01/10 Fukano says another quake could threaten Fukushima operation

BY TATSUYUKI KOBORI STAFF WRITER

2011/10/01

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Hiroyuki Fukano, director-general of the Nuclear and Industrial Safety Agency (Tatsuyuki Kobori)

The head of Japan's nuclear regulator warned that the effort to regain control of stricken reactors at the Fukushima No. 1 nuclear power plant is relying on "makeshift equipment" that might easily be destroyed if another earthquake hits.

Hiroyuki Fukano, director-general of the Nuclear and Industrial Safety Agency (NISA), said in a Sept. 29 interview with The Asahi Shimbun that there is an urgent need to assess back-up systems at the plant as hopes rise that reactors are nearing the relatively stable "cold shutdown" state.

"We have little choice but to keep reactors under the cold shutdown without much change (in the reactor control systems)," he said.

But he warned: "The plant is using some makeshift equipment now. That raises fears that those units could be easily destroyed by another earthquake. We need to assess our back-up systems for the equipment should the units be knocked out by an earthquake."

On Sept. 28, water temperatures at the plant's No.1, No.2 and No.3 reactors fell below 100 degrees for the first time since the start of the crisis in March.

Getting below 100 degrees was one of the conditions stipulated for classifying the reactors as being in "cold shutdown," but a significant reduction in radiation leaking from the reactors is also included in the criteria. There has been no announcement that cold shutdown has been reached.

Fukano said NISA would continue to monitor temperatures, water levels and amounts of radiation leaking from the reactors. When the cold shutdown phase is announced, he said the agency would then outline a detailed plan for keeping the reactors stable.

Fukano's agency, which is part of the industry ministry, and the Cabinet Office's Nuclear Safety Commission of Japan are due to be swallowed up in a new body, provisionally named the Nuclear Safety Agency, to be set up next spring under the Ministry of the Environment.

Fukano said NISA would study lessons learned from the Fukushima accident and present its findings to the new organization.

But he urged caution about one of the key parts of the Democratic Party of Japan-led government's strategy for ensuring safety in the aftermath of the Fukushima disaster: the stress tests being used as prerequisites for the resumption of suspended nuclear plants.

Fukano said: "Some say reactors (that have passed such tests) meet safety standards and therefore there should not be any problem, but questions have been raised as to the appropriateness of the standards themselves (after the March 11 disaster)."