Radiation leaks from fuel rods suspected at Japan's Tsuruga plant

Mainichi

FUKUI (Kyodo) -- Leaks of radioactive substances from fuel rods are suspected to have occurred at a nuclear power plant in Tsuruga, the Fukui prefectural government said Monday, citing a rise in the level of radioactive substances in coolant water.

The operator, Japan Atomic Power Co., will manually shut down the No. 2 reactor of the plant on the Sea of Japan coast and examine the primary cooling system for it. The local government denied that the levels of radioactive substances could threaten the nearby environment.

According to Japan Atomic, 4.2 becquerels of iodine-133 and 3,900 becquerels of xenon gas were detected per cubic centimeter Monday, up from 2.1 and 5.2 becquerels, respectively, during previous measurements conducted last Tuesday.

It is possible that a pinhole has been created in a zirconium alloy encasing fuel pellets, according to sources at Japan Atomic.

The company said the planned shutdown is a precaution following the crisis at the Fukushima Daiichi power station caused by the March 11 earthquake and tsunami. Japan Atomic's regulations require a reactor to be halted when the amount of leaked iodine reaches 40,000 becquerels.

The company said it will increase the frequency of measurements to once a day from once a week before deciding when to shut down the reactor.