Standards

The American Nuclear Society’s Risk-informed, Performance-based Principles and Policy Committee (RP3C) has held another presentation in its monthly Community of Practice (CoP) series. Former RP3C chair N. Prasad Kadambi opened the meeting with brief introductory remarks about the RP3C and the need for new approaches to nuclear design that go beyond conventional and deterministic methods. He then welcomed this month’s speaker: Doug Gerstner, a nuclear safety engineer at Idaho National Laboratory, who presented “Application of a Qualitative RIPB Approach for the MARVEL Microreactor at INL.”

Watch the full webinar here.

ANSI/ANS-54.8-2025, Liquid Metal Fire Protection in LMR Plants, received approval from the American National Standards Institute on September 2 and is now available for purchase.

The 2025 edition is a reinvigoration of the withdrawn ANS-54.8-1988 of the same title. The Advanced Reactor Codes and Standards Collaborative (ARCSC) identified the need for a current version of the standard via an industry survey.

Typical liquid metal reactor designs use liquid sodium as the coolant for both the primary and intermediate heat-transport systems. In addition, liquid sodium and NaK (a mixture of sodium and potassium that is liquid at room temperature) are often used in auxiliary heat-removal systems. Since these liquid metals can react readily with oxygen, water, and other compounds, special precautions must be taken in the design, construction, testing, and maintenance of the sodium/NaK systems to ensure that the potential for leakage is very small.

The American Nuclear Society’s Risk-informed, Performance-based Principles and Policy Committee (RP3C) held another presentation in its monthly Community of Practice (CoP) series.

Watch the full webinar here.

The American Nuclear Society’s Risk-informed, Performance-based Principles and Policy Committee (RP3C) held another presentation in its monthly Community of Practice (CoP) series on May 2.

The American National Standards Institute (ANSI) recently approved two new American Nuclear Society standards covering different aspects of nuclear criticality safety (NCS).

The American Nuclear Society’s Risk-informed, Performance-based Principles and Policy Committee (RP3C) held another presentation in its monthly Community of Practice (CoP) series on April 4.

ANSI/ANS-8.26-2024, Nuclear Criticality Safety Engineer Training and Qualification Program, has been published and is available in the online ANS store. The standard, developed by the American Nuclear Society, received approval from the American National Standards Institute on November 21, 2024, and was published January 10, 2025.

This standard provides guidance for the content of training programs for nuclear criticality safety (NCS) specialists who are responsible for developing the analyses, controls, and safety documentation required for the safe handling of fissionable materials. This standard presents a matrix of training and qualification (T&Q) criteria based on education and experience combined with individual job functions and provides for qualification of experienced staff by documentation. The standard presents a flexible array of competencies for use by management to develop tailored T&Q programs applicable to site-specific job functions, facilities, and operations. This standard stresses the necessity of integrating standard training subjects with operational experience in order to qualify as an NCS engineer.

In February, the Community of Practice (CoP) webinar series, hosted by the American Nuclear Society Standards Board’s Risk-informed, Performance-based Principles and Policies Committee (RP3C), celebrated its fifth anniversary. Like so many online events, these CoPs brought people together at a time when interacting with others became challenging in early 2020. Since the kickoff CoP, which highlighted the impact that systems engineering has on the design of NuScale’s small modular reactor, the last Friday of most months has featured a new speaker leading a discussion on the use of risk-informed, performance-based (RIPB) thinking in the nuclear industry. Providing a venue to convene for people within ANS and those who found their way online by another route, CoPs are an opportunity for the community to receive answers to their burning questions about the subject at hand. With 50–100 active online participants most months, the conversation is always lively, and knowledge flows freely.

A newly published standard is now available at the ANS store.

The standard, ANSI/ANS-8.26-2024, Nuclear Criticality Safety Engineer Training and Qualification Program (revision of ANS-8.26-2007; R2022), presents the fundamental elements of a training and qualification program for individuals with responsibilities for performing the various technical aspects of criticality safety engineering.

The following standards from the American Nuclear Society were published in 2024 and are available in the ANS Store:

Following approval in October from the American National Standards Institute, ANSI/ANS-3.11-2024, Determining Meteorological Information at Nuclear Facilities, was published in late November. This standard provides criteria for gathering, assembling, processing, storing, and disseminating meteorological information at commercial nuclear power plants, U.S. Department of Energy/National Nuclear Security Administration nuclear facilities, and other national or international nuclear facilities.

A comprehensive set of rules and guidelines for floating nuclear power plants, Requirements for Nuclear Power Systems for Marine and Offshore Applications, has been released by the American Bureau of Shipping (ABS). According to the document, which, according to ABS, is the first of its kind for floating power plants, the rules and guidelines have been “developed for classification requirements specific to design, construction, and survey of vessels fitted with nuclear power systems whose generated power is transferred or distributed to onboard industrial or adjacent facilities.”

ANSI/ANS-8.28-2024, Administrative Practices for the Use of Nondestructive Assay Measurements for Nuclear Criticality Safety, was issued on July 15 after receiving approval of the American National Standards Institute in March.

ANSI/ANS-8.28-2024 is now available for purchase in the ANS Online Store.

The latest in the series of ANS Community of Practice (CoP) presentations on risk-informed, performance-based (RIPB) principles, held May 31, 2024, was a departure from past presentations. Rani Franovich and N. Prasad Kadambi provided their perspectives on what is missing in current dialogue on RIPB. What followed was a meaningful discussion and exchange of perspectives regarding what is meant by “performance based.”

ANSI/ASME/ANS RA-S-1.2-2024, Severe Accident Progression and Radiological Release (Level 2) PRA Standard for Nuclear Power Plant Applications for Light Water Reactors (LWRs), received the approval of the American National Standards Institute (ANSI) on May 31, 2024, and was issued on June 17, 2024.

ANSI/ASME/ANS RA-S-1.2-2024 is available in the ANS Online Store.

The American Nuclear Society’s Risk-informed, Performance-based Principles and Policy Committee (RP3C) held another Community of Practice (CoP) on April 26. For this event, the committee welcomed Mory Diané of Oklo. RP3C chair N. Prasad Kadambi led with a brief introduction before Diané shared Oklo's risk-informed, performance-based (RIPB) approach to seismic design categorization and seismic siting characterization.

Diané, a licensing manager with Oklo, is a structural engineer with a background in civil engineering

ANSI/ASME/ANS RA-S-1.1-2024, Standard for Level 1/Large Early Release Frequency Probabilistic Risk Assessment for Nuclear Power Plant Applications, has been published by the American Nuclear Society. The document, which is a joint standard developed with the American Society of Mechanical Engineers by the ANS/ASME Joint Committee on Nuclear Risk Management, received the approval of the American National Standards Institute on February 29, 2024, and was issued on March 15, 2024.

ANSI/ASME/ANS RA-S-1.1-2024, Standard for Level 1/Large Early Release Frequency Probabilistic Risk Assessment for Nuclear Power Plant Applications, has just been published by the American Nuclear Society. The document, which is a joint standard developed with the American Society of Mechanical Engineers by the ANS/ASME Joint Committee on Nuclear Risk Management, received approval of the American National Standards Institute on February 29, 2024, and was issued on March 15, 2024.

Each month on the last Friday from 3:00 p.m. to 4:00 p.m. (ET), the American Nuclear Society’s Risk-informed, Performance-based Principles and Policy Committee (RP3C) holds a Community of Practice (CoP), which is open to all. On February 23, N. Prasad Kadambi, director of his eponymous engineering consultancy firm, presented “Technology-Inclusive Implications of ANSI/ANS-30.3-2022, Light Water Reactor Risk-Informed, Performance-Based Design.”

The American Nuclear Society has published the first voluntary consensus standard for nuclear reactor design that formally incorporates risk-informed, performance-based (RIPB) decision-making in July 2022. ANSI/ANS-30.3-2022, Light Water Reactor Risk-Informed, Performance-Based Design, tells reactor designers how they can incorporate RIPB principles and methods to ensure safety in new commercial light water reactor designs, and it includes a spectrum of options using both deterministic and risk-based approaches. As the first such standard, ANSI/ANS-30.3-2022 represents progress toward the adoption of RIPB principles for nuclear regulation and licensing—a shift the Nuclear Regulatory Commission was directed to make in the Nuclear Energy Innovation and Modernization Act, which became law five years ago.