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Reactor Physics
The division's objectives are to promote the advancement of knowledge and understanding of the fundamental physical phenomena characterizing nuclear reactors and other nuclear systems. The division encourages research and disseminates information through meetings and publications. Areas of technical interest include nuclear data, particle interactions and transport, reactor and nuclear systems analysis, methods, design, validation and operating experience and standards. The Wigner Award heads the awards program.
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International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering (M&C 2025)
April 27–30, 2025
Denver, CO|The Westin Denver Downtown
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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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TerraPower begins U.K. regulatory approval process
Seattle-based TerraPower signaled its interest this week in building its Natrium small modular reactor in the United Kingdom, the company announced.
TerraPower sent a letter to the U.K.’s Department for Energy Security and Net Zero, formally establishing its intention to enter the U.K. generic design assessment (GDA) process. This is TerraPower’s first step in deployment of its Natrium technology—a 345-MW sodium fast reactor coupled with a molten salt energy storage unit—on the international stage.
Shuji Yamamoto, Katsuhei Kobayashi, Mitsuharu Miyoshi, Itsuro Kimura, Ikuo Kanno, Nobuo Shinohara, Yoshiaki Fujita
Nuclear Science and Engineering | Volume 126 | Number 2 | June 1997 | Pages 201-212
Technical Paper | doi.org/10.13182/NSE97-A24473
Articles are hosted by Taylor and Francis Online.
Making use of back-to-back type double fission chambers and a lead slowing-down spectrometer coupled to an electron linear accelerator, the cross section for the 241Am(n,f) reaction has been measured relative to that for the 235U(n,f) reaction in the energy range from 0.1 eV to 10 keV. To avoid the interference between the 241 Am and the 235U resonances, the fission cross section below 1 keV was measured relative to the 10B(n, α) reaction with a BF3 counter, and the result obtained was normalized to the absolute value by the 235U reference data between 200 eV and 1 keV The measured result has been compared with (a) the evaluated nuclear data contained in the ENDF/B-VI and JENDL-3.2 libraries and (b) the existing experimental data, with the evaluated and measured data being broadened using the energy resolution function of the spectrometer.There is general agreement between the evaluated data and this measurement, although some discrepancies are found in the energy region where the cross-section shapes show a pronounced structure. The JENDL-3.2 data are underestimated by a factor in the range 1.2 to 2.3 between 22 and 140 eV, while the more recently measured data by Dabbs, Johnson, and Bemis and the evaluated data in ENDF/B-VI are in good agreement with the measurement within the uncertainties. In the energy range from 1 to 10 keV, the current result is 15 to 18% higher than the evaluations and the data of Dabbs, Johnson, and Bemis. Some of the earlier experimental data that were measured over part of the relevant energy region are not always in agreement with the current measurement. The fission cross section for thermal neutrons was also measured in a pure Maxwellian neutron spectrum field with double fission chambers. The derived result at 0.0253 eV is 3.15 ± 0.097 b, which is obtained relative to the reference value of 586.2 b for the 235U(n,f) reaction. The ENDF/B-VI data are in good agreement with the current measurement, while the JENDL-3.2 value is lower by 4.2%. The ratios of the earlier experimental data to the current value are distributed between 0.89 and 1.02.
