(This post is by Christine McCann)
Here’s the latest of our news bulletins from the ongoing crisis at Japan’s Fukushima Daiichi nuclear power plant.
State of Nuclear Politics in Japan
A joint council of Japan’s parliament is finalizing appointment choices for a 10-person panel, which will investigate the Fukushima Daiichi nuclear disaster. Unlike the government’s third-party expert panel, this group will have authority to summon witnesses under oath and demand documents from power companies, local municipalities, and the central government. The panel will be comprised of experts from a variety of disciplines, including those specializing in nuclear engineering, seismology, radiology, and tsunami studies. Kiyoshi Kurokawa, former head of the Science Council of Japan, is expected to chair the group, and Nobel laureate and chemist Koichi Tanaka is expected to sit on the panel.
Japan’s Nuclear and Industrial Safety Agency (NISA) has assembled a panel to study whether aging facilities contributed to the Fukushima Daiichi nuclear crisis. The panel will eventually make recommendations on safety regulations for plants across Japan, where a third of nuclear reactors are more than 30 years old.
At the same meeting, NISA announced that a subcommittee will examine whether current safety assessments are adequate to determine the future of Reactor 1 at Kyushu Electric’s Genkai plant in Saga Prefecture. Kyushu insists that there is “no safety problem,” but some experts say the reactor should be decommissioned, pointing to faster rates of deterioration and embrittlement than expected. Embrittlement occurs when steel pressure vessels are exposed to intensive neutron radiation, and subsequently weakened. Should temperatures change rapidly, the reactor vessel could then break. The reactor, which first became operational in 1975, went offline for standard safety inspections this week, but could remain down until the subcommittee delivers its report in March. Only nine working reactors remain in Japan, down from 54.
Japan’s Diet is preparing to approve nuclear accords with Jordan, Russia, South Korea, and Vietnam, paving the way for Japanese sales of nuclear equipment and technology. The move comes in spite of popular disapproval in Japan, where anti-nuclear sentiment has grown since the Fukushima disaster in March.
Nuclear experts from China, South Korea, and Japan met at Ministry of Economy, Trade, and Industry (METI) headquarters this week and agreed to quickly exchange pertinent data in case of a nuclear disaster. Japan came under harsh criticism after the Fukushima disaster in March, when it initially withheld information about releasing radioactive materials into the sea. The group has not determined yet which specific information would be exchanged, or how it would be conveyed.
Japan revealed that Masao Yoshida, the former head of the Fukushima Daiichi plant, told workers at the crippled plant to disregard orders to stop injecting seawater into one of the reactors at the height of the nuclear crisis. “I will order you to stop the water injection… but do not listen to it,” he said. Yoshida was chastised by Tokyo Electric Power (TEPCO) for not following orders, but many experts say that his actions prevented further catastrophe. Last week, he was hospitalized for an unknown illness, and has been removed from his post at TEPCO for health reasons.
The governor of Fukushima Prefecture, Yuhei Sato, has announced that he will ask TEPCO to decommission all 10 of its nuclear reactors. Prefectural officials are drafting a reconstruction plan that will no longer rely on nuclear power.
As a result of financial obligations from massive compensation payments owed to victims of the Fukushima Daiichi nuclear disaster, TEPCO has halted construction at its Higashidori plant in Aomori Prefecture. The utility had been building a large advanced boiling water reactor (ABWR). The company has yet to make a decision about a second planned Higashidori reactor, on which construction has not yet started.
TEPCO said this week that contrary to its previous reports, it now believes that 100% of the fuel in Reactor 1 melted, dropping through the containment vessel and melting through 75% of the vessel’s concrete base. Using computer simulations, the utility estimates that 67 cm of the concrete was eroded, leaving only 37 cm (approximately 14 in.) between the melted fuel and reactor container’s steel wall. TEPCO also estimates that 57% of the fuel in Reactor 2 melted and dropped to the bottom of reactor vessel, and 63% in Reactor 3. The Japan Nuclear Energy Safety Organization (JNES) also released a simulation this week, and cautioned that damage may be more extensive than TEPCO’s simulation shows. Some experts have called for a variety of simulations to be conducted and studied, pointing out that the internal status of the reactors remain unknown.
TEPCO has begun to inject nitrogen into pressure vessels of Reactors 1, 2, and 3 at the Fukushima Daiichi plant, in an effort to avoid a hydrogen explosion. The utility is attempting to keep hydrogen levels below 4%; should they rise higher than that, an explosion could occur. NISA is monitoring the situation. In October, TEPCO unexpectedly found hydrogen in piping of reactor #2 at a density of up to 2.9 percent.
TEPCO has reversed an earlier report that stated a hydrogen explosion occurred in Reactor 2 on March 15. The utility now says that based on seismographic data, an explosion occurred in Reactor 4, but not 2. However, company officials have no explanation for high levels of radioactivity that were released on that date, although they admit that radioactive gasses were released. Experts have expressed concern and have called on TEPCO to explain the release of radioactivity.
TEPCO admitted that in the month following the Fukushima disaster, water levels in Reactor 4’s spent fuel pool dropped to within 1.5 meters of a level that would have exposed the fuel. Under normal circumstances, they are covered by seven meters of water. In late April, workers finally covered the fuel assemblies with water.
Power Company Corruption and Scandals
An expose by The Mainichi Daily News revealed that nine power companies purchased tickets to political fundraising parties, in spite of a 1974 pledge to never make political contributions. Most ticket sales were intentionally kept to less that 200,000 yen, which meant that they did not have to be reported. One official from Kansai Electric admitted, “Fundraising parties are important sources of useful information for us.”
Contamination (Includes Human Exposure)
Japan’s Science Ministry plans to measure radiation levels in soil from the no-entry zone within 20 km of the crippled plant. Experts conservatively estimate that between 15 and 31 million cubic meters of radioactive soil will need to be cleared and disposed of, but caution that if contamination is more extensive in the no-entry zone, those numbers—and costs of decontamination—could increase.
TEPCO has discovered high soil radiation levels at the seaport near the Fukushima Daiichi plant. Soil samples measured 870,000 Bq/kg of cesium-137 and 730,000 Bq/kg of cesium-134.
Almost nine months after the Fukushima nuclear disaster, the Ministry of Education, Culture, Sports, Science, and Technology (MEXT) said that it will limit radiation in elementary and junior high school lunches to 40 Bq/kg or less. Measurements will be made available to the public.
Rice shipments from Date City, 60 km from the Fukushima Daiichi plant, have been suspended after samples exceeded government limits of radioactive cesium. One sample measured 1,050 Bq/kg. The government limit is 500 Bq/kg. Osamu Fujimura, Japan’s Chief Cabinet Secretary, revealed that 9 kg had been sold to consumers; it is unknown if the rice was consumed. Last week, shipments from the Onami District were suspended. In October, Fukushima Prefectural officials assured residents that all rice in the prefecture was safe. The prefecture is now inspecting samples in all areas of the prefecture with high levels of radiation, and will ask the central government for assistance with equipment, personnel, and reimbursement of costs.
Decontamination Efforts and Waste Disposal
Japan’s Health, Labor, and Welfare Ministry is advising that only firms specializing in decontamination should be involved in cleanup of areas where annual radiation exposure would be more than one millisievert, and those companies must ensure the safety of their staff. The Ministry may unveil new decontamination safety guidelines as soon as January as part of the Industrial and Safety Health Act.
The chair of an independent advisory panel for the US Nuclear Regulatory Agency said that the Agency’s proposal to require plant owners to improve electrical safety within four and a half years is “way too long.” Changes are being implemented in the wake of the Fukushima nuclear disaster. Said Abdel-Khalik, the panel chair, pointed out that the Fukushima disaster happened over eight months ago, and said, “With all due respect, all we’ve been doing is talk[ing].”