Chernobyl Nuclear Accident Congressional Hearings Transcript

165
taking forceful steps to help close down the dangerous nuclear facilities in the East,
the G-7 Governments would demonstrate their empathy with populations suffering
the impacts of Chernobyl and other nuclear accidents. In addition, the Western nations
would be helping to secure their own well-being by avoiding the possibility of a
second Chernobyl. The closures that FOEI is recommending should be facilitated by
teams of western experts—from the government, non-government, scientific and private
sectors—working in close cooperation with scientists, engineers and non-governmental
experts in the Eastern countries.
A. Overview
II.
REACTOR SAFETY
All Soviet-designed reactors present a serious and imminent threat to environmental
stability as well as to human health. They pose the following threats:
• Ill-conceived reactor design, the legacy of poor Soviet technology, presents serious
risks of accidental leaks or explosions, both major and minor;
• Poor worker training and morale risks serious errors on a day-to-day basis;
• Inadequate capital undermines the ability of plant operators to maintain minimum
safety standards; and
• The lack of uniform regulation and standards for waste disposal results in hazardous
disposal and handling of radiation and radioactive waste.
B. Reactor Design
The Soviets used two basic reactor design concepts: the RBMK graphite reactor, of
the type found at Chernobyl; and the WER pressurized water reactor, of which several
generations have been developed. Each model has unique flaws which pose different
safety risks.
1. The RBMK
The RBMK poses such severe, intractable risks that Adolf Huttl, head of the Nuclear
Energy Division of Siemens International (once one of the world's biggest constructors
of nuclear plants), has rejected the possibility of their upgrade, stating:
"The only answer is to shut them down as soon as possible." * This view has been
echoed by Mr. Klaus Topfer, Germany's environment minister.® The consensus of
the nuclear community comes down against the continued operation of the reactors.
Some of the major design flaws include:
• Positive reactivity feedback: As the reactor operates at lower power levels, the
fission reaction accelerates. Therefore, in the event of low power operation, even the
act of shutting down increases the risk of a serious accident. * " In addition, the flammability
of the graphite moderating agents intensifies the risk of a catastrophe from
either an emergency or a common-cause failure. ' ^
• The reactors have no containment vessels to lessen the impact of radiation
leaks, or protect the surroundings in the event of a core meltdown. ^ ^
• The fuel channels critical to the safety of the reactor have a history of rupture.
• 3
It is important to note that even with upgrades, the RBMK wUl not meet Western
safety standards, according to Huttl and others in the nuclear community.^*
The problems of these reactors are far from solved, as the March 24, 1992, accident
at Sosnovy Bor illustrated. In that case, radiation leaked out from an RBMK
reactor outside St. Petersburg, Russia. On the international scale of seven, the leak
was first given a three (the Chernobyl meltdown received the highest rating of
seven). 15 "The enigmatic accident disconcerted some in the scientific community. Because
RBMK design information has been "closely guarded by the Russian nuclear
bureaucracy," '^ knowledge of RBMK design is not complete in the nuclear community.
* ' This poses additional problems for their backfitting. Western experts will be
backfitting a plant of which they have, at best, only a theoretical understanding.
2. The WER UO/230
Of the WER pressurized water reactors, the first generation model 230 poses by
far the most serious set of risks. According to the IAEA, "These units clearly do not
meet current safety requirements." ^^ The major deficiencies '® include:
• The lack of a containment vessel increases radiation release risk. Adding to this
deficiency, the absence of a pressure relief system impairs the plant's ability to respond
to an emergency, while the reactor vessel's embrittlement, present at almost
every site, increases the risk of radiation release. In fact, at some of the older reactors
at Kozloduy (Bulgaria) and Bohunice (CSFR), the reactor vessels have a high
copper content, which accelerates their embrittlement further. 2°