ANS is committed to advancing, fostering, and promoting the development and application of nuclear sciences and technologies to benefit society.
Explore the many uses for nuclear science and its impact on energy, the environment, healthcare, food, and more.
Explore membership for yourself or for your organization.
Conference Spotlight
2026 Nuclear Energy Conference & Expo (NECX)
August 24–27, 2026
Dallas, TX|Hilton Anatole
Latest Magazine Issues
Jul 2026
Jan 2026
2026
Latest Journal Issues
Nuclear Science and Engineering
September 2026
Nuclear Technology
August 2026
Fusion Science and Technology
Latest News
The human factor in licensing and operating the next generation of nuclear plants
As human factors specialists working at the intersection of human performance and nuclear operations, we are witnessing one of the nuclear sector’s most significant transitions in decades. The emergence of small modular reactors, microreactors, and other advanced designs is reshaping the industry’s landscape. Digital instrumentation and controls, passive safety systems, and increased automation are creating opportunities for greater safety margins and more flexible operation. These same features also fundamentally redefine what it means to “operate” a nuclear plant. Interactions among human roles, automation, and passive systems shape how people maintain awareness, exercise judgment, and intervene when necessary. These developments affect both operational realities and the regulatory foundations on which nuclear safety is built.
Daniel W. Hudson, Mohammad Modarres
Nuclear Technology | Volume 197 | Number 3 | March 2017 | Pages 227-247
Technical Paper | doi.org/10.1080/00295450.2016.1273714
Articles are hosted by Taylor and Francis Online.
In 1986 the U.S. Nuclear Regulatory Commission (USNRC) implemented a safety goal policy in response to the 1979 Three Mile Island accident. This policy addresses the question, “How safe is safe enough?” by specifying quantitative health objectives (QHOs) for comparison with average individual early fatality and latent cancer fatality risk results computed from nuclear power plant (NPP) probabilistic risk assessments (PRAs). Comparisons of PRA results to the QHOs or other subsidiary numerical objectives are used to determine whether proposed regulatory actions should be rejected based on potential safety benefit relative to the level of residual risk to the public, before performing detailed cost-benefit analyses to determine whether they could be justified on their net value basis. Lessons learned from recent operational experience— including the 2011 Fukushima accident—indicate that concurrent accidents involving multiple units at a shared site can occur with non-negligible frequency. Yet, risk contributions from such scenarios are excluded by policy from safety goal evaluations for the nearly 60% of the U.S. NPP sites that include multiple units. The objectives of this paper are to (1) present an approach for estimating multiple unit risk metrics for comparison with the safety goal QHOs using accident scenarios from the State-of-the-Art Reactor Consequence Analyses (SOARCA) Project; and (2) using this approach, evaluate the effects of including risk contributions from concurrent multiunit accidents in safety goal evaluations. The approach is demonstrated using a two-unit case study involving two representative NPP sites that are each comprised of two co-located operating reactor units. This paper (1) summarizes results and insights obtained from the two-unit case study; (2) describes additional considerations for applying methods to sites comprised of two or more units, including other major radiological sources; and (3) identifies potential areas for further research.