Japan pumped nitrogen into a crippled nuclear reactor on Thursday, trying to prevent an explosive build-up of hydrogen gas, as the world's worst nuclear disaster in 25 years fired debate over the safety of atomic power in the United States.
In a sign of growing international concern over radiation fall-out from the earthquake-wrecked Japanese plant, some schools in neighbouring South Korea closed because parents were worried that rain there might be toxic.
Latest data, meanwhile, showed that foreign tourists were shunning Japan during what would normally be one of the most popular seasons to visit the country.
Engineers have been working since Wednesday night to pump nitrogen gas into the containment vessel of reactor No.1 at the Fukushima Daiichi power plant, which was smashed by a 10-metre tsunami that followed the massive earthquake of March 11.
An official at plant operator Tokyo Electric Power (TEPCO) insisted that it was a precautionary measure and the chances were "extremely small" of a repeat of hydrogen gas explosions that ripped through two reactors early in the crisis.
But while the government says the situation has stabilised at the devastated plant, 240 km north of Tokyo, it is still far from under control.
One TEPCO official said 6,000 cubic metres of nitrogen gas would be pumped into reactor No.1 and the utility was preparing gas injections for reactors No.2 and No.3 in the six-reactor plant as a safety precaution.
Engineers did manage on Wednesday to finally plug a leak at reactor No.2, but they still need to pump 11.5 mln litres of contaminated water back into the ocean because they have run out of storage space at the facility.
SAFETY CONCERNS
In Vienna, the head of a U.N. scientific body said based on the information he had now, the Fukushima accident was not expected to have any serious impact on people's health.
Wolfgang Weiss, chairman of the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), said the Fukushima disaster was less dramatic than Chernobyl in 1986 but "much more serious" than Three Mile Island in 1979.
In Washington, Democratic lawmakers raised concerns, in the wake of Japan's crisis, about whether regulators and the nuclear power industry were doing enough to ensure U.S. reactors could withstand worst-case scenarios in the wake of Japan's crisis.
Concerns focused on a Pennsylvania nuclear plant with the same kind of reactor design as the Fukushima facility.
Some lawmakers argued that the U.S. plant could be at risk of meltdown in the case of a severe emergency.
