Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[Orcas George]

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.

I agree that trashing the Pacific is a very serious matter and that the media and industry are too nonchalant about it. I live on an island, my wife trained as a marine biologist, I understand bioaccumulation better than the media ("oh, the sea is so big!)", and will contend that the scope of this disaster to the ocean is far more severe with long term consequences to a wide range of species -- including humans -- from the contamination of the ocean alone. At the risk of getting too political, this incident proves to me that nuclear power is not a solution to other very serious environmental and resource issues that we face. Imagine the consequences if this had happened to one of the reactors on Lake Erie or on top of the Ogallala Aquifier. We can live without electricity, we can't live without safe water and we are seeing how difficult it is to get radiation out of water.

Now for the "however."

First off, the people should not be punished for anything. If the Indian Point reactor went south on us I wouldn't be in favor of dumping the waste on the streets of New York just because New Yorkers happen to be citizens of the country that built the reactor. I don't even think that TEPCO officials should be punished; the problem is with the design and not the people. I have not seen any evidence that this incident is anything other than what you expect to happen when a nuclear plant melts down (or "partially melts down" or "has an oopsie" or whatever the politically correct term is.)

But, back to technical issues, the conseqences of flooding the plant grounds are that it will become nearly impossible to mitigate this problem. We have to get the rods in the spent fuel pools into safe, long term storage and that won't happen if the grounds are contaminated with the highly radioactive stuff they are trying to deal with. We can't just hope that there are no large aftershocks for the next 30 years, or that a roofless building that exploded will be able to handle typhoon-force winds.

So it is not even a matter of trade offs; but if push comes to shove the choice that leaves us with any options at all is to dump it into the sea. I hope there are options before that, like "load up a supertanker" but eventually that probably means "radioactive supertanker at the bottom of the sea." If we let the grounds flood and have to abandon the plant it will all go to the sea anyway.

But again, it is a horrible choice. Nobody really wants to think about what has already happened; when they pick up heavily contaminated seawater 30 kilometers from the plant site you are in a place that we should never have had the slightest odds of getting to. (IAEA report March 24).

It is true that it is difficult to discuss such choices. It is like deciding to amputate somebody's leg after a screw up in the hospital has sickened them. You need to discuss the option without forgetting how horrible the consequences are for the person and absolving the hospital from blame.

 

[NUCENG]

I remember only one action of this kind where NRC ordered a plant to shut down.
It was when a whistleblower revealed that the operators in the control room were sleeping, playing video games etc, but not caring for the reactor.

N: Obviously you haven't done your homework.

You read this between the lines.

N: Now there's a great citation. Clearly that carries the argument.

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."

N: So Japan and Germany have a problem. And yet you hold up Chairman Jaczko as a hero. How did he get there?

In fact, I doubt that it is always for this reason.
In fact, the comments of some Commissioners regarding the extension of the discretion period from three to eight years remind me of a typical soviet style communist party sycophancy.

N: No evidence, no sense, but call it a communist plot. That always works.

As most national nuclear laws around the world are similar to the masterprint of the american system, I suspect it is like here in Germany.

N: Suspicion, another great source citation.

In the wake of the final shutdown of many German reactors it came at light that thousands of safety improvements etc, not only regarding flammable insulation foam, have been delayed by reactor operators for up to 17 years after having been ordered by the authorities.

N: Proving a Geman problem, if it is even true.

Just an example, the Brunsbüttel BWR at the Northern Sea.
It has been offline for some years now.
There had been a hydrogen explosion ripping open some tubes of the primary circuit and spraying radioactive steam.
But the reactor operator didn't consider this an important thing and insisted to operate the reactor until next planned shutdown about half a year later while just letting the leaking water flow into the sump (wetwell).

The nuclear authorities had to battle for three months until, with the help of the federal government, they finally got the reactor operator company agree to shut down the reactor.

In the aftermath of this accident it was revealed that this accident easily could have mutated into an uncontrollable LOCA if some piping cracked by the explosion would have severed the main cooling water circuit.

But the real reason why the authority was unable to allow to restarting the plant was the public pressure in sight of the fact that the NPP piled up more than 400 unremedied violations in a dozen years.

N: And that applies to a US plant how? What part of prompt and effective corrective action program do you not understand?

Jaczko fruitlessly opposed the extension of the discretion period to eight years.
As there is not always the possibility of enforcement after the end of the discretion period, as Jaczko clearly indicates, there can be easily more than ten years from the finding of a violation to when the NRC can order the plant operators to do something about.

N: Your post belongs on the "Other Political Thread, there is not one citation, not one ounce of anything more than uninformed opinion masquerading as conclusions. Your anti-American ravings are getting tiresome. I have been trying to answer a legitimate question about what the term enforcement discretion. You chime in with nothing but hot air. Go away little boy, you bother me!

 

[Quim]

you could even "store" it in an open trench somewhere.

I find that idea far far preferable to dumping high level radioactive waste into the Pacific Ocean.

 

[Atomfritz]

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

Thank you for the information. This dam is about a dozen kilometers away from the plant.

One or two miles southwest of the reactors there are also a few dams. Northwest, in about 2-3 miles there also is a dam. Maybe agricultural only and not connected to the normal grid.

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.

Dams shouldn't be used for radioactive water/sludge storage, as dams are prone to all possible damages like earthquakes. See the Bellona.org documentation about the Mayak complex and its problems with keeping the radioactive water halfway safe.
The only lake that is probably not a dam and appears possibly large enough to dissipate such quantities of radwaste water is directly at the plant area border.
See this picture:

It could be a very convenient last alternative to pump the water in there before contaminating the ocean.
And it could be implemented very quickly, just laying tubes along the red line.

So this could buy quite some time for mankind to save the oceans.

 

[jim hardy]

thanks to the poster who has reverse osmosis experience. Sorry i forgot to note your name...

that technology does a beautiful job of turning municipal water into ultra-pure boiler grade water, but it seems to me a bit on the sensitive side for handling sludge.

Wouldn't an old fashioned moonshine still scaled up to industrial size capture the oil and sludge and most of the contamination too before handing the water to your equipment ?

Perhaps a line of old fashioned package boilers, say surplus WW2 Liberty Ship power plants, should serve as sacrificial distillation pre-cleaners for your high tech stuff . When you can no longer get close to them pick 'em up with a long crane and cart them away.

old jim

 

[etudiant]

It would be truly stupid to allow the site to be flooded, if only because there are a couple of thousand tons of nuclear fuel in it even apart from the corium in the damaged reactors, thus making the accident that much worse.
It may however become necessary to dump at least some of the water into inadequate storage facilities, whether tanks, megafloats or available oil tankers,, because the treatment facility is late and the facility is one good storm away from overflowing.
That said, I'm puzzled by the Kurion columns. We have close to 300 Petabequerels of cesium in the water, as Clancy688s post above documented. Also, we need to change out the cesium cartridges when their activity exceeds 4 millisieverts, according to the TEPCO conference reported by tsutsuji.

The plan was for about a monthly cartridge change, so only a dozen cartridge sets over the expected 1 year cleanup. If the columns have the claimed effectiveness of cutting cesium to 0.1% of the original level or better, that means that dozen sets will together contain nearly 300PBqs of radioactivity, held in cartridges producing a 4 millisievert radiation level of exposure when briefly handled.
This seems wildly implausible. What am I missing?

 

[MJRacer]

http://www.new.ans.org/pubs/magazines/download/a_726

http://www.businesswire.com/news/ho...ion’s-Ion-Specific-Media-based-materials-Mile

A couple of interesting articles on Kurion's technology. Here are some quotes:

"A key aspect of the ISM (Ion Specific Media) is that they are inorganic as compared with conventional organic media."

"Because of strong molecular bonds, however, isotopes remain captured during thermal treatment, eliminating concerns over volatilization of isotopes such as cesium."

"The company’s development program includes the ability to manufacture its media using patent pending sorbent impregnated porous glass microspheres. As a result, during vitrification the media self-supplies the glass frit required for vitrification, ..."

"Kurion has developed an MVS (Modular Vitrification System) that is simple enough to allow generators to safely perform this process onsite. Granted eight patents, the MVS employs a mechanically passive, first-principles, single-use melter internally integral to the customer’s waste container and achieves high volume reduction ..."

"The self-contained system utilizes nonintrusive inductive energy as its heat source to avoid electrodes, thermocouples, and probes normally associated with vitrification processes and that create secondary wastes along with maintenance, safety, and cost concerns. In addition, because the MVS does not rely on high temperatures to ensure glass conductivity and heating as required of joule-heated melters, it is uniquely capable of utilizing low-temperature glass formations to stay below the volatilization temperatures of off-gassing isotopes such as cesium."

"Aside from a small footprint and negligible off-gas, the MVS has the ability to keep the stainless steel waste canister relatively cool while processing. Kurion’s unique proprietary process keeps the waste canister exterior more than 500°C cooler than does the interior process, plus it doubles as a secondary containment."

 

[MJRacer]

thanks to the poster who has reverse osmosis experience. Sorry i forgot to note your name...

that technology does a beautiful job of turning municipal water into ultra-pure boiler grade water, but it seems to me a bit on the sensitive side for handling sludge.

Wouldn't an old fashioned moonshine still scaled up to industrial size capture the oil and sludge and most of the contamination too before handing the water to your equipment ?

Perhaps a line of old fashioned package boilers, say surplus WW2 Liberty Ship power plants, should serve as sacrificial distillation pre-cleaners for your high tech stuff . When you can no longer get close to them pick 'em up with a long crane and cart them away.

old jim

They are planning on using distillation after RO. They call it vapor condensation. That's why I called it the "kitchen sink" approach (except for flocculation).

See http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110609e8.pdf

 

[GJBRKS]

The plan was for about a monthly cartridge change, so only a dozen cartridge sets over the expected 1 year cleanup. If the columns have the claimed effectiveness of cutting cesium to 0.1% of the original level or better, that means that dozen sets will together contain nearly 300PBqs of radioactivity, held in cartridges producing a 4 millisievert radiation level of exposure when briefly handled.
This seems wildly implausible. What am I missing?

The monthly change was named with regards to the oil separating part ,not the cesium filters

These oil filters are somehow accumulating radioactivity where they are not supposed to ,

but the oil needs to be filtered out to avoid damaging the cesium filters.

There are 4 parallel installed processing lines

 

[Orcas George]

TEPCO says it may have absorbed larger-than-expected amounts of radioactive materials along with oil. The utility is now working on measures to solve the issue.

TEPCO says the effort will require time. In addition, depending on the situation, it may have to reconsider the working of the entire system and examine the effect of radioactivity emitted from nearby pipes.

http://www3.nhk.or.jp/daily/english/19_03.html

They need to not panic; messing around with the system will wreck it. They should call in some other filtration professionals (Parker Racor) and brainstorm. Perhaps a big prefilter unit that they can remotely backflush with several in reserve. These things are sitting in warehouses; if it gets fried just bury it with the other radioactive junk. They won't get the GPH they desire but if they can keep the water level from rising while somebody works out plan 'B' that would be good.

RO systems are very finicky since you are pushing stuff at great pressure through rubber it can easily get plugged up or holed. Oil is fatal. The technology really isn't for handling mixed dirt and sludge and oil. They need to get that stuff out first which is a dilemma because the filter to do that will get the most radioactive stuff in it. However a radioactive filter that you can stack somewhere is probably better than radioactive water.

My diesels have filters that separate water from diesel using centerfuge action plus a hydrophrobic membrane. I would be shocked if they didn't have filters like that in the system somewhere.

They will get it fixed if they keep their cool. On the reverse situation diesels will be instantly wrecked if any water gets into the injectors, so the we have really good technology for separating oil and water and particles. I'm convinced there is a part number that will solve this problem, at least in the short term (they may have to change out a machine every day or so.) The important part for now is to get the water cleaned, if they fill up a junkyard with hot equipment we can yell at them later.

 

[etudiant]

The monthly change was named with regards to the oil separating part ,not the cesium filters

These oil filters are somehow accumulating radioactivity where they are not supposed to ,

but the oil needs to be filtered out to avoid damaging the cesium filters.

There are 4 parallel installed processing lines

Thank you for the extra insight on the filter changes.
The question remains for me, how do they plan to capture 300PBqs of cesium in cartridges that need to be manually changed. The cesium is about a million curies worth, unless I've dropped a decimal somewhere.

 

[clancy688]

The cesium is about a million curies worth, unless I've dropped a decimal somewhere.

You did. It's ten million. ;)

I'd be interested in how many becquerels one filter is supposed to capture until it's changed. Or does anybody know how to convert "4 mS/v" of C134 and C137 at a 1:1 ratio into becquerel?

 

[Atomfritz]

]Wouldn't an old fashioned moonshine still scaled up to industrial size capture the oil and sludge and most of the contamination too before handing the water to your equipment ?

Perhaps a big prefilter unit...

Hmm, could a lake serve as temporary storage, oil and particle separator all-in-one?

Thank you for the extra insight on the filter changes.
The question remains for me, how do they plan to capture 300PBqs of cesium in cartridges that need to be manually changed. The cesium is about a million curies worth, unless I've dropped a decimal somewhere.

I also don't understand this. Formerly in https://www.physicsforums.com/showpost.php?p=3333806&postcount=8633" I calculated the mass of a megacurie Cs-134 as 773 grams and of Cs-137 as 11.55 kg.
So alone the cesium contamination in the water could be in the magnitude of a hundred kilograms up.

By the way, the Kurion steel/glass things appear to be designed to be handled remotely and instantly vitrified after getting satiated.
But I miss any statements that there a vitrification plant is projected.

Irradiation sources containing only milligrams of Cs are being transported in heavy lead shielding.
And there have been several detailed IAEA reports on the dire medical outcomes of people touching or approaching such very small sources unshielded.
Other uncanny reports tell about the fate of workers in the irradiation business.

So this is maybe just a calculation mistake?
It would not be the first one, and worse even would be the fact that Tepco, Areva and the other parties involved all overlooked that mistake.

 

[jlduh]

Thank you for the extra insight on the filter changes.
The question remains for me, how do they plan to capture 300PBqs of cesium in cartridges that need to be manually changed. The cesium is about a million curies worth, unless I've dropped a decimal somewhere.

Well, again, this is my main question: how can so much radioactivity which is normally contained inside a so big containment system (a reactor building) be contained in cartridges that have to be handled and stored? What kind of shielding in a cartridge can replace the one from a complete reactor? Contamination will be concentrated in these cartridges but how can this all system be run without huge radiation around pipes, cartridges and so on, making it almost unmanageable with the kind of volumes per day we are talking about?

This is a complete mystery for me...

But maybe this sentence from NHK is a beginning of the answer:

TEPCO says the effort will require time. In addition, depending on the situation, it may have to reconsider the working of the entire system and examine the effect of radioactivity emitted from nearby pipes.

By the way, i checked weather forecast and more than 70mm of rain are anticipated in the area in the next week... so new thousands of tons of water from this "natural cooling" will add soon to the current amount contained in the site. The situation is getting critical this time.

http://www.weather-forecast.com/locations/Fukushima/forecasts/latest

 

[razzz]

Grime, oil and don't forget salt all radioactive. Grime can be settled out in a holding pond, oil need detergent to separate it, and salt needs an acid bath.

Passive filtering would be pumping it to the top and let gravity pull it down through filters and trickle out the bottom for further processing.

All these things and mechanical separation like centrifuges besides heat distillation need added materials that become contaminated. Looks like they picked pressure filtering as the main theme which is working, the pre-clean problems can be overcome but has to be done on a massive scale. They should probably irradiate an empty oil tanker while waiting to figure out what to do. Buy some time storing it elsewhere.

 

[clancy688]

And there have been several detailed IAEA reports on the dire medical outcomes of people touching or approaching such very small sources unshielded.

The Goiana accident would be a very great example (INES 5, 1987, 93 grams, 50 TBq). The orphan source consisted of C137.

So this is maybe just a calculation mistake?
It would not be the first one, and worse even would be the fact that Tepco, Areva and the other parties involved all overlooked that mistake.

If so, then it would rather be a measuring mistake than a calculation mistake. They got the 720 PBq number by measuring each basement / turbine building / etc. alone and adding up the numbers.
I got the 2 * 140 PBq number for C134 and C137 by taking TEPCOs measurements of each basement / turbine building / etc. and adding up the numbers for each single isotope.

The pdf in question: http://www.tepco.co.jp/cc/press/betu11_j/images/110603a.pdf (page 8)

 

[Atomfritz]

Or does anybody know how to convert "4 mS/v" of C134 and C137 at a 1:1 ratio into becquerel?

Important and difficult question.
This http://www.aristatek.com/Newsletter/05%2002%20February/The%20First%20Responder%20Technically%20Speaking.htm" has a description of how this can be calculated and provides various examples.

Quotes:
"For example, the flux of gamma photons from 1 gram of Cesium 137 at a distance of 10 meters in air is 2.7543 (10)9 photons/m2-s. This converts to a dose of 0.402 rem/hr. There is only one gamma energy level to consider (0.66 MeV) and no neutron emissions."
"At 100 meters away, the rem dose for the cesium 137 example would probably be on the order of 0.004 rem/hour."

(See my last post for conversion becquerel->gram. For other isotopes FAS has a list also http://www.fas.org/programs/ssp/nukes/armscontrol/uraniumdirtybombs.html".)
Hope this helps to convert to Sieverts.

 

[clancy688]

Quotes:
"For example, the flux of gamma photons from 1 gram of Cesium 137 at a distance of 10 meters in air is 2.7543 (10)9 photons/m2-s. This converts to a dose of 0.402 rem/hr. There is only one gamma energy level to consider (0.66 MeV) and no neutron emissions."

That would be about 200 Sv/h at 10 meters for all basement water C137 collected in a bucket. Nice. Or rather... "ouch".

 

[MJRacer]

The monthly change was named with regards to the oil separating part ,not the cesium filters

These oil filters are somehow accumulating radioactivity where they are not supposed to ,

but the oil needs to be filtered out to avoid damaging the cesium filters.

There are 4 parallel installed processing lines

If I am not hallucinating, here is what may be happening:

Interesting things happen at interfaces. They tend to collect impurities. Consequently, one way to purify/refine/decontaminate something is to play with interfaces. Sugar is refined by crystallization. After crystals are grown, many if not most of the impurities will be on the surface of each crystal. By controlling the size of each crystal, it is possible to grow crystals of fairly uniform size that are larger than a given size wire mesh. After growing them, the crystal surfaces can be washed off, thus removing a huge amount of impurities in a single step. 2 crystallization steps suffice to produce almost perfectly pure sugar, by exploiting a liquid/crystal interface. Similarly, IIRC silicon is refined by pushing melt zones through a crystal. The impurities collect at the liquid/crystal interface and are pushed out with the melt zone. Beer can be concentrated by lowering its temperature slowly until water crystals form, which are then removed. The result is Eisbock. These are just some examples.

One would have to ask the NEs, but I suspect that highly radioactive water has, until now, almost never been contaminated with hydrocarbons. At Fukushima, several very large fuel tanks for the diesel generators were displaced by the tsunami. I would suspect that the thousands of gallons of fuel inside of them were also spread around the plant site. In designing the water treatment system, it appears to me that a rather conventional approach was taken by removing each contaminant in a separate step. There was no time for test runs.

They chose to remove oil via "dissolved air flotation," thus creating an air/oil/water emulsion with three interfaces: oil/water, air/oil and air/water. Furthermore, there is another interface involving the different viscosities of oil and water. As I said before, impurities tend to collect at interfaces. In this case, after concentrating impurities at the three interfaces, I would suggest that the impurities were trapped within the oil due to the large difference in viscosity between oil and water. Consequently, when the first Kurion ISM (oil and technetium) trapped the remaining oil droplets, it may also have trapped a good bit of all radioactive particulates and not just technetium. Hence, the large and rapid rise in radioactivity of the first cartridge.

They may have just discovered a novel way to remove large amounts of radioactive contamination from water in just three steps: (1) pour bucket of diesel fuel into contaminated water, (2) form air/oil/water emulsion, (3) filter through Kurion oil+technetium cartridge and Bob's your uncle! By trapping the oil droplets in the Kurion cartridge, the hot particles are also trapped. If this is happening, then one should be able to take a sample of what was collected in the first oil+technetium cartridge and see if large quantities of cesium and perhaps iodine are being trapped. They shouldn't be, as the next two cartridges are where the cesium and iodine, respectivelly, are supposed to be trapped.

If my theory is shown to be valid, then no flocculation step is necessary. The system will have shown itself to be effective at trapping hot particles in only 3 steps. However, the operational difficulties of dealing with hot cartridges may be very challenging.

Either that or I am totally wrong.

 

[joewein]

They got the 720 PBq number by measuring each basement / turbine building / etc. alone and adding up the numbers.
I got the 2 * 140 PBq number for C134 and C137 by taking TEPCOs measurements of each basement / turbine building / etc. and adding up the numbers for each single isotope.

The pdf in question: http://www.tepco.co.jp/cc/press/betu11_j/images/110603a.pdf (page 8)

I can confirm your calculations.

From the same data I also get a total of 3 kg of Cs-134 and 44 kg of Cs-137 in 105,100 t of water in units 1-4 and the central rad waste building.

 

[intric8]

Also, if filters reach capacity every 5 hours (assuming that is the worst case scenario), they will be going through roughly 3600 cartridges per month. I wonder if our friends at Kurion have planned for the possible eventuality of supplying many thousands of cartridges over the next year or two? And as clancy pointed out-

That would be about 200 Sv/h at 10 meters for all basement water C137 collected in a bucket. Nice. Or rather... "ouch".

That figure underscores how daunting of a task this recycling idea really is, making it difficult for me to feel optimistic about its long term sustainability.

At this juncture, the ball seems squarely in Kurion's court. Areva hangs around trying to be useful somehow, and Tepco is forced to find other means to store or dispose of the water.

 

[etudiant]

None of the process problems would matter if there were adequate storage for the contaminated water.
Yet 100,000 tons is the capacity of a small tanker. Presumably TEPCO could afford to buy a couple of double hulled tankers for use as a temporary storage depot. The tankers might need to be scrapped after use, but they are cheap, maybe $50mm tops.
In fact, if the water could be transported elsewhere, it would allow a much better shot at setting up and running a decent purification facility, something impossible in this small site where everything has to be shoehorned to fit.
Is there some fatal objection to such an approach?

 

[joewein]

Is there some fatal objection to such an approach?

Using an unmanned tanker anchored within the harbour basin of the plant, it seems like a no brainer to me: There is nothing to lose compared to letting the water drain directly into the ocean.

As for using the tanker to ship out the water however, I suspect the tanker idea becomes more viable only *after* the water has been processed. It was my impression that this was the idea with the floating platform too: Decontaminate the water as much as possible, pump it into the "megafloat" and tow it to Rokkasho-mura for final cleanup.

The radiation on a vessel filled with that much cesium solution should be a serious hazard to any crew and I can't see much political acceptance from any prefecture near the plant to let this pass their coast, let alone dock in a port.

 

[Orcas George]

Here are some objections that I can think of:

1) You are giving the radiation more "legs"; disabled radioactive tanker drifting off of Tokyo would be a Tom Clancy novel, nothing you want in real life.

2) Tankers are not designed to be leakproof, so you could easily have a spill during the filling process -- and that would mean you now have an unapproachable tanker full of radioactive crud. This could be mitigated if we started a couple of months ago, perhaps somebody has and we don't know about it.

3) If another tsunami hits while the tanker is being filled?

4) Fukushima harbor is apparently shallow (they call it the "shallow draft quay") so getting the stuff out to the tanker may be as complicated as the decontamination process, and just as risky. You are going to have long tubes with radioactive water going out to a ship bobbing at anchor, and you cannot allow any of it to spill.

5) I do not know if the bridge of a tanker will be sufficiently isolated from the hold for the crew to be able to operate it if the hold is highly radioactive. The last thing you want is a Mary Celeste situation.

I think railway cars might be a solution, or tanker trucks. (They have a pretty cool radio-controlled excavator, why not a truck cab?) One thing to avoid is all of the radioactive eggs in one basket, as tempting as it sounds. We know how to deal with things like leaking tank cars, leaking tankers are a different matter. (Break out the poly wrap!)

 

[MadderDoc]

It is not plausible that the exhauster after having done relatively little to lower the air contamination over a 5 day operation period, then suddenly over a 12 hour period appears to have decimated it. It is also not plausible that it is due to a measurement or graphing error.

But Tepco could plausibly have opened the door, letting in fresh air. Yesterdays press article reported that taking this step had been authorized.

I wrote this with reference to measurements published in
http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_110617_01-e.pdf

I shall have to eat my words, seeing this document:
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110619e2.pdf

According to this latter document, the radioactive content in unit 2 air on June 18th was back up where it was before and during the first 5 days of exhauster operation -- iow it appears to have had no real effect -- and there is reason to think that the drastic drop displayed by the former document was a fluke and may well not have reflected reality in unit 2. Nonetheless Tepco says it will commence gradually opening the doors to unit 2 starting today (March 19th) -- only now not with reference to any strong effect of the exhauster, but rather with reference to the expectation that opening doors will not significantly change the radioactive content in air at the boundary of the plant.

 

[tsutsuji]

Thank you for the extra insight on the filter changes.
The question remains for me, how do they plan to capture 300PBqs of cesium in cartridges that need to be manually changed. The cesium is about a million curies worth, unless I've dropped a decimal somewhere.

According to http://www.meti.go.jp/press/2011/06/20110609006/20110609006-2.pdf the purifying facility is supposed to produce, over one year :

2,000 m³ of radioactive sludge will be produced. 400 caesium absorption towers will be spent.

I have no idea how the petabecquerels are distributed between the towers/cartridges and the sludge, but the fact that cooling is mentioned only in connection with the sludge made me imagine that the sludge was hotter than the cartridges.

You did. It's ten million. ;)

I'd be interested in how many becquerels one filter is supposed to capture until it's changed. Or does anybody know how to convert "4 mS/v" of C134 and C137 at a 1:1 ratio into becquerel?

My understanding is that the 4 mSv/h

* were measured in the air outside the vessel
* dropped to 1 mSv/h or lower after flushing

So you cannot consider these 4 mSv/h as something measuring directly the radiations inside the cartridge/tower.

 

[GJBRKS]

They may have just discovered a novel way to remove large amounts of radioactive contamination from water in just three steps: (1) pour bucket of diesel fuel into contaminated water, (2) form air/oil/water emulsion, (3) filter through Kurion oil+technetium cartridge and Bob's your uncle! By trapping the oil droplets in the Kurion cartridge, the hot particles are also trapped. If this is happening, then one should be able to take a sample of what was collected in the first oil+technetium cartridge and see if large quantities of cesium and perhaps iodine are being trapped. They shouldn't be, as the next two cartridges are where the cesium and iodine, respectivelly, are supposed to be trapped.

If my theory is shown to be valid, then no flocculation step is necessary. The system will have shown itself to be effective at trapping hot particles in only 3 steps. However, the operational difficulties of dealing with hot cartridges may be very challenging.

The system is an unexpected over-performer.
Perhaps something good will come out of it sooner than expected.

 

[intric8]

Is there some fatal objection to such an approach?

No, though we hope the above statement doesn't turn out to be a real life eventuality with any of the tepco staff.

The long term viability of storing water is also in question, and though i am not professionally in a position to field any recommendations, it sometimes helps to hear observations presented out loud.

 

[clancy688]

If my theory is shown to be valid, then no flocculation step is necessary. The system will have shown itself to be effective at trapping hot particles in only 3 steps. However, the operational difficulties of dealing with hot cartridges may be very challenging.

Well, in that case you'd not only have highly radioactive waste, but highly flammable radioactive waste.

 

[GJBRKS]

Well, in that case you'd not only have highly radioactive waste, but highly flammable radioactive waste.

As I understand it , when diesel , it is not as flammable as gasoline :

http://en.wikipedia.org/wiki/Flammability

http://en.wikipedia.org/wiki/Flash_point

diesel fuel rated 2 as material that must be moderately heated or exposed to relatively high ambient temperatures before they will ignite

 

[Borek]

This can be probably further moderated by additives. Whether it makes sense (that is, doesn't pose additional problems with increased amount of waste) is another question.

However, if the idea is viable, it should work with other oily substances as well, some of them are much less flammable.

 

[tsutsuji]

From NISA's 174th press release http://www.meti.go.jp/press/2011/06/20110619001/20110619001.html (Japanese), there is this figure http://www.meti.go.jp/press/2011/06/20110619001/20110619001-8.pdf provided with the announcement that the water level in the reactor of unit 4 is going to be raised by injecting water from below.

See also the diagram in http://www.47news.jp/CN/201106/CN2011061901000328.html explaining that the water level being too low, the radiations from the shroud and dryers are no longer shielded.

 

[etudiant]

According to http://www.meti.go.jp/press/2011/06/20110609006/20110609006-2.pdf the purifying facility is supposed to produce, over one year :



I have no idea how the petabecquerels are distributed between the towers/cartridges and the sludge, but the fact that cooling is mentioned only in connection with the sludge made me imagine that the sludge was hotter than the cartridges.



My understanding is that the 4 mSv/h

* were measured in the air outside the vessel
* dropped to 1 mSv/h or lower after flushing

So you cannot consider these 4 mSv/h as something measuring directly the radiations inside the cartridge/tower.

Thank you, tsutsuji, for this incremental information.

It does leave me confused.
The Kurion modules were stated to be cesium specific and able to pick up all but 0.1-0.01% of it. Given the close to 50 kg cesium in the water, as joewein calculated in post 10035, there will be a kilogram of cesium per train per month, using all 4 trains and assuming a 1 year operations. That suggests very hot cartridges, excellent from the perspective of the cleanup if the vitrification works, but very hard to reconcile with a 4 mSv/h radiation measure in the vicinity of the cartridge.

 

[tsutsuji]

An Asahi article provides the figures for the radiation measurement after flushing :

Slightly past 3 a.m. on June 18, TEPCO began the purifying operation by pumping in low-level radioactive water, which lowered the radiation levels to 1.76 and 0.95 millisieverts per hour, respectively.
http://www.asahi.com/english/TKY201106180163.html

I previously wrote that the flushing was made with "clean water". That was a bit wrong. Actually it seems that the flushing is performed using the above mentioned "low-level radioactive water".

The Kurion modules were stated to be cesium specific

If you look at http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_110617_04-e.pdf only the red modules (chabazite ?) are cesium specific. The green modules (where the high radiation problem is occurring) are technetium specific and the yellow modules are iodine specific.

In the June 19th press conference ( http://www.ustream.tv/recorded/15480184 ), if my understanding is correct, the NISA people say that the 4 cesium specific red modules are rotated from time to time so that the first module, which bears the biggest burden is not always the same one. Using this rotation system, the facility was supposed to be able to run over an extended time without any cartridge change.

 

[~kujala~]

See also the diagram in http://www.47news.jp/CN/201106/CN2011061901000328.html explaining that the water level being too low, the radiations from the shroud and dryers are no longer shielded.

In the drawing there is an arrow going from the RPV area into the SFP area.

Does this mean that they now have confirmed that there is a (small) leak from the RPV area into the SFP area?

From NISA's 174th press release http://www.meti.go.jp/press/2011/06/20110619001/20110619001.html (Japanese), there is this figure http://www.meti.go.jp/press/2011/06/20110619001/20110619001-8.pdf provided with the announcement that the water level in the reactor of unit 4 is going to be raised by injecting water from below.

I think this was something rmattila suggested a long time ago also as a possibility for the units #1 - #3. The idea was that this route would perhaps better guarantee that the core area would be cooled.

Now this confirms that it is at least technically possible.

 

[etudiant]

According to http://www.meti.go.jp/press/2011/06/20110609006/20110609006-2.pdf the purifying facility is supposed to produce, over one year :



I have no idea how the petabecquerels are distributed between the towers/cartridges and the sludge, but the fact that cooling is mentioned only in connection with the sludge made me imagine that the sludge was hotter than the cartridges.



My understanding is that the 4 mSv/h

* were measured in the air outside the vessel
* dropped to 1 mSv/h or lower after flushing

So you cannot consider these 4 mSv/h as something measuring directly the radiations inside the cartridge/tower.

An Asahi article provides the figures for the radiation measurement after flushing :



I previously wrote that the flushing was made with "clean water". That was a bit wrong. Actually it seems that the flushing is performed using the above mentioned "low-level radioactive water".



If you look at http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_110617_04-e.pdf only the red modules (chabazite ?) are cesium specific. The green modules (where the high radiation problem is occurring) are technetium specific and the yellow modules are iodine specific.

In the June 19th press conference ( http://www.ustream.tv/recorded/15480184 ), if my understanding is correct, the NISA people say that the 4 cesium specific red modules are rotated from time to time so that the first module, which bears the biggest burden is not always the same one. Using this rotation system, the facility was supposed to be able to run over an extended time without any cartridge change.

Thanks for the added input.
This makes the design much clearer. It appears to reflect a sensible set of choices, which would also allow the entire set of skids to be changed out monthly. Consequently, there would be no need either for workers to manhandle each cartridge individually, which had been my perception before. So the cartridges might be fairly hot, but still within acceptable range.
Still, current reality is that the system has not yet really been run and time is short. Any further comments on possible fallbacks?

 

[tsutsuji]

In the drawing there is an arrow going from the RPV area into the SFP area.

Does this mean that they now have confirmed that there is a (small) leak from the RPV area into the SFP area?

The drawing's caption ピットの水がプールに流入　means "the water in the pit flows into the pool".

The article text says プールにつながるピットの水位も低下した : "the pit being connected with the pool, the water level in the pit dropped too".

Further explanations are provided in http://www.asahi.com/national/jiji/JJT201106190076.html : between March 15th and March 20th the water level in the spent fuel pool was so low that the difference of pressure between the pit and the pool allowed water to leak from the pit to the pool. After March 20th the water rose in the pool and the gate between the two became watertight again.

 

[Orcas George]

Has anybody seen a report on how long it takes to replace the filter skid, and how many filter skids they have? It is a modular unit that is designed to be replaced.

I hope the issue isn't that since Kurion is a start up, they don't have the resources to manufacture filter units very quickly. That would have been a bad choice of supplier.

From the media reports, it doesn't seem like this first filter unit is anything very special. It seems to be a carbon filter with zeolite instead of carbon. (Oh, excuse me, "surfacant treated zeolite (STZ)" which means that they sprayed soap on it.)


There is surely a plant in China that can stamp out a few of these per day. Given the urgency to the world, a phone call from the Japanese government to one of the big manufacturers would get an expidited response.

If that is the issue start looking for a bunch of DHL trucks to appear on the webcam soon.

 

[SteveElbows]

The drawing's caption ピットの水がプールに流入　means "the water in the pit flows into the pool".

The article text says プールにつながるピットの水位も低下した : "the pit being connected with the pool, the water level in the pit dropped too".

Further explanations are provided in http://www.asahi.com/national/jiji/JJT201106190076.html : between March 15th and March 20th the water level in the spent fuel pool was so low that the difference of pressure between the pit and the pool allowed water to leak from the pit to the pool. After March 20th the water rose in the pool and the gate between the two became watertight again.

Thanks very much for the translation.

Is Unit 5 mentioned anywhere? Because the latest TEPCO status update seems to suggest this work has now ben done at 4 & 5:

- From 9:14 am to 11:57 am on June 19, we injected fresh water to the
reactor wells and pools for setting temporary equipment of Unit 4 and
Unit 5, in order to improve the working environment (to reduce radiation
dose) in the 5th floor of the reactor building of Unit 4 and Unit 5.

From http://www.tepco.co.jp/en/press/corp-com/release/11061907-e.html

 

[elektrownik]

Thanks very much for the translation.

Is Unit 5 mentioned anywhere? Because the latest TEPCO status update seems to suggest this work has now ben done at 4 & 5:



From http://www.tepco.co.jp/en/press/corp-com/release/11061907-e.html

This must be mistake, according to tepco unit 5 is perfect fine, reactor is loaded with fuel and closed

 

[MadderDoc]

<..>After March 20th the water rose in the pool and the gate between the two became watertight again.

Ouch. There goes the only decent explanation we had of the hot water in the reactor cavity.

 

[SteveElbows]

This must be mistake, according to tepco unit 5 is perfect fine, reactor is loaded with fuel and closed

I looked at the Japanese version of this TEPCO info and I think it only mentions 5th floor, not reactor 5. Perhaps someone could confirm, in which case it is indeed an error with the English version.

http://www.tepco.co.jp/nu/f1-np/press_f1/2011/htmldata/bi1574-j.pdf

 

[MiceAndMen]

From NISA's 174th press release http://www.meti.go.jp/press/2011/06/20110619001/20110619001.html (Japanese), there is this figure http://www.meti.go.jp/press/2011/06/20110619001/20110619001-8.pdf provided with the announcement that the water level in the reactor of unit 4 is going to be raised by injecting water from below.

See also the diagram in http://www.47news.jp/CN/201106/CN2011061901000328.html explaining that the water level being too low, the radiations from the shroud and dryers are no longer shielded.

Does this relate to the need to keep the contents of the equipment pool (e.g. the steam dryer and the steam separators) covered? Going in through the bottom of the reactor would be taking the long way around, and implies that debris on the refueling floor will prevent access to the top of the equipment pool for quite a while yet.

 

[MadderDoc]

<..> Going in through the bottom of the reactor would be taking the long way around, and implies that debris on the refueling floor will prevent access to the top of the equipment pool for quite a while yet.

The chosen route for feeding the water also puzzled me, but I can't see how it implies that access to the equipment pool is prevented by debris and will be so prevented for quite a while yet. There could be many other reasons why this route has been chosen.

 

[joewein]

I looked at the Japanese version of this TEPCO info and I think it only mentions 5th floor, not reactor 5. Perhaps someone could confirm, in which case it is indeed an error with the English version.

http://www.tepco.co.jp/nu/f1-np/press_f1/2011/htmldata/bi1574-j.pdf

Your reading is correct, it mentions only the 5th floor of unit 4, but not unit 5:

６月 19 日午前９時 14 分から午前 11 時 57 分まで、４号機原子炉建屋５階の環境改善（線
量低減）のため、同号機原子炉ウェルおよび機器仮置きプールに淡水の注水を行いまし
た。

This confirms the leak between the reactor pit and the pool between March 15 and 20, which is assumed to have saved the fuel in the pool from worse damage.

I am wondering how much of the temperature of the water in the reactor pit can be explained by heat conduction through the gate separating them. The reactor well itself sits insulated inside the containment, so not that much heat should flow via its walls.

 

[jim hardy]

MJRacer

Re your separation by oil ---
you obviously have experience ... thank you for contributing.

i pray you are on to something. Those guys deserve a break.

If oil has affinity for these contaminants, (and why not? oil has great surface tension)

perhaps the answer was embarassingly simple - dairy equipment , modern version of the old hand-cranked cream separator , might do the pretreatment job. Sure would be nice to have 90% of the contamination bottled up in a few drums of oil . They could be wrapped in lead sheet and handled with forklifts.

Your elegant solution would be right in line with Mother Nature's sense of humor.

i'm watching for that one.

thanks -

old jim

 

[Orcas George]

Tepco plans to destroy the treatment system:

The leak was found at 9PM on June 18 by the worker conducting the inspection. The safety valve [rupture disk] of the oil/technetium unit was broken, and there was water between the cylinder [vessel] that contains zeolite and the container that holds the cylinder. The safety valve is designed to break when the pressure inside the vessel gets high. TEPCO believes it may be the result of having to repeatedly start and stop the pump. The purpose of the safety valve is to prevent the hydrogen leak during the system halt. TEPCO is considering closing the valve leading to the safety valve during the operation.

http://ex-skf.blogspot.com/

Can I shout "NO" loud enough for them to hear me in Japan? You do not do this. If a fuse blows, you do not replace it with a straght wire unless you want to burn up your house. It is the same with water pressure.

The problem that they are facing is called "water hammer." It is a well known phenomon. All they need to do is put an inverted cylinder into the system to absorb the shock from start up/shut down. There are better solutions but this is what they have time for. It is possible that there are water hammer arresters in the system and they are simply flooded and need to be drained. If there is nothing to deal with water hammer in the system, then Kurion is a bunch of snake oil salesmen.

 

[MiceAndMen]

It's good to see the IAEA is as committed to transparency as ever. The 151 IAEA member states will meet this week in Vienna for 5 days.

IAEA Director General Yukiya Amano called the ministerial meeting to learn lessons from the March 11 Fukushima accident and plot strategies to improve nuclear safety.

http://www.bloomberg.com/news/2011-06-20/fukushima-disaster-failures-kept-behind-closed-doors-at-un-atomic-meeting.html

 

[GJBRKS]

http://www3.nhk.or.jp/daily/english/20_13.html

Tokyo Electric Power Company, or TEPCO, halted the filtering system only 5 hours after it went into full operation on Friday. Readings around one of the system's devices indicated higher-than-expected radiation levels.

TEPCO engineers suspect that the density of radioactive substances in the contaminated water was greater than had been predicted.

They initially thought that the device had absorbed large volumes of oil and sludge containing radioactive material. But in a test conducted on Sunday, high radiation levels were registered for equipment set to the lowest of 3 absorption levels.

In another test on Monday, TEPCO adjusted the flow of the contaminated water through the equipment.

This is bad if the initial monthly change has to be revised to 5 hours due to an elevated density ...
2 orders of magnitude shift in projected contamination ?
What would this do for the schedule ?
I suspect they do not know yet why , and this would be the simplest explanation , allthough it then means they were wrong on the total level of contamination from the start

 

[joewein]

The sensible thing to do would be to progress from the lightly radioactive water used last week for testing to the next more radioactive water in storage.

At the end of the day, one cubic meter freed up is a cubic meter, doesn't matter how contaminated it was if it can now be reused for cooling instead of 500 t of additional water per day from the dam.

You don't want to have the most radioactive water from the unit 2 basement in the system while you still iron out the kinks. I assume that's what they would be doing too. Even more surprising then when they should declare that things are going wrong because the water was too radioactive!