Japan to instruct utilities on safety, supply

TOKYO, July 20 (Reuters) Japan's trade minister was set to order the nation's 11 nuclear power utilities today to make strict checks on safety and set up fire fighting units at their plants, after a powerful tremor this week caused radiation leaks at the world's biggest nuclear power station, media reported.

Amari was set also to hold an emergency meeting on how to maintain electricity supplies, public broadcaster NHK said, after Monday's quake forced Tokyo Electric Power Co (TEPCO) to close indefinitely the huge Kashiwazaki-Kariwa power plant.

Fears about the safety of Japan's nuclear industry -- which supplies about one-third of the country's electricity -- have been renewed by the leaks and a small fire at the TEPCO plant in the northwestern city of Kashiwazaki, hard hit by the 6.8 magnitude quake on Monday that killed 10 people.

TEPCO has been criticised for slow response to the fire in an electrical transformer after the quake.

A trade ministry official confirmed Amari would issue instructions to the utilities, but declined to give details.

TEPCO supplies power to the greater Tokyo area, where peak demand of 68 million kilowatts is forecast during the capital's humid summer.

Shutting the Kashiwazaki-Kariwa plant deprives TEPCO of up to 8.2 million kilowatts of output, which may force it to start up coal- or oil-fired thermal plants.

The firm has asked six utilities to help replace lost production and said power supplies were sufficient for now.

TEPCO has acknowledged that the tremor was stronger than the plant, whose first reactor came on stream more than 20 years ago, had been designed to withstand.

The utility also said it assumed that the fault that caused this week's tremor was one found nearly 30 years ago, as the plant was being built.

The fault had not caused concern at the time, but based on more recent scientific knowledge, it now appears that it is some 20-30 km long -- about three times longer than what TEPCO thought previously -- and runs directly under the plant.

The trade ministry said yesterday that TEPCO had found that radioactive iodine was found in an exhaust pipe filter even after the plant automatically shut down after Monday's quake, although the amounts were not enough to damage the environment.

TEPCO had said on Tuesday that radioactive iodine, cobalt-60 and chromium-51 had been emitted into the atmosphere, but not enough to harm people or the environment.

Authorities have ordered the Kashiwazaki-Kariwa plant to remain closed until its safety is assured.

Quake-proofing regulations for Japan's 17 nuclear power stations were tightened last year, requiring utilities to reassess risks to their plants -- a process that one official said could take more than two years.

REUTERS AM DS1255