Nuclear accident

September 30, 1999, Japan experienced one of the most serious nuclear accidents in the history of nuclear energy. It happened in a reprocess plant in Tokai village of the suburb about 120 km away from Tokyo. Even anyone who has no specific knowledge about the field could hardly believe the cause of the accident. During reprocessing work in the plant, the workers put highly enriched uranium into inappropriate reprocessing vessel, with a bucket at once to omit the appropriate process regulated by the plant’s manual. Exactly saying, the process they ware supposed to do was also inappropriate. The manual they used was not approved by the government. The plant had been doing the illegal reprocessing work since 10 years ago.

What happened next was that the fuel attained criticality only to emit the huge amount of radioactivity exceeding permissible levels enough. Nuclear fuels such as uranium or plutonium become critical when the certain amount of those fuels converge in one spot. Chain nuclear fusion resulting from emitting neutron generates big energy. This mechanism works in nuclear reactors. Different form the reactors, the reprocessing plans was not proper facility for generating huge energy. As a result, two workers have died afterward because of the exposure of too much radiation. The residents around the plan faced the radiation risk.

Learning from the lesson, the government passed a new law for special countermeasures against nuclear hazards. It makes obligatory to have inspection once a year and sets up off-site centers near those nuclear facilities to monitor the radiation levels. If the radiation leaked from the facilities exceeds certain level, the off-sites centers will take emergent measures for the leakage of radiation and give warnings to neighbors. Residents near there can take some quick countermeasures themselves such as putting on thick cloths to avoid the exposure of radiation, or escaping from the houses as far as possible.

This kind of measures particularly for disastrous accidents tends to depend on the authority including governments. However, on the sides of residents too, self-protections measures are absolutely necessary. Measures for safety do work when citizens and authorities cooperate with each other.

As far as nuclear accidents are concerned, I don’t have nothing to do with the accident that happened in the reprocessing plant. To say clearly, I was almost within 10-kilometer scope of the plant at the moment when it happened. At that time, I was going and coming almost every day for my insurance job between Mito (the capital city of the Ibaraki prefecture) and Hitachi(the born place of an electronic giant, Hitachi). I often drove a business car by the reprocessing plan usually during lunchtime because I allot the lunchtime for moving to save time as many businesspersons do. Since the accident occurred during lunchtime, I was supposed to drive very near there. But as God sometimes smiles me, I was luckily in my client’s office a little far from the plant. Nevertheless, I knew the fact 3 hours later. Even the residents living near the plant was given the first warnings 2 hours later. Although food-related businesses such as agriculture or fishery had been heavily damaged, fortunately there were not bodily victims except the workers in the plant. We should have been notified much earlier in such serious accidents.

Theses nuclear-related accidents have been seen often in Japan particularly in recent years. What's outstanding is human mistakes. Like the case of the reprocessing plant I have been mentioning, it's not facilities but humans that cause serious accidents. What's worse in the recent accidents is that parties concerned intentionally manipulate what's happening in nuclear facilities. One covered up the causes of accidents to escape from the responsibilities. Another changed the data of insulating materials for used fuels. In nuclear facilities such as reactors, there are certain levels of safety devices if something happens to the machines. When it comes to human factors, however, there seems to be no safety device.

<The map of nuclear facilities>

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