like to see serious attention to reprocessing fuel. I believe we will still need geological storage of high level wastes.

 

[Rive]

An example of the sort of study I refer to is this one http://www.osti.gov/bridge/servlets/purl/6409677-0h1aot/6409677.pdf

Thanks.

It's interesting that the expected failure pressure is close to the expected containment cap failure pressure, if I take it right. So if this one failed then the other one might failed too.

Regarding the 'new' videos: did anybody managed to find the U3 FHM?

 

[nikkkom]

If your number is correct and spent fuel after 90 years is only 10% of the radiation levels of 4 year old fuel, I have to paraphrase a previous comment of mine, "10% of a big number is still a big number."

Sure. I am not implying that 90 year old fuel is harmless. Of course not. It is still so radioactive that it can kill nearby human in seconds if unshielded.

I would like to see serious attention to reprocessing fuel.

Me too.

I see no harm, though, in keeping spent fuel in dry casks for many years before reprocessing. It actually should make reprocessing easier. In 100 years, Kr-85 decreases by the factor of 1000 (meaning that airborne releases are greatly reduced), Cs-134 by 10^15 (practically zero), Cs-137 and Sr-90 by 10. What's not to like?

I believe we will still need geological storage of high level wastes.

Sure. Unless someone is willing to make an electric generator powered by heat of canisters filled by Cs-137 and Sr-90. :D

 

[SteveElbows]

Thanks.

It's interesting that the expected failure pressure is close to the expected containment cap failure pressure, if I take it right. So if this one failed then the other one might failed too.

Regarding the 'new' videos: did anybody managed to find the U3 FHM?

Given the locations of some of the steam we saw escaping from several reactors (most clearly number 3), I don't think many people would be at all surprised if drywall head was a leak point.

As for the FHM, I would not be at all surprised if it left the building during the explosion. There was more than enough debris to the immediate south of reactor 3 building to account for this, and I don't think the media or TEPCO were too interested in reporting its location. If it was ejected then I don't think it tells us much really.

 

[SteveElbows]

This one? Appears to be towards the SE corner of the Unit 4 SFP. We've never seen right into this SE corner of the pool perhaps due to the limitations of the camera rig they are using.

I didn't see any of the Unit 4 reactor void, which clip was that?

Yes that's the one. Any ideas about it? I wondered if perhaps it had been mishandled and damaged at some time in the past, and so was kept on its own? Or is there any such thing as a 'dummy' fuel bundle used for some purpose?

As for unit 4 reactor well, I made a stupid mistake having watched too many videos in one sitting. I knew it didn't look like the reactor well should, but I thought maybe it was something that had been temporarily placed in the region during the reactor shroud work. In fact it was the cask area of the fuel pool that you mention, my mistake.

 

[Rive]

As for the FHM, I would not be at all surprised if it left the building during the explosion.

Well, I would. Lot of other, less stable stuff remained there on the top...

But anyway, it's just my stupid theory about the falling overhead crane, pushing through the FHM on the drywell cap - no worth in discussing it without further details :-)

Yes that's the one. Any ideas about it?

IIRC the SE corner is where a 'Fuel Inspection Machine' or something like that were suspected. (It was around May, maybe...) I've posted a picture about it somewhere... It's for manual dry inspection of new bundles.

 

[SteveElbows]

Well, I would. Lot of other, less stable stuff remained there on the top...

But anyway, it's just my stupid theory about the falling overhead crane, pushing through the FHM on the drywell cap - no worth in discussing it without further details :-)

I don't see much other stuff remaining at that level of reactor 3. There is mostly just the overhead crane, and lots of roof debris.

I don't tend to see enough debris under the crane to account for the FHM, although the area is such a mess that I cannot be entirely certain. Certainly some portion of the circular plugs that sit above the drywall can be seen on a couple of different videos or images. A very small portion can be seen on old videos that showed steam escaping from the area where the edge of the reactor drywall connects to the storage pit/pool. Such footage tended to indicate that the overhead crane beam on this side had fallen quite neatly down to this level, quite parallel with the floor. And in the following image I believe we can see quite a portion of the eastern side of the cap. I will illustrate the area in question shortly.

http://www.tepco.co.jp/en/news/110311/images/111008_05.jpg

 

[SteveElbows]

OK so here is a version of the above image which I have marked. Within the yellow area is the edge of the circular drywell plug I mentioned. Within the orange area is possible another part of the plug edge, but I am less certain of this one. The X marks the spot where other images & video have shown steam escaping in the past.

This is a document which shows the area I marked with an X. The gap along the narrow edge of the removable pit gate is the main feature of interest due to the longstanding impression that this was a well visible point of containment failure, but in this case I am posting it so we can see what the edge of the drywell plugs looks like for comparison with above image.

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_110924_02-e.pdf

 

[SteveElbows]

Also please note that I cannot be certain that I have identified plug edges correctly in that photo, it could be something else, but the position seems about right.

 

[Rive]

... the position seems about right.

Agree. You can even see the FHM rails near the plug. Good find.
[URL]http://www.houseoffoust.com/fukushima/tepco_pics/R3_july21_1.jpg[/URL]
(The circle marks the pool gate: the rail is on the left near the reactor well.)

The 'spanner' (look it up in the thread here) was more in the way of the destruction than the FHM and it's still on the top level... More or less. So I think the FHM should be there too.