Has Fukushima's Reactor No. 1 Gone Critical?

Discussion in 'The Water Cooler' started by whoosh, Apr 2, 2011.

  1. whoosh

    whoosh Cooler King
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    On March 23, Dr. Ferenc Dalnoki-Veress, a Research Scientist at the Monterey Institute of International Studies saw a report by Kyodo news agency that caught his eye. It reported that Tokyo Electric Power Company (TEPCO) had observed a neutron beam about 1.5 km away from the plant. Bursts of neutrons in large quantities can only come from fission so Dalnoki-Veress, a physicist, was faced with an alarming possibility: had portions of one of Fukushima's reactors gone critical?
    To nuclear workers, there are few events more fearful than a criticality accident. In such a scenario, the fissile material in a reactor core--be it enriched uranium or plutonium--undergoes a spontaneous chain reaction, releasing a flash of aurora-blue light and a surge of neutron radiation; the gamma rays, neutrons and radioactive fission products emitted during criticality are highly dangerous to humans. Criticality occurs so rapidly--within a few fractions of a second--and so unpredictably that it can suddenly kill workers without warning. There have been 60 criticality incidents worldwide since 1945. The most recent occurred in Japan in 1999, at an experimental reactor in Tokai, when a beam of neutrons killed two workers, hospitalized dozens of emergency workers and nearby residents, and forced hundreds of thousands to remain indoors for 24 hours.
    Dalnoki-Veress did not see any further reference to a neutron release. But two days after the Kyodo agency report, on March 25, TEPCO made public measurements of different isotopes contributing to the extremely high measured radioactivity in the seawater used to cool reactor No 1. Again, a piece of the data jumped out at Dalnoki-Veress: the high prevalence of the chlorine-38 (CL-38) isotope. CL-38 has a half-life of 37 minutes, so would decay so rapidly as to be of little long-term safety concern. But it's very presence troubled Dalnoki-Veress. Chlorine-37 (CL-37) is part of natural chlorine that is present in seawater in the form of ordinary table salt. In order to form CL-38, however, neutrons must interact with CL-37. Dalnoki-Verress did some calculations and came to the conclusion that the only possible way this neutron interaction could have occurred was the presence of transient criticalities in pockets of melted fuel in the reactor core.
    Yesterday, he published those calculation in a paper for the blog ArmsControlWonk. The paper makes clear that if a criticality accident occurred at Fukishima, it could happen again—and while such a possibility poses minimal danger to Japanese citizens outside of the 20km exclusion zone, it means the emergency workers at Fukushima are operating in even more dangerous conditions than anyone realized. "It is important for TEPCO to be aware of the possibility of transient criticalities when work is being done; otherwise workers would be in considerably greater danger," the paper concludes. "This analysis is not definitive proof but it does mean that we cannot rule out localized criticality."


    Read more: Has Fukushima’s Reactor No. 1 Gone Critical? - Ecocentric - TIME.com
     
  2. whoosh

    whoosh Cooler King
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    So according to this report, the only thing we have to worry about is chlorine, which has a radioactive life of 37 minutes? No mention of plutonium, cesium, strontium or other radioactive materials, only chlorine. It’s obvious the disinformation shills are working overtime to keep their precious markets from collapsing.
    Every person who is withholding information from the public in this disaster is guilty of the most heinous crimes against humanity. This article is just pure BS. It looks like it was written by the CEO of TEPCO, or the person working fro him since the esteemed figure went AWOL during the crisis.
    “Tokyo Electric Power Co., the Fukushima Dai-Ichi plant’s operator, and Japan’s nuclear watchdog, dismissed the threat of renewed nuclear reactions, three weeks after an earthquake and tsunami triggered an automatic shutdown. Tokyo Electric has been spraying water on the reactors since the March 11 disaster in an effort to cool nuclear fuel rods.
    “The reactors are stopped, so it’s hard to imagine re- criticality,” occurring, Tsuyoshi Makigami, a spokesman for the utility, told a news conference today.”
    Yeah, because TEPCO has been so transparent and so successful at stopping this disaster and has been spot on accurate in their prognostications. Of course we should believe the PR spokesperson!
    “Japan’s Nuclear and Industrial Safety Agency said there’s no possibility of uncontrolled chain reactions.”
    OMFG! These people must be suffering from radiation poisoning. We have four melt downs and two more on the way (because when the plant has to be abandoned, there will be no one to control reactors 5 and 6, or any others in the area as well). But no, rest assured that we will not have any more uncontrolled chain reactions. Don’t worry abut the chlorine!
    “Ethereal blue flash” may occur during “localized criticality” -Bloomberg « Energy News
     

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