Troubles at Takahama nuclear plant

The injunction issued by the Otsu District Court on Wednesday to halt the operation of reactors 3 and 4 at Kansai Electric Power Co.’s Takahama nuclear power plant in Fukui Prefecture — which had just been reactivated earlier this year after clearing the post-Fukushima reactor standards — should serve as a strong warning to the power industry, the government and the nuclear regulators.

Even before the court injunction, back-to-back problems had occurred in a span of 10 days involving reactor 4 at the plant, raising doubts about the company’s safety management. The fact that the reactor fell into a state of cold shutdown shortly after its restart was enough to cause concern among the public that the firm is obsessed with putting its reactors back online to the point of failing to take sufficient caution in ensuring their safety. Other power companies should also take the court decision and what happened at the Takahama plant seriously and make sure they don’t neglect the lessons from the triple meltdowns at Tokyo Electric Power Co.’s Fukushima No. 1 plant five years ago.

On Feb. 29, just three days after reactor 4 was rebooted and Kansai Electric was preparing to generate and transmit electricity, an alarm went off to indicate problems with the generator and the transformer. The alarm triggered the insertion of 48 control rods, deactivating the reactor. The unit is now in a cold shutdown condition with the temperature of the primary coolant kept below 93 degrees Celsius. The company suspects that an electrical current stronger than a preset level flowed from the transmission line, leading a monitoring device near the transformer to detect it and set off the alarm upon the start of power generation and transmission.

On Feb. 20, just six days before the reactor was rebooted, 34 liters of radioactive water leaked into a building attached to the reactor when the utility injected water into a pipe connected to the reactor’s primary cooling system. The cause turned out to be a bolt that had been insufficiently tightened.

These troubles point to the possibility that Kepco rushed to restart the reactor without adequate checks of components and training of workers. A key factor behind the rush may be the liberalization of the electricity retail market in April. Apparently, major utilities are trying to secure an advantage vis-a-vis their competitors in the deregulated market by utilizing their nuclear power plants.

After the Nuclear Regulation Authority introduced more stringent safety standards in 2013 based on the lessons from the Fukushima crisis, power companies applied for NRA safety screening of 26 reactors at 16 nuclear power plants. Takahama’s reactor 4 is the fourth to go back online based on the new standards. Reactor 3 at Takahama was reactivated in January and reactors 1 and 2 at Kyushu Electric Power Co.’s Sendai plant in Kagoshima Prefecture were rebooted last August and October, respectively.

There has been a worrisome emergence of signs that not only the power industry but also the government and nuclear regulation authorities are pushing the restart of reactors without assuming a sufficiently cautious attitude toward nuclear power generation.

The government’s electricity supply outlook envisages nuclear power accounting for 20 to 22 percent of the nation’s total power supply in fiscal 2030. This assumes that some reactors will operate beyond the legal threshold of 40 years. A 2012 revision of the law regulating reactor operations introduced a rule that units in principle cannot be operated beyond 40 years, although a one-off extension for up to 20 years is possible with NRA approval. The government at that time characterized such an extension as “the rarest of exceptions.” But a recent statement by NRA chief Shunichi Tanaka suggests that extending their life beyond the 40-year limit can instead be the norm. He said that if power companies spend enough money on renovations, they can overcome the technical problems inherent in aging reactors. The statement seems to ignore the fact that a reactor’s pressure vessel cannot be replaced or reinforced once it has become brittle from bombardment of neutrons for decades. Such a position runs counter to the common-sense principle that in handling a potentially highly dangerous technology like nuclear power, prudence must be the default position.

A recent revelation by Tepco also highlights its sloppiness in handling the Fukushima disaster. It admitted that as recently as late February, an employee noticed a description in its disaster management manual stating that a reactor must be declared “in meltdown” if 5 percent or more of its fuel rods are determined to be “damaged.” As of March 14, 2011, the company estimated that 55 percent of the fuel rod assemblies of reactor 1 and 25 percent of those at reactor 3 were “damaged.” The next day, it estimated that 35 percent of the fuel rod assemblies at reactor 2 were damaged. Still, Tepco refused to use the word “meltdown” for about two more months despite widespread public skepticism. It is deplorable that the company failed to heed such an important description in its own manual. This only deepens suspicions over the company’s lack of sincerity in dealing with accidents at nuclear power plants.

Given such circumstances, it will be difficult for the power industry, the government and the nuclear regulators to persuade the public that the power companies have fundamentally changed their attitude concerning the risks of nuclear power for the better. The power companies should rethink their rush to restart their reactors, which is driven by their desire to improve short-term profitability, and examine whether they are qualified to manage the risks involved in nuclear power generation so that a Fukushima-type catastrophe will never be repeated. This is all the more important because of Wednesday’s court injunction.

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