The U.S. nuclear safety chief said Tuesday that he is comfortable with Japan's announcement that its tsunami-damaged nuclear power plant has reached stable conditions, brushing off skepticism raised by experts.
Gregory Jaczko, chairman of the U.S. Nuclear Regulatory Commission, said significant progress has been made at the Fukushima Dai-ichi nuclear power plant since the March disaster and that he welcomes Japan's decision to now move toward a cleanup and the plant's eventual closure.
Measures taken by Japan have been consistent with how the U.S. would handle a similar crisis, he said.
"I feel very comfortable that they have really completed the requirements that are necessary to move on to the next stage," Jaczko told reporters a day after inspecting the Fukushima plant. "These are really significant milestones that have been achieved and I think they made the right determination to move on to the next stage in the decontamination and decommissioning activities."
Prime Minister Yoshihiko Noda announced last Friday that the plant has achieved "cold shutdown conditions," saying significant progress had been made in the nine months since the March 11 tsunami sent three reactors at the plant into meltdowns in the world's worst nuclear crisis since Chernobyl in 1986.
The announcement officially paves the way for a new phase that will eventually allow some evacuees back to less-contaminated areas currently off limits.
Fully closing the plant safely is expected to take 30 or more years.
Experts say the plant 140 miles (230 kilometers) northeast of Tokyo is running with makeshift equipment and remains vulnerable to cold weather and earthquakes.
Jaczko said the plant has made "tremendous progress in ultimately bringing the reactors themselves to conditions in which there is no energy left in the reactors to have an offsite release of radiation."
Their temperatures have decreased significantly and the heat produced by the reactor fuel is very low, he said.
Jaczko said it was a "humbling experience" to see the severe damage to the reactors and the facilities during his visit.
He said continuing efforts to analyze the conditions of the reactor cores are very important.
"It will be many years until someone is able to actually get into Unit 1 and Unit 2 and Unit 3 to really understand the condition of the fuel," he said.
Jaczko promised continuing support for Japan's decades-long cleanup effort.