On April 25, 2002, more than a thousand plaintiffs,
mostly citizens, filed a lawsuit against Chubu Electric Power
Company, the operator of Hamaoka nuclear power station in
Hamaoka town, Shizuoka prefecture, claiming that all the Hamaoka
nuclear reactors should be shut down.
There are four nuclear reactors in Hamaoka,
with Hamaoka 3 and 4 currently operating. Last November, Hamaoka
1 (BWR, 540 MW) had two major accidents; one was a pipe rupture
caused by a hydrogen explosion and the other was a water leak
from the reactor vessel. Due to these accidents, Hamaoka 1
and 2, both of which were constructed in the 1970s, have been
temporarily shut down. While the causes of the accidents have
not been fully clarified, Chubu Electric has said that it
would resume the operation of Hamaoka 2 in the near future
(This could be within a few months.)
The Hamaoka nuclear power plants are located
in the middle of an intraplate earthquake-prone region, where
the Great Tokai Earthquake is expected to occur. This quake,
which a number of seismologists have predicted will occur
within a few years, could well be 15 to 30 times more powerful
than the 1995 Hanshin earthquake.
In spite of citizens’ and scholars’ concern,
the Japanese government and Chubu Electric have been insisting
that these nuclear power plants were constructed in accordance
with the government safety guidelines, and would withstand
any seismic movements, though there has never been any instance
in the world in which a nuclear power plant was hit by a M8
class earthquake. There are also many concerns relating to
the plants’ aging.
According to a simulation done by Kyoto University,
if Hamaoka 2, 3, and 4 had major accidents simultaneously,
and evacuation were not carried out properly, 21.6 million
people, 17% of the entire Japanese population, would be killed
by acute and late radiation effects.