Extending the life of nuclear power plants : technical and institutional issues

Abstract

Managing nuclear power plant aging is one of the important technical issues which needs to be addressed by utilities in order to extend the operating life of some of the early LWR power stations. Plant managers must understand complex aging phenomena, identify aging effects, anticipate failure, and mitigate the aging process. Typically, the age-related design limits of crucial components are not known, and this information usually does not appear to be easily available from the equipment vendor. Electrical cables, insulation and instrumentation are most susceptible to age-related degradation. material degradation due to corrosion is the main costly problem affecting a small but important portion of piping and major equipment. Upgrading the plant, replacing aging equipment, and implementing good maintenance, surveillance and spare parts inventory control programs are actions a utility can take to extend the life of operating nuclear plants. Considerable institutional uncertainties are associated with nuclear plant life extension. These spring mainly from the absence of clearly defined policies by the U.S. Nuclear Regulatory Commission stating the technical and procedural requirements for plant life extension. From precedents established to-date, it is reasonable to expect plant operation to be permitted for most plants for a total of 40 years after start of commerical operation. As a large share of the net discounted benefits of extended life operation may be derived from the first decade of additional life, the basis for utility investments for life extension is thus assured.