Quake-hit nuclear plant shut down indefinitely
By John Boyd
First Published July 2007
It may be on a major fault line, say experts
PHOTO: Toyko Electric Power Co.
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19 July 2007—Three days after a deadly earthquake
damaged the world’s most powerful nuclear
complex, the woes for operator Tokyo Electric Power Co.
(TEPCO) continue to multiply after experts determined
that the
Kashiwazaki Kariwa facility—about 200
kilometers north of Tokyo—may be located on a previously
undetected extension of a major fault line. After
reviewing the extent of the damage to the plant—some 50
separate incidents—the mayor of Kashiwazaki City, near
where the plant is located in Niigata Prefecture, on the
coast of the Sea of Japan, ordered a complete shutdown
of the entire facility until its safety can be assured.
TEPCO officials estimate it could take until the end
of August to repair the damage and carry out safety
checks. But then the power company will have to convince
authorities that the facility is safe to operate—no easy
task when experts from the Japan Meteorological Agency
are now saying the plant may be in an active part of the
region’s earthquake zone.
At a press briefing Wednesday, Akira Fukushima,
deputy director general for safety examinations at
Japan’s Nuclear and Industrial Safety Agency, said:
“Because the earthquake was of a scale larger than the
facility was built to withstand, the minister [of the
Ministry of Economy, Trade, and Industry; METI] has
directed that operation of the reactors not begin until
their safety is assured.” He added that last September
the Nuclear Safety Commission revised its guidelines for
plant design, and TEPCO will have to take these new
standards into consideration.
The facility was built to withstand a magnitude of
6.6, considerably lower than the 6.8-magnitude
earthquake that struck at 10:13 Monday morning, killing
10 people and leaving scores of thousands without
electricity and water. Given that magnitude is based on
a base-10 logarithmic scale, a 0.2 increase represents a
200 percent jump in the amplitude of the earthquake’s
vibrations and a greater than 600 percent increase in
the energy released. So major structural reinforcements
may be required to ensure the plant’s safety.
Meanwhile, TEPCO has come under strong criticism from
authorities and growing anger from the local inhabitants
after it was revealed that TEPCO bungled efforts to deal
with the damage. It initially underreported the extent
of the problems and delayed making its findings known.
Chief among the criticisms were TEPCO’s inability to
deal with a fire in a power transformer outside one of
the reactors and the late discovery that coolant
containing a small amount of radioactive material had
spilled and found its way into the sea. In addition, the
utility initially reported that the quake had knocked
over 100 barrels of low-level radioactive waste; the
number was eventually found to be 400, and among those
some 40 barrels had their lids dislodged. TEPCO says
that because so many troubles arose simultaneously when
the quake hit, it didn’t have the personnel to deal with
all of them immediately and was also unable to inform
authorities as quickly as it should have.
On a more positive note, four of the seven reactors
in use at the time of the earthquake shut down
automatically when the first tremors were felt; the
other three reactors were already closed for
maintenance. Both TEPCO and METI also say that the
amounts of radioactive material that escaped had
negligible impact on the environment. That hasn’t
stopped hundreds of worried summer vacationers from
canceling hotel reservations in the area, though.
Summer is the time of peak power demand, so TEPCO is
planning to start up a number of fossil-fuel power
stations not currently in operation to help cover the
shortfall left by the closure of the 8.21 gigawatt
complex. TEPCO is also asking six other regional power
suppliers to provide it with electricity from their
systems to help the area get through the hottest weeks.
For more about earthquakes in Japan
When the next big earthquake hits Tokyo, engineers
bet even a few seconds can save lives, see “How to
Master a Seismic Disaster.”
The Japan Meteorological Agency is responsible for
tracking earthquakes and other natural disasters in and
around Japan. On its Web site, you can see a plot of
earthquakes that have occurred there during the past
week: http://www.seisvol.kishou.go.jp/eq/weekly_map/japan/weekly.shtml.
For a more global view, see the U.S. Geological
Survey's weekly worldwide map of earthquakes. It shows
disturbances with magnitudes of 4.0 or greater (or 2.5
or greater within the United States and adjacent areas): http://earthquake.usgs.gov/eqcenter/recenteqsww.