JAPAN | Stress tests eyed for all N-reactors / May pave way to restarting idled plants

Posted on July 7, 2011


JAPAN | YOMIURI | 7 July 2011

The government intends to introduce so-called stress tests on the nation’s nuclear reactors to determine how well they can withstand severe accidents caused by massive earthquakes, tsunami and other extreme events, industry minister Banri Kaieda said Wednesday.

The government is expected to fast-track the safety check system as it hopes exhaustive testing will pave the way for idle nuclear reactors, such as the reactors at the Genkai nuclear power plant in Saga Prefecture operated by Kyushu Electric Power Co., to resume operations.

Amid concerns over the narrowing margin of power supply and demand, the government believes the stress tests will endorse the safety of nuclear reactors, sources said.

Yet the introduction of additional safety checks may delay the resumption of the reactors.

Economy, Trade and Industry Minister Kaieda did not specify when the tests would be conducted, merely saying, “[The government] will take adequate steps to ensure [power] supply is unaffected.”

Europe has been conducting such tests since June in the wake of the Great East Japan Earthquake and the crisis at the Fukushima No. 1 nuclear power plant, operated by Tokyo Electric Power Co.

The International Atomic Energy Agency has also referred to the need for member nations to conduct similar assessments.

Existing safety checks enabling the construction of nuclear reactors do not factor in severe incidents such as damage to the reactor core.

Measures to be taken in the event of such an incident are left in the hands of the power companies that operate nuclear reactors. It had been considered that a loss of power could be restored within eight hours.

The envisaged tests are expected to use computer simulations of, for example, damage caused by earthquakes with intensity levels beyond those foreseen under the current safety standards.

The tests would determine to what extent nuclear reactor safety could be maintained in the event of such large-scale disasters and how well the reactors could withstand them.

By simulating such severe conditions, the tests are expected to help safety regulators pinpoint weaknesses in equipment such as power sources, pumps and pipes. Operators would then be asked to reinforce the equipment in question.

The Economy, Trade and Industry Ministry’s Nuclear and Industrial Safety Agency will hold consultations with the Cabinet Office’s Nuclear Safety Commission to decide on checklists and other test details, the sources said.

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