(Update) Hatoyama says in his Nature article that his team had the TEPCO data on chlorine-38 re-analyzed, and came to the conclusion that chlorine-38 was in the water in the basement of Reactor 1, and the density was 1.6 million becquerels/milliliter, just as TEPCO had originally reported. (reading the Japanese translation by Nature Asia.) About his thinking on Reactor 3 nuclear explosion, go to my new post.
Back in March and April, there was a little fuss about recriticality happening in one or more of the reactors at Fukushima I Nuclear Power Plant because of the announcement by TEPCO of the detection of chlorine-38 in the water in the turbine building. Based on that announcement, Hiroaki Koide of Kyoto University was the first researcher (I think) in Japan who said recriticality may have happened.
Chlorine-37, stable isotope in seawater may acquire neutron and become unstable chlorine-38. The source of neutron? Fissioning uranium somewhere nearby.
Then, TEPCO denied it later, as one of many "mistakes" they supposedly made in identifying the radionuclides.
But now, apparently in the Nature magazine article that he wrote with a DPJ politician in Japan's Lower House, he says the following, according to Yomiuri Daily (English) (12/16/2011):
In the article, Hatoyama criticizes Tokyo Electric Power Co., the operator of the crippled plant, for disclosing only limited information to Diet committees. He also hints at the possibility of recriticality at the plant and says there is still much about the crisis that needs clarification, including the state of the molten fuel within the nuclear reactors.
Hatoyama also says that he and Taira obtained data on samples of contaminated water TEPCO obtained from the basement of the plant's No. 1 reactor and asked an outside research institute to reanalyze them.
Results showed that radionuclide chlorine 38, one of the isotopes released during recriticality, "was indeed present," he claims.
TEPCO reported at one point that it found chlorine 38 in the sampled water, but the utility later retracted that statement, saying there was a mistake in the analysis.
The Japanese version of this article says exactly the same. And the very interesting thing is that hardly anyone paid attention when the article came out on December 15 in Japanese. The number of tweets for the article is only 12. I saw the headline of the article at Yomiuri, but I didn't think much of it at all and skipped it, partly because I don't care to read anything this former PM of Japan, whose nickname is "space alien", writes.
But to give him some credit, he held a weekly study group in the early weeks and months of the nuclear crisis, inviting researchers who were then ridiculed by the mainstream media and politicians as "extreme" - those who said the Fukushima I Nuke Plant accident and the resultant radiation contamination were far more serious than admitted by the government and the MSM.
Judging by the number of Japanese readers retweeting the Japanese version of Yomiuri article that I just tweeted, it is news to them, too.
The title of the article is "Hatoyama: Nationalize Fukushima N-plant". A boring title, on purpose, probably, so that no one reads it. TPTB couldn't afford to attract attention to "recriticality" when they were about to announce a cold shutdown of the plant. Yomiuri did its patriotic duty.
(H/T to enenews for noticing the details beyond the headline.)