Saturday, August 20, 2011

#Fukushima I Nuke Plant: Toshiba's SARRY Joins the Underperformers at the Plant

TEPCO released the result of the decontamination by Toshiba's SARRY (cesium absorption) after the start of the full run, and it was OK (according to TEPCO) but not as spectacular as the manufacturers (Toshiba, IHI, and the US's Shaw) had claimed.

SARRY achieved the decontamination factor (DF) of about 50,000, instead of 1 million the manufacturers had confidently hoped. The DF of 50,000 means that the system was able to reduce the amount of radioactive materials (in this case, cesium) to one-50,000th after the treatment.

It is still much better than Kurion, whose most recent DF is slightly less than 350 (reducing the redioactive materials to one-350th.

There goes, for now at least, the idea of just using SARRY and bypassing Kurion and AREVA in decontaminating the water. The desalination unit needs the treated water to have radioactive materials at one-100,000th of the initial contaminated water, at least. TEPCO still needs at least two of the three decontamination units.

From TEPCO's handout for the press on August 20:


netudiant said...

The absolute performance is probably less critical than the sustainability of the process. If SARRY can run reliably 90% of the time, it would be a tremendous help, even if the water is only decontaminated to one one thousandth, rather than the one millionth initially hoped for. The best is the enemy of the good in this instance.
Japan is better served if 99.9% of the contamination can be captured quickly, before additional accidents can spread the dirt further.
In this context, is TEPCO no longer updating the water levels inside the plant? Success is when these drop steadily, but if they are not reported, it is a bad sign.

arevamirpal::laprimavera said...

@netudiant, the problem seems not so much the lower DF itself, but whether the DF is high enough for the reverse osmosis. The max that RO membrane can work is 100 becquerels/cubic centimeters, according to TEPCO, and SARRY can reduce cesium to 20 becquerels/cubic centimeter. So it should be enough for RO but not really a comfortable margin for TEPCO, considering whatever else is in that treated water.

TEPCO is not measuring what's in the highly concentrated salt water after the RO and evaporation. The reason is "Because no one will go anywhere near."

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