Japan's nuclear watchdog said it will seek to address unanswered questions about the Fukushima nuclear disaster in a report to be submitted to the Vienna-based International Atomic Energy Agency by year-end.
Japan's nuclear watchdog said it will seek to address unanswered questions about the Fukushima nuclear disaster in a report to be submitted to the Vienna-based International Atomic Energy Agency by year-end.
The Nuclear Regulation Authority reached the decision May 1 at an inaugural meeting of its investigative panel.
The Japanese government, the Diet and other parties set up their own individual investigation commissions in the aftermath of the reactor meltdowns at the Fukushima No. 1 nuclear power plant triggered by the March 11, 2011, Great East Japan Earthquake and tsunami.
Although they released their respective reports by July 2012, many aspects of the disaster remain unclear.
The NRA plans to focus its inquiry on those issues that the panels failed to agree upon.
During the May 1 meeting, the NRA presented a list of unresolved issues from the reports. Studies were started immediately on two of them: If the "isolation condensers," or key cooling equipment for the No. 1 reactor, were damaged, and what caused the hydrogen explosion in the No. 4 reactor building.
Whether the No. 1 reactor's isolation condensers were damaged has been a focus of investigations because of the implications with regard to the adequacy of anti-seismic measures implemented by the government and Tokyo Electric Power Co., the plant operator. While the Diet's Fukushima Nuclear Accident Independent Investigation Commission said the earthquake--not the tsunami--may have damaged the condensers, the government's Investigation Committee on the Accident at the Fukushima Nuclear Power Stations said such a scenario is unlikely.
In February 2012, a TEPCO official dissuaded members of the Diet investigation panel from conducting an on-site survey in the No. 1 reactor building by misinforming them that it was "pitch-dark" inside and unfit for inspections. After it emerged in February that the inside was not "pitch-dark" at the time, NRA Chairman Shunichi Tanaka said he would push for an inspection of the No. 1 reactor.
The NRA panel plans to conduct studies and compile reports successively on an issue-by-issue basis, according to NRA officials. As the IAEA is expected to release its own investigation report on the Fukushima nuclear crisis by the end of 2014, the NRA said it hopes the international nuclear watchdog can draw on the NRA's investigation results.