It is not yet clear why the cooling systems of the Onagawa nuclear plant, which is much closer to the epicentre of the Friday earthquake, have restarted normal functioning while those at a plant further away continue to spring unpleasant surprises. Reactors at the Fukushima Daiichi nuclear plant were designed to withstand a magnitude 8.2 earthquake. Nobody planned for 15 times stronger tremors. Amazingly, the reactors survived these relatively soundly. Then the tsunami took down the backup power. There are now murmurs about faulty design. If the diesel-powered generators had been placed at higher elevations, they may not have been flooded (but would have been more vulnerable to the quake). If the reactors hadn?t been placed so close to each other, problems wouldn?t have gotten compounded as fast and repair work would not have been as difficult (although operational efficiency would have been more challenging). Hindsight is 20-20, they say.
Not a Chernobyl
Amidst an increasing array of ifs and buts, it?s difficult to get a lock on radiation hazards. The hitherto celebrated calm of the Japanese population also seems to be melting down. People locked down in their houses elsewhere without food, fuel and water supplies are growing disgruntled with all the attention being bestowed upon Fukushima. People locked down in the Fukushima neighbourhood are wondering if their government is being transparent. Experts are flaunting completely opposite risk assessments.
EU energy chief G?nther Oettinger has said, ?We are somewhere between a disaster and a major disaster.? Others insist that even people within Japan, forget on foreign shores, are unlikely to experience really harmful radiation doses even in the worst-case scenarios. This argument gains strength when we compare Fukushima with Chernobyl.
In Chernobyl, when a botched safety experiment blew the top of the nuclear plant, radioactive material flew high into the atmosphere and across national borders. But the Chernobyl reactor actually didn?t have any containment facility to slow the release of radiation. By contrast, the Fukushima reactors not only boast each core being protected by a 20cm-thick steel container and then a steel-reinforced concrete outer structure, the fact that they have been shut down for almost a week now means that there is less fresh radioactive material available for release. Of course, there could be a disaster scenario where the fuel rods get heated enough to force radiation through even the secondary containment, or the spent fuel could boil dry and catch fire. With attempts to cool the reactors running aground, these are not unlikely scenarios.
But the Soviet leadership was in denial mode in the initial stages, which is different from how the Japanese have acted. Children kept on drinking contaminated milk. Pills that flood the thyroid to prevent it from absorbing radioactive iodine were not distributed early. So the major health impact, an increase in the incidence of thyroid cancer, could have been mitigated much better. The Japanese are not making the same mistakes.
50 brave men
Acute radiation sickness was the fate of the Ukrainian firemen who calmed down the fuel rods in Chernobyl in 1986. Most of them were dead within weeks of their brave feat. The skeletal crew that?s been manning the cooling at Fukushima or the soldiers that have been flying over it with water are looking at similar dangers. As compared to the maximum of 50mSv of radiation that workers in American nuclear plants are supposed to be exposed to in a year, these Japanese workers have been hit with levels as high as 10mSv per hour. But radiation beyond the evacuated limits remains at non-hazardous levels. And even the worst-case forecasts do not anticipate it travelling beyond Japan?s borders. Wind, rain and distance are all playing up support.