Eight months after the crisis at the Fukushima Daiichi nuclear powerplant, the site has become a massive construction site. In fact, Japan is about to reach an important milestone: putting into cold shutdown Fukushima Daiichi's four damaged reactors.
Last month, the Tokyo Electric Power Co. (TEPCO), the plant's owner, announced it would stabilize the crippled reactors and have the nuclear fuel cooled below 100 degrees Celsius by the end of December.
The March 11 tsunami caused the loss of power to cooling systems that led to core melting, hydrogen explosions that blew apart reactor buildings, and massive releases of radiation. More than 100,000 residents had to be evacuated from as far as 30 kilometers away.
Gradually, the nuclear threat has been brought under control. There is no longer talk of uncontrolled spontaneous fission or explosions that would release additional massive radiation. A month ago, some evacuated residents were allowed to return home, though areas close to the stricken plant are still off-limits.
Radiation levels around the reactors have declined to the point that, early in November, journalists were allowed to visit the plant for the first time since the earthquake and tsunami.
According to TEPCO, 3,200 workers swarm over the site every weekday, erecting the temporary structures, operating water decontamination facilities and building more tanks for storing decontaminated water. Currently, 90,000 tons of water is stored in tanks, and about 40,000 tons more has accumulated at the bottom of the damaged reactor buildings.
Getting workers on-site is a time-consuming, laborious process. At a staging area on the edge of the 20-km evacuation zone, everyone must don Tyvek protective suits, gloves, plastic booties over their boots, respirator masks and radiation detectors. At the end of their shifts, they are checked for radiation exposure. The government has set a limit of 250 millisieverts per year as an emergency measure for those working at Fukushima Daiichi.
Although radiation levels have dropped significantly, they are still high. The media crews recorded doses of 300 microsieverts per hour near the reactors. This amount means that even though the reactors are stabilized, "the radiation remains high, so when it comes to daily work on-site, there is still danger," plant chief Masao Yoshida told the reporters.
Initially, TEPCO had warned that achieving cold shutdown might take until early 2012. Reaching the milestone early "is not a surprise since I suspected that TEPCO had given us a conservative estimate" on the schedule, says Hisashi Ninokata, a nuclear engineer at Tokyo Institute of Technology. However, he says, it is important to note that contaminated water in the basements of the reactor buildings has not yet been properly contained. The risk posed by this material is low, he says, but he is still concerned about how TEPCO intends to confine it. He also thinks the 30-year dismantling target is "too optimistic."
In fact, the Fukushima clean up could last longer than the commercial use of nuclear power in Japan. By some polls, a majority of the public now opposes the use of nuclear power. Several members of the ruling Democratic Party of Japan have called for nuclear power to be phased out. Officially, the government is setting up a panel to rethink the nation's energy policy. A report is due next summer. Meanwhile, the Ministry of Education has shifted the focus of nuclear-related research to safety. Research into future nuclear-power generation schemes, such as at the experimental Monju fast-breeder reactor, has been put on hold. Education Minister Masaharu Nakagawa told the press last month in Tokyo that Monju would be maintained until the role of nuclear power is clarified in the new energy policy.
To reassure the public, the Japanese government ordered utilities to subject their nuclear facilities to stress tests to verify their safety under earthquake and tsunami loads. Unlike in Europe where independent nuclear regulatory agencies set test criteria, in Japan a unit of the Ministry of Economy, Trade and Industry is deciding what standards to apply, which makes Ninokata cautious. "Distrust [of] the Japanese government by Japanese is not easily removed," he says. He also questions a process that will not be subject to a review by outside experts.
Forty of Japan's 54 commercial nuclear reactors are currently offline. Most were taken off-line for routine maintenance. The government ordered those that are considered vulnerable to natural disasters to shut down pending safety reviews. One reactor at Kyushu Electric Power Co.'s Genkai nuclear powerplant automatically shut down due to technical glitches. And in the aftermath of Fukushima, local elected officials have been hesitant to give the necessary nod to restart the plant.
Anticipating possible power shortages during peak demand in the winter months, the government has asked businesses and consumers to conserve electricity, setting targets of 10% in the Osaka area and 5% on the southern island of Kyushu. Without mandating targets, the government is asking Tokyo-area consumers to cut power consumption.
Goshi Hosono, the minister of nuclear-power policy and administration, accompanied journalists on a recent visit to the plant. It was his fourth visit to the site since May. Addressing workers in the plant’s on-site disaster headquarters to thank them for their heroic efforts, he noted that working conditions have steadily improved. He said he was relieved to know the reactors are heading toward stabilization. But he also reminded them that 30 years of hard work lay ahead.