Expert who worked at Sandia Labs: ‚ÄúTEPCO data suggest that fission is ongoing‚Ä¶ This is bad news‚ÄĚ ‚ÄĒ ‚ÄúTruly scary‚ÄĚ that nobody in Japan seems to know basics of reactor accident progression
April 21st, 2011
After 5 Halflives, I-131 Higher than Cs-134/137 Suggests Ongoing Criticalities, Gerson Lehrman Group, April 19, 2011:
‚Ä¶ Japanese regulators NISA and MEXT seem oblivious of the mysterious fact that I-131 Bq ‚Äúreactor density‚ÄĚ is still often reported double the Cs-134/137 Bq. The TEPCO data suggest that fission is ongoing despite the reactor shutdowns. This is bad news. ‚Ä¶
Everyone with just a very basic understanding of reactor safety should know that once a reactor is scrammed, U-235 is no longer fissioning, and I-131 has no parent which can be decaying to create it in an ongoing process‚Ä¶ the water circulating in intact SNF pools should have absolutely no detectable I-131 in them. ‚Ä¶
[I]t has been almost five full 8-day halflives for their I-131 to decay to stable xenon. At t=0, as we say, the Bq of I-131 and Cs-134 and Cs-137 would all be approximately equal, but, after five I-131 halflives, the ‚Äúreactor density‚ÄĚ radioactivity of I-131 should be only 1/2**5=~3% of what it was originally. Go look at all the data of relative radioactivity that TEPCO is reporting with dates of April 19, 2011 and you‚Äôll see that instead of I-131 being below the levels of the two cesiums, I-131 is often twice as high as the two cesiums always reported.
The fact that nobody in Japan seems to know basics of reactor accident progression that I learned at Sandia Labs in early 1980s is truly scary, because it suggests they are playing with these broken/leaking reactors and SNF pools inside at least three buildings totally destroyed by steam explosions ‚Ä¶ as if the reactors and their SNF pools are broken toys that they‚Äôre using trial and error to try fixing.