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 ANS Annual Conference
May 31–June 3, 2026
Denver, CO|Sheraton Denver
Latest Magazine Issues
Jan 2026
Jul 2025
Latest Journal Issues
Nuclear Science and Engineering
January 2026
Nuclear Technology
December 2025
Fusion Science and Technology
November 2025
Latest News
The Meta-Vistra deal: A closer look
With last Friday's announcement regarding its vision for nuclear energy, Meta has entered into 20-year power purchase agreements (PPAs) for more than 2,600 MW of electricity from a combination of three Vistra-owned nuclear plants to support the tech behemoth's planned operations in the PJM region.
Brian Cohn, Todd Noel, Jeffrey Cardoni, Troy Haskin, Douglas Osborn, Tunc Aldemir
Nuclear Science and Engineering | Volume 197 | Number 1 | June 2023 | Pages S45-S56
Technical Paper | doi.org/10.1080/00295639.2023.2177076
Articles are hosted by Taylor and Francis Online.
Nuclear security relies on the method of vital area identification (VAI) to determine which locations within the nuclear power plant (NPP) need to be protected from radiological sabotage. The VAI methodology uses fault trees (FTs) and event trees (ETs) to identify locations in the NPP that contain vital equipment: structures and components that may result in reactor significant core damage if direct or indirect sabotage occurred. However, the traditional FT/ET process cannot fully capture the dynamics of NPP systems and mitigating measures at play. Existing safety systems or possible operator procedures may be able to avert or mitigate core damage despite the loss of one or more vital areas. Dynamic probabilistic risk assessment (DPRA) methodologies are those that, unlike traditional probabilistic risk assessment, explicitly consider time effects when modeling a system. One common DPRA methodology is that of the use of dynamic event trees (DETs) that drive computer models of a system with user-specified branching conditions to account for uncertainties in a scenario. The DPRA process allows analysts to explore the uncertainties and state space of a scenario in a systematic fashion. A scenario was developed that uses the novel leading simulator/trailing simulator methodology to perform a DET analysis of a combined nuclear safety and nuclear security analysis. The scenario under consideration models the successful sabotage of a vital area by adversaries and determines the effects of timing and the extent of sabotage, as well as possible recovery actions, on the state of the plant. The results of this integrated analysis include the timing and extent of core damage as well as the extent of any radiological release that may occur as a result of sabotage.