Nuclear Plant Aging Research (NPAR) Reports.
A comprehensive Nuclear Plant Aging Research (NPAR) Program was implemented by the NRC in 1985 to identify and resolve technical safety issues related to the aging of SSCs in operating NPPs, both during the initial operating license period as well as periods of license renewal, that have important safety functions [16, 17]. The NPAR Program was directed at gaining knowledge and understanding of the degradation processes within NPPs with an emphasis placed on identifying and characterizing the mechanisms of material and component degradation during service and using research results in the regulatory process. The research included evaluating methods of inspection, surveillance, condition monitoring, and maintenance as a means of managing aging effects that may impact safe plant operation. Goals of the program were to: (1) identify and characterize aging effects that, if unchecked, could cause degradation of SSCs and thereby impact plant safety;
- (2) identify methods of inspection, surveillance, and monitoring, and evaluate the residual lifetime of SSCs that will ensure the timely detection of significant aging effects before loss of safety function; and
- (3) evaluate the effectiveness of storage, maintenance, repair, and replacement practices in mitigating the rate and extent of degradation caused by aging. During the conduct of the NPAR Program over 80 technical reports were prepared. Of these reports, one addressed concrete structures  and one addressed metal containments .
Technical Reports in NUREG Series (NUREGs).
NUREG Series Publications are reports or brochures on regulatory decisions, results of research, results of incident investigations, and other technical and administrative information. The publications can be in the form of: publications prepared by NRC staff (NUREG-nnnn) or contractors (NUREG/CR-nnnn), brochures prepared by NRC staff (NUREG/BR-nnnn), conference proceedings prepared by NRC staff or contractors (NUREG/CP-nnnn), and publications resulting from international agreements (NUREG/IA-nnnn). NUREGs prepared by the NRC staff are available (http://nrc.gov/reading-rm/doc-collections/nuregs/staff/) as well as those prepared by contractors (http://nrc. gov/reading-rm/doc-collections/nuregs/contract/). Two NUREG publications, in addition to the two reports discussed in the previous section prepared under the NPAR Program, provide information related to NPP containment structures and license renewal [20, 21].