Testing of real-time version of RELAP5-3D for a boiling water reactor

Simulators are an important part of training nuclear power plant operators, as well as verification and validation of control systems. This requires a code which must not only produce an accurate representation of the plant's behavior, but must also do so in real time without problems caused by instability. RELAP5-3D is a best-estimate thermal-hydraulic code which was developed at the Idaho National Laboratory for the U.S. Nuclear Regulatory Commission [Error. Reference source not found.]. GSE Systems is developing a real-time version of RELAP5-3D for use in simulators. This version is currently undergoing testing at The Pennsylvania State University for use with boiling water reactors, using an input model of the Peach Bottom power plant. In order to run in real time, the model must be optimized for efficiency while maintaining accurate results. The input deck that is being developed thus has fewer core channels and fewer nodes inside and outside of the core compared to its reference model. Several transient scenarios are being simulated with this model, such as loss of coolant accidents and turbine trips. The results will be qualitatively evaluated, and it will be demonstrated that the model can run stably without failure for any realistic situation. (author)