Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[NUCENG]

They used CAMS to try to estimate percentage core damage early on, and I don't think the numbers generated were well regarded by people at the time.

http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110427e19.pdf

If these percentages referred to amount of fuel that's ended up in containment, rather than the percentage of fuel that was damaged, then maybe I could buy into the numbers a bit. But yes, I think its better to presume that CAMS is more useful for detecting much smaller amounts of damage that could occur under a situation much less dire than what happened at Fukushima.

http://adamswebsearch2.nrc.gov/idmws/DocContent.dll?library=PU_ADAMS^pbntad01&LogonID=507a9449dcb934f4b821c20b93e649ed&id=003957314

CAMS has two functions as a post-accident monitoring instrument per RG 1.97:
Low Range (minimum from 1 to to 1e4 R/hr) is used for detection and verification of a breach in reactor coolant pressure boundary. High Range (up to 1e7 R/hr) is used for detection of significant releases, release assessments, long term surveilance and emergency plan actuations.

It is supposed to respond over an energy range from 60 keV to 3 MeV within an accuacy factor of 2.

I think the low required accuracy is because you can't predict the time varying energies of fission product decays. It is useful for trending and is not meant to read out in human dose. When you are talking about 1E7 R/hr does it really matter whether it kills you in 1 minute or 1 minute 17.5 seconds?

Edit: The detectors are outside containment. CAMS has pumps which draw samples from the drywell or wetwell to the detectors and returns to the source.

 

[westfield]

I wonder if anyone here has been able to identify where this photo was taken?

http://www.tepco.co.jp/en/news/110311/images/110611_05.jpg

In the Tepco handout page the photo has this mysterious caption which does not really make any sense:
"Side Part of Skid of Water Treatment Facility of Fukushima Daiichi Nuclear Power Station
(pictured on June 9, 2011)
Pictured at South Side on 4th floor of Unit 4 Reactor Building"

At first the pattern of the sun shining in there made me think the photo is facing west (ie the photographer has basically turned 90 degrees to his right after taking http://www.tepco.co.jp/en/news/110311/images/110611_04.jpg" shot ) but so far I havn't found a match from the outside.

But then there is an "I" beam rail up at the ceiling with a chain block at the end of it which appears as though it mayt extend outside the building, which made me think of the green scaffolding that was set up on the eastern side of Unit 4 before all this happened. However, I thought that was one level down. But if it is facing east that would mean the sunlight is shining in from a northerly angle which doesn't seem right does it?

I will try and find an outside image to match but I don't have high hopes.

edit: this photo like many other really brings home to me how old the equipment is in these plants.

Edit edit : But the concrete floor "joists" seem to tend to run E\W in #4 so that messes with that.

 

[joewein]

I hope they have check valves installed so that the 'solution' does not become a siphon and drain the pool should a failure occur....

The pipe hooked up to the handrail does not reach into the spent fuel pool. It pours the water into the pool from above. Therefore no check valve is necessary.

 

[thehammer2]

I'm sure they will, but just so it's said, I hope they have check valves installed so that the 'solution' does not become a siphon and drain the pool should a failure occur....

I suspect that they'll use an airgap. It's simple and it's how your water supply is unable to set up a siphon and drain your sink or bathtub. If they don't put an airgap, I hope they wouldn't extend the pipe to the bottom of the pool. If they must terminate in the pool, I'd only stick the pipe into the pool a few inches below the pool's level. Then it can only drain the pool until it lowers the pool enough to take in air and break suction.

Reason I bring this up is that checkvalves or siphon breakers fail and relying on them to prevent siphons isn't inherently safe, though it is safer than nothing if you have a closed system. With the pool, you can introduce the airgap and completely eliminate the possibility of draining the pool that way.

EDIT : I see someone else had the same thought right before me

 

[joewein]

At first the pattern of the sun shining in there made me think the photo is facing west (ie the photographer has basically turned 90 degrees to his right after taking http://www.tepco.co.jp/en/news/110311/images/110611_04.jpg" shot ) but so far I havn't found a match from the outside.

But then there is an "I" beam rail up at the ceiling with a chain block at the end of it which appears as though it mayt extend outside the building, which made me think of the green scaffolding that was set up on the eastern side of Unit 4 before all this happened. However, I thought that was one level down. But if it is facing east that would mean the sunlight is shining in from a northerly angle which doesn't seem right does it?

The sun light appears to come in from the left.

The EXIF data of the picture says it was taken at 16:36 (late afternoon), which would make the left West (towards sunset).

The wall on the right, behind the electrical box would be on the East (towards the turbine hall). We'd be looking north (towards unit 3). If this is the fourth floor as claimed then our back would be facing the hole in the http://www.tepco.co.jp/en/news/110311/images/110611_04.jpg" from the outside. The top of the pool would be a floor above, the pool itself behind the wall on the right.

The previous picture taken from inside through the 4F hole (seen from the outside with the red Putzmeister truck) was taken at 16:29, 7 minutes earlier. Both share the same GPS coordinates:

Latitude: 37, 25, 24.67 (North)
Longitude: 141, 1, 54.81 (East)

According to Google Earth this point is hundreds of meters from unit 4, so I am not sure what the deal is there.

 

[~kujala~]

NRC has now officially corrected the claim made by Gregory Jaczko that the unit #4 spent fuel pool would have dried up at some point:

Spent fuel pool never dried up at Fukushima plant: U.S. regulator
http://www.breitbart.com/article.php?id=D9NSMF980&show_article=1

 

[joewein]

New question for PF Newbie
On this thread;
http://www.huffingtonpost.com/2011/...ment-radiaton-estimate-doubles-_n_871887.html (which now has over 6100 comments)

See comment today at 7:27, 3:47 and 9:39

☆ A number of us have been discussing what is causing the chart to look like this:
...We have two different ideas: http://atmc.jp/plant/rad/?n=1

It's been discussed here before, e.g.
https://www.physicsforums.com/showpost.php?p=3323788&postcount=8312

See also my blog post at:
http://www.joewein.net/blog/2011/05/30/fukushima-1-unit-5-water-pump-fails/
"Unit 1 dry well radiation levels"

 

[Cire]

Yes. According to TEPCO and NISA, the fuel rods in Units 1-3 melted down, probably totally. Corium is a mixture out of control rods, fuel cladding, fuel elements, and, in case the reactor was breached, steel and concrete. Basically everything which mixed with the molten fuel.

But since there's molten fuel present, there's also corium.

Melting down doesn't automatically imply corium. A meltdown can be cladding splitting open and dumping pellets to the bottom of the RPV.

 

[SteveElbows]

My best idea is that the numbers in the press article might be a -- perhaps somewhat positively skewed -- representation of data as it looked a few days ago, maybe when a Tepco application was made to authorities -- I imagine opening the reactor building to the environment would be one of those things that the utility would need official permission to do.

It seems clear from the Tepco press releases, that the full data set you reference includes the time for initiation of the air purification, quote Tepco,
"-We installed local exhausters and started to operate them at 12:42 pm on
June 11 in order to improve the working environment inside Reactor
Building of Unit 2."
and the full dataset then does not seem to support that there has been a reduction of the Cs isotopes over the period of operation so far, nor that the reduction of I-131 has had the magnitude expressed in the press article.

Ah well, the latest data shows a major drop, not sure why it trended in this fashion.

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_110617_01-e.pdf

Also thanks to people for their thoughts on CAMS and use for measuring percentage of core damage.

 

[SteveElbows]

Sounds like we will soon have an updated roadmap, and a TEPCO account of the first 5 days to chew over:

http://www3.nhk.or.jp/daily/english/17_17.html

http://www3.nhk.or.jp/daily/english/17_09.html

Not sure if we will get the 5-day account in english straight away or not, nor whether there will be much new in it.

 

[clancy688]

Melting down doesn't automatically imply corium. A meltdown can be cladding splitting open and dumping pellets to the bottom of the RPV.

Of course, but that didn't happen at Fukushima. I think it's VERY unlikely that we're only dealing there with dumped pellets. It's a full scale meltdown in all three reactors.
Remember TMI. The coolant loss there was nothing compared to the loss at Fukushima. And still corium formed.

 

[Borek]

Of course, but that didn't happen at Fukushima. I think it's VERY unlikely that we're only dealing there with dumped pellets. It's a full scale meltdown in all three reactors.

Truth is we don't know what have happened. No doubt there is a mess inside, but stating anything as a known fact is premature.

 

[MadderDoc]

Ah well, the latest data shows a major drop, not sure why it trended in this fashion.
http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_110617_01-e.pdf
<..>

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.

 

[clancy688]

Truth is we don't know what have happened. No doubt there is a mess inside, but stating anything as a known fact is premature.

That's why I said that dumped pellets are unlikely instead of impossible. We won't know for sure what's actually present in- or outside the RPV. We'll get facts when they open up the reactors, which won't happen during the next few years. So we should work with the most likely scenario. That is, in my opinion, and especially if we take TMI2, the time the cores were uncovered and the water height in the vessels during the melting (In Unit 1 possibly zero) into consideration, the presence of corium. Moreover most discussers here seem to have implemented the presence of corium into their reasoning. So I don't see much problems telling that corium is very likely present.

 

[biggerten]

The pipe hooked up to the handrail does not reach into the spent fuel pool. It pours the water into the pool from above. Therefore no check valve is necessary.

That will do the trick.

By the way, the water decontamination system is now online -

http://www3.nhk.or.jp/daily/english/17_34.html

 

[DSamsom]

By the way, the water decontamination system is now online -

http://www3.nhk.or.jp/daily/english/17_34.html

looking at the pictures of the decontamination system, i wonder how they are going to deal with the huge buildup of radioactivity in the filtersystems. Have they figured out a way to get rid of the radiating sludge fully automatically?

 

[etudiant]

looking at the pictures of the decontamination system, i wonder how they are going to deal with the huge buildup of radioactivity in the filtersystems. Have they figured out a way to get rid of the radiating sludge fully automatically?

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 :).

 

[SteveElbows]

Well this months roadmap update didnt contain anything surprising, or at least not that I've noticed. Perhaps a few small details of note, but none that I can think of off the top of my head.

http://www.tepco.co.jp/en/press/corp-com/release/11061702-e.html

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

 

[Astronuc]

Is the presence of corium a fact?

Thanks in advance.

No. It is based on an analysis, apparently with conservative assumptions regarding heat transfer, or lack thereof. It is a fact that there is significant damage to the fuel. We won't establish the 'facts' until the vessel head is removed and the cores are visually inspected. Comments regarding fuel melting and corium are speculative for now.

There is certainly the question of whether or not the cores of units 1, 2 and 3 actually received the cooling water that was being pumped into the vessels. Some instruments indicated coolant levels in the core, but perhaps those instrument measurements are unreliable. If the vessel penetrations were breached early in the event, then it could be that the injected water simply flowed out. 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.

It also appears that TEPCO and NISA believe there was/is water in the lower plenums of the RPVs, and if that is so, then the fuel is less likely to have melted.

 

[MiceAndMen]

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 :).

I don't remember reading about the average spent fuel load that was originally expected in your average BWR SFP, but I'm sure that those loads increased in large part due to the lack of off-site storage. High density racks for Spent Fuel Pools speak to the fact that the loads initially designed for have been exceeded. I guess that's pretty common knowledge nowadays, both in Japan and in the U.S. at least.

To now, the attitude seems to have been "we'll just continue to accumulate spent fuel on-site for the forseeable future and someone will eventually figure out how to deal with it." Hopefully the Fukushima Daiichi situation provides impetus going forward to deal with the off-site spent fuel repository "problem" in Japan. Too bad no such thing will happen in the U.S. and spent fuel will continue to accumulate at the plants indefinitely. One cannot continue to kick that can down the road forever.

 

[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