TOKYO (AP) -- Experts on Friday expressed skepticism about a plan to build a costly underground frozen wall at Japan's crippled nuclear plant, a development that could delay the start of construction on the project.
The experts and Japanese nuclear regulatory officials said during a meeting in Tokyo that they weren't convinced the project can resolve a serious contaminated water problem at the Fukushima Dai-ichi plant, which suffered multiple meltdowns following the 2011 earthquake and tsunami.
The frozen wall is a 32 billion yen ($320 million) government-funded project to surround the plant's four crippled reactors and their turbine buildings with an underground ice wall to block groundwater from flowing into the buildings' basements and mixing with highly radioactive water leaks from the melted cores.
Government officials say a feasibility test at the plant, run by Tokyo Electric Power Co., proved successful and that they hope to start construction in June, though the project could be delayed because of the experts' concerns.
Toyoshi Fuketa, a commissioner with Japan's Nuclear Regulation Authority, said the hydrological impact of a frozen wall to the area was unclear.
"We need to know if a frozen wall is really effective, and more importantly, we need to know whether a frozen wall may cause any trouble," Fuketa said.
International experts have raised similar concerns.
Dale Klein, a former U.S. Nuclear Regulatory Commission chairman who now heads a supervisory panel for TEPCO, said he was not convinced the frozen wall is the best option and is worth the high cost. He also suggested that the government and TEPCO review the plan to balance risk and benefit and see whether they should spend the money elsewhere.
"Any time you make a decision, it should be based on current, relevant science, and you have to strike a balance between science and policy," Klein said in an interview Thursday in Tokyo. "At the end of the day, it may be a good alternative. But I'm just not convinced."
Experts have said that while a frozen wall is a proven technology, the size and planned duration of use at Fukushima is unprecedented.
TEPCO is setting up a bypass system to pump up groundwater before it hits the contaminated reactor area as a way to reduce the amount of underground contaminated water. The plant is also installing another groundwater drainage system around the reactor buildings, which some experts say could serve as a sufficient alternative to an ice wall.
More than three years after the March 2011 meltdowns, the plant is still plagued by a massive amount of contaminated water. Repeated water leaks from storage tanks and other mishaps at the plant have hampered a decommissioning effort that is expected to take decades and caused environmental concerns among local fishermen.