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Nuclear Criticality Safety
NCSD provides communication among nuclear criticality safety professionals through the development of standards, the evolution of training methods and materials, the presentation of technical data and procedures, and the creation of specialty publications. In these ways, the division furthers the exchange of technical information on nuclear criticality safety with the ultimate goal of promoting the safe handling of fissionable materials outside reactors.
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2025 ANS Annual Conference
June 15–18, 2025
Chicago, IL|Chicago Marriott Downtown
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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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.
Peter Yarsky, Kevin Coyne, Cynthia Taylor, Chad Oelstrom
Nuclear Technology | Volume 211 | Number 2 | February 2025 | Pages 358-376
Research Article | doi.org/10.1080/00295450.2024.2326375
Articles are hosted by Taylor and Francis Online.
Risk plus Some Attributes (R + SA) is a method that risk informs the prioritization of inspection activities related to new fuel cycle facility construction. The method uses information available in the Integrated Safety Analysis (ISA) summary to compute the risk-informed importance score of each item relied on for safety (IROFS) referenced in the ISA summary. The approach is based on approximating the risk for each accident sequence and then apportioning that risk to IROFSs associated with that sequence. Once the IROFS risk-informed importance score is computed, the importance score can be adjusted to account for other factors besides the risk. These other factors capture attributes of the IROFSs that affect the prioritization they should receive for inspection. An example of an attribute is the complexity of the IROFSs; complex as opposed to simple IROFSs warrant a higher inspection priority. This paper provides a description of the theoretical and mathematical framework of the R + SA methodology.