In November, I visited JCO Co.’s nuclear fuel-processing plant — a subsidiary of Sumitomo Metal Mining Co. — where Sept. 30 a level-5 nuclear incident took place. The plant is located 110 km from Tokyo in the small town of Tokaimura, Ibaraki Prefecture. The plant is in an area that is a blend of residences and light industry. The nearest industry is less than 80 meters from the site of the accident and the nearest residential housing only 20 meters further away. There is a school in the vicinity, and when I stood outside the small, concrete building where the accident took place, I could hear children’s shrill voices from the nearby playground.
The rather simple, official version of what happened holds that the accident was caused by employee negligence. Three employees were engaged in a solvent extraction process. Failing to follow procedures in the operating manual, the employees used a bucket to transfer uranium oxide into a precipitating tank. The uncontrolled transfer led to a situation where the critical mass of uranium in the tank became sufficient for a self-sustaining nuclear reaction to start.
At this point, a blue flash took place and vast amounts of radiation were released. One worker, who recently died, received 17,000 times the recommended maximum annual dose. Because no emergency procedures had been established to deal with such an event, criticality continued for more than 20 hours until action could be taken to drain the water from the cooling jacket surrounding the precipitation tank. This was necessary because the water had been reflecting neutrons coming from the nuclear reaction in the precipitating tank, helping to sustain the criticality.
Finally, the criticality was terminated by adding a boron solution, which absorbs neutrons.
Yet the official story is too simple, for it fails to explain the deeper reasons behind the accident. In reality, it was negligence by workers and management driven by competition and government deregulation, and compounded by risk management strategies that did not even encompass the art of the possible let alone consider the unthinkable.
Despite the special nature of the nuclear industry and endless safety plans, no one had thought to include the possibility of a criticality accident in the emergency plan, despite the fact that there have been seven such accidents in the United States, one in Britain and 12 in Russia, and all but one were triggered by uranium in solution or slurry. Thus when the Tokai accident occured, the cooling jacket could only be drained manually.
When an attempt was made to drain the water, the controls were found to be stuck. Nobody knows why, but the system had almost certainly not been used for almost three years. So they were forced to smash the valve. This action still failed to drain the water, which was finally forced out by pumping in argon gas under pressure. As a result of this delay, the criticality continued spewing out radiation for more than 20 hours. In fact, it was only discovered Oct. 11, 12 days after the accident, that radioactive iodine was still being released into the atmosphere because a ventilating system had been left on.
When the accident happened, reaction was painfully slow and inadequate. It took more than three hours before evacuation was ordered to more than 350 meters from the accident site. During that time, a number of workers in an adjacent factory suffered exposure to radiation, along with many JCO Co. employees.
Japan’s Science and Technology Agency has estimated that during criticality, at a point 80 meters from the accident site — where the closest public street lies — radiation would have been 160 times higher than the annual recommended exposure dose, At 200 meters from the site it would have been 13 times higher and 350 meters from the sight, where the limit of evacuation was set, it would have been twice as high. The health hazards of radiation are not generally considered to rise gradually with exposure rather than be triggered suddenly. Thus many were exposed to an albeit limited, but nevertheless not insignificant, health hazard that will manifest itself over the coming decades and generations.
The three workers who triggered the accident deliberately shortcut the process, but the company’s own operations manual failed to conform to normal procedures. If the workers were aware of this first breach of procedure, it is hardly suprising that with the company signposting the ability to change the rules in the interests of speed and profit, they chose to cut a further corner.
While the workers were all long-term employees of the company — two having worked there for 10 years and the third for 14 years — the procedure they were engaged in was an unusual one. It was an operation only undertaken once every three years or so. This task for them was extra work and something to be done quickly so they could get back to their normal work in the second fabrication plant where they did reconversion work and handled solid-waste disposal. For two of the three workers, it was the first time they had undertaken the operation, and none of them had training in criticality control.
On that fateful morning, they were processing the last of seven batches of material. They were well ahead of schedule and probably expecting congratulations for a job well done rather than contamination.
In the broader context, since Japan was hounded by the U.S. and to a lesser extent Europe, along the path of what is euphemistically called “structural reform,” the economy has seen deregulation and downsizing, retrenchment and redundancies. Sumitomo Metal, the owner of the Tokai plant, has been losing money and ground to Mitsubishi, the only other indigenous player in the sector of nuclear industry. Jobs have been lost.
Sumitomo’s problems stemmed from the Electric Utility Industry Law of 1995, which opened up the industry to fierce competition from U.S. manufacturers with cheap nuclear fuel. A few years ago, the annual demand for uranium conversion in Japan was just over 1,000 tons, with production split 60:40 between Sumitomo and Mitsubishi Nuclear Fuel Co. However, the demand for Tokai’s material had dropped sharply in the last three years as U.S. competition ate into the market. Since 1996, the number of production workers at the Tokai plant has been reduced by more than half, from 138 to 68.
This matrix of problems is not limited to Japan. It may well be right and proper for the full rigors of free trade to sweep aside vested interests and practices in the majority of industrial sectors. For companies in the interest of commerce to cut fat to the bone may work in telecommunications and transport, financial services and fishing. It does not work in anyone’s interests in the nuclear industry where the cost of errors is monumentally asymmetrical to any possible benefit. Tokai’s criticality on Sept. 30 was not a Japanese accident, but a nuclear one. Unless that it is understood, we will fail to draw the lessons this disaster must teach us for the future.
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