Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[joewein]

However the following document does contain some pictures that I don't think I've seen before, outside reactor 3 building (demolished the damaged vehicle entrance tunnel by the looks of it). And also, joy of joys, a view of the site looking down from the top of the slope where the webcam is, so that we can actually see the ground around the reactors and further to the left of reactor 1 than normal. Its not very high res within this pdf, but it still gives me a much improved sense of the state of a good chunk of the site these days. (that photo, or rather 3 photos stitched together, is on page 13)

http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110617e4.pdf

Yes, that was a worthwhile read.

Of interest to me was the description of a plan to fix the presumed unit 2 torus leak (page 4):

Open a hole in floor of 1st floor of R/B and fill grout in the torus

By surrounding the donut-shaped suppression chamber with concrete they are hoping to stop outflow of water from the containment through the cracked torus.

I think that work will be very tricky because they'll effectively have to pour concrete under water. Normally, when you construct concrete foundations of bridges, etc. in a river you get rid of the water first, which won't be possible here. It reminds me of the trouble they had plugging that water leak in the trench near unit 2 back in April. Anyway, they say they'll try out their plan in a lab first. Will they build a mockup of a broken, flooded torus?

What's worse, the water in and around the torus is highly radioactive. They're talking about drilling down into the basement from the first floor, but next door in unit 1 they measured 3000-4000 mSv/h in a location where steam rises into the first floor from the basement, which is the worst figure measured anywhere in Fukushima Daiichi outside the containments so far.

The document shows a lot of visual details of preparations for pouring concrete (page 19). Looks like one of the Putzmeister trucks (dubbed "zousan 3" = Elephant 3) will finally get used for its original purpose. I think I saw that the Putzmeister trucks used for pouring water are referred to as "kirin" (giraffe).

There's a diagram showing the newly installed 32 steel pillars under the unit 4 spent fuel pool (SFP) getting embedded into a concrete wall (page 18). So the steel is ultimately just meant as reinforcement bars, with the concrete carrying the load.

They also show a system "under consideration" of a cooling system within the reactor building (page 2), with water pumped from the basement of the reactor building through a heat exchanger into the RPV. The current plan is to pump water from the basement of the turbine hall, treat it and then feed some of it back into the RPV. Do they think sufficient time with the treatment cycle plan would decontaminate the containment enough that a cooling cycle without decontamination will become feasible? Given that they will be paying some $500 million to Areva SA for water treatment by early next year, maybe they have a strong incentive to eventually skip the filtration step.

 

[joewein]

One the other hand, since the water found in the base of the reactor building was heavily contaminated with radioisotopes, it is likely the water contacted the fuel, so it seems there was water in the cores, or at least in the RPVs.

Whether fuel pellets lie at the bottom of the RPV or melted there or melted through to the concrete floor of the dry well, water injected into the RPV would have passed the fuel and picked up cesium and iodine, simply following gravity from the feedwater or fire suppression lines.

Once pellets melted, the volatile elements would have evaporated and later condensed in the suppression chamber and/or the dry well. Water leaking from the containment would first have picked up major contamination from there even if it didn't directly pass what's left of the core.

In fact, the less water was in the core in the first couple of days the more cesium and iodine would have escaped from inside melting ceramic pellets, later recondensing elsewhere in the containment. Therefore I see the high levels of radioactivity in the water in the building basements not so much as hopeful evidence that fuel did receive minimal cooling, but perhaps that it did not.

I am more encouraged by moderate temperature readings at the RPVs, but who knows what sensors can still be trusted at this stage?

 

[sigyn]

Problems with cleaning water ?

"The level of radiation at a machine to absorb cesium has risen faster than our initial projections,"

...

"Officials had said earlier this week that large and growing pools of radioactive water at the Fukushima Daiichi plant were in danger of spilling into the sea within a week unless action was taken quickly."



http://news.yahoo.com/s/nm/20110618/ts_nm/us_japan_nuclear;_ylt=Aq_cxFl3pVcRyWkwjsf.5gJZ.3QA;_ylu=X3oDMTJudThtOGhmBGFzc2V0A25tLzIwMTEwNjE4L3VzX2phcGFuX251Y2xlYXIEcG9zAzExBHNlYwN5bl9wYWdpbmF0ZV9zdW1tYXJ5X2xpc3QEc2xrA2phcGFuMzlzdGVwYw--

 

[etudiant]

Problems with cleaning water ?

"The level of radiation at a machine to absorb cesium has risen faster than our initial projections,"

...

"Officials had said earlier this week that large and growing pools of radioactive water at the Fukushima Daiichi plant were in danger of spilling into the sea within a week unless action was taken quickly."



http://news.yahoo.com/s/nm/20110618/ts_nm/us_japan_nuclear;_ylt=Aq_cxFl3pVcRyWkwjsf.5gJZ.3QA;_ylu=X3oDMTJudThtOGhmBGFzc2V0A25tLzIwMTEwNjE4L3VzX2phcGFuX251Y2xlYXIEcG9zAzExBHNlYwN5bl9wYWdpbmF0ZV9zdW1tYXJ5X2xpc3QEc2xrA2phcGFuMzlzdGVwYw--

Perhaps this is mixed news, rather than all bad.
The good news is that the Kurion cesium adsorbing material is clearly doing its job well.
The bad news is that the water is so contaminated that the cesium build up may make the cartridges too dangerous to handle. Judging from the few pictured that have been released, the plant does not appear to be automated, so that the periodic replacement of spent cartridges is a manual task. That may not be feasible if the cesium level is too high.
It is surprising that this development was not anticipated in the design. Or is my understanding just wrong?

 

[razzz]

Since concrete (which is usually rock(s), sand and cement) and even grout (which is cement and sand) are heavy than water, the mix will displace the water (force it out and away). Concrete could dilute (water washes out the cement) but pumping in more would overcome that. Many additives available for concrete mix design properties.

Problems ex. torus leak is not where anticipated, torus has or develops (due to added weight) other leak areas where in effect one has to fill the entire area in and around the torus with this concrete mix, decay heat causes the concrete to setup faster than desired, water finds or causes other passages to subsoil, disturbing the coolant flow creates a mini-disaster, air-pockets occur leaving voids, contaminated coolant discharge is raised to a higher level and so on and so on.

Well, that's why you have architects and engineers to draw up a plan. Seems a bit early in the game to me unless they know something we don't.

 

[Luca Bevil]

Problems with cleaning water ?

"The level of radiation at a machine to absorb cesium has risen faster than our initial projections,"

...

"Officials had said earlier this week that large and growing pools of radioactive water at the Fukushima Daiichi plant were in danger of spilling into the sea within a week unless action was taken quickly."



http://news.yahoo.com/s/nm/20110618/ts_nm/us_japan_nuclear;_ylt=Aq_cxFl3pVcRyWkwjsf.5gJZ.3QA;_ylu=X3oDMTJudThtOGhmBGFzc2V0A25tLzIwMTEwNjE4L3VzX2phcGFuX251Y2xlYXIEcG9zAzExBHNlYwN5bl9wYWdpbmF0ZV9zdW1tYXJ5X2xpc3QEc2xrA2phcGFuMzlzdGVwYw--

Very alarming news after a few hours of operation...

This equipment was supposed to operate in an almost continuos basys.

We should suppose they began processing an heavier than average contaminated water..

Why ?

And what countermeasures could be available ?

I feel like we wll never see the end of this nightmare.

 

[Orcas George]

Let us hope for the best, perhaps an instrument problem.

Apparently someone left a valve closed on the Kurion machine and overpressurized it, damaging a relief valve and releasing 6000 liters of water. They fixed that yesterday but perhaps there was more damage to the machine than thought? I was a little concerned that they started up so quickly after replacing that damaged valve, testing should have started over from step #1 as soon as anybody placed a wrench on the equipment.

The problem with that system is that if it does have a leak when processing the hot stuff, it becomes expensive junk. For something so mission critical, I have heard the "leak" word an awful lot these last few weeks. I may be jumping to conclusions that it is a leak related problem, but otherwise it doesn't make much sense. The designers knew that they would be handling highly radioactive water so I would assume that shielding was designed into the machine.

Once again TEPCO's vagueness leaves us all wondering.

 

[jlduh]

In theory, the cesium, which represents the vast bulk of the activity afaik, is mostly adsorbed in the Kurion zeolite columns, which are sealed cartridges. So exchanging these would be fairly easy and quick, although looking at the pictures, there is no room for a robot handler, so people will have to take the radiation hit to make the exchange. These cartridges are apparently designed for direct vitrification, so provided Kurion can keep the cesium inside while the cartridge is getting glassified, rhat contamination can be safely locked away.

The rest of the process looks much more messy, as AREVA has indicated they expect several thousand cubic meters of toxic radioactive sludge to be produced. Japan has said the wastes will be stored in Japan, so we may look for an urgent search for a waste repository.
Maybe in Okinawa or some similar out of the way location :).

Well, reading this news

http://www3.nhk.or.jp/daily/english/18_10.html

is no good news and to tell you the truth when they announced that kind of plan for treating so much water with so much contamination with a system put in place in 2 months in a total last resort mode, i didn't believe this could work: it looks kind of magical to remove contamination from water for non specialists and citizens and medias but there is no free lunch, contamination has to go somewhere and be even more concentrated: there is no process to reduce radioactivity, there are only some to separate it (to some extent) from other medium, in this case water. Does this kind of "magical" process already happen somewhere in the world in an industrial fashion, with so much contamination at first i mean and at such a rate, 1200 tons per day? I don't think so!

One way or another, the contamination that was contained in the pellets + zirconium rods + pressure vessel + containment vessel (with steel and more than 1 meter thickness concrete) will have to be concentrated somewhere, and this somewhere will be with no real containment except the cartridges! How can we believe this can really happen and work, especially in a last resort installation put in place in 2 months like this one?

That's why I said a long time ago that i strongly think that the final containment of this mess will be the pacific ocean. I still hope to be really wrong. But my hope is more miracle based than science based.

 

[NUCENG]

Well, reading this news

http://www3.nhk.or.jp/daily/english/18_10.html

is no good news and to tell you the truth when they announced that kind of plan for treating so much water with so much contamination with a system put in place in 2 months in a total last resort mode, i didn't believe this could work: it looks kind of magical to remove contamination from water for non specialists and citizens and medias but there is no free lunch, contamination has to go somewhere and be even more concentrated: there is no process to reduce radioactivity, there are only some to separate it (to some extent) from other medium, in this case water. Does this kind of "magical" process already happen somewhere in the world in an industrial fashion, with so much contamination at first i mean and at such a rate, 1200 tons per day? I don't think so!

One way or another, the contamination that was contained in the pellets + zirconium rods + pressure vessel + containment vessel (with steel and more than 1 meter thickness concrete) will have to be concentrated somewhere, and this somewhere will be with no real containment except the cartridges! How can we believe this can really happen and work, especially in a last resort installation put in place in 2 months like this one?

That's why I said a long time ago that i strongly think that the final containment of this mess will be the pacific ocean. I still hope to be really wrong. But my hope is more miracle based than science based.

I am trying to figure out your point. I assume you don't want them to give up and pump this water into the sea, even though that would fulfill your prediction. They are just starting up this process and will have some startup issues.

 

[GJBRKS]

Well, reading this news

http://www3.nhk.or.jp/daily/english/18_10.html



One way or another, the contamination that was contained in the pellets + zirconium rods + pressure vessel + containment vessel (with steel and more than 1 meter thickness concrete) will have to be concentrated somewhere, and this somewhere will be with no real containment except the cartridges!

I haven't examined the design yet , but it would seem logical to suppose that there would be a multitude of cartridges to absorb and replace.

The news makes it look like one of the cartridges is experiencing a buildup , perhaps due to an uneven distribution of contaminated water.

They would have to look at ways to regulate the parallel flow and processing.

Either that or the level of contamination is much higher than expected , or the filter is doing a better job than anticipated

 

[Calvadosser]

jlduh: "That's why I said a long time ago that i strongly think that the final containment of this mess will be the pacific ocean. I still hope to be really wrong. But my hope is more miracle based than science based."

I am trying to figure out your point. I assume you don't want them to give up and pump this water into the sea, even though that would fulfill your prediction. They are just starting up this process and will have some startup issues.

I think jlduh is simply expressing what I and many others have come to believe. That the indications are that the consequences to the accident at Fukushima are not being dealt with effectively and that, if this is correct, some very large releases of radioactivity into the ocean will be the result. Nobody is suggesting TEPCO give up their efforts and we ernestly hope that our lack of confidence in what they are attempting is proved unfounded.

 

[jlduh]

I am trying to figure out your point. I assume you don't want them to give up and pump this water into the sea, even though that would fulfill your prediction. They are just starting up this process and will have some startup issues.

I'm not criticizing Tepco attempts to put "something" in place, of course. I'm criticizing Tepco attempts to put in place these kind of last resort solutions NOW, in the current situation where prototype process has no time to be prototype.

The total imprepareness for managing that kind of situation is softly covered by the generic term "Beyond design basis accident and expectations". Let me tell you that anger, distress, fear and current or future suffering of people is "beyond design basis human acceptation" also.

The problem is that when things are considered as "impossible to happen", nothing is done to anticipate the consequences, and this water treatment story started a few days before overflowing of contaminated water is a typical example. This is the all story of this Fukushima disaster in fact: Fukushima is an impossible accident, but consequences are real.

I'm a little bit fed up with that kind of rhetoric in which some consider accidents impossible but THEN very easily present as "possible" what are in fact very improbable solutions to (try to) manage consequences of these "impossible" accidents!

I think they just screwed up in the way they placed the word "impossible", in fact. But this is a critical and even criminal mistake, at least IMHO.

But this leads to one real technical question to specialists: does it ever exists in production in the world a system to separate so much contamination at a such rate of 1200 tons per day (even letting aside the question: can it be installed and started up in 2 months which is the "cherry on the cake", as we say in french?)

If this exists, then I will admit that my comments above are biased or even wrong.

If not, then I will tend to think that they are just biased... by facts?

 

[Luca Bevil]

I apologise if this point has already been discussed and was just I that had not enough time for recognising it.

I just came across this analisys
http://allthingsnuclear.org/post/4704112149/how-many-cancers-did-chernobyl-really-cause-updated

nothigh that appeared extraordinarily new as of now, but it was clearly written and well presented so I kept reading until my attention was catched by this statement:

"The momentary loss of power closed the main steam isolation valves (MSIVs). As shown in the diagram above, there are two MSIVs in each of the four pipes carrying steam from the reactor vessel to the turbine. The fail-safe position of the MSIVs is closed. When power was lost, the MSIVs closed. Steam being produced by the reactor core’s decay heat had been traveling through the steam lines to the turbine.
When the MSIVs closed, that steam could no longer travel this path. In addition, the normal supply of makeup water to the reactor vessel to compensate for water leaving as steam is via the feedwater system.
The feedwater system features steam-driven pumps. The source of steam for the feedwater pump turbines is taken from the steam lines downstream of the MSIVs. Thus, closure of the MSIVs made the feedwater pumps unavailable.
The successful start of both emergency diesel generators restored power to essential plant equipment. The operators would have been able to re-open the MSIVs. But that step, if taken, would not have been longlasting.
The emergency diesel generators do not provide power to the equipment handling the steam
collecting in the main condenser. Normally, the pressure inside the condenser is maintained as close to perfect vacuum conditions as can be obtained. The near-vacuum conditions help pull steam through the turbine. As condenser vacuum is lost, sources of steam to it are automatically isolated. Thus, if re-opened, the MSIVs would have soon automatically re-closed".

Now if the statement is correct, and I am not extrapolating erroneously, that seems to suggest to me that EVEN IF the EDG had not failed the EDG provided power would have not been enough for the condenser to operate correctly.

In this case what would have been done to prevent meltdown ?
I can only think of external, out of loop, water injection and repeated venting.
In other words in such designs assuming grid connection fail, but EDG do not fail, what is the expected release to the environment ?
It would seem to me that in such cases at least a TMI2 pattern if not probably much more could be expected (may be something in a INES 5, or even INES 6 if grid connection takes several days to restore, classification range ?).

Not that reinsuring to say the least... one would wonder what could happen in different designs, like PWRs for example..

but for that I guess would be better to open different threads.

 

[rmattila]

Now if the statement is correct, and I am not extrapolating erroneously, that seems to suggest to me that EVEN IF the EDG had not failed the EDG provided power would have not been enough for the condenser to operate correctly.

That's right; the large seawater pumps supplying cooling water to the condensers are too large to be run with the EDGs. Therefore, for the situations where the normal heat transfer route is lost due to loss of external power, the plant is equipped with auxiliary/emergency cooling systems - so called safety systems.

These systems supply water to the reactor, which is converted to steam and directed to the containment suppression chamber/condensation pool (instead of the condenser). The heat is supposed to be transferred from the condensation pool to the sea via dedicated heat transfer systems which are small enough to be run with the EDG power. This is quite usual operation mode of the BWR plants whenever the large seawater pumps stop for some reason. The problem at Fukushima was the loss of these safety systems designed to run when the systems for normal operation are not used - not the loss of the normal operation systems, which is just an operational occurrence - supposed to take place once a year or so.

 

[Luca Bevil]

That's right; the large seawater pumps supplying cooling water to the condensers are too large to be run with the EDGs. Therefore, for the situations where the normal heat transfer route is lost due to loss of external power, the plant is equipped with auxiliary/emergency cooling systems - so called safety systems.

These systems supply water to the reactor, which is converted to steam and directed to the containment suppression chamber/condensation pool (instead of the condenser). The heat is supposed to be transferred from the condensation pool to the sea via dedicated heat transfer systems which are small enough to be run with the EDG power. This is quite usual operation mode of the BWR plants whenever the large seawater pumps stop for some reason. The problem at Fukushima was the loss of these safety systems designed to run when the systems for normal operation are used - not the loss of the normal operation systems, which is just an operational occurrence - supposed to take place once a year or so.

Thanks.
That would be Residual Heat Removal System - Suppression Pool Cooling Function I suppose.

I see.
While reading a BWR manual on line - I incorrectly assumed that these functions would use subsystems or sections of the heat exchanger in the condenser and hence got alarmed when reading that the condenser to be operated needs low pressure to be maintened on its outlet on the primary side.

 

[NUCENG]

I'm not criticizing Tepco attempts to put "something" in place, of course. I'm criticizing Tepco attempts to put in place these kind of last resort solutions NOW, in the current situation where prototype process has no time to be prototype.

The total imprepareness for managing that kind of situation is softly covered by the generic term "Beyond design basis accident and expectations". Let me tell you that anger, distress, fear and current or future suffering of people is "beyond design basis human acceptation" also.

The problem is that when things are considered as "impossible to happen", nothing is done to anticipate the consequences, and this water treatment story started a few days before overflowing of contaminated water is a typical example. This is the all story of this Fukushima disaster in fact: Fukushima is an impossible accident, but consequences are real.

I'm a little bit fed up with that kind of rhetoric in which some consider accidents impossible but THEN very easily present as "possible" what are in fact very improbable solutions to (try to) manage consequences of these "impossible" accidents!

I think they just screwed up in the way they placed the word "impossible", in fact. But this is a critical and even criminal mistake, at least IMHO.

But this leads to one real technical question to specialists: does it ever exists in production in the world a system to separate so much contamination at a such rate of 1200 tons per day (even letting aside the question: can it be installed and started up in 2 months which is the "cherry on the cake", as we say in french?)

If this exists, then I will admit that my comments above are biased or even wrong.

If not, then I will tend to think that they are just biased... by facts?

OK, I.m still trying. Are you suggesting that this type of recovery system should have been prototype tested and standardized before the accident? That is a valid idea, but since that didn't happen, we are seeing the prototype go through its birthing pains in an actual emergency.

 

[intric8]

1 of 24 cartridges reached capacity within 5 hours time. Given the volume of water and Cs content therein, we can speculate that under normal operations, after every 5-10 hours an additional cartridge would max out and require manual removal.

Let's face facts - this water cleansing operation will prove notoriously expensive not only monetarily, but in precious time and cumulative exposures to staff, especially if each cartridge is removed manually.

I think this was a bit unanticipated by tepco, and that the areva staff are getting an earful right about now. Areva was provided the appropriate data and indicated that each cartridge would be http://www.google.com/hostednews/ap/article/ALeqM5jlXd5_F1goJBmZByasNwAiP6EoRA?docId=d223ba8d656345f2972d68b492c83187" .

 

[ManuBZH]

I think this was a bit unanticipated by tepco, and that the areva staff are getting an earful right about now. Areva was provided the appropriate data and indicated that each cartridge would be http://www.google.com/hostednews/ap/article/ALeqM5jlXd5_F1goJBmZByasNwAiP6EoRA?docId=d223ba8d656345f2972d68b492c83187" .

Well, in this case, it is Kurion's system (cesium absorption) which is not working as expected. Not Areva's water decontamination one (yet?).

 

[joewein]

Let's face facts - this water cleansing operation will prove notoriously expensive not only monetarily, but in precious time and cumulative exposures to staff, especially if each cartridge is removed manually.

I recall recently seeing an interview with someone from Areva in which they were introducing the treatment system and explained that it was being provided at a fixed price, as they were not going to take advantage of TEPCOs troubles to make a great profit.

If indeed all cartridges were included then -- ignoring the practical problems involved in frequently swapping cartridges for the moment -- Areva would have a problem. Kurion would make money in the short term if they sell more cartridges to Areva, but it would be bad for their business relationship if the cartridges don't last as advertised.

Ultimately none of the three companies will be happy if the solution sold to the public doesn't work.

 

[swl]

Well, in this case, it is Kurion's system (cesium absorption) which is not working as expected. Not Areva's water decontamination one (yet?).

[STRIKE]"The (TEPCO) official said teams working at the plant believed the radiation rise could be linked either to sludge flowing into the machinery absorbing caesium or a monitoring error caused by nearby pipes carrying contaminated water."[/STRIKE]

Bold text highlighted by me.

[STRIKE]http://ibnlive.in.com/news/radiation-spike-halts-work-at-japan-nplant/160610-2.html[/STRIKE]

Please see following post by Tsuji san.

 

[tsutsuji]

Or walked into a greenhouse in the middle of Summer to water the plants.

For reference, the yield strength of polyethylene is about 4,000 psi or about 25 MPa. About 1/3 that of copper (at 70 MPa).

So, a 1 mm square string could support ~2.5 kg. Or a 25 mm x 1 mm strip could support ~62.5 kg.

We will wait and see, but I am optimistic that it isn't in tatters by this time next year.

The cover is not made of polyethylene, but of polyesther fabric coated with PVC (polyvinyl chloride), like truck covers or tarpaulins : http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110614e17.pdf

They are using 40mil poly pond liner (40mil = 1mm).

Where did you find the 1 mm thickness data ?

I haven't examined the design yet , but it would seem logical to suppose that there would be a multitude of cartridges to absorb and replace.

The news makes it look like one of the cartridges is experiencing a buildup , perhaps due to an uneven distribution of contaminated water.

They would have to look at ways to regulate the parallel flow and processing.

Either that or the level of contamination is much higher than expected , or the filter is doing a better job than anticipated

The absorption facility is divided into 4 parallel lines (see the figures on http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_110612_01-e.pdf and http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_110617_04-e.pdf ). Yesterday they started only two. And both of them are having the unexpected high radiation trouble. 4.7 mSv/h was measured on line No. 1 and 3.9 mSV/h on line No. 3. (No.2 and No.4 were unused).

The absorption towers displaying these radiation levels are the oil and technetium removing towers, at the entrance of the system. Three possibilities were mentioned during the NISA's press conference on June 18th ( http://www.ustream.tv/recorded/15456089 ) :

* To do without the oil and technetium absorption tower (starting directly with the cesium removal towers) ;
* Use of silica sand to filter oil
* Changing the location of the radiation sensor

The first two will be tested on June 18th and 19th, using different solutions on each line and making comparisons.

If my understanding is correct, most of the oil is removed by the Toshiba oil separator mentioned in http://mdn.mainichi.jp/mdnnews/news/20110616p2a00m0na013000c.html before the water enters the Kurion-made facility. There is hardly any technetium in the water so there is no harm in bypassing the oil and technetium removal tower.

Flushing with clean water had been started, and the radiation level had decreased to around 1 mSv/h at the time of the press conference.

OK, I.m still trying. Are you suggesting that this type of recovery system should have been prototype tested and standardized before the accident? That is a valid idea, but since that didn't happen, we are seeing the prototype go through its birthing pains in an actual emergency.

Having to design a solution from scratch is not unlike the various attempts to plug and pump the Deepwater Horizon oil spill. However, the water purifying facility is not totally made from scratch, because the Kurion-made part is "an improved version of the reputable TMI water treatment", and the Areva-made part "has a track record at the reprocessing plant at La Hague" : http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110609e8.pdf

"The (TEPCO) official said teams working at the plant believed the radiation rise could be linked either to sludge flowing into the machinery absorbing caesium or a monitoring error caused by nearby pipes carrying contaminated water."

Bold text highlighted by me.

http://ibnlive.in.com/news/radiation-spike-halts-work-at-japan-nplant/160610-2.html

What was said in the press conference is the possibility that radioactive particles may combine with oil to form something similar to "salad dressing".

 

[etudiant]

We have, according to NISA, the bulk of the contamination onsite in the water. many terabequerels worth. The treatment will hopefully move this to the filters and the processing sludge, leaving (fairly) clean water.
The plan is to exchange the cartridges when the ambient radioactivity exceeds 4 millisievert, which has happened very quickly, unsurprising given the extent of the water contamination. Yet the stated expectation was that this level would only be reached after a month.
So the problem is why did anyone expect the filters to last so long if the water is so dirty?
Afaik, the bulk of the contamination is from the cesium and the Kurion filters are designed to pick up the cesium, which they appear to be doing. So the problem is that because the filters cannot be changed out automatically, they can only serve for a brief period before they must be changed, lest they become too contaminated for humans to handle.
This seems like a design flaw. What am I missing?

 

[Astronuc]

We have, according to NISA, the bulk of the contamination onsite in the water. many terabequerels worth. The treatment will hopefully move this to the filters and the processing sludge, leaving (fairly) clean water.
The plan is to exchange the cartridges when the ambient radioactivity exceeds 4 millisievert, which has happened very quickly, unsurprising given the extent of the water contamination. Yet the stated expectation was that this level would only be reached after a month.
So the problem is why did anyone expect the filters to last so long if the water is so dirty?
Afaik, the bulk of the contamination is from the cesium and the Kurion filters are designed to pick up the cesium, which they appear to be doing. So the problem is that because the filters cannot be changed out automatically, they can only serve for a brief period before they must be changed, lest they become too contaminated for humans to handle.
This seems like a design flaw. What am I missing?

It could be that the filters worked very efficiently, or it could be a matter of communication or rather miscommunication. Is it perhaps the water is more highly contaminated, or is it perhaps that the water chemistry is such that the collection of the intended radioisotope(s) was much more efficient than expected. If the collection reached a limit in hours instead of weeks, then that's two orders of magnitude difference in collection rate. So one must ask, is the concentration of radioisotope(s) so high, or so specific (i.e., not so many different metal ions (each with a different decay constant) competing for the same amount of absorber), or . . . ?

If a filter is too hot to manually handle, then obviously it must be handled remotely, just as with any radioactive source or object. Normally enriched fuel is handled with thin gloves, while MOX fuel is handled remotely, often in glove boxes (with heavier gloves) if an individual must do 'hands on' work.

 

[elektrownik]

Someone here computed that in basements of reactors and turbine buildings contain 1/2 of Chernobyl core (amount of cesium and iodine), so yes there is change problem but also there would be thousands of radioactive filters to store somewhere...

 

[Astronuc]

OK, I.m still trying. Are you suggesting that this type of recovery system should have been prototype tested and standardized before the accident? That is a valid idea, but since that didn't happen, we are seeing the prototype go through its birthing pains in an actual emergency.

Adding to NUCENG's comment - I believe the water treatment system is based on current AREVA technology used in their waste treatment streams either in their reprocessing plants or remediation programs. What we don't know is what access AREVA has had to the TEPCO site, or what information has been provided by TEPCO to AREVA concerning the contaminated water.

 

[Luca Bevil]

Given the Tsutsuji post just added, it would seem that the first (oil+technetium removal) stage was uncorectly designed/dimensioned and picks up too much radioactive material.

I am hoping it can be skipped and/or fixed in a few days.

It is now critical to have that kind of recirculation in place before contaminated water inventory becomes unmanageable, with sore consequences.

 

[etudiant]

Quoting from tsutsuji's informative and comprehensive post: ' said in the press conference is the possibility that radioactive particles may combine with oil to form something similar to "salad dressing" '.

What this makes clear is that nothing about this cleanup is easy.
The removed oil will apparently be intensely contaminated, so that facility too will generate a serious waste stream.
In effect, the processes only buy time and hopefully allow the plant to get pumped out, with the radioactivity moved to a mountain of contaminated cartridges, spent co-precipitation agent and perhaps waste oil.

 

[clancy688]

Someone here computed that in basements of reactors and turbine buildings contain 1/2 of Chernobyl core (amount of cesium and iodine), so yes there is change problem but also there would be thousands of radioactive filters to store somewhere...

That someone would be me.

According to http://www.tepco.co.jp/cc/press/betu11_j/images/110603a.pdf" TEPCO pdf, there's ~140 PBq C137 and C134 each and ~430 PBq I131 flowing around in all basements.
I wouldn't trust the iodine numbers, since they added up measurements which lie one month (=four half times) apart, but the Cesium should be correct...

 

[SteveElbows]

Any real news on what is happening at Fukushima?

I don't know what news you are expecting, but I think its quite possible that you will remain frustrated for a long time. It is always possible that a major new event may happen, but we can see now that months can pass without anything drastic happening. They may learn something new & important about the state of one or more reactors, but don't hold your breath waiting for this, it could take years.

I was hoping I may learn something from TEPCOs report on the first 5 days of the disaster, which NHK mentioned a few days ago. Well I've seen Japanese version of this, and computer translated bits of it, and I struggle to see what new information it contains. It does not seem to add much to the picture we already had, although I have to wait for proper translation to be sure. ( http://www.tepco.co.jp/en/press/corp-com/release/11061805-e.html )

Next week there is IAEA conference, where we might learn a few new details, but there is every chance we won't learn much from this either, since we already saw reports that were sent to IAEA about what TEPCO and NISA etc think happened.

Given that we already know that very bad things happened, I am not really sure why some people are expecting some smoking gun evidence to emerge, or have felings that massive new events must be happening that are getting covered up. Certainly there are many questions, and I expect more answers at some point, but our impatience does not tell us anything, and I haven't seen any radiation monitoring data that makes me think anything noteworthy has happened in recent weeks. Sometimes there is weak evidence that something may have happened, but so far good evidence never comes along to back it up, so I assume its just people clutching at straws in a desperate bid to find something new.

 

[NUCENG]

It is a bit more difficult.



Yes, corrective measures must be taken in a specified timeframe.
But, what are "corrective measures"?
http://pbadupws.nrc.gov/docs/ML0536/ML053620142.pdf" gives some definitions.

One of the "corrective measures" specified there is that the nuclear operator company has three years to make a statement that this problem is no safety risk.
Bingo, safety restored!

And most times the regulatory authority will not be able to check if that statement is correct.
One of the reasons is that the NRC is way understaffed to be able to perform its control duties. (Thanks to NUCENG for pointing this out!)

So it can take decades to have safety problems corrected.

They just make sure the problem is "being addressed" in a bureaucratically correct manner.
And, so it all is in order, no need to complain...

For example, there are reports stating that still about a dozen NPPs in USA have that old highly-flammable insulation used in Browns Ferry.
The operators state that this is safe and just use smoke generators instead of candles when checking insulation tightness.

And the NRC just has no time / manpower to check this and demand some real remedial action.

This bureaucracy phenomenon is well-known in other countries also.
So safety upgrades are often being installed in a "reasonable" timeframe of up to almost two decades, if at all.


This problem is well-known for long time, probably some decades.
It will be addressed by the nuclear industry in reasonable time, whatever this means. (see above)

Corrective Actions are actions to bring the condition into compliance plus actions to address the extent of condition (fix it all not just the current example) plus measures to prevent recurrence.

Compensatory measures may be taken in the interim while corrective actions are being performed. Compensatory measures for fire protection might be to station a fire watch in an area until the condition is corrected.

We are talking about enforcement discretion for a condition believed to be a violation of regulatory requirements. If a company sits on its hands for three years and then declares it not required, that violation still needs to be closed out by the regulators. You seem to pick that option out of context to insinuate that is all that will be done. If NRC believes the licensee is deliberately stalling corrective actions, they can whthdraw enforcement discretion or apply enforcement action for violations of requirements for prompt and effective corrective action programs. So BINGO right back at ya.

"And most times the regulatory authority will not be able to check if that statement is correct." Opinion based on nothing.

Your comment about under staffing is interesting. Are you trying to imply that the nuclear industry is making staffing decisions? Could you please cite your sources? Neither the President not the Congress can make a budget, and the threats of government shutdowns and defaults make long-term planning challenging. That is politics and a failure in leadership. THat is why the NRC staff requested the extension - so they can give adequate review to ensure plant safety.

Similarly the fact that fire protection is still an open sore is as much the fault of NRC as the industry. Internal disagreements within NRC are sometimes as close to warfare as this thread. And before you jump to conclusions, these battles are the engineers dilemna: "Better is the enemy of good enough."

And in spite of all my criticisms at the end of the day this flawed system still has established a record of continuous improvement in safety, reliability and production without building new plants and that record isn't threatened by your unsupported claims and opinions. There have been over 3500 US reactor years since the Browns Ferry Fire and we are still seeking ways to improve on that.

 

[Orcas George]

Where did you find the 1 mm thickness data ?

In the linked video; the wording was "approximately 1mm", also in other reports. This was from the guy doing the presentation; later on he said "I'm told it is really thick." This is in the English translation of the audio, so caveat emptor.

The absorption towers displaying these radiation levels are the oil and technetium removing towers, at the entrance of the system. Three possibilities were mentioned during the NISA's press conference on June 18th ( http://www.ustream.tv/recorded/15456089 ) :

* To do without the oil and technetium absorption tower (starting directly with the cesium removal towers) ;
* Use of silica sand to filter oil
* Changing the location of the radiation sensor

Call my cynical but I think I know where this story is heading...

If my understanding is correct, most of the oil is removed by the Toshiba oil separator mentioned in http://mdn.mainichi.jp/mdnnews/news/20110616p2a00m0na013000c.html before the water enters the Kurion-made facility. There is hardly any technetium in the water so there is no harm in bypassing the oil and technetium removal tower

This is something that I almost know a little about (I use a RO system to desalaniate seawater which is one reason I'm concerned about all the radiation dumped into the Pacific.) We have a really tricky engineering problem here. They need a very efficient oil separator before Areva's reverse osmosis system or they will destroy the membrane. The percentage of oil allowed in has to be very close to zero at these volumes. I don't imagine that oil and Zeolite interact well together. They must not remove the oil separator tower from the system. They do not have time to clean a water treatment system of radioactive oil.

 

[mrcurious]

Tepco did not fail to anticipate current circumstances, they failed to implement. Safety standards for the current crisis were rejected in favor of a less severe tsunami projection. Your anger at them not being prepared is noted but to use an American phrase, that horse has left the barn.

Last resort solutions are all that are available to them at this point. Judgement might be better directed on how effective they implement not why they are necessary, which is a question for post crisis analysis where answers can be more complete.

 

[Luca Bevil]

I don't know what news you are expecting, but I think its quite possible that you will remain frustrated for a long time. It is always possible that a major new event may happen, but we can see now that months can pass without anything drastic happening. They may learn something new & important about the state of one or more reactors, but don't hold your breath waiting for this, it could take years.

I was hoping I may learn something from TEPCOs report on the first 5 days of the disaster, which NHK mentioned a few days ago. Well I've seen Japanese version of this, and computer translated bits of it, and I struggle to see what new information it contains. It does not seem to add much to the picture we already had, although I have to wait for proper translation to be sure. ( http://www.tepco.co.jp/en/press/corp-com/release/11061805-e.html )

Next week there is IAEA conference, where we might learn a few new details, but there is every chance we won't learn much from this either, since we already saw reports that were sent to IAEA about what TEPCO and NISA etc think happened.

Given that we already know that very bad things happened, I am not really sure why some people are expecting some smoking gun evidence to emerge, or have felings that massive new events must be happening that are getting covered up. Certainly there are many questions, and I expect more answers at some point, but our impatience does not tell us anything, and I haven't seen any radiation monitoring data that makes me think anything noteworthy has happened in recent weeks. Sometimes there is weak evidence that something may have happened, but so far good evidence never comes along to back it up, so I assume its just people clutching at straws in a desperate bid to find something new.

Hi Steve for me critical are now news (hopefully good news) about the working of the water processing plant.

It does not seem to be flowing smoothly (to say the least) I do not see much of contingency backup planning, other than saying that the plant has to work, and overspilling of highly radioactive water would be definitely a drammatic problem.

 

[Orcas George]

It does not seem to be flowing smoothly (to say the least) I do not see much of contingency backup planning, other than saying that the plant has to work, and overspilling of highly radioactive water would be definitely a drammatic problem.

The contingency is to dump the water into the Pacific, which is terrible but not much different than what has been (and may still be) going on. It would be a big step backwards but better than flooding the plant grounds and making everything inaccessable.

They have been working on turning the harbor into an ersatz storage pool so they must have that in the back of their minds as well.

The goal at this point is to avoid irreversable steps. I'm pretty sure that they will be able to get some form of treatment working if they keep their cool; it probably will not work as well as advertised but may be "good enough".

Let's say that I am not as enamored of the nuclear power option as I used to be...

 

[Luca Bevil]

The contingency is to dump the water into the Pacific, which is terrible but not much different than what has been (and may still be) going on. It would be a big step backwards but better than flooding the plant grounds and making everything inaccessable.

They have been working on turning the harbor into an ersatz storage pool so they must have that in the back of their minds as well.

The goal at this point is to avoid irreversable steps. I'm pretty sure that they will be able to get some form of treatment working if they keep their cool; it probably will not work as well as advertised but may be "good enough".

Let's say that I am not as enamored of the nuclear power option as I used to be...

Well I for one never was... :-)

that personal opinion apart, discharging radioactive water into the Pacific is not feasible, Corea and China would be raising too harsh protests, maybe if nothing else proves possible they will try with the megafloat as a temporary storage...

it could may be fail later on, but an accident will be in any case more tolerable than a deliberate act...

probably building another more stable facility would have been a safer and more stable option than makeshift containers...

do you think they ruled that out till now because of costs or because of time constraints ?

 

[robinson]

What is the date for water to start going into the ocean? If they can't fix the problem?

 

[Luca Bevil]

http://www3.nhk.or.jp/daily/english/18_18.html

TEPCO says the contaminated water could overflow from storage facilities in about one week, unless the system resumes operating.

TEPCO says depending on the cause of the problem, it may slow the decontamination process from the originally-planned 1,200 tons per day.

Saturday, June 18, 2011 22:12 +0900 (JST)

Time is running short... desperately so

 

[Quim]

The contingency is to dump the water into the Pacific, which is terrible but not much different than what has been (and may still be) going on. It would be a big step backwards but better than flooding the plant grounds and making everything inaccessable.

IMO it would be better to flood the Fukushima site and have the Japanese pay the cost of their series of blunders, rather than trashing the Pacific.

There seems to be more than a little insensitivity to the consequences of dumping large amounts of radioactive contaminants into the Pacific.

Case in point:

And no, I don't care about the whales glowing in the dark. They can use a break from Japanese "marine biology research" anyway.

This is no trivial matter and it is certainly no joking matter, and you, the guys of the industry had better get out front on this or you are sealing the doom for the NPP industry.

Zapperzero's post has been gnawing on me ever since I first read it, but I am trying to avoid contentious issues so I hoped somebody else would challenge that "joke."

If TEPCO starts dumping quantities of radioactive waste into the Pacific it is likely to generate more ill will towards your industry than some of you seem able to imagine.

And I for one, don't see one iota of difference between dumping it in the harbor or the open ocean. If they can't clean up the water they have how are they going to clean up that amount of water? The answer is that they won't. They will try to let the publicity die down and they will issue confusing press releases and generally spew fog. In the meantime the harbor waters will be finding paths to the open ocean for the next 150 years (five half lives of cesium.)

 

[Borek]

IMO it would be better to flood the Fukushima site and have the Japanese pay the cost of their series of blunders

Care to elaborate? "Fukushima site" is already flooded - water filled up every basement, there is no other place at "Fukushima site" that could hold water. It will soon start to leak to the Pacific, so what you wrote doesn't make sense to me.

 

[Quim]

Care to elaborate? "Fukushima site" is already flooded - water filled up every basement, there is no other place at "Fukushima site" that could hold water. It will soon start to leak to the Pacific, so what you wrote doesn't make sense to me.

Were they to bring in Earth moving equipment they could in a few days time create a gully surrounded by a berm lined with something to reduce the leakage into the ground.

That would be the short term emergency action needed.
Then they could work on a mid term solution.
Then they could work on a long term solution.

 

[ManuBZH]

If it was so trivial to make a big water-proof hole, they would have obviously done it.
As it takes weeks to make simple water/radiation-proof storage tanks, I highly doubt that's an easy task at all...

 

[zapperzero]

If it was so trivial to make a big water-proof hole, they would have obviously done it.
As it takes weeks to make simple water/radiation-proof storage tanks, I highly doubt that's an easy task at all...

Obviously nothing. It really is trivial. Dig, drop in pre-assembled metal section, weld to previous section, pour some concrete, cover with dirt, rinse, repeat. Three months of doing this would have produced quite a big water-proof hole.

It does not "take weeks to make simple water/radiation proof storage tanks". It's irrelevant either way. The tanks installed on-site have been bought from inventory, not manufactured since the accident.

That being said, I understand why TEPCO would want to solve the issue and start recirculating water and so I understand why they have chosen to expend effort in other ways.

EDIT: if you wanted to go all Russian about it, you could even "store" it in an open trench somewhere.
http://en.wikipedia.org/wiki/Lake_Karachay

 

[MJRacer]

(snip)
This is something that I almost know a little about (I use a RO system to desalinate seawater which is one reason I'm concerned about all the radiation dumped into the Pacific.) We have a really tricky engineering problem here. They need a very efficient oil separator before Areva's reverse osmosis system or they will destroy the membrane. The percentage of oil allowed in has to be very close to zero at these volumes. I don't imagine that oil and Zeolite interact well together. They must not remove the oil separator tower from the system. They do not have time to clean a water treatment system of radioactive oil.

I would agree. Oil would foul both the ion-exchange towers and the RO membranes. By bypassing parts of the system, they risk rendering the entire system non-functional. I have seen that happen in a municipal water treatment facility, where there was an accumulation of errors followed by attempts to "fix" them by bypassing parts of the treatment. The result was great damage to the system with markedly reduced treatment effectiveness.

One of the things that puzzles me is why they have the ion-exchange towers ahead of the flocculation (they call it co-precipitation). All the water treatment systems I am familiar with (the ones I operated, the ones I helped design and those operated and designed by others that I became familiar with) always had the flocculation step before sand filters, carbon filters, ion-exchange or RO. The reason for this is that it reduces fouling of the downstream processes. The term "salad dressing" I would interpret as the formation of an emulsion of oil with hot particles. I would use flocculation followed by filtration before the ion-exchange step. The problem is that flocculation would create a floc bed that would probably become highly radioactive and so would create operating difficulties. Second, filtration of the floc with sand or anthracite filters (which are normally periodically back-washed) would be impractical when treating radioactively contaminated water. The filter beds would become hot and back-washing would create more highly concentrated water that would, in turn, then have to be treated again.

Unfortunately, the filtration step is an essential component of flocculation. There is no point to flocculation, unless one filters the effluent from the flocculation step. Filtration by disposable membrane or DE might be an alternative, but installing that capacity at Fukushima would take some time. However, dealing with the emulsion otherwise is not going to be easy and bypassing the oil separation towers is risky. Although I have compared flocculation with the co-precipitation step, as a caveat I want to say that they might not, in fact, be equivalent. In other words, doing the co-precipitation step before the ion-exchange may not be an option. Unfortunately, the amount of detailed information that has been released about the co-precipitation step is small. It is hard for me to tell exactly what they are doing in that step.

In summary, it would appear to me that they are throwing the proverbial "kitchen sink" at the problem. They appear to be using every means of treating water that is available, but, in general terms, the technology being used is fairly standard. What is special about the various steps is in the details. The only water treatment technology that seems to be missing is a flocculation followed by filtration step after oil separation and before ion-exchange, assuming that the co-precipitation step is significantly different that it would not be technically recommended to simply do that step before ion-exchange.

 

[Atomfritz]

If it was so trivial to make a big water-proof hole, they would have obviously done it.
As it takes weeks to make simple water/radiation-proof storage tanks, I highly doubt that's an easy task at all...

I doubt the local geology will allow for the installation of a second "Lake Karachay"...
(After Mayak stopped ducting its effluents into Techa River because of high Ob River contamination they used a local lake, Karachay, as nuclear effluent dump.
At the boundary of the lake the radiation is about 600 Roentgens/hr.)

P.S.L I see Zapperzero had the same thought about the same time...

Surprise: I am not linked to any industry, I am not working for any industry. And I find your accusations mildly insulting.

I also don't know how Quim comes to thinking that Borek is a nuclear industry professional.
He appears just to be neutral for me.
But, I prefer green hair. It just looks better. :)

 

[zapperzero]

The only water treatment technology that seems to be missing is a flocculation followed by filtration step after oil separation and before ion-exchange, assuming that the co-precipitation step is significantly different that it would not be technically recommended to simply do that step before ion-exchange.

Co-precipitation is just what it says on the tin - salts are formed and precipitated out of solution, in the hopes that the radioactive alkali will precipitate along with the normal ones. Not something you need to do with regular water .

I have wondered myself why no flocculation - perhaps they don't expect to see fine particulates or heavy metals in significant quantities? I understand those are the main targets for flocculation?

 

[zapperzero]

I doubt the local geology will allow for the installation of a second "Lake Karachay"...

It's awful to think about, but they already have a lake nearby. They are drawing water from it to cool the reactors, in fact. It would be possible, I'm afraid, to dump it back in. There's no emoticon for horror, or I would have used it :P. Although I'm not sure polluting the ocean is the better alternative.

 

[ManuBZH]

It's awful to think about, but they already have a lake nearby. They are drawing water from it to cool the reactors, in fact. It would be possible, I'm afraid, to dump it back in. There's no emoticon for horror, or I would have used it :P. Although I'm not sure polluting the ocean is the better alternative.

To be precise, they are taking water from Sakagarbagea dam, here:
http://metalwings05.fc2web.com/dam/07_fukushima/sakagarbagea/index.html

 

[MiceAndMen]

Adding to NUCENG's comment - I believe the water treatment system is based on current AREVA technology used in their waste treatment streams either in their reprocessing plants or remediation programs. What we don't know is what access AREVA has had to the TEPCO site, or what information has been provided by TEPCO to AREVA concerning the contaminated water.

No, we do know this. From AREVA themselves:

For three weeks, AREVA has sent radioactive effluent treatment specialists to Japan to participate in work groups with Tepco. Backed by large teams in France, Germany and the United States, they proposed a method based on a co-precipitation concept.

http://us.arevablog.com/2011/04/19/...contamination-process-for-the-fukushima-site/

They had hands-on access to the site for 3 weeks prior to making their proposal.

 

[MJRacer]

Co-precipitation is just what it says on the tin - salts are formed and precipitated out of solution, in the hopes that the radioactive alkali will precipitate along with the normal ones. Not something you need to do with regular water .

I have wondered myself why no flocculation - perhaps they don't expect to see fine particulates or heavy metals in significant quantities? I understand those are the main targets for flocculation?

On co-precipitation, I would assume that the process shares some similarities chemically with flocculation. Some equate flocculation with coagulation/precipitation, while others distinguish between coagulation and flocculation. It can get to be very technical and, in my experience, has a lot of trial and error aspects to it (hence jar tests). In that regard, flocculation may interfere with their co-precipitation and/or the co-precipitation would be too specific to do before ion-exchange as it is not intended to remove oil emulsions. On flocculation, you are right that particulates and heavy metals are removed by it, but flocculation can be a pretty broadband treatment method. It is very effective and fairly cheap per liter, so it is also very cost effective. It makes the job of subsequent more expensive treatment methods more effective and cheaper (by reducing fouling). A further thought is that the "salad dressing" may be partially the result of the oil separation step using air flotation. In short, this is a mess that is compounded by lack of time and sheer scale.

 

[MiceAndMen]

In Japan, Germany etc there are many discussions about this interesting phenomenon of fraternalization of the nuke industry and the authorities.
People work for one side, then change their side at early retirement.
There is much money at work to which motivates people working at the regulatory to be "cooperative".
If they cooperate well they might be thanked with a well-paid leisure job.
They get much money without really have to work.
They just have to do lobby working at their former colleagues in the regulatory authority.
So these know well: "Cooperate and you'll have good income without having to work later.

This has been happening in Japan and the US as well. In the US it is known as the "revolving door", and people rotate between private industry and the agencies that are supposed to regulate them. One does not regulate too strongly lest he make enemies that would preclude a nice paycheck in the future.

To be fair, it is not just a problem in the nuclear power industry. It also exists in the financial industry where "regulatory capture" is pervasive and results in watered-down regulation at best and policy disaster at worst.

The problem exists in just about every industry where lobbyists ply their trade.