LAPUR5.2 Analysis on Regional Mode Stability

[[abstract]]Under certain condition, boiling water reactors (BWRs) are susceptible to couples neutron-thermalhydraulic instabilities and may induce in-phase (core wide mode) instability and out-of-phase (regional mode) instability. In order to prevent instability event from happening, in each BWR reload core design, fuel vendors are required to provide instability boundaries on power/flow map to assure safety operation of the nuclear reactor. For the purpose of establishing a capability to carry out independent verification of the vendor's results, according to Chinshan unit 2 cycle 22 reload core design, this research is studied with the aim of setting stability boundary by the code of LAPUR5.2 and SIMULATE-3. Besides, this research also makes use of fractional changes of decay ratio to evaluate parametric sensitivity for the core wide and regional mode on the realistic stability operating boundary. According to the results of parametric sensitivity study, current investigate have shown that some of parameters have different characters between core wide mode and regional mode.[[fileno]]2060121030027[[department]]工程與系統科學