ICONE19-43489 PRESSURIZED WATER REACTOR VESSEL INTERNALS GUIDE TUBE GUIDE CARD WEAR AGING MANAGEMENT

Abstract

In order for the pressurized water reactors to qualify for life extension, they have to meet the requirements of MRP-277 (Reference 1). MRP-227 lists the various reactor internals components that need to be inspected in order for a plant to qualify for life extension; the upper internals guide tube guide cards are one such component. Aggressive guide card wear in a plant can lead to violation of plant technical specifications, safety issues in the event of insertion, failure of one or more rod cluster control assemblies, or even result in plant shutdown or outage extensions. Owing to the criticality of the guide card wear, as discussed above, the Pressurized Water Reactor Owners Group (PWROG) initiated a guide card wear measurement project, led by Westinghouse. Under this program, wear of the guide cards at three identified lead plants was observed and measured, and, an engineering review of the wear data was completed, and plant specific recommendations based on the engineering reviews was provided. To support this program, Westinghouse also developed criteria to prevent or mitigate guide card wear, which governs the guide card wear measurement. In addition, preliminary root cause analysis was performed for one of the aggressively wearing plants, where some wear aggravating causes and mitigating techniques were determined. Therefore, this paper will discuss Westinghouse's guide card wear criteria and measurement technique, guide card wear trends obtained from measurements conducted in the guide card wear program, possible guide card wear aggravating causes and guide card wear mitigating techniques.