Air decontamination to begin at stricken nuclear plant

Tokyo - Workers in protective suits and equipped with oxygen tanks were preparing late Monday to install air decontamination equipment at a quake-damaged turbine building in north-eastern Japan.

The machines were hoped to reduce radioactivity inside reactor 1 at the damaged Fukushima Daiichi nuclear power plant, and allow workers access to repair the cooling system, operator Tokyo Electric Power Co (TEPCO) said Monday.

The staff installing the air purifiers will be the first people inside the building since a hydrogen explosion on March 12.

The plant has been releasing radioactive substances into the air and sea since a magnitude-9 earthquake and tsunami hit the plant on March 11.

The four purifiers will be ready by Thursday, and should remove 95 per cent of the radioactive substances in the air of the turbine building, TEPCO was quoted as saying by Jiji press agency.

Last week, remote-controlled robots found radiation levels in the pump room of 1,120 millisieverts per hour, the operator said, indicating a possible leak from the reactor core.

The maximum radiation exposure allowed for male nuclear workers is 250 millisieverts over the course of a year.

Meanwhile, local officials in Koriyama City, 50 kilometres west of the plant, said they found sewage sludge containing 26,400 becquerels of radioactive caesium per kilogram, Jiji Press reported citing local government officials.

Slag at the plant, made from reduced sewage, had 334,000 becquerels per kilogram, Jiji said.

The caesium could have been released by explosions and fires at the nuclear plant after the quake and tsunami, and been washed into the sewage system by rain, the officials were quoted as saying.

Fukushima prefecture suspended the plant's supplies of processed sludge to a cement company on Sunday, although 500 tons have been delivered for recycling since the start of the nuclear crisis.

Local officials were to examine other treatment facilities in the prefecture, Jiji reported.

Also Monday, fears of a possible leak from another nuclear plant in central Japan proved groundless after an inspection by the Japan Atomic Power Co at its Tsurunga plant.

But it was considering closing reactor 2 at the plant because of technical problems, said the company, which plans to add two more reactors at the plant.

Fukui Prefecture, on the north coast of central Japan, has a total of 13 nuclear power reactors in operation at its plants along the seaboard.