The Studies on Risk-informed evaluations for Inservice Inspection and Inservice Testing of Nuclear Power Plant

• Main Authors: Yuan-Chih Li, 李元志
• Other Authors: Kuen-Tsann Chen
• Format: Others
• Language: en_US
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/08418143227380424816

博士 === 中興大學 === 應用數學系所 === 99 === Implementing Risk-Informed Inservice Inspection/Testing (RI-ISI/IST) provides good aspect to the nuclear power plant licensee as an alternating program in current ASME Section XI and 10 CFR 50.55a relevant requirements. RI-ISI/IST concentrates inspection and testing resources on high significant components, reduces exceeded inspections and tests, increases plant’s availability, lows down Dose rate on the plant’s staff and achieves cost saving on plant’s operation and maintenance under nuclear safety expectation. Furthermore, implementing RI-ISI/IST also gives a feature on prospective licensing change basis to licensee. To facilitate the applications of RI-ISI/IST , several regulatory guides and ASME code cases have been developed. However these rules were often restricted in qualitative descriptions. The quantitative descriptions for RI-ISI/IST were still limited. In this thesis, the systematically quantitative and qualitative risk methodologies combined plant specific Probabilistic Risk Assessments (PRA) that be both applied to Inservice Inspection (RI-ISI) and Inservice Testing (RI-IST) were developed. These methodologies were successfully used to re-evaluate the ISI program of recirculation piping system with IGSCC problems and IST program including motor operated valves (MOV), air operated valves (AOV), check valves (CV) and heat exchangers. Benefits of the Risk-informed ISI and IST were also to demonstrate to be received by the inspection or testing resource concentration on the components of high significance safety category (HSSC), reductions of inspection or testing frequencies, dose exposure for the plant staffs and cost of maintenance.