Japan's nuclear regulator has expressed alarm at increased contamination by the seafront near the Fukushima nuclear power plant.
Fukushima's operator Tokyo Electric Power, also known as Tepco, has acknowledged problems are mounting at the crippled power station north of Tokyo, the site of the world's worst atomic disaster since Chernobyl in 1986.
Yesterday, the company said radiation levels in groundwater had soared, suggesting highly toxic materials from the plant were getting closer to the Pacific more than two years after three meltdowns triggered by a massive earthquake and tsunami.
Shunichi Tanaka, head of the new Nuclear Regulation Authority, told reporters he believed contamination of the sea had been continuing since the March 2011 catastrophe.
"I think contamination of the sea is continuing to a greater or lesser extent," he said. "It was contaminated at the time of the accident, but I think it has been continuing for the last two years. Coming up with countermeasures against all possible scenarios is a top priority."
The NRA "strongly suspected" radiation was contaminating the Pacific, Kyodo news agency said in an earlier report from a weekly NRA commission meeting, citing Tanaka.
In the days after the tsunami, a plume of radiation from explosions fell over wide areas of the land and sea and toxic materials, such as caesium, were later found to have leaked through channels in the ground on the side of the station by the sea, prompting expressions of concern from South Korea and China.
Tepco said it was checking Tanaka's comments and could offer no immediate comment.
Tepco said yesterday an observation well between the damaged reactor No. 2 and the sea showed levels of radioactive caesium-134 and ceasium-137 had soared over the weekend.
Last month, Tepco found lower levels of caesium in groundwater flowing into the plant on ground some distance from the sea.
The operator has been flushing water over the melted fuel rods in three reactors to keep them cool for more than two years, but contaminated water has been building up at the rate of an Olympic-size swimming pool each week.
The news follows an announcement by a senior regulator that Japan may restart several nuclear reactors, shut down since the crisis began, in about a year – a day after new safety rules went into effect designed to avoid a repeat of the disaster.
Getting units restarted is a key government goal to reduce the import bill for fossil fuel to run conventional stations. Only two of Japan's 50 reactors are connected to the grid and operators applied to restart 10 on Monday.
"Some units are projected (to restart) one year from now, though I don't know how many," Kenzo Oshima, a commissioner of Japan's Nuclear Regulation Authority. "It is hard to imagine that all the applications would be rejected, though we don't know what the outcome will be at the moment."
He did not identify the reactors that are likely to restart.