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Division Spotlight
Fusion Energy
This division promotes the development and timely introduction of fusion energy as a sustainable energy source with favorable economic, environmental, and safety attributes. The division cooperates with other organizations on common issues of multidisciplinary fusion science and technology, conducts professional meetings, and disseminates technical information in support of these goals. Members focus on the assessment and resolution of critical developmental issues for practical fusion energy applications.
Meeting Spotlight
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
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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Nuclear Technology
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Latest News
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.
Tracy E. Stover, Dennis Mennerdahl, Dominic D. Winstanley, Christopher Tripp, Kermit Bunde, Douglas Bowen
Nuclear Technology | Volume 208 | Number 4 | April 2022 | Pages 644-687
Technical Paper | doi.org/10.1080/00295450.2021.1938910
Articles are hosted by Taylor and Francis Online.
Calculated critical and subcritical data for systems of mixed oxides of plutonium and uranium are presented for review and subsequent incorporation into a revision of ANSI/ANS 8.12. The system specifications were prepared in parallel with the ISO standard ISO 11311:2011, involving experience from international mixed oxide fuel fabrication facilities. Data are presented for two mass fractions of plutonium to uranium plus plutonium (at 12.5% and 35%), damp mixed oxide density up to a theoretical density of 11.03 g/cm3 (for the 12.5% mass fraction, ignoring the variation due to plutonium isotopic content) and up to a density of 3.5 g/cm3 (for the 35% mass fraction), three plutonium isotopic mass fractions (100% 239Pu, 95% 239Pu with 5% 240Pu, and a reactor grade composition with 20% 240Pu and the balance 239Pu, 241Pu, and 242Pu), systems at two moderation conditions (water mass fractions at 3% and at optimal conditions) and systems at two water reflector conditions (nominal 2.5 cm and full 30.0 cm). Parameters of interest presented are values of volume (L), infinite cylinder diameter (cm), infinite slab thickness (cm), mass (kg), cylinder linear density (g/cm), and slab areal density (g/cm2). Values are presented at calculated multiplication factors of 1.000, 0.980 and 0.950. Calculations were made by various subject matter experts with various computational programs and cross section libraries. Validation methods were reviewed and discussed herein though data propagated to revision of ANSI/ANS 8.12 will reflect a conservative subcritical margin selected based on expert judgment.
