Abstract
For a nuclear power plant (NPP), there are three power uprate levels: Measurement Uncertainty Recapture (MUR), Stretch Power Uprat (SPU), and Extended Power Uprate (EPU). The purpose of this study is to analyze the stability of a light water reactor which is under power uprate condition (MUR).In this study, we are focusing on the stability issue such as monitoring the status of a power uprated core and the precautions against the operation point entering the unstable region, etc. The computer code --- LAPUR5.2 is chosen as the tool for calculation. Based on the data from KuoSheng (Unit I) and ChinShan (Unit II) nuclear power plants, four operation points are calculated by LAPUR5.2 for assumed power uprate tasks. These simulation results are compared with the results from other U.S. NPPs which have successful experience in power uprate. Some stability problems which may take place in Taiwan’s NPP during the power uprate tasks are discussed in this study.The research results show that a limited power uprate (MUR), usually within 2% of the core power level, will not make the decay ratio exceed 0.8. In many simulation cases the decay ratio is much less than 0.8. Therefore, it is certain that MUR can hardly affect the stability of a nuclear power plant.