A private think tank says the total cost of the Fukushima disaster could reach ¥70 trillion ($626 billion), or more than three times the government’s latest estimate.

In a study Saturday, the Japan Center for Economic Research said costs of dealing with the heavily damaged Fukushima No. 1 nuclear plant run by Tokyo Electric Power Company Holdings Inc. could rise to between ¥50 trillion and ¥70 trillion.

In December, the government estimated the costs would reach roughly ¥22 trillion.

“If costs rise, the public burden could greatly increase. The country’s nuclear policy needs to be reviewed,” JCER said.

The government’s initial expectations pegged the costs at ¥11 trillion.

But a study by the Ministry of Economy, Trade and Industry said that the final figure could turn out to be double the sum estimated in 2013.

Following that, the government decided to raise electricity rates to secure the money needed to cover compensation payments to the evacuees.

According to METI’s estimates, the bill for compensation payments will be ¥8 trillion, a figure the JCER decided to adopt.

The JCER, however, estimates the cost of the decontamination work will hit ¥30 trillion, or five times more than the government’s estimate of ¥6 trillion. The think tank based this calculation on a presumption that radioactive substances will be disposed of at a nuclear facility in the village of Rokkasho in Aomori Prefecture.

The government is seeking a way to treat radioactive soil and other waste in Fukushima Prefecture that could grow to roughly 22 million cu. meters, but where and how to dispose of it has yet to be decided.

Costs related to this procedure are not included in the government’s calculations.

In the meantime, JCER estimates that the cost of decommissioning the crippled reactors, which is expected to take 30 to 40 years, will reach ¥11 trillion. The government’s estimate is ¥8 trillion.

JCER also estimates that treating the contaminated water stored in hundreds of tanks at the plant will cost ¥20 trillion unless it is dumped into the ocean after being diluted as recommended by regulators.