TIME: Almanac 1993/TIME Almanac 1993.iso/time/031891/0318300.000

Text File | 1992-08-28 | 5.8 KB | 118 lines

                                                                                SCIENCE, Page 87

Mid-Life Crisis for Nukes


Designed to last 40 years, U.S. atomic plants face increased
maintenance woes and may soon be perilously past their prime

By CHRISTINE GORMAN -- With reporting by Robert Ajemian/Boston


    Like many of the technicians and engineers who run them,
nuclear power plants in the U.S. are pushing middle age. So
far, only nine of the nation's 112 commercial reactors, which
were designed and licensed to run for 40 years, have passed the
midpoint of their careers. But by 1995, 40 more plants will
celebrate their 20th birthday. Because of that, and because no
new plants have been ordered since 1978, within four years 44%
of America's atomic facilities will be past their prime. At a
time when the Bush Administration is pushing for a renewed
emphasis on nuclear power, there is growing concern about the
safety of the country's geriatric plants.

    Fueling these worries is a new rule, scheduled to be enacted
in June by the Nuclear Regulatory Commission, that would
stretch the legal life-span of many atomic plants to 60 years.
Although the NRC says it will ensure that the industry
addresses age-related issues, some scientists charge that the
agency's safety guidelines are not stringent enough to prevent
catastrophic accidents. Forty years ago, "these nuclear plants,
after concerted study, were granted a finite number of years
to operate," says M.I.T. physicist Henry Kendall, who shared a
Nobel Prize last year for discovering subatomic particles called
quarks. "Now the industry wants to extend that time by 20
years. They're changing the rules of the game." Nuclear
officials dispute the charge, pointing out that the 1954 Atomic
Energy Act contained provisions for license renewal.

    First in line for a new lease on life is the oldest
commercial reactor in the U.S., the 30-year-old Yankee nuclear
power plant in Rowe, Mass. "Yankee Rowe" reliably produces more
than 1 billion kW-h of electricity a year -- about one-sixth
the capacity of its more modern counterparts -- and boasts an
excellent safety record. However, after decades of absorbing
the high-energy neutrons that are released during nuclear
reactions, the walls of Yankee Rowe's reactor vessel have begun
to weaken. Just how much is not clear. This so-called reactor
embrittlement is potentially the most dangerous problem faced
by aging atomic plants, because a crack in these walls could
expose the highly radioactive reactor core.

    At an NRC hearing last September, Neal Randall, one of the
agency's engineers, testified that based on worst-case
calculations, he believed the "Yankee Rowe vessel is quite
brittle" and was therefore unsafe to operate even for the
remainder of its license. The precise extent of the problem is
uncertain because the utility has run out of easily accessible
test samples of the original steel used in building the vessel.
Ideally, such samples are periodically examined for hidden
cracks, allowing scientists to determine how much embrittlement
has occurred. Although Randall's opinion was a minority view,
it electrified the plant's critics. The utility has promised
to take new weld samples from within the reactor vessel
sometime next year.

    "We're not saying that aging problems do not exist," says
Andrew Kadak, the Rowe plant's chief executive officer. "But
we address them constantly. It cost $40 million to build this
plant, and we've put another $40 million into it to keep it
current and efficient." Kadak insists that Yankee's reactor
vessel can operate safely for another 20 years: "We believe we
can prove that." Among other things, he says, engineers use
more advanced techniques to detect flaws and are developing an
annealing process that would strengthen irradiated metal. The
key point "is the size and thickness of our vessel," he argues.
"At eight inches, the walls are as thick as at brand-new
plants."

    Surprisingly, most of the age-related problems in nuclear
facilities are not triggered by radiation but are due to more
ordinary kinds of wear and tear. Corrosion can lead to leaks
in the steam generators of some reactors, causing the eventual
rupture of component tubes and the escape of radioactive water.
Such a sequence of events was probably responsible for the
accident in Mihama, Japan, last month, which resulted in the
release of a small amount of radiation into the sea and air.

    Of course, faulty design or parts would exacerbate the
problems of aging. In one of the most acrimonious legal battles
ever to hit the nuclear industry, the Duke Power Co. of
Charlotte, N.C., has accused Pittsburgh-based Westinghouse of
fraudulently selling it 16 defective steam generators. The
utility claims that the generators, which were installed at two
of its plants in the late 1970s, cost more to maintain than
normal and may have to be replaced as soon as 1995, long before
the end of their life-span. Duke estimates the cost of putting
in new generators to be in excess of $600 million. Others in
the industry are closely following the case, which is scheduled
for trial in 1993, since identical Westinghouse generators are
in place at 14 other U.S. facilities.

    Aging is a concern even outside the containment structures
of nuclear reactors. Although the pipes that crisscross such
facilities have been designed to withstand tremendous changes
in pressure and temperature, they are not immune to corrosion.
Nuclear engineers confidently predict that they can find and
replace worn-out equipment before it presents a hazard. But as
many a householder can sadly attest, pipes do not always signal
when they are about to burst. For nuclear reactors as for human
beings, growing old frequently brings on unexpected -- and
irreversible -- problems.