By Osamu Tsukimori
TOKYO (Reuters) - The operator of the wrecked Fukushima nuclear plant won rare praise from monitors on Monday for its efforts to decommission the site, but the specialists also said the company still faced steep challenges, particularly in managing contaminated water.
A huge earthquake and tsunami in March 2011 triggered three meltdowns at the Fukushima Daiichi nuclear station, the worst nuclear disaster since Chernobyl in 1986, and exposed a lack of preparation by Tokyo Electric Power Co, or Tepco.
The company has floundered for much of the last 2-1/2 years in dealing with several problems at the site, including a series of leaks of radioactive water into the Pacific Ocean.
But it has proceeded with initial decommissioning steps, including the tricky removal of spent fuel rod assemblies from a badly damaged reactor building. The entire process is likely to take decades and costs ten of billions of dollars.
"It's nice to see the good progress Tepco has made in the last several months," Dale Klein, a former chairman of the U.S. Nuclear Regulatory Commission, told a meeting of the Nuclear Reform Monitoring Committee.
"There's obviously a lot more work to be done, but it's very positive progress....Spent fuel movement at (reactor) No. 4 went very well. You have demonstrated a very positive approach to safety culture."
But Klein added: "You've also made good progress in water management. But again water will continue to be a challenge at the Fukushima site."
The Monitoring Committee, which includes four members from outside Tepco, was set up in September 2012 in response to calls for independent experts to monitor pledges to raise standards of safety culture. It held its fifth meeting on Monday.
Barbara Judge, a British-based nuclear expert, also pointed to "extremely good progress" by the company.
"...But nuclear safety is a long proposition. And it's only beginning," she said. "I'm disappointed that it's not going as fast as we would have liked it to. There is still reluctance by some of the members to ask the hard questions."
The plant is located 220 km (130 miles) northeast of Tokyo.
BETTER WORKING CONDITIONS
Judge praised improvements in working conditions for those overseeing the clean up and decommissioning process, saying the efforts would make "working at Fukushima easier for them and better for the company and better for the country".
Tepco last month began the delicate task of removing more than 1,500 brittle and potentially damaged assemblies from unstable reactor No. 4, its first steps to decommissioning the station after bringing the melted reactors under control.
By Monday, the Tepco website said it had removed 44 fuel assemblies, including 22 irradiated used rods.
Klein said so far the removal has gone "very well," adding that "the most important thing is that the cores are cooled and the spent nuclear fuel is cool".
Tepco estimates that removing all the rods from the reactor will take a year, although some experts say that is an ambitious target.
But Tepco's difficulties have focused on radioactive water leaks and in July it first acknowledged, after months of denial, that the water had spilled into the Pacific. Its management of water leaks has improved since the government said in September it was stepping into oversee the process.
The International Atomic Energy Agency, the U.N. watchdog for nuclear power, is currently undertaking an inspection of the Fukushima site after issuing rare criticism of Tepco during a visit earlier in the year.
(Reporting by Osamu Tsukimori; Editing by Aaron Sheldrick and Ron Popeski)