Chernobyl Nuclear Accident Congressional Hearings Transcript

72
questions concerning fuel behavior during severe accidents in a liquid metal
cooled
reactor.
The DOE and INEL are involved in the assessment of the severely damaged core
in the TMI-2 reactor. This assessment has determined that the TMI-2 accident
resulted in a significant amount of fuel melting; approximately 50 percent of
the core was molten at some time during the course of the accident. Therefore,
a substantial release of fission products occurred. But, unlike the
Chernobyl accident, the amount of fission products released from the TMI-2
reactor to the environment posed no significant threat to the public. The
scenario for the progression of the accident would indicate that the
relocation of a molten core into a reactor lower plenum that remains full of
water will probably result in coolable debris which will arrest the accident
progression. Thus, the reactor primary vessel integrity is maintained. The
understanding of severe accidents and source term phenomena from this work
correlates with the results of small-scale tests such as those conducted at
PBF.
Each of the facilities and test programs I have just described has contributed
to an information base from which the adequacy of comnercial reactor designs
and their safety and regulatory criteria are confirmed. This data base is
also instrumental in the development and verification of computer codes used
to predict reactor plant response during reactor accidents. Thus, DOE
supported reactor materials, behavior, and safety research have built and
continue to build the foundations for safe and reliable nuclear power plant
design and operation.