Nearly 17,000 tons of spent fuel are stored at power plants nationwide, almost entirely in spent fuel pools. Their storage space is 70 percent filled on average. Most pools would max out within several years if Rokkasho were to close down, forcing spent fuel to be returned, according to estimates by a government fuel-cycle panel.
Rokkasho alone won’t be able to handle all the spent fuel coming out once approved reactors go back online, and the clock is ticking for operators to take steps to create extra space for spent fuel at each plant, Nuclear Regulation Authority Chairman Shunichi Tanaka said.
‘‘Even if we operate Rokkasho, there is more spent fuel coming out than it can process. It’s just out of balance,’’ he told the AP.
A more permanent solution — an underground repository that could keep nuclear waste safe for tens of thousands of years — seems unlikely, if not impossible.
The government has been drilling a test hole since 2000 in central Japan to monitor impact from underground water and conduct other studies needed to develop a potential disposal facility. But no municipality in Japan has been willing to accept a long-term disposal site.
‘‘There is too much risk to keep highly radioactive waste 300 meters (1,000 feet) underground anywhere in Japan for thousands or tens of thousands of years,’’ said Takatoshi Imada, a professor at Tokyo Technical University’s Decision Science and Technology department.