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
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.
Meeting Spotlight
2024 ANS Annual Conference
June 16–19, 2024
Las Vegas, NV|Mandalay Bay Resort and Casino
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!
Latest Magazine Issues
May 2024
Jan 2024
Latest Journal Issues
Nuclear Science and Engineering
June 2024
Nuclear Technology
Fusion Science and Technology
Latest News
Constellation Energy’s earnings skyrocket as investors eye AI
Investor’s Business Daily reported May 10 that the first-quarter earnings of Constellation Energy, the largest operator of nuclear power plants in the United States, surged 858 percent to reach a share price of $2.78, partly as a result of promising expectations regarding demand for artificial intelligence data centers. The S&P 500 stock value of Constellation jumped 3.7 percent on May 8 to $208.
Bobbi Riedel, Christopher M. Perfetti, Forrest B. Brown
Nuclear Science and Engineering | Volume 198 | Number 6 | June 2024 | Pages 1276-1287
Research Article | doi.org/10.1080/00295639.2023.2249787
Articles are hosted by Taylor and Francis Online.
The goal of this study is to evaluate the accuracy of different upper subcritical limit (USL) calculational methods for loosely coupled and novel neutronic systems. This study varied the separation distance over five center-to-center separation distance intervals for four loosely coupled models and explored seven single-system neutronic models. Each of these 27 systems was simulated using MCNP6.2 with 200 randomly perturbed, continuous-energy ENDF/B-VII.1 cross-section files that are in the TENDL 2019 library. The distribution of the values from these perturbed runs was used to calculate stochastic 99/99 USL values for each model iteration. USLs were also estimated for these 20 systems using the Whisper 1.1 code, and the Whisper-identified relevant benchmarks were used to further analyze the relationship between the region-wise USL calculation and the overall system USL calculations. Sensitivity data files were produced using MCNP6.2 and then used with the Oak Ridge National Laboratory TSURFER and USLSTATS methods to estimate USLs for a cross-method USL comparison. A windowing study was performed when using the USLSTATS method to determine the efficacy of the method using datasets with differing degrees of similarity to the given application case. The results show that USLs for each of the loosely coupled system models were higher USLs than the calculated stochastic USLs. The single-system uranium models also displayed a consistently lower stochastic USL as compared to the USL calculational methods, while the single-system plutonium models showed close agreement between the stochastic USLs and the other USL calculational methods.