By Kevin Krolicki and James Topham
TOKYO, Sept 13 (Reuters) - Japan should begin preparing to release a massive tide of water from the wrecked Fukushima nuclear plant into the Pacific Ocean, once it regains public trust and can confirm the water has only low levels of radiation, a U.S. adviser to the plant's operator said on Friday.
Lake Barrett, a former head of the Department of Energy's Office of Civilian Nuclear Waste Management, spent nearly a decade at the U.S. Nuclear Regulatory Commission and led the clean-up operations after the 1979 partial meltdown at the Three Mile Island nuclear plant. He has been brought in by Tokyo Electric Power (Tepco) to advise it on the lengthy decommissioning process at Fukushima.
He said work should begin now to pump groundwater from the plant before it reaches wrecked reactors - a measure that has been stalled by local opposition.
"They should start pumping as soon as practical," said Barrett, adding that groundwater would have to be released into the sea along with water that had been treated to remove most radiation - by a system designed by Toshiba Corp.
"I believe in a matter of a few months ... early next year ... water will be cleaned up and be ready to be discharged," he said in an interview.
But Barrett, who has said he would feed his grandchildren fish caught off the Fukushima coast if the clean-up proceeds as planned, said Tepco has lost its credibility to reassure a jittery public. "When Tepco says: 'trust me, this water is safe,' that's not enough," he said.
Barrett toured the Fukushima plant on Thursday and met Tepco's president Naomi Hirose, part of an effort by the utility and Japan's government to show they are following through on a pledge to take control of irradiated water leaks at Fukushima.
Tepco has been battling to contain a tide of contaminated water at the plant, which suffered reactor meltdowns after the station was crippled by a massive 2011 earthquake and tsunami.
"NOW IS THE TIME"
The utility is pumping 400 tonnes of highly radioactive water out of the reactor buildings' wrecked basements every day, treating it to remove most radiation and storing the water in hundreds of makeshift tanks around the plant. Some 330,000 tons of contaminated water - enough to fill more than 130 Olympic swimming pools - has been pumped into storage pits and above-ground tanks at the facility.
Tepco plans to more than double the storage capacity of tanks at Fukushima by 2016, but doesn't have a plan beyond that. At least one tank has sprung a leak.
Tepco has tried to win local support for a "bypass" that would route groundwater around the plant and into the sea, reducing the amount of contaminated water that must be treated and stored. Local fishermen oppose the plan and have delayed its implementation.
Barrett said Japan's consensus-style of decision making risked delaying a practical step that would allow Tepco to focus on more critical problems.
"My sense is that they're hesitant to do this because it's a burden for the Japanese people, a burden for the fishermen, so maybe we'll just continue with more tanks," he said. "But you're just delaying the problem. Now is the time to deal with it."
Barrett said he urged Hirose to make Tepco more open to expertise from overseas. Foreign contractors and consultants have been largely excluded from the clean-up.
"I recommend they integrate foreign expertise within the Japanese system," he said. "It's something where they know they have to do better."
He said concerns raised by South Korea and China over the continued leaks of radiated water at Fukushima "political posturing."
"This is healthwise a big nothing," he said. (Editing by Ian Geoghegan)