NPP License Renewal and Aging Management: Lessons Learned Halfway Through

摘要

The NRC is nearly half-way through an anticipated 12-year cycle for license renewal, beginning with the Calvert Cliffs Nuclear Power Plant (NPP). The NRC is using this experience to update the license renewal guidance (LRG) documents to support the process. The process of power reactor license renewal has produced considerable experience in recent years, with 33 NPP operating licenses already renewed and license renewal applications (LRAs) for 16 additional NPPs being processed (Table 1). If NRC approves the applications currently being reviewed, approximately 50% of the licensed operating reactors will have extended their life span by 20 years. As license renewal is voluntary, the licensee decides whether to seek license renewal and, if so, the timing of the LRA. To further improve the effectiveness and efficiency of the review, the NRC has established a streamlined process for reviewing LRAs in a consistent and timely manner. The NRC has developed a number of internationally available LRG documents to describe the interrelated aspects of preparing and reviewing LRAs. As an example, the Generic Aging Lessons Learned (GALL) Report catalogs plant structures and components; lists the materials, environments, aging effects and mechanisms; and documents how existing commonly used plant programs can be used or modified to mitigate or manage these aging effects. The LRG documents published in 2001 have been revised to incorporate lessons learned from the review of these previous LRAs. An operating experience review, for both domestic and international reactors, was also performed to study aging degradation of passive components.