BOOK REVIEW
March Madness
Robert Bernero
Three Mile Island: A Nuclear Crisis in Historical
Perspective. J. Samuel Walker. xii + 303 pp. University of
California Press, 2004. $24.95.
The accident at Three Mile Island Nuclear Generating Station in
Pennsylvania on March 28, 1979, was "the single most important
event in the fifty-year history of nuclear power regulation in the
United States," says J. Samuel Walker. Many critics of nuclear
power point to the accident as a turning point for the industry,
noting that no new plants have since been ordered in the United
States and that many planned in prior years were subsequently canceled.
Walker provides a gripping, detailed account of the accident and an
analysis of its impact and significance in Three Mile Island: A
Nuclear Crisis in Historical Perspective. It is his fourth
book as the official historian of the U.S. Nuclear Regulatory
Commission (NRC). In the preface Walker assures readers that he had
complete independence as the author and that the NRC placed no
restrictions on what he could say. However, Walker provides an
historical account of the events; he does not evaluate the
performance of the NRC during those events.
The first two chapters effectively fill readers in on the historical
context for the accident, giving a brief overview of the
government-supported growth of commercial nuclear power in the 1960s
and 1970s, and describing the emerging controversy during that
period over the safety of nuclear power. The public worried both
about the risk of accidents and about routine low-level releases of
radioactive material. (The latter concern was inspired in large part
by fears of cancers caused by exposure to radioactive fallout from
nuclear-weapons testing.)
Many people contended that the Atomic Energy Commission (AEC) could
not acceptably regulate nuclear power at the same time that it was
engaged in promoting it. So as Walker recounts, Congress passed the
Energy Reorganization Act of 1974, dividing the AEC into two
entities: the NRC, which was charged with regulating commercial
nuclear technology, and the Energy Research and Development
Administration, which assumed all of the other roles of the AEC and
later evolved into the U.S. Department of Energy. Walker provides
some interesting descriptions of the last days of the AEC and the
selection of members of the new commission.
Reacting to the OPEC oil crisis of 1973, the Nixon and Ford
administrations launched Project Independence, an effort to meet our
energy needs without depending on foreign sources. President Ford,
in his 1975 State of the Union address, set a goal of having
"200 major nuclear power plants" in operation within 10
years. Nevertheless, a "nuclear power slump" ensued.
Walker attributes the failure to follow Ford's plan to rising
costs—the energy crisis drove up the fuel prices for electric
utilities, and the then-rampant inflation in interest rates made it
hard to raise capital for new plants—and to a decline in the
demand for electricity that occurred because the country was in a
recession. Very high interest rates persisted through the end of the
1970s. By late 1975, 122 out of 191 nuclear power projects had been
deferred and 9 had been canceled.
In chapter 3, Walker gives a simplified explanation of the principal
safety issues with reactors of the same type as Three Mile Island
Unit 2, where the accident took place. Even though he uses fairly
plain language, readers who are not already familiar with the
technology involved may find this material tough going.
Nevertheless, this chapter is a useful technical preamble to the
account of the accident itself.
The core of the book consists of six chapters, one covering each of
the 5 days (Wednesday, March 28, through Sunday, April 1, 1979) of
the crisis phase of the accident and another covering its immediate
aftermath. Walker draws on the full panoply of sources for his
presentation of events, but principally on the report of the Kemeny
Commission, which President Carter appointed immediately after the
disaster to investigate its causes and make safety recommendations,
and the Rogovin Report, which was the product of the NRC's own
inquiry into the matter. These chapters are well annotated:
References include the full set of specific sources for a
passage, not just citations for quotations.
Walker describes events and actions in language that any reader can
easily understand. His account is quite accurate. I was a member of
the NRC staff assigned to prepare the Rogovin Report, and I feel
that Walker has caught the essential character of the remarkable
degree of confusion that prevailed throughout the course of the
emergency. That confusion was caused by the inadequate flow of
information between all of the responsible parties: the plant
operators (Metropolitan Edison Co.) and their own management,
Governor Richard L. Thornburgh and other Pennsylvania authorities,
the NRC headquarters staff and the Commission, and the NRC regional
staff and headquarters staff who went to the site early in the
accident. Walker includes short background descriptions of key
participants to enhance understanding of their actions.
The chain of events that precipitated the crisis at the plant
included a number of minor equipment failures, but operator errors
(to which design flaws contributed) converted those malfunctions
into a major accident. The first problem occurred at about 4:00 a.m.
on Wednesday in the turbine building, in the condensate cleanup
system, while the plant was operating at about 97 percent power. The
pumps in the condensate system turned off for unknown reasons,
leading to a trip, or shutoff, of the turbine and the pumps that fed
water back into the steam generator. This in turn caused the nuclear
reactor to automatically shut down—a response the operators
were trained to expect. They were also trained to expect that an
energy surge into the steam-generating system would follow, because
even after a reactor trips from full power and nuclear fission
stops, immediate radioactive decay of isotopes in the core continues
to generate about 5 percent as much heat as is produced when the
plant is operating at full power.
The energy surge into the steam-generating system increased pressure
in the reactor coolant system and in a device called the
pressurizer, causing the pilot-operated relief valve (PORV) to open
to relieve that pressure. This too the operators were trained to
expect, but they were not trained to recognize the symptoms
that would ensue if the valve stuck open, as it did. They had no way
of directly ascertaining the water level in the pressurizer. When
the valve stuck open, venting steam and reactor coolant into the
containment building, water was being lost from the pressurizer, but
operators didn't realize it; instead they got the false impression
from the high pressure readings that the reactor cooling system was
overfilling, and they worried that the pressurizer was "going
solid"—reaching a state of being entirely filled with
water (rather than water plus a cushion of steam)—a condition
they were trained to avert. For hours the operators acted on the
misperception that the cooling system was overfilling (taking such
ill-advised steps as turning off the water pumps in the emergency
core cooling system) and ignored all other contrary signals,
including high temperatures in the core, instability in the flow of
reactor coolant, high radiation in the containment building and so
forth. It was not until 6:22 a.m. that a shift supervisor who had
just arrived on the scene figured out that the PORV must be stuck
open, and closed its backup, a block valve.
Therein lies the confusion that characterized the accident: The
operators did not really understand what had happened and were
unable to explain it to their own management, to the NRC, to the
State of Pennsylvania or to the public.
The devastation of the reactor core—about half of which
melted, releasing great amounts of hydrogen gas into the reactor
coolant system and into the containment building—was
essentially over by the evening of the first day, Wednesday.
Thursday, Friday, Saturday and Sunday were occupied by slowly
cooling down the reactor and venting the hydrogen from the reactor
coolant system. An understanding of what had happened was slow to
penetrate the fog of confusion that prevailed at all levels. So
there was an evacuation crisis on Friday morning, and fears that the
hydrogen bubble might catch fire or explode extended even into
Sunday, when President Carter visited the site. Fortunately, the
grievous damage to the reactor did not result in any injuries or
deaths, in large part because of the robust design of all of the
plant's systems.
The book describes all this and concludes with an interesting
discussion of the long-term effects of the crisis at Three Mile
Island. This last chapter covers the extensive investigations that
followed the accident, and the analyses, recommendations and reforms
that resulted from them. The incident was "a major
embarrassment and a severe setback" to the fortunes of the
nuclear industry; however, it was not really a singular turning
point, since—as noted above—many nuclear power projects
had already been deferred or canceled years earlier. After the
accident, another 19 planned nuclear plants were canceled, including
some that were nearly completed.
The TMI-2 cleanup took 11 years and cost about $1 billion. Although
at the time of the accident, damage to the core was believed not to
be extensive, continuing investigations ultimately revealed that
about 70 percent of the core had been damaged and 50 percent of it
had melted. Some nuclear critics had asserted that a core meltdown
would inevitably breach containment. In the 1960s, nuclear critics
had coined the term "the China syndrome" to describe an
accident in which a core would overheat and melt through the bottom
of a plant and down through the Earth's core toward China, and two
weeks before the accident at Three Mile Island, a movie called
The China Syndrome was released, a thriller about the
dangers of nuclear power. But at Three Mile Island, the pressure
vessel did not fail (which would have allowed the core to fall into
the containment structure), even though it was not designed to
withstand the heat the accident generated. Researchers concluded
that when a portion of the molten core first reached the bottom of
the vessel, it was cooled by the small amount of water that was
still there and solidified into a crust that helped protect the
vessel floor from the heat.
Walker reports that studies looking for long-term health effects
from radiation released during the accident have reached conflicting
conclusions. But it appears any increase in cancers is slight enough
that it may have occurred by chance.
This is a comprehensive historical account, with 42 pages of notes,
an essay on sources and a 13-page index. But despite these scholarly
trappings and the complexity of the events described, the book is
eminently readable.