The Nuclear Regulatory Commission has denied “without prejudice” Oklo Power’s application to build and operate its Aurora microreactor in Idaho, the agency announced yesterday. The denial, according to the NRC, is due to the California-based firm’s failure to provide sufficient information on several crucial topics regarding the Aurora design.

In March 1972, Stephen Hanauer, a technical advisor with the Atomic Energy Commission, met with Norman Rasmussen, a nuclear engineering professor at the Massachusetts Institute of Technology. The AEC had recruited Rasmussen to develop a report, The Reactor Safety Study (WASH-1400), to estimate the probabilities and consequences of a major nuclear power plant accident. With thousands of safety components in a modern reactor, the task was mind-boggling. Rasmussen proposed a novel approach based on more powerful computers, “fault tree” methodology, and an expanding body of operational data. By calculating and aggregating probabilities for innumerable failure chains of components, he believed he could develop a meaningful estimate of overall accident risk. WASH-1400 would be a first-of-its-kind probabilistic risk assessment (PRA).

As 2021 closes, Nuclear News is taking a look back at some of the feature articles published each month in the magazine. The June issue reviewed some topics in human factors and instrumentation and controls such as the article below that looks at the NRC's review of digital instrumentation systems in the current fleet.

The Nuclear Regulatory Commission^a first formally developed infrastructure for the review of digital instrumentation and control (I&C) systems in the 1990s. Although the current fleet of nuclear power plants in the United States was originally designed and constructed with analog systems, the U.S. nuclear industry has for more than 30 years been working to upgrade these older systems with modern digital equipment.

Probabilistic risk assessments (PRAs) have advanced the safe operation of the U.S. reactor fleet over many decades. Risk insights from PRAs have provided information from many different perspectives, from what is most important to maintain at a facility to a better understanding of how to address new information regarding safety issues. The methods and tools that have supported the creation and enhancement of PRA models were established through multiple decades of research, starting with WASH-1400, The Reactor Safety Study,¹ published in 1975, through the comprehensive plant-specific models in use today.

Metz

A number of years ago, historian and writer Chuck Metz Jr. was at the Bush’s Visitor Center in Tennessee’s Great Smoky Mountains when he ran into former Nuclear Regulatory Commission official Harold Denton and his wife. Metz was at the visitor center, which opened in 2010 and is now a tourist hotspot, because, as he explained to the Dentons at the time, he had overseen the development of its on-site museum and had written a companion coffee-table history book.

The chance meeting turned into a friendship and a fruitful collaboration. Denton, who in 1979 was the public spokesperson for the NRC as the Three Mile Island-2 accident unfolded, had been working on his memoir, but he was stuck. He asked Metz for help with the organization and compilation of his notes. “I was about to retire,” Metz said, “but I thought that exploring the nuclear world might be an interesting change of pace.”

Denton passed away in 2017, but by then Metz had spent many hours with his fast friend and was able to complete the memoir, Three Mile Island and Beyond: Memories of a Life in Nuclear Safety, which was published recently by ANS. Metz shared some of his thoughts about Denton and the book with Nuclear News. The interview was conducted by NN’s David Strutz.

In a July 1 letter to President Biden, ANS President Steven Nesbit and ANS Executive Director/CEO Craig Piercy stated that a full complement of five commissioners is essential to the effectiveness of the Nuclear Regulatory Commission in protecting public health and safety while enabling the deployment and applications of nuclear technology.

The Nuclear Regulatory Commission has halted efforts to consider allowing U.S. nuclear power plant owners to request 40-year license renewals for their facilities, the agency announced on Facebook and Twitter on July 2. Currently, the maximum potential operating lifespan for a plant is 80 years: 40 years with the original license, 20 more with an initial license renewal, and another 20 with a second renewal.

The American Nuclear Society (ANS) requests President Biden restore the U.S. Nuclear Regulatory Commission (NRC) to five commissioners by naming and expediting nominees to the agency. The impending vacancy of Commissioner Annie Caputo’s seat after June 30 will reduce the five-member NRC to three commissioners. NRC commissioners are appointed by the president and confirmed by the Senate for staggered five-year terms.

As the U.S. nuclear industry moves into plant life extension and subsequent license renewals, the modernization of safety instrumentation and control (I&C) systems holds significant potential to transform plant operations. Automated system diagnostics, equipment health monitoring, and performance indications reduce the need for manual surveillance activities and enable condition-based maintenance, resulting in improved system reliability and reduced maintenance costs. Despite these benefits, adoption of digital I&C systems for safety-related applications across the domestic nuclear fleet has been slow. U.S. nuclear power plants that do choose to embrace the transition from analog to digital are in good company; international plants have successfully implemented digital safety systems for more than a decade. Furthermore, digital safety systems are also the first choice of the growing small modular reactor (SMR) and advanced reactor (AR) communities.

Peter Lyons, former Nuclear Regulatory Commission commissioner (2005–2009) and assistant secretary of energy for nuclear energy (2011–2015), has passed away.

American Nuclear Society President Mary Lou Dunzik-Gougar and executive director/CEO Craig Piercy issued the following statement on May 3:

“We are saddened to hear about the death of Peter Lyons. An ANS fellow and member since 2003, Pete will be remembered for his inspiring leadership and distinguished public service career that spanned five decades. His legacy and vision for a nuclear renaissance will continue to inspire future generations of nuclear professionals. Our thoughts today are with his family and loved ones.”

Statement from American Nuclear Society President Mary Lou Dunzik-Gougar and Executive Director and CEO Craig Piercy:

The health and safety of the public and protecting people from the consequences of a significant release of radioactive material has been a top priority since the early days of the civilian nuclear energy program. After World War II, it was realized that the core inventory of radionuclides is a potential hazard. From this knowledge, emergency planning zones (EPZs) for nuclear power plants were established.

March 11 will mark the 10-­year anniversary of the Fukushima Daiichi event, when a 45-­foot tsunami, caused by the 9.0-­magnitude Great Tohoku Earthquake, significantly damaged the reactors at Japan’s Fukushima Daiichi nuclear power plant. In response to this event, the U.S. Nuclear Regulatory Commission took actions to evaluate and mitigate beyond-­design-­basis events, including a new requirement for the staging of so-­called Flex equipment, as well as changes to containment venting and improvements to emergency preparedness. The U.S. Department of Energy also addressed beyond-­design-­basis events in its documented safety analyses.

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).

ANSI/ASME/ANS RA-S-1.4-2021, “Probabilistic Risk Assessment Standard for Advanced Non-Light Water Reactor Nuclear Power Plants,” has just been issued. Approved by the American National Standards Institute (ANSI) on January 28, 2021, this joint American Society of Mechanical Engineers (ASME)/American Nuclear Society (ANS) standard sets forth requirements for probabilistic risk assessments (PRAs) used to support risk-informed decisions for commercial nuclear power plants and prescribes a method for applying these requirements for specific applications.

ANSI/ANS-RA-S-1.4-2021 and its preview are available in the ANS Standards Store.

Fusion devices have yet to sustain a burning plasma and produce usable energy, so it should come as no surprise that there is not yet a framework for regulating commercial fusion energy.

Fusion and fission are two very different ways to release nuclear energy. But how different could their regulation be? There are many possible answers to two central questions: Who will regulate commercial fusion (in the United States, that authority could reside with the Nuclear Regulatory Commission or an Agreement State operating under NRC oversight), and what aspects of a fusion plant will they regulate?

On behalf of America’s nuclear professionals, we applaud President Biden for designating ANS member Christopher T. Hanson as chair of the U.S. Nuclear Regulatory Commission (NRC).

The NRC plays a critical role in ensuring nuclear technology and materials are used safely to provide zero-carbon energy, detect and treat cancer, and protect the food supply, among many other applications.

NRC commissioner Christopher T. Hanson participates in the commission briefing on the agency’s response to the COVID-19 pandemic. Photo: NRC

President Biden designated Christopher T. Hanson as the 18th chairman of the Nuclear Regulatory Commission over the weekend. Hanson replaces Kristine Svincki who resigned from the NRC as chairman on January 20. Svinicki was the longest-serving commissioner in the agency's history (2008-2021).

“I am honored to have been selected by President Biden to serve as the next NRC chairman and to lead the talented women and men who oversee the licensing and regulation of our nation’s civilian use of radioactive materials,” said Hanson. “I look forward to building on Chairman Svinicki’s many accomplishments as the commission takes on new challenges and faces new opportunities as nuclear energy technologies continue to evolve and uses of nuclear materials expand in the future.”

On behalf of America’s nuclear professionals, we thank Chairman Kristine Svinicki for her service and leadership at the U.S. Nuclear Regulatory Commission.

Chairman Kristine Svinicki announced today that she intends to leave the Nuclear Regulatory Commission on January 20. She issued a statement in a press release from the NRC.

Chairman Svinicki has served as a commissioner under three administrations and is the longest serving member of the commission. She was first appointed to the commission by President Bush in 2007, was reappointed in 2012 by President Obama, and was designated chairman by President Donald J. Trump on January 23, 2017. Her term would have ended on June 30, 2022.