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2013年4月12日 (金)

原発新規制基準 ゼロリスクにとらわれるな

[The Yomiuri Shimbun] April 12, 2013
NRA should not get caught up in myth of completely 'risk-free' reactors
原発新規制基準 ゼロリスクにとらわれるな(4月11日付・読売社説)

The Nuclear Regulation Authority has approved the final draft of new safety standards to be applied to the nation's nuclear power plants.

Taking lessons from the nuclear crisis at Tokyo Electric Power Co.'s Fukushima No. 1 nuclear power plant, the new standards will require operators of nuclear power plants to prepare for earthquakes and tsunami larger than those they had estimated prior to March 11, 2011.
Measures to prevent critical accidents, such as meltdowns of nuclear reactors, were also incorporated in the new standards, including energy supplies from multiple power sources and reinforcing reactor cooling systems.

It is indeed necessary to correct the weaknesses of the old safety standards in place before the nuclear crisis. However, although many people--including those inside the NRA--complained during the deliberation process that the nuclear regulatory body was going too far in seeking to reducing the risk from nuclear power plants to zero, their views were hardly reflected in the final draft.

New standards overly strict

It is clear that the final draft has a number of flaws.

One of them is the requirements on active faults found under nuclear power plants. In the previous safety standards, faults that were confirmed to have moved within 130,000 years were judged as active faults. However, the final draft will require operators to expand the scope of investigation significantly--movements within the past 400,000 years will be subject to investigation.

The nuclear regulatory body has already adopted the new criteria for researching active faults at idle nuclear power plants. While conducting the research, Acting NRA Chairman Kunihiko Shimazaki has repeatedly called on power companies to prove that they are "100 percent sure" that there are no active faults. A clause reflecting Shimazaki's requirements is expected to be included in the new safety standards.

However, it is obvious that Shimazaki's demands are extremely unscientific. Power companies should pursue approaches based on engineering, such as reinforcing the safety equipment at nuclear power plants so the power plants will be able to withstand seismic activity.

Some experts have raised concerns about other measures laid out in the final draft, pointing out their "excessiveness." One example is the requirement of filtered vents, which would help release pressure from nuclear reactors in the case of a serious accident.

The new safety standards will obligate all of the nation's nuclear power plants to install filtered vents. However, last month, the United States concluded it is unnecessary to install the filtered vents in its nuclear reactors for the time being, after hearing expert opinion. It is understandable that a senior official of the U.S. Energy Department raised concerns that Japan's strict standards may affect nuclear power plants in other countries.

After collecting public opinion on the final draft, the nuclear regulatory body plans to put the new standards into effect in July, or earlier if possible. Based on the new standards, the NRA will check whether the nation's idled nuclear reactors are suitable for restart.

Restart of N-plants urgent

What is important is to improve the efficiency of inspections. According to the NRA, it will only be able to check three nuclear power plants at a time due to a shortage of officials possessing sufficient expertise. The nuclear regulatory body must reinforce its inspection framework by taking such steps as recruiting talented people.

Flexibility is also crucial. Measures should be introduced in accordance with the specific conditions of each nuclear power plant. It is not realistic to demand all nuclear power plants have the same amount of fire extinguishing equipment, for example.

To pass inspections, nuclear power plants will be required to introduce retrofits reflecting the latest safety measures for nuclear reactors. Improving safety is important, but we are concerned that the plan would lead to higher costs, forcing power companies to shut down some reactors.

The nation's power supply faces a tough situation. The price of electricity has gone up after the price hike for fuel for thermal power plants. It is urgent to restart power plants once their safety is confirmed.

We ask the NRA to judge whether nuclear power plants are eligible for restart, without being swayed by the current public desire for the absolute safety of nuclear power plants.

(From The Yomiuri Shimbun, April 11, 2013)
(2013年4月11日01時30分  読売新聞)


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