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.

White

The American Nuclear Society’s Risk-informed, Performance-based Principles and Policy Committee (RP3C) on March 29 held another presentation in its monthly Community of Practice (CoP) series. The presenter, Patrick White with the Nuclear Innovation Alliance (NIA), talked about the current status of efforts to develop a new regulatory framework for advanced reactors—known as 10 CFR Part 53 or simply Part 53. White serves as the research director of the NIA, where he leads their research as well as analysis-based stakeholder and policymaker engagement and education. White’s March 29 presentation is publicly available on YouTube and at ANS’s publication platform Nuclear Science and Technology Open Research (NSTOR).

RP3C chair N. Prasad Kadambi opened the CoP with brief introductory remarks about the RP3C before he welcomed White as the session’s presenter.

White covered three main topics: the history of the existing regulatory frameworks for new reactors, progress to date on the development of the Part 53 rule for advanced reactors, and the current status and next steps for the Part 53 rulemaking process.

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.

Grossi

Recent observations have indicated that warm water has been discharged near the light water reactor at the Yongbyon Nuclear Scientific Research Center in North Korea, which is consistent with the purported commissioning of the LWR—a process that takes time for any new reactor—and suggests that the reactor has now reached criticality.

“The LWR, like any nuclear reactor, can produce plutonium in its irradiated fuel, which can be separated during reprocessing, so this is cause for concern,” said Rafael Mariano Grossi, director general of the International Atomic Energy Agency. “It remains the case that without access to the facility, the agency cannot confirm its operational status.”

Safety concern: Grossi went on to say that the agency does not have sufficient information to make an assessment about the Democratic People’s Republic of Korea site, but that nuclear safety remains the paramount issue when starting a new reactor. Agency inspectors have had no access to North Korea since they were expelled in 2009.

Researchers at Idaho National Laboratory in early 2023 manufactured commercial-grade high-assay low-enriched uranium (HALEU) fuel pellets to the specifications of a General Electric accident tolerant fuel design, INL announced November 21. A team working at INL’s Experimental Fuels Facility at the Material and Fuels Complex fabricated about two dozen uranium dioxide pellets using HALEU enriched up to 15 percent U-235.

Ken Petersen
president@ans.org

I have jumped on the fusion power bandwagon! Power from fusion is going to happen. When I look at it, there are several factors that reinforce this. Technology has advanced and moved from basic science/research to engineering solutions. Several breakthroughs in supportive technologies have made fusion power plants a possibility. Finally—and most importantly—the private sector is heavily involved and investing to help move engineering solutions forward. This has resulted in a few dozen fusion companies developing different technologies with the same power generation goals. It is very reminiscent of the development of LW fission reactors in the 1950s and ’60s.

Technology has advanced in regard to materials and especially high-temperature superconducting magnets, high-energy lasers, and computer modeling. These improvements have allowed machines to become smaller and achieve the density, temperature, and time needed for fusion to occur.

The Nuclear Regulatory Commission is requesting comments on the regulatory basis for a proposed rule for light water reactor fuel designs featuring high-assay low-enriched uranium (HALEU), including accident tolerant fuel (ATF) designs, and on draft guidance for the environmental evaluation of ATFs containing uranium enriched up to 8 percent U-235. Some of the HALEU feedstock for those LWR fuels and for advanced reactor fuels could be produced within the first Category II fuel facility licensed by the NRC—Centrus Energy’s American Centrifuge Plant in Piketon, Ohio. On September 21, the NRC approved the start of enrichment operations in the plant’s modest 16-machine HALEU demonstration cascade.

Nuclear thermal hydraulics—for light water reactors or advanced reactors cooled by gas, metal, or salt—is all about defining safety and performance margins as things heat up.

The Nuclear Regulatory Commission has directed its staff to issue a final rule and associated regulatory guide that applies risk-informed, performance-based emergency preparedness requirements to small modular reactors and other new technologies, the agency announced on August 14. The technologies include non–light water reactors, research and test reactors, and medical radioisotope facilities.

Lightbridge Corporation, which is continuing to work closely with national laboratories on the manufacture and testing of its metallic fuel rod designs for light water reactors, just announced the results of an investigation on the casting process for molten uranium and zirconium with Pacific Northwest National Laboratory under the Department of Energy’s Gateway for Accelerated Innovation in Nuclear (GAIN) program.

The OECD Nuclear Energy Agency is offering the first International School on Simulation of Nuclear Reactor Systems (SINUS) workshop in May this year, with the topic “Reactor Single- and Multi-Physics Simulations Based on Light Water Reactor (LWR) Uncertainty Analysis in Modeling (UAM) Benchmark.”

Registration for the workshop is available online.

The nuclear community is undergoing a moment of unprecedented interest and growth not seen in decades. The passage of the bipartisan Infrastructure Investment and Jobs Act and the Inflation Reduction Act are providing a multitude of new funding opportunities for the nuclear community, and not just the current fleet. A mix of technologies and reactor types are being evaluated and deployed, with Vogtle Units 3 and 4 coming on line later this year, the Advanced Reactor Demonstration Projects of X-energy and TerraPower, and NuScale’s work with Utah Associated Municipal Power Systems to build a first-of-a-kind small modular reactor, making this is an exciting time to join the nuclear workforce.

The Department of Energy is offering cost-shared funding that could lead to the demonstration of an “energy park” drawing 20–300 MW of thermal energy from a U.S. nuclear power plant under a funding opportunity amendment issued in August by the DOE’s Office of Nuclear Energy Light Water Reactor Sustainability (LWRS) program, in coordination with the DOE’s Office of Energy Efficiency and Renewable Energy Hydrogen and Fuel Cell Technologies Office.

The American Society of Mechanical Engineers/American Nuclear Society Joint Committee on Nuclear Risk Management (JCNRM) has issued a new edition of its flagship standard, ANSI/ASME/ANS RA-­S-­1.1-­2022, Standard for Level 1/Large Early Release Frequency Probabilistic Risk Assessment for Nuclear Power Plant Applications. This standard was approved by the JCNRM, the ANS Standards Board, and the ASME Board on Nuclear Codes and Standards before being approved on May 11 by the American National Standards Institute (ANSI), earning the title of an American National Standard. With most of the text stable for the past year, the production process was started early, allowing the 400-­page standard to be published on May 31, 2022.

Steven P. Nesbit

As I write this column, it’s late September, and I’m sitting in Dulles Airport waiting for my connecting flight back to Charlotte from Vienna, Austria, where I attended the 65th General Conference of the International Atomic Energy Agency. It was quite an experience, and I want to share a few observations with you. But first, let me provide some background on the IAEA, which is perhaps not as well-­known to Americans as to those in other countries.

The IAEA was established in 1957 within the United Nations family and as an outgrowth of President Dwight Eisenhower’s famous 1953 “Atoms for Peace” speech. It is the world’s central intergovernmental forum for scientific and technical cooperation in the nuclear field. The objectives of the IAEA’s dual mission—to promote and control the use of the atom—are defined in Article II of the IAEA Statute.

When Utah Associated Municipal Power Systems (UAMPS) in 2015 announced its plan to develop the Carbon Free Power Project (CFPP) using NuScale Power’s modular light water reactor design, it envisioned the construction of a dozen 50-MWe modules for a plant that could produce a total of 600 MWe. The CFPP’s target output later rose to 720 MWe, when UAMPS opted to scale up to 60-MWe modules. In late June, the plans changed once again, as UAMPS participants chose to build 77-MWe modules but downsize the plant from 12 units to six, which would yield 462 MWe—about 64 percent of the 720 MWe that could have been generated from 12 of the 60-MWe modules.

Operators at the Advanced Test Reactor at Idaho National Laboratory have begun a nine-month outage to perform a core internals changeout. When the ATR is restarted in early 2022, the top head closure plate of the pressurized water test reactor will have new access points that could permit the irradiation of more fuel and material samples in the reactor’s high-flux neutron conditions.

ANS publishes standards that set forth requirements for the design, manufacture, or operation of a piece of equipment. These standards can address computer firmware and software, and can address the necessary physical and functional features of equipment, its safe application, or some combination of these. These standards are applied on a voluntary basis, and when adopted by a state or federal agency, they becomes part of their mandatory codes.

ANS standards are available at the ANS Standards store.

The following standards have been approved, published, or are open for comment.