RETRAN simulation of a BWR [boiling water reactor]/6 load rejection transient

Gulf States Utilities (GSU) has a single-unit boiling water reactor that began commercial operation in 1986. As part of the continually improving engineering support for the River Bend Station (RBS), GSU is developing in-house capabilities to assess reactor performance during steady-state and transient conditions. To achieve this goal, many programs were taken from the Electric Power Research Institute Reactor Analysis Support Package and other support programs were developed at GSU. The codes used for core physics and transient analysis at RBS consist of 12 major computer programs. Additionally, many smaller computer programs transfer data, collate data, and perform minor calculations. The primary system analysis computer program used at RBS is RETRAN-02. Currently, the methods development effort that will allow GSU to perform technical specification changes and reload analyses is ∼70% complete. Various transient events that have occurred at RBS are being simulated as part of GSU's method evaluation. This paper presents the results of a loss of electrical load event that occurred on August 25, 1988. This event was initiated when the outside power supply was interrupted while the plant was operating at 100% power and 100% core flow. During the event, both the high pressure core spray (HPCS) and reactor core isolation cooling flows were initiated