Saturday, June 2, 2012

High Beta Radiation on Floor Surface in Reactor 2 Building at #Fukushima I Nuke Plant


As Toshiba workers splashed strippable paint on the floor at the Truck Bay Door of the Reactor 2 building (southwest corner) and stripped the paint to remove radioactive materials on the floor to lower the radiation for the future work (installing thermocouples), they were mostly removing the radioactive materials emitting beta radiation.

Outside Fukushima I Nuclear Power Plant, if the gamma radiation levels are measured in microsievert/hour in single or double-digit (i.e. 2 microsieverts/hour or 20 microsieverts/hour), they are considered high. The samples of the "black dust (thing, material, plant, dirt, etc.) measure anything from 0.6 microsievert/hour to over 50 microsieverts/hour depending on the locations, usually measuring gamma ray only.

At the entrance of the Reactor 2 building, the radiation levels on the floor are measured in millisieverts/hour. Of the four decon methods tried on the floor, vacuuming and strippable paint were somewhat effective in reducing the gamma radiation. Strippable paint was the most effective in reducing the beta radiation, and wet mopping and vacuuming were somewhat effective. Dry mopping spread the beta contamination, instead of reducing it.

10 millisieverts/hour is 10,000 microsieverts/hour.

I'm waiting to see if TEPCO does the nuclide analysis of the vacuumed dust or stripped paint, but TEPCO being TEPCO I don't have much hope. I'd love to know what kind of radioactivity by what nuclide would cause such high radiation levels.

From TEPCO's Working Group meeting reference material, pages 8 to 18 (I added English labels; 5/28/2012):



All this work is to later install thermocouples in the Containment Vessel, and that will have to be done by human workers. The Truck Bay Door is one of the two ways to get to the possible installation locations (there are two). Near one of the installation location candidates, there is a spot whose surface radiation exceeds 3,000 millisievert/hour (3 sieverts/hour or 3 million microsieverts/hour, take your pick). TEPCO's first choice is to install on top of the TIP Room by entering from the Truck Bay Door (access route 1, in blue). They may not be too keen to do the installation work near 3,000 millisievert/hour location...

7 comments:

Atomfritz said...

Thank you LaPrimavera for this again very good article and the annotations in the Tepco documents! It puts up really some interesting questions.

I really hope Tepco will publish an isotope analysis of that contamination mix.
Gamma (cesium) radiation is almost an order of magnitude lower than beta. If only gamma was measured this place would look way less bad.
This again proves the propaganda dogma wrong that you only need to care for gamma radiation.
So we can assume with some certainty that there could be quite a lot alpha+beta hotspots the unsuspecting citizen wouldn't detect and believe to be "safe" because his/her equipment only detects gamma.

Regarding the actual measurements in the four stages of decontamination, I am getting somewhat confused.
The before/after measurements of the different stages seem not to match:

Before After
Dry mopping 20 20
Wet mopping 13 8
Vacuuming 10 8
Strippable p. 10 4

I thought, for example, the values after dry mopping should be the same before wet mopping, and so on, but they aren't.
Maybe the higher-than-expected before values could have been caused by re-contamination? Or, what did I get wrong? Any idea?

Anyway, it will be very interesting to learn how they proceed with the decontamination inside the reactor building.
Provided they do it at all, as this test decontamination can well be regarded a failure.

Alpha and beta contamination doesn't matter so much as these particles are absorbed by the workers' protective gear.
Actually the gamma decontamination factor is what matters. And a gamma reduction of not even 40% isn't really relevant (see figure 5.1 in the Tepco document).
Especially if one considers that most of the gamma shine inside the reactor buildings apparently doesn't come from the floors, but from the surroundings (tubing, walls, ceilings) I think it's quite questionable whether a floor-only decontamination will be worth the effort.
It would possibly make sense only if the workers' passageways would additionally be thoroughly shielded with leaded paravents.

Anonymous said...

They may be trying to clean up the beta emitters because of Bremsstrahlung radiation that will be emitted from lead shielding.

Anonymous said...

5 minutes later=same

itsfukncommunism said...

After 30% core melt there is ABSOLUTELY NO WAY TO STOP THE REACTION “unless you have meltable neutron poisons integrated into the fuel but, no one has instituted these, they exist though” , you can assume this will go to the final worst conclusion ie; fukushima 1 plant, 6 reactors 6 spent fuel pools and common spent fuel pool and dry casked fuel and possible nuclear weapons development plutonium pits and u235 tampers and shells and lithium deuteride etc on site all fissions/fusions “the fusion can happen if deuterides are around”
fukushima daini “fukushima #2 plant” 4 reactors 4 spent fuel pools and common spent fuel pool and dry casked fuel and possible nuclear weapons development plutonium pits and u235 tampers and shells and lithium deuteride etc on site all fissions/fusions. It’s easy to infer this once the site is “prohibitively hot” which it is now, hence no babysitting.
I would like to stress the hunt should be on for PICTURES/INTEL ON DAINII, ONAGAWA, TOKAI, FUKUSHIMA DAICHI REACTORS 5/6 AND POSSIBLE OTHERS, I BELIEVE THERE IS A REASON FOR THEIR NON EXISTENCE, I SUGGEST EVERYONE WORK TO RECTIFY THIS THEN HAVE ENENEWS POST/ HEADLINE ANY CURRENT INTEL ON THOSE LISTED ABOVE. PICTURES WILL DO AS INTEL AS WE HAVE SEEN HOW VISUALLY DESTRUCTIVE UNCONTROLLED NUCLEAR FUEL CAN BE.
Yellow/brown/green smoke is burning nuclear fuel, for reference
fresh fuel “non mox” burning/etc=bad but still deadly, no cesium/strontium/other fission made products
fresh fuel “mox” burning/etc =very bad+has plutonium and bomb grade u235 no cesium/strontium/other fission made products
spent fuel “non mox” burning/etc = EXTREMELY BAD+lots of plutonium bomb grade uranium 235 and 2000 other fission or so made products.
spent fuel “mox” burning/etc = EXTREMELY BAD+lots of plutonium bomb grade uranium 235 and 2000 or so other fission made products.
You could quite safely generalize and be correct that all the fuel here and there/everywhere is in the EXTREMELY BAD category and be upwards of 99% correct and by nucleide content it would also be safe to just call it all spent/used mox “the worst” hope I made it clear. Just one spent fuel pool of extremely bad can wipe out Japan very easily, should the wind be not so “favorable” which it was when 3 blew for the most part, this is happening, this will go to it’s final conclusion “all fuel fissions”<noteworthy<. They will not "get lucky" again when it comes to the wind, that was a one off and they should seriously consider that.
I said this whole spiel for the most part march14 2011 on a post on google groups.
One final thing, I have seen satellite pictures of dainii "fukushima2plant" and believe you can see the reactors melted down by what you see in the water as the meltdown ejects all sorts of crap out the intake pipes into the ocean which you can see from the satellite picture in the bay in front of the nuclear plant, it's very telling.

itsfukncommunism said...

or post to ex-skf would be ok too, or fukushima diary, anywhere you can, please/tx

Anonymous said...

http://fukushima-diary.com/2012/06/the-moment-when-edano-lied-to-the-people/#comment-229583

yukio edano is a male rooster sucker
質問、どのようにか、なぜこの男はまだ生きている?日本を召し上がれ!
この男は、問題とコストが日本のために正確に最悪の事態に住んでいるプロの嘘つきである、彼は問題であり、それを解決します。私達はすべてそれは電車の前の子をスローするように間違っている知っているが、彼がした、"基本的に"、あなたや私はそれが間違っている知っているので、もし人のどんなことを聞くでしょうか?
ことを行うだろう誰か...右のそれを行うためにそれを楽しむために持っているでしょうか?
ヤクザ、枝野幸男をご覧ください。... TXしてください。

Atomfritz said...

On the PF tsutsuji has made a big effort to translate the whole Tepco document this article refers to.

See 2nd and following posts on this page:
http://www.physicsforums.com/showthread.php?t=480200&page=841

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