Abstract
After the measurement uncertainty recapture power uprates, Kuosheng Nuclear Power Plant has uprated the power to 2943 MWt. Recently, Taiwan Power Company is concerned in stretch power uprated plan and uprates the power to 3030 MWt, which is 105% of the designed power. Before the stretch power uprates, several transient analysis should be done for ensuring that the power plant could maintain stability in high power operating conditions. The advanced thermal hydraulic analysis code TRACE which is conducted by U.S. NRC was applied for overpressurization transient including main steam line isolation valves closure, turbine stop valves closure and turbine control valves closure. This closure of valves increased the dome pressure; as a result, the void fraction inside the reactor core decreased. Declination of the void fraction will increase the reactivity feedback; hence, the power increased rapidly until the reactor scram. Further, with safety relief valves open, the dome pressure would not exceed the criteria regulated by ASME. In addition, to cover the insufficiency of thermal hydraulic code, fuel rod transient analysis code FRAPTRAN was applied. To perform fuel rod transient analysis, thermal information from TRACE code would be entered into FRAPTRAN with power history. In addition, DAKOTA code was applied to concern the influence of fuel rod manufacturing tolerance. With uncertainty bands from DAKOTA analysis, the criteria could be judged with more confidence. This research successfully established a procedure of thermal hydraulic and fuel rod property analysis. Further, with SNAP interface, the FRAPTRAN and DAKOTA were combined successfully to perform the uncertainty analysis. Also, a FRAPTRAN uncertainty data extracting program, which can capture several interesting parameters at the same time, was developed in this research.