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The U.S. Nuclear Regulatory Commission (NRC) has undertaken a program to lay the technical foundations for defining proactive actions to manage degradation of materials in light water reactors. The current focus is existing plants; however, if applied to new construction, there is potential to better monitor and manage plants throughout their life cycle. This paper discusses the NRC’s Proactive Management of Materials Degradation program and its application to nuclear power plant structures, systems, and components. [ABSTRACT FROM AUTHOR]

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]

In this shrinking world, what happens in an industry in one country can significantly affect the same industry elsewhere around the globe. In April 1986, a nuclear accident destroyed Unit 4 of Ukraine’s Chernobyl nuclear power plant, focusing worldwide attention on the dozens of Soviet-designed reactors still in operation. The Chemobyl accident led to public concerns about all operating nuclear power plants and, in some countries (e.g., Italy and Sweden), to proposals for nationwide plant closures or moratoriums on new construction. However, for most former Soviet Union countries, plant shutdown was and still is not a viable option—the plants produce a significant percentage of each nation’s total electricity, and those countries do not have sufficient economic resources to develop alternative power sources. In cooperation with similar programs initiated in Canada, Japan, and western European countries, the U.S. Department of Energy (DOE) is conducting a comprehensive effort to reduce risks at Soviet-designed nuclear power plants until they can be shut down or brought into compliance with international standards. This paper describes DOE-supported initiatives with participating host countries to: • improve reliability and accuracy of nondestructive evaluation equipment used for in-service inspection • transfer technologies and infrastructure to improve in-service inspections • enhance management systems for training and certifying host-country in-service inspection personnel The goal of these initiatives to enhance the use of international standards (ASME, ASNT, European Standards EN, and ISO) in operating and regulatory practices at Soviet-designed nuclear power plants. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

It is anticipated that guided ultrasonic wave (GUW) techniques will eventually see widespread application in the nuclear power industry as there are several near-term and future needs that could benefit from the availability of GUW technologies. Already, GUW techniques are receiving consideration for inspecting buried piping at nuclear power plants and future applications may include several Class 1 and 2 components. To accept the results of a nondestructive examination of safety critical components, the U.S. Nuclear Regulatory Commission requires that the examinations be performed using qualified equipment, personnel, and procedures. As the use of GUW techniques becomes more frequent, qualification may be required. Performance demonstration has been the approach to qualifying conventional NDE methods in the nuclear power industry. This paper highlights potential issues and research needs associated with facilitating GUW qualification for the nuclear power industry. Parametric studies of essential inspection parameters are necessary to understand their influence on inspection performance. The large volume sampling capability introduces several challenges for qualifying GUW techniques including the quantification of performance, potential interference caused by the presence of multiple flaws in the inspection region, and the practicality of manufacturing several large qualification specimens. Computer simulation may have a significant role in reducing the experimental burden associated with qualifying GUW techniques for nuclear power plant examinations. [ABSTRACT FROM AUTHOR]