Chernobyl Nuclear Accident Congressional Hearings Transcript

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generations of RBMK designs to improve on this situation,
but to this date we are unaware of any operating or underconstruction
Soviet RBMK with a full primary containment in
the sense we in the West define full containment.
To us, full containment means complete enclosure of all
reactor and primary support systems for the reactor such
that any design basis accident is contained inside. Full
primary containment is achieved typically in the U.S. by
building a strong, thick steel and concrete containment
vessel around all primary reactor systems. The containment
is either large enough to contain the peak pressure anticipated
for the worst design basis accidents, or has sufficient
"pressure suppression" or steam condensing capacity to
contain that worst case peak pressure. Most U.S. LWRs have
containments with design pressures of about 60 psi with
ultimate yield strengths as high as 3 times that figure.
For some U.S. containments with lower design pressures, such
as BWR MK-3 and ice condensers, sufficient pressure suppression
capacity is installed to limit the worst case accident
peak pressure to a much lower value that is well within the
containment design. Needless to say, the capability of a
containment to perform its design purpose successfully is
not merely a function of its design pressure, but also its
size and pressure suppression capacity. Finally, "full
containment" as defined by the U.S. implies the ability to
isolate completely and rapidly all containment penetrations,
such as main steam and main feedwater piping under accident
conditions.
We have heard of reports based on Soviet technical literature
that credit the Chernobyl Unit 4 with containment. We
have studied the Soviet literature and believe such claims
probably are not correct in the sense that we define "full
containment." This lack of containment seems to be sub-
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