Matthew Denman

Probabilistic risk assessment is a systematic methodology for evaluating risks associated with a complex engineered technology such as nuclear energy. PRA risk is defined in terms of possible detrimental outcomes of an activity or action, and as such, risk is characterized by three quantities: what can go wrong, the likelihood of the problem, and the resulting consequences of the problem.

Matthew Denman is principal engineer for reliability engineering at Kairos Power and the chair of the American Nuclear Society and American Society of Mechanical Engineers Joint Committee on Nuclear Risk Management’s Subcommittee of Standards Development. As a college student at the University of Florida, Denman took a course on PRA but didn’t enjoy it, because he did not see its connection to the nuclear power industry. Later, during his Ph.D. study at the Massachusetts Institute of Technology, his advisor was Neil Todreas, a well-known thermal hydraulics expert. Todreas was working on a project with George Apostolakis, who would leave MIT to become a commissioner of the Nuclear Regulatory Commission. The project, “Risk Informing the Design of the Sodium-Cooled Fast Reactor,” was a multi-university effort funded through a Department of Energy Nuclear Energy Research Initiative (NERI) grant. Todreas and Apostolakis were joined in this project by a who’s who of nuclear academia, including Andy Kadak (MIT, ANS past president [1999–2000]), Mike Driscoll (MIT), Mike Golay (MIT), Mike Lineberry (Idaho State University, former ANS treasurer), Rich Denning (Ohio State University), and Tunc Aldemir (Ohio State University).

“The American Nuclear Society is monitoring the situation at the Taishan reactor site in China. According to Framatome and the plant operator CGN, the plant is operating within established safety parameters.

The Economist published a video earlier this month trying to answer the question of why is nuclear so unpopular. The video is paired with a story that appeared on The Economist's website advocating for a well-regulated nuclear industry. The video starts off with very dramatic images of nuclear weapons and scenes from popular culture like Godzilla, The Simpsons, and the recent HBO miniseries Chernobyl. The video provides a quick history of nuclear science and technology starting with Eisenhower's Atoms for Peace speech in an attempt to prove to the viewer that "nuclear is one of the safest, most reliable, and sustainable forms of energy, and decarbonizing will be much more difficult without it."

The impact of COVID-19 has placed a sharp focus on not only the importance of keeping key personnel safe but also how to better manage risk with fewer resources on site, writes Ola Bäckström, a product manager for risk at Lloyd’s Register, for Power magazine.

One unexpected result is the acceleration of interest in digitization initiatives. Ten years of digital innovation since the Fukushima accident in March 2011 have brought new ways of modeling and managing risk, and new solutions have been brought to market that are allowing for the safe operation of nuclear power plants.

The digitalization of plant designs is one area of risk assessment that can now be completed automatically. The latest technologies consider more than just schematics and equations, much to the benefit of this new era of nuclear. For instance, digital data combined with international best practices, site-specific data, and an engineer’s own experience can provide a deeper level of insight and analysis than ever before—and faster. Bäckström adds that not just new projects but aging assets can also benefit from digitalization. As more data are input, risk managers can run more accurate simulations and better model existing plants.

ANS President Mary Lou Dunzik-Gougar took to the video screen on November 18 during the 2020 ANS Virtual Winter Meeting for the President’s Special Session on radiation risk, echoing a comment by Exelon Nuclear’s Bryan Hanson, the Winter Meeting’s general cochair, who earlier in the week characterized radiation as one of the most misunderstood aspects of nuclear.

“I think that’s very true,” Dunzik-Gougar said. “So much misconception and misunderstanding. I have always had a passion for communicating about such things as radiation, helping people understand the nature of radiation and the relative risks of nuclear, but mostly about its benefits. But I think we in the industry can better prepare ourselves with knowledge about radiation and its impacts and also educate ourselves on how to talk about the risks of radiation with people not in our own echo chambers to help change the perception among a broader scope of people.”

The panel of experts assembled to help impart some of that knowledge to session attendees included Amir A. Bahadori, assistant professor at Kansas State University; Donald A. Cool, a technical executive at the Electric Power Research Institute and a former senior executive at the Nuclear Regulatory Commission; Paul Locke, associate professor at the Johns Hopkins Bloomberg School of Public Health; and Shaheen Dewji, assistant professor at Texas A&M University.

Mary Lou Dunzik-Gougar

Last month I asked if you’ve ever wondered why nuclear isn’t commonly considered the choice for clean power production. I also provided what I hope will be useful information as you make the case for nuclear in discussions about clean energy. In addition to being the cleanest form of energy today, nuclear is also safe, reliable, and scalable. This month, let’s talk safety.

Like the term “clean,” “safety” can mean something different to everyone. As measured by the number of deaths per unit of electricity produced, nuclear is on the same order of magnitude as “renewables” and other low-carbon sources of energy.