Trial fitting of the cover for Fukushima Daiichi Nuclear Power Station Unit 1, at Onahama port, 24 June 2011. TEPCO

By arevamirpal::laprimavera
19 July 2011 That’s an amazing reduction from the maximum emission of 2,000 terabecquerels per hour on March 15, it is actually one-2 millionth of the maximum, says TEPCO in the Reference No. 2 of the progress report on the “roadmap” to God knows where. Is this number, 1 billion becquerels per hour emission, good? TEPCO’s Matsumoto, in the press conference on July 19, avoided the judgment, and said he didn’t know, but it was one-2 millionth of what it had been on March 15. On closer reading of the document, though, I noticed one strange thing about this emission number. TEPCO is talking about the radiation emission measured in cesium (cesium-134 and -137), not in iodine equivalence. To come up with the iodine-131 equivalence, you have to multiply cesium-134 by 3, and cesium-137 by 40 (according to INES handbook). TEPCO doesn’t even give the breakdown of cesium 134 and -137 in its calculation of 1 billion becquerels/hour number. Other nuclides have even higher multiplier: americium-241 is 8,000, plutonium-239 is 10,000. If half of 1 billion becquerels is cesium-134 and the other half is cesium-137, then in iodine-131 equivalence like in the previous calculations, the emission would be: (0.5*3)+(0.5*40) = 1.5+20 = 21.5 billion becquerels/hour Instead of 1 billion becquerels/hour, it would be 21.4 billion becquerels/hour in iodine equivalence, or 516 billion becquerels in one day. In less than 2 days, we would be talking about over 1 terabecquerels. […]

1 Billion Becquerels Per Hour Emission of Radioactive Materials from Fukushima I Nuke Plant at the End of June