The accident at Three Mile Island revealed many areas for improvement in the safety of nuclear power that have been addressed continuously in the past 40 years.
Part one of this article, published in the May 2019 issue of Nuclear News[1] and last Friday on Nuclear Newswire, presented insights from the 1979 accident at Three Mile Island-2 and addressed several issues raised by a previous Nuclear News piece on the accident[2]. Part two discusses safety improvements that have been made by both the industry and the Nuclear Regulatory Commission over the past 40 years.
Presidential nominations to the U.S. Nuclear Regulatory Commission (NRC)
Statement from American Nuclear Society President Steven Nesbit and Executive Director and CEO Craig Piercy:
Sparked by an article on the TMI accident that appeared in the March 2019 issue of Nuclear News, ANS past president William E. Burchill (2008–2009) offered his own views on the subject. Part 1 of the article appeared in the May 2019 issue of NN and Part 2 was published in June 2019.
The accident at Unit 2 of the Three Mile Island nuclear power plant on March 28, 1979, was an extremely complex event. It was produced by numerous preexisting plant conditions, many systemic issues in the industry and the Nuclear Regulatory Commission, unanticipated operator actions, previously unrecognized thermal-hydraulic phenomena in the reactor coolant system (RCS), and the unprecedented challenge of managing a severely degraded core.
The cover of the August 1969 issue of Nuclear News (left), an image of Brunhilde, the dog that had the first nuclear-powered pacemaker in the U.S. (center) and the cover of the December 1970 Nuclear News (right).
In this first installment of a #ThrowbackThursday post, Nuclear News provides a review of radioisotope-powered pacemakers in response to an article in The Wall Street Journal. The article, published earlier this week, looks at the issue of disposing of nuclear-powered pacemakers, although considering how few are still in use today, it seems like this is really much ado about nothing.
An artist's rendition of Oklo’s Aurora powerhouse. (Image: Gensler)
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.
September 10, 2021, 8:22AMUpdated December 31, 2021, 7:15AMNuclear NewsThomas R. Wellock An aerial view of the Hanford reservation and Columbia River that shows the N (nearest), KE/KW (center), and B (top right) reactors. (Photo: U.S. DOE )
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).
Chuck Metz Jr. discusses his collaboration with Harold Denton, whose memoir interweaves a retelling of the Three Mile Island accident events with stories of his career-long advocacy for nuclear safety.

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.
Former commissioner Annie Caputo left the NRC when her term expired at the end of June.
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.
U.S. Nuclear Regulatory Commission headquarters (photo: U.S. NRC)
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.
Vacancies undermine the U.S. Nuclear Regulatory Commission’s mission
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.