A flash of blue light was the first sign that something was wrong, horribly wrong. Last Thursday morning at 10:35, three workers at a uranium conversion plant in Tokaimura, the epicenter of Japan's nuclear power industry, saw a glow emanating from inside a large stainless steel tank they were filling with a uranium solution. It's too bad the flash wasn't detected by any of the 310,000 residents in the surrounding areas who would go on about their normal lives for hours--risking dangerous exposure to radioactivity--before being informed of the accident. It's too bad they couldn't see it in the Prime Minister's office in Tokyo, 130 km to the southwest, or rescue efforts might have begun more quickly than they did. It's too bad they couldn't see it a few kilometers away at the Tokaimura town hall, or at the fire station, from where three firefighters were dispatched to the uranium plant without any protective gear because they thought they were going to treat someone having a seizure. Instead, word of Japan's worst nuclear accident trickled out far more slowly than did the poisonous fumes from the steel tank. The town's mayor didn't find out for at least an hour, and Prime Minister Keizo Obuchi didn't realize the seriousness of the incident until the afternoon. The people of Tokaimura also didn't know how bad things were until officials started advising those living closest to the plant (some houses are less than 200 m away) to evacuate. Those who live farther away spent the next terrifying day bunkered in their homes, windows and doors tightly sealed. The townsfolk had no idea if they had already been exposed. They should have told us right away, says Hideyoshi Hirohara, 16, who was outside with his high-school gym class even as the radioactive leak threatened his neighborhood. A lot of people saw this on TV before the town said anything about it.
By the time the mess was cleaned up the following day, at least 49 people were being treated for radiation exposure. The three workers--who had been exposed to radiation levels estimated to be as high as those surrounding Chernobyl during its 1986 disaster--and the three firefighters sent to answer their distress call were all hospitalized. At one point radiation levels in Tokaimura were reportedly 15,000 times higher than normal. On the rare occasions in which similar accidents have occurred elsewhere, the nuclear chain reactions have usually been halted after just a few seconds when, typically, automatic safety systems kick in to stop the process. But at Tokaimura last week, the reaction went on, unabated, for 20 hours. As time dragged on, plodding officials in Tokyo and in Ibaraki prefecture dithered and displayed an inability to come to grips with a serious crisis. They really haven't thought through the consequences of relying on nuclear power, says Gregory Jones, a senior policy analyst at California's Rand Corp. who specializes in nuclear hazards. Accidents are going to happen from time to time, and they're woefully unprepared for it.
Luckily, last week's accident wasn't of Chernobyl-like proportions. Nor was it as bad as Three Mile Island, the 1979 meltdown in the U.S. state of Pennsylvania. But it was frightening, nonetheless, because a potentially explosive and lethal situation was clearly out of hand in a heavily populated area. For the better part of a day, a nuclear chain-reaction continued, unchecked, in a facility whose equipment and personnel were incapable of stopping it. The Tokaimura unit is part of the fuel supply line for an experimental fast-breeder reactor nearby. At the conversion plant, uranium is combined with nitric acid to produce uranium dioxide; this is taken to another facility where it is combined with plutonium to produce the enriched uranium pellets used as fuel at power plants. What happened on Thursday, according to JCO Co., the subsidiary of Sumitomo Metal Mining that operates the plant, is that workers mixed too much uranium--16 kg instead of the maximum allowed 2.4 kg--with the nitric acid. They used stainless steel buckets to pour the liquefied uranium solution into a large tank. By doing so, they bypassed the usual procedure of feeding the uranium solution through a device that measures the proper amount to be distributed to the tank, apparently because the plant had received an order to produce a higher grade of the uranium compound. News reports in Japan say the workers, who each had at least 10 years of experience, were not practiced in mixing the uranium solution in this unorthodox manner.
The result was a potent radioactive cocktail. The concentration of uranium was so much higher than usual that by the time workers had poured the seventh bucketful of the concoction into the tank, it triggered nuclear fission. That happens when a neutron is absorbed into the nucleus of a uranium atom, causing the nucleus to break open and release energy and toxic substances such as radioactive iodine and radioactive cesium. Neutrons continue to bombard more uranium atoms, and the chain reaction continues. It is normal for fission to occur in nuclear reactors that have equipment to modulate the reactions. But it isn't supposed to happen at fuel-conversion plants. And the plant operators conceded last week they weren't prepared to handle the consequences.
As all hell was breaking loose inside the plant, the people of Tokaimura had no idea anything was amiss. Members of the Kawano family went ahead and used water from their well--within the area in which people were advised to bunker down--to wash vegetables, make miso soup and brush their teeth. Teenager Yoshitaka Nanbara wandered around the neighborhood and to a friend's house, a few yards from the plant's back fence, two hours after the accident. The two spent another hour playing Biohazard, a game that involves biological warfare, on a Sony PlayStation machine. The loudspeakers mounted on telephone poles outside were silent.
Tokaimura, a sprawling coastal town, should be prepared for nuclear accidents. Its 33,900 residents live in the vicinity of 15 nuclear-related facilities. The town has a Nuclear Energy Science Museum, road signs with cartoon drawings of Albert Einstein and avenues with names like Atomic Research Street. One of Japan's earliest nuclear power facilities, a research institute, opened here in 1956. The town has witnessed three other accidents in the past four years: a radiation leak at another plant in 1995, a fire and explosion at a nuclear-waste treatment plant in March 1997 and the discovery of 2,000 drums leaking radioactive waste in August 1997. But Tokaimura seemed to have learned little from those earlier experiences as it fumbled to deal with last week's crisis. The government's response was child-like, said Takashi Hirose, an anti-nuclear activist.
Prime Minister Obuchi also appeared slow to act: his office wasn't informed of the potentially lethal mishap for several hours. We must admit that we were behind in dealing with this accident, says Hiromu Nonaka, chief secretary of the Prime Minister's cabinet. Even after they were told, Japan's leaders concede they didn't initially take the news seriously. As a result, it wasn't until the afternoon--more than five hours after the accident--that the 160 residents who live closest to the facility were told to evacuate to a community center. Technicians in gray jumpsuits scanned the residents' bodies with Geiger counters to measure the levels of radioactivity. Later that day, loudspeakers in neighboring towns within a 10-km radius blared warnings to more than 310,000 people to stay inside, close doors and seal windows. Don't go out, the voice cautioned. When we have more information, we will tell you.
For the next 12 hours, Japan wasn't sure what was happening. It started to rain Thursday evening, and people wondered if that would spread the radiation. On Friday morning, communities around the plant looked like ghost towns. Train service was halted. Police officers in white suits and face masks stopped motorists from entering contaminated areas. Convenience stores, restaurants and schools were all shuttered. Still no one knew: Was this a minor screw-up or a full-blown catastrophe? Obuchi went on national TV, only to say that officials weren't sure what exactly had gone wrong or how to stop the reaction inside the plant. As the hours ticked by, no emergency crews were dispatched to the site. What did seem clear was that Japan once again was failing to respond effectively to a crisis. After the 1995 earthquake in Kobe, victims complained that rescue crews arrived distressingly late. This time, too, the official response seemed to play out in slow motion.
The bright blue light that flashed at the Tokaimura plant was a reminder of something else: the less-than-stellar safety record of Japan's nuclear power industry. A country that has 52 nuclear plants and gets one-third of its energy from nuclear power can't afford to be lax. But the industry has been plagued by accidents, plant shut-downs, leaks and repeated attempts to cover things up. Although the earlier incidents provoked a major shakeup in the administration of Japan's nuclear regulatory agencies, they still seem to escape adequate scrutiny. The foul-ups would almost be comical if they weren't so serious. In July, just after a leak at a nuclear reactor in Fukui prefecture, operators gave 90 visitors a tour outside the plant, even though they hadn't yet found the source of the leak and didn't know the extent of the damage. (As it turned out, the damage was benign and no one was hurt.) Videotape documentation of another plant accident was tampered with by the plant operator in 1995. After managers at another Tokaimura plant, where an explosion occurred in 1997, tried to hide the incident, Ryutaro Hashimoto, then Prime Minister, steamed, I am so angry that I cannot utter a word.
There was even less to say after the jaw-dropping account of what happened on Thursday. Carrying highly concentrated uranium around in buckets? Using seven times more of the material than usual? It sounds like the guy who did this either didn't have a procedure to follow, didn't understand or know it, or just didn't comply, says Dick Snell, a nuclear engineer at a radioactive repository project near Las Vegas. Suitably embarrassed, JCO Co.'s president, Koji Kitani, prostrated himself and apologized to residents who may have been exposed to high levels of radiation. We cannot escape our responsibility, says a company spokesman.
On Friday, people in and around Tokaimura had been told it was safe to come outside again. But despite the assurances that the hazard had passed, some worried about the next flash of blue light. Satomi Akutsu, who is six months pregnant, waited in a community center as technicians checked her for radiation exposure. The metal wand was silent as it brushed against her body. There were no beeps. She was safe, for now. I didn't know that this kind of factory was even here, she said. I'm relieved we're O.K., but I want to move out of this place. For Japan's atomic-power industry, however, there is no escaping responsibility for this nuclear nightmare.