MRP-227 REACTOR VESSEL INTERNALS INSPECTION PLANNING AND INITIAL RESULTS AT THE OCONEE NUCLEAR STATION UNIT 3

摘要

The U.S. PWR industry has proactively developed generic inspection requirements and standards for reactor vessel (RV) internals. The Electric Power Research Institute (EPRI) Pressurized Water Reactor (PWR) Materials Reliability Program (MRP) has issued MRP-227-A and MRP-228 with mandatory and needed requirements based on the Nuclear Energy Institute (NEI) document NEI 03-08. In addition, the U.S. Nuclear Regulatory Commission (NRC) has issued a Safety Evaluation Report (SER) containing additional requirements for licensees planning to implement the guidelines developed in the MRP-227-A report. Initial examinations performed at the Oconee Nuclear Station Unit 1 (ONS-1) in the fall of 2012 and at Oconee Nuclear Station Unit 2 (ONS-2) in the fall of 2013, which were the first two Babcock & Wilcox (B&W) units to perform an exam of the RV internals using the MRP-227 guidelines, identified several minor degradation issues. In April 2014, ONS Unit 3 (ONS-3) shut down for refueling and completion of the MRP-227 inspection of the RV internals. This paper will discuss the decision planning efforts required for implementing the MRP-227-A and MRP-228 requirements and the results of these initial inspections, with emphasis on the most recent ONS-3 results.