Sunday, June 19, 2011

#Fukushima I Nuke Plant: Another Leak in Kurion's System at "Rapture" (Rupture) Disk

Since the entire water treatment system was stopped in the early hours of June 18 after only 5 hours of full run due to the faster than expected rise in radiation level on the Kurion's oil/technetium separation unit, TEPCO has been using the low contamination water to clean out the system.

Well, while they were doing the cleaning run, they found another leak in the same oil/technetium separation unit.

From Asahi Shinbun (10:27PM JST 6/19/2011):


TEPCO announced on June 19 that it found a new leak in the water treatment system for highly contaminated water at Fukushima I Nuclear Power Plant. The amount of leak was about 30 liters of the low contamination water that the company was using to clean out the system after the trouble [of the oil/technetium unit] was found. The leaked water has already been collected.

 18日午後9時ごろ、点検中の作業員が見つけた。放射性物質や油分の吸着に使うゼオライトを入れた装置の安全弁が壊れ、円筒形の装置を囲う容器とのすき 間に水がたまっていた。安全弁は内部の圧力が高まると破れる仕組み。東電はポンプの動作と停止を繰り返した影響が考えられるという。安全弁は停止中に水素 がたまるのを防ぐ目的で取り付けているため、運転中は安全弁の手前の弁を閉めるなどの対応を検討する。

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.

It looks like this water treatment system will have to involve carbon-based workers on a regular basis, instead of automatic, remote-controls.

Here's the detailed diagram of the hydrogen venting system that includes the rupture disk, which TEPCO labeled as "rapture disk". I thought that was funny. The difference in pronunciation between "rupture" and "rapture" totally escapes the Japanese.

(From the press conference handout on June 19; cleaner copy at the link)


netudiant said...

Apparently the design was to switch the water flow sequentially so that each of the 4 skids that carry the cesium adsorbing cartridges would spend some time getting the initial water inflow and thus the greatest load. Note that this requires a complex set of valves that have to be reset correctly every time, else problems ensue, as we have already seen.
The plan was to then pull out the entire set of skids for replacement, so manual intervention would be minimized.
The problem is that the initial filtering stage, which was simply to remove any oil plus any technitium before the cesium columns, was quickly burdened by much more radioactivity than expected. The cause is believed to be radioactive particles caught in an emulsion formed by the oil/water separation stage which precedes the column.
A better oil/water separator will be needed before the cleaning can resume.
A good outline from TEPCO is here:

Anonymous said...

Robbie001 sez:

If they keep fooling around they may just break the “rapture” disk and bring on the second coming (if you believe in that stuff). This is going a lot worst than I though. I was looking for months of 24/7 operation at this point I’ll be surprised if they can run it for a solid week. All of this and now they need to flood areas of the reactor buildings that don’t even hold fuel. The sad fact is I might be right, they may have to dilute this water to treat it. I said that a long time ago in a galaxy far away (or so it seems). I knew they’d need a special waste treatment facility I just didn’t realize how special it would have to be turns out it might be so special it doesn't exist.

“TEPCO is considering closing the valve leading to the safety valve during the operation”.

Well that’s good its only there for safety anyway and nothing’s safe about Fukushima. You’re right; they’ll need to find some desperate homeless people to do some “jumping” in the future. I wonder where TEPCO could find such people? The sad thing is TEPCO will probably be praised as the largest (temporary) employer of disaster victims when the official history of Fukushima is written. And of course “a good time was had by all” will be the caption for that photo.

Automation doesn’t work unless it is vigorously tested before use this sort of action points to utter desperation. The nuclear industry just can’t bring themselves to admit some “carbon’s” gotta burn to address the issue because a reliable functional Mr. Radiation Roboto doesn’t exist. They really need the fantasy that no one died at Fukushima to be true to hold any shred of public confidence so they’re willing to handle the problem as if holding a stinky diaper at arm’s length for as long as it takes. Too bad for them their diaper is still being filled 100 days later.

Anonymous said...

The Russians, to their credit, immediately realized they had a world-shaking event on their hands.

They greeted their problem as men, it was not going to just "STOP", they responded as best any humans could to TRY to bring it under control.

The world is contemptuously looking at these TEPCO exec freaks with the politicians in their pockets, waiting for them to show some manhood.

They don't appear to have it, by this point.

They are an insult to a culture capable of producing Zen.

Anonymous said...

Dear arevamirpal::laprimavera,

You have a lot of facts but no truth. You have an idea of what is going on inside the building but you are not on the inside. I stood over the rupture disk when the leak took place. None of the scenarios that you posit ever came true. They found the disk. it was damaged and it was replaced and the vessel put back in service. If you wish to have the truth along with some facts please feel free and contact me at you can call me Chandler. email me and i will send you proof i know what i'm talking about.

And thanks for the pictures of some of the destruction. Having been there for 5 weeks my heart breaks for the people who have lost so much.

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