Health consequences for people who have not been at the site look set to be effectively zero from events so far. Significant emissions of dangerous radio-iodine, the main health hazard which could eventuate, don’t look to be on the cards from the cores: and the spent fuel at the No 4 pool – not having been involved in a chain reaction for months – no longer has significant quantities of iodine-131 in it, this isotope having a half-life of 8 days.
The last remaining possibility of serious consequences would appear to be that of severe heating in the spent rods at No 4 melting them down and so perhaps causing significant airborne emissions of longer-lived radioisotopes such as caesium, or even heavy fuel metals. This would be unlikely to affect peoples’ health given the evacuation and public protection measures already in place, but it might mean areas having to be abandoned for lengthy periods as occurred after Chernobyl.
However, airborne dispersal of radioactives from Chernobyl was driven by the fact that they were mixed with graphite (carbon) coolant which remained on fire for days, carrying carbon soot mixed with radioactives far from the site. Fires at Fukushima’s cooling pool thus far have been doused within hours, and there seems no obvious reason why large amounts of rod material should become airborne even if rods do melt down in defiance of the Japanese industry’s assurance that they won’t.
“If someone can explain to me how those heavy particles, the heavy metals and even the non-gaseous fission products can be carried over a wide area, I’d like to hear it because I don’t know a mechanism where that could happen in these sort of reactors,” Professor Barry Brook told Australian media yesterday [4]. Brook is director of Climate Science at the University of Adelaide’s Environment Institute.
“To be honest, and I don’t want to sound too optimistic, but I think the worst is probably over,” added the prof, who is a longstanding advocate of nuclear power as a means to battle climate change.
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Sounds to me like even if things so to Hell in a handbasket, there isn’t much to worry about. Concern? Definitely! But not worry. Then again, inducing panic gets ratings and sells papers, so why listen to science?