In Fukushima Prefecture, a state of emergency was proclaimed after the 2:46
p.m. Friday earthquake knocked out a backup power system, depriving the
Oganawa boiling water reactor facility of the energy needed to cool rising
temperatures in the fuel rods. Although the temperature was running 50% over
normal, at about 750 degrees Fahrenheit, it remained well below the
2,200-degree design limit for preventing "cladding failure," said Margaret
Harding, a veteran nuclear industry engineer familiar with the afflicted
reactor from her work with General Electric.
"Remember, these are ceramic pellets. It takes a lot of heat to melt them,"
Harding said of the nuclear fuel rods.