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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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2024 ANS Winter Conference and Expo
November 17–21, 2024
Orlando, FL|Renaissance Orlando at SeaWorld
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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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Nuclear new build procurement considerations
It may seem counterintuitive, but the best time to enhance the ability to support operations and maintenance for a new plant is before construction starts. This is one of many lessons learned by the currently operating nuclear fleet. As construction and startup of many nuclear facilities was completed, it quickly became evident that the ability to efficiently support operations and maintenance was limited. Most of the information necessary to establish and manage procurement of spare and replacement items, maintenance, and configuration of the facilities was unavailable and had to be gathered on a case-by-case, “on-demand” basis. Absence of necessary information and the associated challenges resulted in the need for staff augmentation and multiyear-long projects to develop equipment bills of material and maintenance programs and to perform technical evaluations for the huge quantities of spare and replacement items being requested.
Tim D. Bohm, Mohamed E. Sawan
Fusion Science and Technology | Volume 77 | Number 7 | November 2021 | Pages 813-828
Technical Paper | doi.org/10.1080/15361055.2021.1908783
Articles are hosted by Taylor and Francis Online.
In the design of fusion reactors, determining radiation levels due to neutrons and photons (gammas) throughout the reactor and its surroundings is important. Radiation transport codes need to have accurate cross-section libraries in order to produce accurate results. The Fusion Evaluated Nuclear Data Library (FENDL) is an international effort coordinated by the International Atomic Energy Agency, Nuclear Data Section, that assembles a collection of the best nuclear data for fusion applications. In the current FENDL-3.1d data library, neutron cross sections for 65 of the 180 isotopes present in the library come from ENDF/B-VII.1.
Monte Carlo–based neutronics calculations using cross-section libraries from FENDL (versions 2.1 and 3.1d), ENDF/B (versions VII.1 and VIII.0), and candidate new evaluations for key structural elements/isotopes such as iron and chromium were performed. The calculations were performed in reactor-relevant models including a one-dimensional (1-D) cylindrical model of ITER, a three-dimensional (3-D) computer-aided design (CAD)–based model of ITER, and a 3-D CAD-based model of the U.S. Fusion Energy System Studies Fusion Nuclear Science Facility (FNSF).
The results show that neutron fluxes calculated with different cross-section libraries can be as much as 12% higher and as much as 8% lower than those calculated with the reference cross-section library (FENDL-2.1). Nuclear heating calculated with different cross-section libraries can be as much as 14% higher and as much as 8% lower than those calculated with the reference cross-section library. Iron displacements per atom calculated with different cross-section libraries can be as much as 9% higher and as much as 9% lower than those calculated with the reference cross-section library. Helium production calculated with different cross-section libraries can be as much as 19% higher and as much as 2% lower than those calculated with the reference cross-section library. Tritium production in the ITER 1-D model’s nonbreeding regions calculated with different cross-section libraries can be as much as 246% higher and as much as 5% lower than those calculated with the reference cross-section library. The tritium breeding ratio in the FNSF 3-D model calculated with different cross-section libraries averaged 1% higher at the inboard and 1.4% higher at the outboard than those calculated with the reference cross-section library.