BWR-LTAS: a boiling water reactor long-term accident simulation code

The BWR-LTAS code was developed by the SASA program at Oak Ridge National Laboratory for the detailed study of specific accident sequences at Browns Ferry Unit One: station blackout, small break LOCA outside primary containment, loss of decay heat removal, loss of vessel water injection, and anticipated transient without scram. The primary use of the code has been to estimate the effects of operator actions on the timing and course of events during the part of the sequence leading up to but not including severe fuel damage. This report documents the basis of the methods used to simulate the response of parameters in reactor vessel, primary coolant system, primary containment, and other reactor systems. Sample results are included in the appendix.