Effects of early pump trip on the time-to-core uncovery for a TMI-type accident
This article summarizes thermal-hydraulic analyses performed with the Transient Reactor Analysis Code (TRAC) pertaining to one aspect of the pumps on/pumps off question for small breaks in pressurized water reactors (PWRs). In addition to the base case (pumps on) calculation, which reproduced the initial part of the Three Mile Island (TMI) accident, parametric calculations were performed to determine the effects of pumps on/pumps off for a TMI-type accident in which the break is located at the top of the pressurizer through the power-operated relief valve (PORV). The results of these calculations show that for the pumps-off case, core uncovery will occur approximately one hour sooner than the pumps-on case. The main reason for the earlier core uncovery for the pumps-off is a larger PORV flow rate calculated as a result of a high calculated system pressure. Therefore, based on this analysis, the primary system pumps should be left running as long as possible for a TMI-type accident. 4 refs., 10 figs.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 5655418
- Report Number(s):
- LA-UR-81-1507; CONF-810806-2; ON: TI85015349
- Resource Relation:
- Conference: ANS conference on small break loss of coolant accident analysis in LWR's, Monterey, CA, USA, 25 Aug 1981
- Country of Publication:
- United States
- Language:
- English
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