Nuclear Power Plant NDE Challenges — Past, Present, and Future.

The operating fleet of U.S. nuclear power plants was built to fossil plant standards (of workmanship, not fitness for service) and with good engineering judgment. Fortuitously, those nuclear power plants were designed using defense-in-depth concepts, with nondestructive examination (NDE) an important layer, so they can tolerate almost any component failure and still continue to operate safely. In the 30+ years of reactor operation, many material failures have occurred. Unfortunately, NDE has not provided the reliability to detect degradation prior to initial failure (breaching the pressure boundary). However, NDE programs have been improved by moving from prescriptive procedures to performance demonstrations that quantify inspection effectiveness for flaw detection probability and sizing accuracy. Other improvements include the use of risk-informed strategies to ensure that reactor components contributing the most risk receive the best and most frequent inspections. Another challenge is the recent surge of interest in building new nuclear power plants in the United States to meet increasing domestic energy demand. New construction will increase the demand for NDE but also offers the opportunity for more proactive inspections. This paper reviews the inception and evolution of NDE for nuclear power plants over the past 40 years, recounts lessons learned, and describes the needs remaining as existing plants continue operation and new construction is contemplated. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]