Physics Expert On Nuclear Reactor reports that Japan’s fears of nuclear mayhem recede as the nuclear reactor at Fukushima Daiichi starts to cool.

For a few unnerving hours, Japan faced a bleak and unsettling prospect. The devastation wreaked by Friday’s earthquake and tsunami seemed set to be followed by a nuclear meltdown that could have spread radioactive waste over large parts of the country. Fears of a nuclear fallout were raised when a massive explosion rocked the Fukushima Daiichi atomic power plant following damage to one of its reactors in Friday’s earthquake.

“To reduce the pressure, you would have to release some steam into the atmosphere from the system,” said physics expert Professpr Patrick H. Regan, professor of nuclear physics at Surrey University. “In that steam, there will be small but measurable amounts of radioactive nitrogen 16 [produced when neutrons hit water]. This remains radioactive for only about five seconds, after which it decays to natural oxygen.”

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