Chernobyl Nuclear Accident Congressional Hearings Transcript

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pressure buildup inside the TMI containment, but without any
adverse consequences. The TMI containment building design
was strong enough to contain overpressures from both escaping
steam, and from hydrogen release and burn. In comparison,
the Chernobyl accident appears to us to indicate a
weakness in the Soviet RBMK design with respect to containing
fission products and chemical energy.
SAFETY SYSTEM DIFFERENCES
The final area of U.S. and Soviet designs that I wish to
address is safety systems. This topic is perhaps the most
difficult area of comparison, but also is an area that may
yield the most useful applications to our industry. Soviet
nuclear power plant safety criteria and systems will be
difficult to analyze, not only because of the limited number
of Soviet papers on the subject, but because we believe that
the description of a safety system in Soviet literature does
not necessarily mean the system described is in fact
installed, tested, and available to perform its design function
on each Soviet reactor. This makes it hard to do the
kind of safety analysis and risk assessment that we do on
U.S. LWRs. We understand that a Soviet design may call for
three emergency diesels, where in fact the plant may operate
before the third diesel is delivered to the site. We read a
translation of a Soviet paper that describes the safety
value of adding a turbine driven auxiliary feedwater pump.
It may be describing a desired feature that is not yet
installed, despite the implication that it is part of the
design. It is our understanding that such a feature was
not installed at Chernobyl. We also question whether tests
and computer analyses of various modes of degraded heat
transfer inside pressure tubes were part of the design
process, or were conducted later to study the effects of
accidents not considered originally, or to study the details
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