The costs to decommission 79 nuclear facilities owned by the Japan Atomic Energy Agency have been estimated to total ¥1.9 trillion over some 70 years, according to the agency.
The estimated sum covers costs for scrapping buildings and disposing of radioactive waste, but does not include maintenance costs. The JAEA owns 89 nuclear facilities.
A nuclear fuel reprocessing plant in the village of Tokai, Ibaraki Prefecture, is the most costly at ¥770 billion.
In June last year, the JAEA said costs for decommissioning the Tokai plant would total ¥1 trillion. The latest estimates do not include the ¥217 billion in costs for solidifying highly radioactive wastewater.
The JAEA said estimated decommissioning costs total ¥150 billion for the Monju prototype fast-breeder reactor in Tsuruga, Fukui Prefecture, ¥75 billion for the Fugen advanced converter reactor and ¥88 billion for a plutonium fuel plant in Tokai.
The JAEA did not include maintenance and other costs in the estimates as they are variable depending on facilities and decommissioning work phases, an official said.