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Division Spotlight
Nuclear Nonproliferation Policy
The mission of the Nuclear Nonproliferation Policy Division (NNPD) is to promote the peaceful use of nuclear technology while simultaneously preventing the diversion and misuse of nuclear material and technology through appropriate safeguards and security, and promotion of nuclear nonproliferation policies. To achieve this mission, the objectives of the NNPD are to: Promote policy that discourages the proliferation of nuclear technology and material to inappropriate entities. Provide information to ANS members, the technical community at large, opinion leaders, and decision makers to improve their understanding of nuclear nonproliferation issues. Become a recognized technical resource on nuclear nonproliferation, safeguards, and security issues. Serve as the integration and coordination body for nuclear nonproliferation activities for the ANS. Work cooperatively with other ANS divisions to achieve these objective nonproliferation policies.
Meeting Spotlight
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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High-temperature plumbing and advanced reactors
The use of nuclear fission power and its role in impacting climate change is hotly debated. Fission advocates argue that short-term solutions would involve the rapid deployment of Gen III+ nuclear reactors, like Vogtle-3 and -4, while long-term climate change impact would rely on the creation and implementation of Gen IV reactors, “inherently safe” reactors that use passive laws of physics and chemistry rather than active controls such as valves and pumps to operate safely. While Gen IV reactors vary in many ways, one thing unites nearly all of them: the use of exotic, high-temperature coolants. These fluids, like molten salts and liquid metals, can enable reactor engineers to design much safer nuclear reactors—ultimately because the boiling point of each fluid is extremely high. Fluids that remain liquid over large temperature ranges can provide good heat transfer through many demanding conditions, all with minimal pressurization. Although the most apparent use for these fluids is advanced fission power, they have the potential to be applied to other power generation sources such as fusion, thermal storage, solar, or high-temperature process heat.1–3
J. L. Wormald, J. C. Holmes, M. L. Zerkle
Nuclear Science and Engineering | Volume 197 | Number 8 | August 2023 | Pages 1800-1813
Technical papers from: PHYSOR 2022 | doi.org/10.1080/00295639.2022.2138063
Articles are hosted by Taylor and Francis Online.
Zirconium carbide (ZrC) is a candidate material for advanced high temperature reactors, including space nuclear thermal propulsion applications. Thermal scattering laws (TSLs) are generated in the incoherent approximation for carbon bound in ZrC [C(ZrC)] and zirconium bound in ZrC [Zr(ZrC)], using ab initio lattice dynamics methods. Disordered alloy theory is introduced to improve treatment of isotopic composition within the elastic scattering cross section. Localized higher-energy vibrational modes and the presence of a phonon band gap in C(ZrC) cause quantized oscillation in the TSL atypical of nonhydrogenous solids. These oscillations yield a significant likelihood of large energy downscattering and upscattering interactions such that the quanta of energy transfer affecting neutron thermalization is substantially greater than classically expected. MC21 critical mass calculations of ZrC mixtures with high-enriched uranium demonstrate an impact of TSLs when compared to a free-gas treatment for thermal neutron–driven 235U loadings. The critical mass of homogenous mixed moderator systems of ZrC and reactor-grade graphite are also sensitive to the ZrC TSL. Moreover, the effect of quantized energy exchange on the neutron spectra is found to influence the temperature feedback coefficient.
