TRAC-PF1 (Transient Reactor Analysis Code-PF1) Analyses of Potential Pressurized-Thermal-Shock Transients at Calvert Cliffs/Unit 1: A Combustion Engineering PWR (Pressurized Water Reactor).

摘要

Los Alamos National Laboratory participated in a program to assess the risk of a pressurized thermal shock (PTS) to the reactor vessel during a postulated overcooling transient in a pressurized water reactor (PWR). We provided the thermal-hydraulic analyses of three general accident categories: steamline breaks, runaway-feedwater transients, and small-break loss-of-coolant accidents. These postulated accidents included multiple operator and equipment failures. We found the results of the analyses to be very sensitive to the initial conditions of the plant. If the plant was initially at hot-zero power (compared to full power), the decay heat was much less, which made it possible for the same accident initiator to produce significantly lower downcomer temperatures. However, routine operator actions may reduce the consequences of any of these simulated accidents if the prescribed pressure-temperature relationships are followed.