Integrated MELPROG/TRAC analyses of a PWR station blackout

Conference · Sat Dec 31 23:00:00 EST 1988

DOI:https://doi.org/10.1016/0029-5493(91)90076-T· OSTI ID:5910067

Heames, T. J.; Smith, R. C.

A complete, coupled, mechanistic analysis of the entire reactor coolant system during a station blackout (TMLB') has been completed using MELPROG/TRAC. The analysis includes the loss of all coolant pump seals at 100 minutes into the accident; in all other respects the case is identical to a previous station-blackout analysis. Both cases were initiated at the start of the accident and followed through boiloff of the water, failure of the control and fuel rods, oxidation of the Zircaloy and the formation of U-Zr-O eutectics, failure of the vessel internal structures due to melting and loading, massive core disruption and subsequent vessel failure. The two cases reached significantly different end conditions. The basic TMLB' resulted in a high pressure (15 MPa) vessel failure approximately 4 hours after accident initiation. The addition of a 12.5 mm hole in each pump seal resulted in a significantly lower pressure (0.27 MPa) at vessel failure, almost 10 hours after accident initiation. Therefore, high pressure melt ejection (HPME) and subsequent direct containment heating (DCH) were predicted not to occur in the TMLB' accident scenario with pump seal failure. This significant difference in end conditions demonstrates the need for a detailed, as well as mechanistic, treatment of the important physical processes within the complete reactor coolant system. The calculation shows the capabilities of MELPROG when coupled to TRAC, and that the resulting tool gives the user the potential to correctly predict, and therefore manage, an accident by determining the final results of possible operator interventions. 9 refs., 9 figs., 2 tabs.

• Research Organization: Sandia National Labs., Albuquerque, NM (USA)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 5910067
• Report Number(s): SAND-88-7158C; CONF-890819-10; ON: DE89010434
• Country of Publication: United States
• Language: English

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PUMPS
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REACTOR ACCIDENTS
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