Natalie Yonker

It’s all about finding the sweet spot: performing the correct maintenance at the correct interval (that is, the longest possible) with the correct resources (people, parts, and plant conditions) in a safe and efficient manner.

When engineering and maintenance teams adjust periodic maintenance (PM) intervals for plant components, they must take into consideration operating history, industry experience and guidelines, and vendor recommendations. This data, in conjunction with risk assessment, can be used to stretch maintenance intervals. If a valve fails before the scheduled PM, for example, the PM interval may be too long. But if a valve is overhauled during every refueling outage and the soft parts still look new each time, extending the PM interval would save money via man-hours, parts, and scope. A smaller outage work scope results in shorter outages, which results in less money spent on replacement power for the utility. That’s the real savings.

The new standard ANSI/ANS-30.3-2022, Light Water Reactor Risk-Informed, Performance-Based Design, has just been issued by the American Nuclear Society. Approved by the American National Standards Institute (ANSI) on July 21, 2022, the standard provides requirements for the incorporation of risk-informed, performance-based (RIPB) principles and methods into the nuclear safety design of commercial light water reactors. The process described in this standard establishes a minimum set of process requirements the designer must follow in order to meet the intent of this standard and appropriately combine deterministic, probabilistic, and performance-based methods during design development.

The ASME/ANS Joint Committee on Nuclear Risk Management (JCNRM) has achieved a significant milestone in the advancement of probabilistic risk assessment (PRA) technology. ANSI/ASME/ANS RA-­S-­1.4–2021 [1], Probabilistic Risk Assessment Standard for Advanced Non-­Light Water Reactor Nuclear Power Plants, has been approved by the JCNRM, the ANS Standards Board, the ASME Board of Nuclear Codes and Standards, and the American Nuclear Standards Institute.

Nuclear power plants not only provide the nation’s largest source of carbon-­free electricity, they also can operate 24 hours a day, 365 days a year to augment intermittent renewables such as wind and solar. Further, studies show that nuclear energy is among the safest forms of energy production, especially when considering factors such as industrial accidents and disease associated with fossil fuel emissions. All said, nuclear has the potential to play a key role in the world’s energy future. Before nuclear can realize that potential, however, researchers and industry must overcome one big challenge: cost.

A team at Idaho National Laboratory is collaborating with experts around the nation to tackle a major piece of the infrastructure equation: earthquake resilience. INL’s Facility Risk Group is taking a multipronged approach to reduce the amount of concrete, rebar, and other infrastructure needed to improve the seismic safety of advanced reactors while also substantially reducing capital costs. The effort is part of a collaboration between INL, industry, the Department of Energy’s Advanced Research Projects Agency–Energy (ARPA-­E), and the State University of New York–Buffalo (SUNY Buffalo).

Garrick

B. John Garrick, ANS Fellow and member since 1956 and an international authority on quantitative risk assessment, died on November 1 due to complications from a fall. He was 90.

Garrick, a distinguished adjunct professor of materials science and engineering at the University of California at Los Angeles, established his trailblazing theory on risk sciences in his Ph.D. thesis, which contributed to building the foundation of probabilistic risk assessment. Also referred to as quantitative risk assessment, it offers a guide to corrective actions to eliminate threats and to best practices for managing low-probability, high-consequence events resulting from natural and man-made disasters.

Since the 1980s, the nuclear power industry in the United States has worked to enhance the regulatory framework for nuclear facilities by making it more risk-informed and performance-based (RIPB). This has had some success in improving safety and reducing regulatory burden by focusing resources on the most risk--significant areas and allowing greater flexibility in choosing ways to achieve desired safety outcomes. However, there are further opportunities for the use of RIPB approaches in addressing current regulations and applying implementation tools, and in developing new RIPB regulations and advanced tools to further sharpen the focus on risk and performance outcomes.