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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.
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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
Satish Kumar Dhurandhar, S. L. Sinha, Shashi Kant Verma
Nuclear Science and Engineering | Volume 196 | Number 5 | May 2022 | Pages 600-613
Technical Paper | doi.org/10.1080/00295639.2021.2003650
Articles are hosted by Taylor and Francis Online.
In the nuclear fuel structure, most spacers are constructed with vanes that increase turbulence flow mixing downstream of the spacer and therefore enhance the heat transfer rate. The objective of this work is numerical evaluation of the effects of a spacer without a vane and a spacer with a vane (hereinafter referred to as spacer/spacer with vane) on the flow and heat transfer of water at supercritical pressure downstream to the spacer of the annular channel. In this study, computational fluid dynamics (CFD) models of the annular channel have been developed considering spacer/spacer with vane. Experimental data for the heated annular channel have been used to validate the same CFD model (as the geometry used for the experiment) using the CFD code ANSYS Fluent. The CFD results show good agreement with the experimental data used, and hence, the developed CFD models of the annular channel that consider spacer/spacer with vane can be simulated with adequate precision for the flow and heat transfer downstream to the spacer. The effects of spacer/spacer with vane on heat transfer and flow behavior of water have been studied with numerical simulations for the following parameters: mass fluxes of 500 and 1000 kg/m2·s, heat flux of 400 kW/m2, pressure of 25 MPa, and inlet water temperature of 350°C. The results obtained through the simulations show that the spacer with vane has a remarkable influence on flow and heat transfer downstream to the spacer vane against spacer without a vane in an annular channel. Raising the flow velocity is an effective approach to reduce wall temperature and enhance the heat transfer in the channel. The range of the spacer effect in the enhancement of heat transfer is observed from X/D = 0 to 45 in the downstream direction. In addition, the simulation results for the Nusselt number ratio of the present CFD models have been compared with correlation data established by several researchers in a downstream direction to the spacer/spacer with vane, and qualitatively proper agreement has been found.
