TOKYO, Jan 28: Enough plutonium to produce 25 nuclear bombs is unaccounted for at a Japanese nuclear facility, but the deficit is mostly due to measuring shortcomings and miscalculations, an official said on Tuesday.

The nuclear fuel reprocessing plant in Tokaimura, some 100kms north of Tokyo, has extracted 6,890kgs of plutonium from spent nuclear fuel since it began operating in 1977.

But the total was 206 kilos short of the plutonium initially estimated to have been produced by reprocessing spent nuclear fuel from power plants, an education and science ministry official said.

The official at the ministry’s nuclear safeguard office said that the case had been reported to the International Atomic Energy Agency (IAEA), the United Nations nuclear watchdog.

The finding was also reported to the Japanese government’s Atomic Energy Commission on Tuesday.

The ministry denied the possibility that any plutonium had been illegally removed from the facility.

It is known to take between five to eight kilos of plutonium to produce a nuclear bomb.

Of the missing plutonium, 94 kilos is presumed to have dissolved into waste water without being measured, the official said, adding that another 29 kilos disintegrated into a different type of element, the official said.

“In other cases, plutonium may have been stuck to fuel tubes or mixed with waste water being processed to be solidified in glass and disposed of,” he said.

The official also pointed to possible “errors in the estimate of plutonium extracted in the process.”

The report was based on inspections at the Tokaimura facility under IAEA safeguard rules designed to prevent the transfer of nuclear materials for production of nuclear weapons.

Tokaimura, a Pacific coast complex of nuclear-related facilities, made headlines in 1999 when the world’s worst nuclear plant accident since Chernobyl in 1986 occurred at a uranium reprocessing plant there.

At that time, three workers set off a critical reaction when they poured too much uranium into a precipitation tank. Two of the three later died.

Safety concerns at nuclear facilities in Japan were highlighted on Monday when a high court upheld the suspension of operations of a troubled experimental fast-breeder reactor which has been shut since an accident in 1995.—AFP