The alarming news coming from Japan's Fukushima Daiichi nuclear power plant doesn't worry one of Atlanta's experts on nuclear reactors.
Farzad Rahnema, a Georgia Tech professor of nuclear engineering, had been reading stories that hinted at the possibility of a meltdown at the plant, which was shaken by the massive earthquake there. But he said the details he'd gleaned from those accounts, and from industry reports, suggested that a meltdown was unlikely.
The word conjures images of the Chernobyl plant in the former Soviet Union, and the devastation it wrought when its reactor melted down. Will the Fukushima plant disgorge hot nuclear fuel, dumping radiation into the air and sea?
"I don't think this thing is anywhere close to that," said Rahnema, an expert in reactor physics. He added a caveat -- his opinion was based on "sketchy" details. But he said the fact that plant officials hadn't deemed it necessary to activate an emergency cooling system was reassuring.
Despite a loss of power to the plant's primary cooling system, it appeared officials were able to obtain backup power, he said, basing that opinion on a terse statement issued by the Tokyo Electric Power Company at about 4 p.m. Friday Atlanta time. It said the water level necessary to cool the reactor fuel had been "maintained."
That wouldn't have been possible without backup power, Rahnema said. "If the water level in the reactor is maintained," he said, "that's good news."
Even if the reactor core were to melt down, Rahnema said it probably would not produce the dire consequences seen in Chernobyl. That plant had few of the safety features required in Japan. Even if the Fukushima reactor were to melt the central pressure vessel that contains it, he said, the radioactive fuel would still be held within a concrete containment, something he said was lacking in the Chernobyl design.
Still, if officials cannot get the plant online, they'll have to control the temperature of the nuclear fuels with standby power, possibly for months. The nuclear reaction will continue at least that long, Rahnema said.
The nuclear reactions "have a long half life, so they continue creating heat," he said. But the heat from the reaction drops significantly within a day after the reactor is shut down, to as little as 1 percent of the amount when it was at full power, he said. "It's easy to manage."
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