Here’s the latest of our news bulletins from the ongoing crisis at Japan’s Fukushima Daiichi nuclear power plant.
State of the Fukushima Reactors
TEPCO officials are facing considerable scrutiny and criticism from both domestic and international experts after cooling functions were lost for 29 hours at the spent fuel pools of reactors #1, #3, and #4, as well as a shared pool storing 6,377 fuel assemblies at the Fukushima Daiichi nuclear power plant earlier this week. Power at the plant went out briefly just before 7 pm on Wednesday, but after it was restored, the cooling systems were still inoperable. Cooling functions at the reactors themselves were not affected.
The affected spent fuel pools are collectively home to 8,800 fuel assemblies, each of which holds 60 rods, for a total of 528,000 nuclear fuel rods at risk of melting down if they overheat. That process would have begun once temperatures within the pools reached 65ºC. At reactor #4’s pool, this would have taken just four days. In that scenario, water would begin to evaporate, exposing the assemblies and eventually, leading to meltdowns. The Asahi Shimbun said that if a meltdown had occurred, the results “had the potential to become catastrophic.” The utility is being criticized for delayed reporting to the Nuclear Regulation Authority (NRA) and local officials in Fukushima, where residents would be forced to flee their homes for a second time if another nuclear disaster were to occur, as well as for lax oversight of the crippled reactors and safety equipment. TEPCO spokesman Masayuki Ono said, “If you say we were complacent about making our decision [to announce the malfunction to the public] and dealing with the situation, I can’t deny that.”
Fifty TEPCO workers, in HAZMAT suits to protect them from high radiation, were dispatched to try to fix cables attached to the cooling system. Eventually, they discovered that the problems stemmed from a malfunction in a temporary switchboard that occurred when a rat entered the switchboard’s housing and presumably ran across live terminals, shorting the system and electrocuting itself in the process. Its burned body was found lying near the charred switchboard. The switchboard controlled cooling systems for the pools at reactors #3 and #4, as well as the common pool. But, because workers had temporarily connected them while doing maintenance work, it was connected to the pool at #1, which also lost cooling functions.
The temporary switchboard was brought to the plant immediately following the March 2011 meltdowns, and is still sitting on the back of the truck in which it was delivered. (Backup cooling pumps for the plant’s reactors are also sitting in a truck; hoses stretch several kilometers between them and the reactors.) The switchboard was not equipped with backup power, and was exposed to the elements because a section was left open to allow cables to pass through. Officials admitted that doing so “leaves the system vulnerable” to corrosive salt air, rainwater, and rodents. The utility is being criticized for not taking prophylactic action against the rats, which could cause other damage. Before the charred rat was discovered onsite, Professor Masanori Aritomi, from the Tokyo Institute of Technology observed, “Due to the recent strong wind, seawater and sand from the nearby beach may have blown into the power panel…and caused the power panel to short out.” The incident highlights the overall precarious situation at the power plant and TEPCO’s lax maintenance of critical safety equipment.
TEPCO spokesman Ono admitted that the situation at the plant remains bleak: “The Fukushima plant still runs on makeshift equipment, and we are trying to switch to something more permanent and dependable which is more desirable. Considering the equipment situation, we may be pushing a little too hard.” The incident revealed that more than two years after the triple meltdowns occurred following a magnitude 9.0 earthquake and massive tsunami, TEPCO still has not established backup power sources for cooling functions at the spent fuel pools.
TEPCO did not disclose the power outage until three hours after it began, prompting local officials to demand that the utility install backup power for spent fuel pools, increase equipment monitoring, and immediately inform residents if problems occur. Officials expressed concern that residents who are preparing to move back into the Prefecture will feel even more concern about whether or not it is safe to do so. Fears about radiation contamination are already a major issue. Masahide Matsumoto, who is mayor of the Village of Katsurao, noted, “We will be in trouble unless Tokyo Electric Power Company (TEPCO) properly investigates the cause [of the outage] and restores power.” Yuko Endo, chief of Kawauchi Village, agreed. “We don’t believe that the Fukushima disaster is under control.” “This clearly shows that the plant has not been stabilized,” said Futaba Mayor Shiro Izawa. Acknowledging the high radiation levels that make working conditions difficult, NRA Chairman Shunichi Tanaka warned that more blackouts might occur again in the future, and suggested that the company needs to prevent worst case scenarios. “What will be important is to implement measures to prevent fatal events from happening”—hardly reassuring words to those considering moving back to areas recently declared by the government to be once again habitable.
Ono downplayed the need for backup power sources at the spent fuel pools. “Even if the cooling system for spent fuel pools halts, it takes a while [in the case of the pool at reactor #4, four days] before the pool temperatures begin to rise [to dangerous levels]. We concluded that there was no need to install multiple power sources like the ones in nuclear reactors.” The government’s chief spokesman, Yoshihide Suga, also downplayed the incident: “In a sense, we have put in place measures that leave no room for worry.” TEPCO clearly hasn’t learned lessons from the March 2011 meltdowns, in which power loss led to a triple meltdown. Muneo Morokuzu, Professor at the University of Tokyo, said, “Overseas experts and others have been giving considerable attention to Japan’s management of spent nuclear fuel. TEPCO had to deal with this situation using emergency measures. But now, even more than two years since the accident, their handling of the latest case is dismal. TEPCO should seriously administer their facilities on the assumption that all sorts of devices, including power distribution panels, could break down.”
TEPCO has discovered yet another bent fuel rod at its Kashiwazaki-Kariwa plant, raising concerns about potential nuclear accidents there. The rod was touching another rod, which could lead to a nuclear disaster. The latest event was graded Level 1 on the International Nuclear and Radiological Event Scale (INES). Late last year, another instance of two rods touching was discovered. TEPCO is in the process of examining assemblies at the Kashiwazaki-Kariwa plant, as well as at its other facilities. The company hopes to restart the reactors at Kashiwazaki-Kariwa, which with seven reactors is the largest nuclear plant in the world, but public opposition to the restart has been strong.
Nuclear Regulation Authority
The NRA announced this week that it will delay safety investigations at reactors #3 and #4 at Kansai Electric’s Oi power plant in Fukui Prefecture until September, when the reactors are already scheduled to go offline for routine maintenance. The move negates an earlier statement by NRA Chairman Shunichi Tanaka, who said in January that the NRA might take the Oi reactors offline before September; new regulations go into effect in July. At the time, Tanaka said that the Oi reactors would not be exceptions to the new rules. Analysts say that the decision will set a precedent, allowing reactors to continue operating even if significant new safety regulations are put into place, and suspect that considerable lobbying efforts by the nuclear industry contributed to the change. Although the NRA is denying that claim, a senior official from Kansai Electric admitted, “While we have made an array of requests [to politicians and government officials], I never expected they would come true so soon.” An official from the Federation of Electric Power Companies agreed, saying, “The approval for Oi has virtually set the stage for the restarts of other reactors.” Harumi Kondaiji, an Assembly Member in Tsuruga, criticized the decision. “The logic behind it prioritizes the economy over life. This marks the first step toward the erosion of public trust in the NRA.”
Other Nuclear Politics in Japan
Kansai Electric Power Company (KEPCO) admitted this week that it is expecting a shipment of mixed-oxide fuel (known as MOX) from French nuclear company Areva, but would not say how it will be used. The fuel contains plutonium and is considered a national security risk because of concerns that terrorists could secure it for use in making nuclear weapons. MOX fuel has been used at KEPCO’s Takahama plant, which has been shut down since March 2011. Analysts suspect that KEPCO is preparing for its plants to go online soon after the NRA enacts new regulations in July. (Source: NHK)