As all of us who work with nuclear energy know the US nuclear industry is engaged in a multi-year effort to generate power more efficiently, economically and safely. A key goal includes a significant reduction in operating expenses. This initiative is termed “Delivering the Nuclear Promise” (DNP) and is supported by nuclear utilities, vendors such as Structural Integrity, the Nuclear Energy Institute (NEI), Institute of Nuclear Power Operations (INPO), and the Electric Power Research Institute (EPRI).
10CFR50.69’ Risk Informed Engineering Programs (RIEP) is a regulation that enhances safety and provides the potential for large cost savings. This regulation allows plant owners to place systems, structures and components (SSCs) into one of the four risk-informed safety class (RISC) categories as indicated in the graphic below.
Industry experience to date suggests that 75 percent of safety-related SSCs can be categorized as RISC-3, low safety-significant (LSS), based on low risk. This is important because (a) it provides a focus on safety significance and (b) RISC-3 SSCs are exempted from “special treatment” requirements imposed by 10CFR50 Appendix B and other regulatory requirements (shown in the boxes at the bottom of page).
Since safety-related SSCs remain safety-related and retain their safety functions, what are “alternative treatments” and how do they generate cost savings? The difference is the level of rigor plant owners need to apply when demonstrating safety functions will be met.
Two DNP efficiency bulletins have been issued by NEI for the 50.69 initiative:
The savings associated with implementing 10 CFR 50.69 will be site specific based on plant design, number of systems categorized and alternative treatments implemented. EB 17-09 estimates a reduction between $1M-$3M in parts and maintenance per year for each unit.
Once SSCs for a system (or systems) have been categorized using NEI 00-04, 10 CFR 50.69 SSC Categorization Guidance, plants can remove RISC-3 SSCs from the scope of programs that are no longer applicable. RISC-3 SSCs are discussed in NEI 16-09, Risk-Informed Engineering Programs (10 CFR 50.69) Implementation Guidance, along with some general guidance for each of the requirements that no longer apply.
There are several EPRI reports providing general guidance for alternative treatments. These include:
The industry is also working on development of alternative treatment guidance for specific regulatory programs and development of generic tools/templates to streamline and automate documentation and maintenance for utilities.
Structural Integrity’s expertise has long involved the prevention of failures of structural and mechanical components using risk insights and probabilistic methods. We have supported implementation of EPRI’s risk-informed ISI program at many BWR and PWR plants as well as risk-informed repair/replacement activities. We regularly apply probabilistic analysis to reduce conservatisms where standard techniques are not cost-effective.
With the addition of Tobolski-Watkins to our team see, (page 25) and previous additions of Anatech, Finetech and our electrical services group, our core expertise has expanded to every type of component that would benefit from the establishment of alternative treatments.
Beyond these capabilities, Structural Integrity has for decades contributed to the development of EPRI and other industry applications that leverage VIEWSavailable technical knowledge and actual plant information to reliably determine the useful life of SSCs in both nuclear and critical non-nuclear applications. The application of tools such as pc-CRACK, SI:FatiguePro, pc-SAFER, LPRimLife, and PlantTrack already contributes to significant cost savings by helping plants avoid unnecessary
replacements, defer replacements until a time that allows for a more cost-effective planning and procurement, or to implement other lower cost alternatives.
Our experience with component testing (TRU Compliance, page 26) and involvement with industry standards committees provides our experts with useful insights that can be successfully applied to development of alternative treatments having a solid technical basis.
As one of the most trusted independent providers of engineering and technical services, SI looks forward to supporting this important industry initiative.