The situation at the quake- and tsunami-stricken Fukushima Daiichi nuclear powerplant in Japan was brought under control days ago. It remains the case as this is written that there have been no measurable radiological health consequences among workers at the plant or anybody else, and all indications are that this will remain the case. And yet media outlets around the world continue with desperate, increasingly hysterical and unscrupulous attempts to frame the situation as a crisis.
Here's a roundup of the latest facts, accompanied by highlights of the most egregious misreporting.
First up, three technicians working to restore electrical power in the plant's No 3 reactor building stood in some water while doing so. Their personal dosimetry equipment later showed that they had sustained radiation doses up to 170 millisievert. Under normal rules when dealing with nuclear powerplant incidents, workers at the site are permitted to sustain up to 250 millisievert before being withdrawn. If necessary, this can be extended to 500 millisievert according to World Health Organisation guidance.
None of this involves significant health hazards: actual radiation sickness is not normally seen until a dose of 1,000 millisievert and is not common until 2,000. Additional cancer risk is tiny: huge numbers of people must be subjected to such doses in order to see any measurable health consequences. In decades to come, future investigators will almost certainly be unable to attribute any cases of cancer to service at Fukushima.
Nonetheless, in the hyper-cautious nuclear industry, any dose over 100 millisievert is likely to cause bosses to pull people out at least temporarily. Furthermore, the three workers had sustained slight burns to their legs as a result of standing in the radioactive water - much as one will burn one's skin by exposing it to the rays of the sun (a tremendously powerful nuclear furnace). They didn't even notice these burns until after completing their work. Just to be sure, however, the three were sent for medical checks.
So - basically nothing happened. Three people sustained injuries equivalent to a mild case of sunburn. But this was reported around the globe as front-page news under headlines such as "Japanese Workers Hospitalized for Excessive Radiation Exposure". Just to reiterate: it was not excessive.
Reporters clamoured to know more - in particular how could the water in the basement of the reactor building have become so radioactive - no less than "10,000 times normal". One might note that in general radiation levels 10,000 times normal mean that you could achieve a tiny fraction of an extra percentage point of cancer risk by being exposed for a fortnight or so.
Japanese government spokesmen briefing the press obligingly gave a list of possibilities. Among these was the possibility that the suppression chamber at No 3 may be leaking water or steam due to damage (as well as doing so due to planned venting operations which are being carried out on purpose).
The suppression chamber is technically part of the core's primary containment, though in fact the core itself lives in its own central cocoon at the middle of the doughnut-shaped, water-filled suppression chamber. The plant owner, TEPCO, in conjunction with Japanese government officials, stated that the No 3 suppression chamber might have suffered damage well over a week ago: this possibility was well known. We here at the Reg reported it back then, and not being goldfish we still remember doing so.