As the March 2011 reactor meltdowns at Tokyo Electric Power Co.’s Fukushima No. 1 power plant demonstrated, loss of power sources for an extended period of time at a nuclear power plant — known as a “station blackout” (SBO) — can lead to catastrophic results. It was recently reported that the Nuclear Safety Commission colluded with Tepco over the nation’s SBO-related safety standard about two decades ago.
This revelation and the recent government decision to restart the Nos. 3 and 4 reactors at Kansai Electric Power Co.’s Oi nuclear power plant in Fukui Prefecture only serve to reinforce the widespread belief that the government is continuing to protect the interests of the nuclear power industry even in the wake of the Fukushima disaster.
In 1990, the government issued a safety standard stating that there is no need to take into account SBOs lasting 30 minutes or longer in designing a nuclear power plant. Because preparations for long SBOs had become obligatory overseas, in 1991 the NSC established a working group to consider a revision of the safety standard. The group consisted of five experts and officials from Tepco, Kepco and the then Japan Atomic Energy Research Institute, which had a cooperative relationship with the power companies.
Because Tepco and Kepco opposed incorporating preparations for long SBOs into the design standard, the then Science and Technology Agency, which was serving as NSC’s secretariat, asked the two power companies to “compose sentences” stating why there is no need to consider preparations for SBOs lasting more than 30 minutes and to submit them.
The working group subsequently adopted Tepco’s explanation that nuclear power plant design in Japan has an adequate margin of safety, and that if a nuclear power plant is operated properly, the level of safety will be sufficient.
In June 1993, the working group issued a report saying that even if an SBO occurs, it would not lead to a severe accident. As a result, the government safety standard was not revised.
It is clear that what the NSC basically did was let a power company write the draft of its report. Given that the meltdown at Fukushima No. 1 might have been prevented had the safety standard been revised, those involved in the process should be deeply ashamed of their actions.
In October 2011, the NSC purportedly made public “all” the documents it had related to the process. Only after the Diet committee investigating the Fukushima nuclear accident demanded further disclosure did the NSC release additional documents in early June revealing that the working group had asked Tepco and Kepco to “compose sentences.”
The NSC must make public all its documents before it is abolished to make way for the establishment of a new nuclear regulatory authority around September.