TRAC Calculations of Overcooling Transients in PWRs for Pressurized Thermal Shock Analysis
This paper briefly describes the overall pressurized thermal shock (PTS) program at Los Alamos with emphasis on TRAC-PF1 calculations of severe overcooling transients in pressurized water reactors (PWRs). Overcooling transients for both the Oconee-1 and Calvert Cliffs-1 nuclear plants have been performed. A summary of results for several calculations are presented for the Oconee-1 PWR along with detailed discussions of two of the most severe overcooling transients predicted [main steam-line break and turbine-bypass valve (TBV) failures]. The calculations performed were plant specific in that details of both the primary and secondary sides were modeled in addition to a detailed model of the plant integrated control system (ICS). For the Oconee-1 main steam-line break transient, a minimum downcomer fluid temperature of ∼405 K was predicted. For the transient involving the failure of one bank of TBVs to close after initially opening following reactor and turbine trips, an extrapolated downcomer fluid temperature of ∼365 K was estimated. The latter temperature is at the nil-ductility temperature (NDT) limit (∼365 K) for Oconee-1.
KeywordsPrimary System Pressurize Water Reactor Nuclear Regulatory Commission Steam Line Secondary Side
Unable to display preview. Download preview PDF.
- 1.R. C. Kryter, et. al., “Evaluation of Pressurized Thermal Shock,” Oak Ridge National Laboratory report ORNL TM-8072, NUREG/CR-2083 (October 1981).Google Scholar
- 2.Safety Code Development Group, “TRAC-PF1: An Advanced Best-Estimate Computer Program for Pressurized Water Reactor Analysis,” Los Alamos National Laboratory report (to be published).Google Scholar
- 3.J. D. White, “List of Oconee-1 Transients for Thermal-Hydraulic Calculations,” Oak Ridge National Laboratory letter, (December 1982).Google Scholar
- 4.B. Bassett, et. al., “TRAC Analyses of Severe Overcooling Transient for the Oconee-1 PWR”, Los Alamos National Laboratory report (to be published).Google Scholar