[en] Nuclear steam generators designed for a 40-year service life may need replacement in 10 years or less because of corrosion and denting in the steam and feedwater side of the generator tubes. Corrective actions allow tubes to be plugged and removed when the walls thin beyond the acceptable point, but this reduces some of the surplus heat-transfer surface. Some utilities add sleeves to damaged tubes if costs and personnel exposure requirements allow. The key to extending plant life is careful monitoring and control of water chemistry in this area, particularly during outages. Other procedural changes in cleaning and maintenance to prevent leakage of air and cooling water into the condenser and to deaerate feedwater should prove effective

[en] Design control in its simplest form involves control of drawings, specifications, and calculations to ensure uniform adherence to design bases; a matching between as-built as as-designed, and proper updating of drawings, specifications, and calculations to reflect the as-built. This is not sufficient to maintain availability however. Other lists and data bases that directly affect operations and maintenance need also to be updated: operator and staff training programs to reflect new design, maintenance schedules and equipment histories to show new components, and spare parts additions and deletions to support the new devices. Much has been done to make better design change packages, but too little is still being done to follow through completely with the design change process. This paper provides a review of cases in this area

[en] The objective of this study was to examine reactor trips for design or procedural root cause mechanisms, which, if corrected, could lead to significant improvements in nuclear power plant outage rates. The data used in this study were extracted from newly required scram reports contained in 1984 licensee event reports (LERs) and operating plant experience (OPEC) data. Previous work from Stone and Webster and the Institute of Nuclear Power Operations had identified the feedwater, auxiliary feedwater, and condensate systems as prime contributors to reactor and turbine trip events. Hence, the study focused on trip mechanisms originating in the feedwater, auxiliary feedwater, and condensate systems (OPEC code 07) but included system interactions with other equipment and systems (e.g., main steam-feed mismatch) as appropriate

[en] Two topics---configuration management and life extension---have emerged in the nuclear utility industry in the last several years. Although these two topics have surfaced from quite independent paths, major points of overlap are evident. This paper reviews many of these points

[en] The ability to extend the licensed life of a nuclear power plant requires that technical, economic, and regulatory criteria be satisfied. Two ongoing Electric Power Research Institute/US Department of Energy funded pilot studies are looking at the technical and economic aspects from a plant wide viewpoint to life extension. In each, structures have been identified to have a potentially strong effect on the viability for extended life because of the possible major cost, schedule, and person-rem factors should major refurbishment, modifications, or replacement be required. This paper reviews the degradation mechanisms and counterbalancing design features for one of these pilot plants in the studies. It further reviews the recommended ongoing practices to be followed to better ensure that life extension for the structures remains a future option

[en] The utility goal of reliable, economic nuclear power production is supported by a range of technical services provided by engineer/constructors and others. This paper presents some Stone and Webster technical services that relate to areas with profound impact on plant reliability and performance: (1) design services aimed at improving component reliability; (2) maintenance, operations and outage management services; (3) materials management-related services, such as analysis of plant-wide spare part needs; (4) training support services; and (5) occupational radiation exposure and decontamination services. Because various areas of plant performance are interrelated, the use of an integrated technical services approach will enhance a utility's plant performance improvement program

[en] This paper presents the results of a study in support of NUPLEX activities to identify the major degradation issues important to life extension of both conventionally reinforced and prestressed concrete containments for PWRs and to determine any additional measures necessary to ensure their continued leak tightness and structural integrity. The degree to which any degradation mechanism occurs depends on the site-specific construction and quality control practices, and the particular containment exposure conditions, operating environment history, and design details. The modes of deterioration are addressed relation to the factors which may either increase or decrease the likelihood of occurrence. Corrosion of the liner appears to be the major concern with containment longevity. A program to establish reliable techniques to monitor areas of the liner, generally inaccessible to direct observation, needs to be developed. The report concludes that these containments possess the attributes necessary to resist or minimize the potential deterioration processes and that whatever deterioration may occur is likely only to cause a small reduction in the inherent overpressure capacity. In addition, the currently performed inspections and tests are capable of ensuring continued safety, but additional measures may be advisable for those areas which are difficult to assess because of lack of access