The Nuclear Regulation Authority said Friday it will scrutinize all simulations for the potential spread of radioactive materials from atomic power plants after it was found that the projections were riddled with mistakes.

“We would like to be sure that there will be no more errors, so the simulations are being thoroughly checked again,” NRA spokesman Hideka Morimoto told a news conference.

More mistakes were announced Tuesday. The NRA said errors were found in wind direction data for Kyushu Electric Power Co.’s Genkai power plant in Saga Prefecture and Sendai plant in Kagoshima Prefecture.

The fallout simulations are based on a severe accident similar to the disaster at the Fukushima No. 1 plant. The projections indicate what areas would experience fallout of up to 100 millisieverts of radiation in the first seven days of such a crisis.

The NRA planned to disclose the corrected projections Thursday but canceled after the Japan Nuclear Energy Safety Organization (JNES), the body that drafted the simulations, announced there may be further data-input errors in the corrected version.

Morimoto said the NRA’s secretariat has questioned the capability of the JNES team that drafted the projections, as inputting data should be a very basic task. It ordered the JNES to thoroughly review all of the projections in collaboration with the NRA.

He added it was still unclear when the NRA will be able to release the corrected results.

The projections were drafted based on annual meteorological data, including prevailing wind directions and speeds and rainfall at every nuclear plant in Japan.

Exposure to 100 millisieverts would raise the lifetime risk of dying of cancer by 0.5 percent, according to the International Commission on Radiological Protection, a group of radiation experts.

The simulations were first disclosed Oct. 24 as references for local governments to identify areas in need of special attention when drafting disaster prevention plans.

Five days later, the NRA said azimuth data were erroneously entered for some of the plants, which resulted in flawed fallout projections being issued that caused confusion in municipalities and residents near the plants.

Edano cautious on Tepco


Industry minister Yukio Edano is cautious about providing additional financial support to Tokyo Electric Power Co. for decontamination work and compensation arising from the nuclear crisis.

“First of all, it is important that the company steadily carries out reforms under the framework based on existing law, and firmly fulfills its responsibilities,” Edano told reporters Thursday in Tokyo.

The request was made in Tepco’s business strategy for fiscal 2013 and 2014, which noted the total costs for decontamination work, compensation and other expenses related to the meltdowns at its Fukushima No. 1 plant could double to ¥10 trillion.

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