Tokyo Electric Power Co.’s efforts to keep radioactive water at its stricken Fukushima No. 1 power station from spilling into the sea have been ineffective, according to the Nuclear Regulation Authority.
“Our conclusion is that little effect has been seen” in Tepco’s measures, NRA Commissioner Toyoshi Fuketa said at an NRA panel meeting Tuesday, citing an increase in the levels of radioactive materials in some seawater samples collected near the plant.
Tepco is pumping up groundwater and has injected a water-stopping agent into the ground near the plant’s port in order to curb the flow of radioactive groundwater into the sea.
Despite such efforts, the levels of cesium-137 in seawater samples collected between the water intakes for reactors 1 and 2 inside the port rose to around 100 becquerels per liter this month from around 10 becquerels between late June and early July.
“It is reasonable to assume that the total amount of radioactive materials flowing into the sea has risen,” said Masaya Yasui, an emergency response official at the NRA secretariat.
Radioactive water from the damaged reactors “may be leaking directly into the sea instead of mixing with groundwater before making its way into the sea,” Fuketa said.
Last week, Tepco said the cesium level was 1.4 becquerels per liter of seawater sampled on Oct. 8 at a point 1 km from the seawall of the power plant, far below the safety limit of 10 becquerels for drinking water set by the World Health Organization.
But radioactive cesium was detected at the point for the first time since the firm started radioactivity checks there in mid-August.
The industry ministry now plans to introduce a system to examine the advisability of what nuclear experts call the “final” disposal method for highly radioactive waste from spent nuclear fuel every five years, a ministry official said Tuesday.
The ministry showed the drafted five-year review plan for the permanent underground disposal program to an expert panel the same day, hoping for the plan to facilitate finding of a municipality to host the final disposal facility.
Under the existing program, geological surveys and construction of a final disposal facility will be carried out for 30 years after a municipality agrees to host the facility. The facility will continue work to bring in and bury nuclear waste deep underground till it is shut down more than 40 years later. After the shutdown, the waste will be stored there for tens of thousands of years before it becomes no longer toxic to humans.
The ministry wants to revise the program to allow underground disposal to be replaced by safer disposal, if such a method is found in the more than 70 years till the facility’s closure.
The draft plan also clarifies the stance of putting priority on the host municipality’s preference on when to start operation of the disposal facility and shutter it.
The ministry aims to reflect the new plan in the final disposal program, which is now under review by the government, as well as the government’s basic energy policy.
Spent fuel at the nation’s atomic plants, all of which are currently offline, has been stored on-site at the facilities, but the storage pools are believed to be near capacity.
Meanwhile, no community has volunteered to host the “final” storage site.