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.
Division Spotlight
Radiation Protection & Shielding
The Radiation Protection and Shielding Division is developing and promoting radiation protection and shielding aspects of nuclear science and technology — including interaction of nuclear radiation with materials and biological systems, instruments and techniques for the measurement of nuclear radiation fields, and radiation shield design and evaluation.
Meeting Spotlight
Nuclear and Emerging Technologies for Space (NETS 2025)
May 4–8, 2025
Huntsville, AL|Huntsville Marriott and the Space & Rocket Center
Standards Program
The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
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May 2025
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Nuclear Science and Engineering
June 2025
Nuclear Technology
Fusion Science and Technology
Latest News
First concrete marks start of safety-related construction for Hermes test reactor
Kairos Power announced this morning that safety-related nuclear construction has begun at the Oak Ridge, Tenn., site where the company is building its Hermes low-power test reactor. Hermes, a scaled demonstration of Kairos Power’s fluoride salt–cooled, high-temperature reactor technology, became the first non–light water reactor to receive a construction permit from the Nuclear Regulatory Commission in December 2023. The company broke ground at the site in July 2024.
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.