More doubts about "Great Icewall"

May 4, 2014

More experts challenge Tepco’s ‘Great Icewall’ for Fukushima No. 1

http://www.japantimes.co.jp/news/2014/05/04/national/experts-challenge-tepcos-great-icewall-fukushima-1/#.U2ZyLFfi_IX 

AP

Experts on Friday heaped further criticism on a plan to build a costly underground frozen wall around the radiation-tainted Fukushima No. 1 power plant, a development that could delay the start of the experimental project.

The experts and nuclear regulatory officials said at a meeting in Tokyo on Friday that they weren’t convinced the project can resolve the serious problems involving contaminated water at the plant, which suffered multiple meltdowns following the 2011 megaquake and tsunami.

The frozen wall is a ¥32 billion state-funded project to surround the plant’s four crippled reactors and turbine buildings with an ice wall to block groundwater from flowing into their basements and mixing with highly radioactive water leaking from the cores.

Toyoshi Fuketa, a commissioner with the Nuclear Regulation Authority, said the hydrological impact of creating a frozen wall in 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.

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.

International experts have raised similar concerns.

Dale Klein, a former U.S. Nuclear Regulatory Commission chairman who now heads a supervisory panel for Tepco, on Thursday said he was not convinced the frozen wall is the best option and 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 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 the 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.

See also :

May 2, 2014

Nuclear expert doubts ice wall will solve Fukushima plant leaks

http://www.japantimes.co.jp/news/2014/05/02/national/nuclear-expert-doubts-ice-wall-will-solve-fukushima-plant-leaks/#.U2dUtFKKAuU 

Kyodo

An international nuclear expert expressed skepticism Thursday about Tokyo Electric Power Co.’s plan to set up an experimental ice wall to ultimately stop radioactive water from escaping from the troubled Fukushima No. 1 nuclear plant.

“I’m not convinced that the freeze wall is the best option,” former U.S. Nuclear Regulatory Commission Chairman Dale Klein, who heads a supervisory panel tasked with overseeing the operator’s nuclear safety efforts, said in an interview with Kyodo News.

“What I’m concerned about is unintended consequences,” Klein said.

“Where does that water go and what are the consequences of that? I think they need more testing and more analysis,” he said.

Former British Atomic Energy Authority Chairwoman Barbara Judge, who was also present at the interview in Tokyo and is part of the panel, said there is a need to assess during the summer whether the ice wall method will work.

The remarks by the two overseas experts came at a time when concerns over the plan are being raised by the Nuclear Regulation Authority and engineering experts. Their opinions may cast a shadow on Tepco’s plan to begin operating the ice wall by the end of next March.

“No one has built a freeze wall this long for this period of time. Typically, you build a freeze wall for a few months,” Klein said.

Faced with a string of problems including radioactive water leaks at the Fukushima plant, Tepco will try to freeze 1.5 km of soil around the leaking basements of reactors 1 to 4.

The ice wall is meant to block groundwater from seeping into the buildings’ basements and mixing with highly toxic water used to cool the three crippled reactors.

“I am much in favor of the bypass system,” Klein said, referring to the groundwater bypass system used by Tepco to divert groundwater from the plant into the sea to reduce the amount of water seeping into the reactor buildings.

“The freeze wall is expensive,” he said, urging Tepco and the government to look at the cost of building one and whether the plan is making the “best use of limited resources.”

“I would encourage them to get international advice a little bit more,” Klein said of Tepco’s decontamination and decommissioning plans.

He also urged Tepco to work with and share information with authorities in the United States and Britain, given that they are more experienced in water management and decontamination at former military or weapons-related sites.