NRA panel and Diet Commission differ on cause of disaster

July 19, 2014

March 2011 power loss at Fukushima plant caused by tsunami: regulator

http://mainichi.jp/english/english/newsselect/news/20140718p2g00m0dm059000c.html

TOKYO (Kyodo) -- The power loss at the Fukushima Daiichi nuclear plant's No. 1 reactor in March 2011 was triggered by tsunami, Japan's nuclear regulator said Friday, denying the possibility raised by the Diet's investigation commission that it could have been caused by the powerful earthquake.

The Nuclear Regulation Authority's interim report on the 2011 nuclear disaster said the power loss -- which led to the failure to cool the reactor and resulted in a meltdown -- and damage to equipment occurred as tsunami waves flooded the plant, citing results of its on-site probe.

Panels of the Diet, the government, plant operator Tokyo Electric Power Co. and the private sector have separately released investigation reports so far, but they differ regarding some issues.

While the reports of the government and TEPCO panels concluded that the power loss was caused by tsunami waves, the Diet-appointed panel noted the possibility of the earthquake as the cause. The possibility raised by the Diet panel implies TEPCO failed to prepare for earthquakes as well as tsunami.

NRA officials said they will continue their investigation.

July 18, 2014

NRA panel: Tsunami led to Fukushima meltdown

http://www3.nhk.or.jp/nhkworld/english/news/20140718_53.html 

A panel of experts at Japan's Nuclear Regulation Authority has concluded that the tsunami triggered the meltdown during the 2011 Fukushima nuclear accident.

The panel presented on Friday a draft interim report on its probe into the accident.

The experts' conclusion differs from that of a Diet commission about the loss of an emergency power source at the Number One reactor at the Fukushima Daiichi nuclear power plant.

In its report released in July 2012, the commission suggested the possibility that the massive earthquake caused the reactor to lose power before the tsunami hit the plant.

But the expert panel says data found after the report was issued shows that the arrival of the tsunami coincided with the time the reactor lost power.

The panel rejects the conclusion by the Diet commission that the quake damaged pipes of the reactor and led to the meltdown.

The experts say they will continue their probe and interview former members of the commission before releasing a final report.

Jul. 18, 2014 - Updated 11:21 UTC