OKYO, Aug. 10 — A steam pipe that blew
out Monday, killing four workers at a Japanese nuclear power plant,
had not been inspected in 28 years and had corroded from nearly half
an inch to a thickness little greater than metal foil, the
authorities said today.
"To put it bluntly, it was extremely thin — it looked terrible
even in the layman's view," Shoichi Nakagawa, Japan's minister of
economy, trade and industry, told reporters today after touring the
power plant in Mihama, about 200 miles west of here.
Although the carbon steel pipe carried 300-degree steam at high
pressure, it had not been inspected since the power plant opened in
1976. In April 2003, Nihon Arm, a maintenance subcontractor,
informed Kansai Electric Power Co., the plant owner, that there
could be a problem. Last November, the power company scheduled an
ultrasound inspection for Aug. 14.
"We thought we could postpone the checks until this month," Akira
Kokado, the deputy plant manager, told reporters at Mihama. "We had
never expected such rapid corrosion."
The police opened an investigation today to determine why 221
workers were in the reactor facility at the time of the accident.
The subcontractor has said the workers were preparing for Friday's
inspection shutdown.
On Monday, four days before the scheduled shutdown, superheated
steam blew a two-foot wide hole in the pipe, scalding four workmen
to death and injuring five others seriously. The steam that escaped
was not in contact with the nuclear reactor and no nuclear
contamination has been reported.
Initial measurements showed that the steam had corroded the pipe
from .4 inches to .06 inches, less than one-third the minimum safety
standard. Kansai Electric said in a statement today that the pipe
showed "large-scale corrosion."
"We conducted visual inspections, but never made ultrasonic
tests, which can measure the thickness of a steel pipe," Haruo
Nakano, a Kansai Electric spokesman, told reporters.
In response to the accident, Japan's Nuclear and Industry Safety
Agency ordered four other power companies that own nuclear plants
with the same type of pressurized water reactors to conduct
ultrasound inspections of their pipes. The inspections are to
involve nearly half of the country's 52 nuclear power plants.
After television news helicopters swarmed over the plant on
Monday, government officials jumped today to assure the public that
a full investigation will take place.
"We must put all our effort into determining the cause of the
accident and to ensuring safety," Prime Minister Junichiro Koizumi
said. He added that the government would respond "resolutely, after
confirming the facts."
But government leaders also tried to bolster flagging public
support for nuclear power.
"Nuclear power has a significant impact in our lives," Mr.
Koizumi told reporters today. "We have to pay close attention so
that our lives won't be affected by this accident."
Mr. Nakagawa, the industry minister, said, "We must not undermine
trust in nuclear energy policy."
The government has planned to build an additional 11 reactors
this decade, increasing the nation's reliance on home-based nuclear
power to 40 percent of electricity needs. Already slowed by local
opposition, this program may now be stalled.
"In Japan, it's virtually impossible to build new nuclear
facilities now," Asahi Shimbun, a liberal newspaper, said in an
editorial today. "But facilities are wearing out, and there are
worries about increasing problems with corroding pipes, rupturing
valves and the reactor core."
The Nihon Keizai, a business daily, worried that the accident
could undermine public support in Japan for nuclear power.
"We must find the cause of the accident and urgently come up with
measures to prevent such an accident from happening again," the
newspaper editorialized. "This accident seriously damaged public
confidence in nuclear safety and our nuclear measures."
The Yomiuri, a conservative newspaper, warned: "Care must be
taken not to overemphasize the dangers involved in the operation of
nuclear power stations, which could lead to an overreaction.
Operations at other nuclear power plants must not be
undermined."
Japan has the world's third-largest nuclear power industry, after
the United States and France.
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