The government is expected to shoulder most of the sum, putting a huge financial burden on the public.

The agency carries out work to mix high-level radioactive liquid waste, produced when spent nuclear fuel is reprocessed, with glass, aiming to convert the waste into solid form and reduce the risk of leaks. The work is seen taking 217 billion yen over the next decade.

In addition, it will cost some 140 billion yen to demolish the facility, 250 billion yen to process radioactive waste, including through solidifying work, and 380 billion yen to bury the waste, the agency estimates.

Meanwhile, the estimate does not include maintenance costs for the facility, currently standing at 5 billion to 6 billion yen a year.

The estimate is "not necessarily precise," the agency said, citing the length of the work and lack of previous similar projects.

The final costs for the dismantling and decommission work may balloon further. The agency has not even been able to select a location for burying radioactive waste.

A particularly difficult problem is where to dispose of high-level waste mixed with glass. Even electricity companies remain unable to find places to bury the waste. (Jiji Press)