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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
Utility Working Conference and Vendor Technology Expo (UWC 2024)
August 4–7, 2024
Marco Island, FL|JW Marriott Marco Island
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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Latest News
Vogtle-3 shuts down for valve issue
One of the new Vogtle units in Georgia was shut down unexpectedly on Monday last week for a valve issue that has since been investigated and repaired. According to multiple local news outlets, Georgia Power reported on July 17 that Unit 3 was back in service.
Southern Company spokesperson Jacob Hawkins confirmed that Vogtle-3 went off line at 9:25 p.m. local time on July 8 “due to lowering water levels in the steam generators caused by a valve issue on one of the three main feedwater pumps.”
Corey Trujillo, Mustafa Hadj-Nacer, Miles Greiner (Univ of Nevada, Reno)
Proceedings | 16th International High-Level Radioactive Waste Management Conference (IHLRWM 2017) | Charlotte, NC, April 9-13, 2017 | Pages 917-924
In this paper, the effect of rarefaction on the fuel cladding temperature is investigated. To do this, we apply a temperature-jump thermal-resistance to ANSYS/Fluent CFD simulations of a vacuum drying operation in geometrically-accurate two and three-dimensional models of a loaded nuclear fuel canister. The numerical model represents a vertical canister and basket loaded with 24 Westinghouse 15 × 15 PWR fuel assemblies. The model includes distinct regions for the fuel pellets, cladding and gas regions within each basket opening. Symmetry boundary conditions are employed so that only one-eighth of the package cross section is included. The canister is assumed to be filled with helium. A uniform temperature of 101.7°C is employed on the canister outer surfaces to conservatively model canister surrounded with boiling water.
Steady-state simulations are performed for different fuel heat generation rates and helium pressures, ranging from atmospheric pressure to 100 Pa. These simulations include conduction within solid and gas regions, and surface-to-surface radiation across all gas regions. Constant thermal accommodation coefficients, which characterize the effect of the temperature-jump thermal-resistance at the gas-surface interface are employed. The peak cladding temperature and its radial and axial locations are reported. The maximum allowable heat generation that brings the cladding temperatures to the normal radial hydride formation limit (TRH = 400°C) is also reported. The results of the three-dimensional model simulations are compared to two-dimensional model simulations for the same heat generation rate and pressures.
The results show that the rarefaction condition causes the temperature of the rods to significantly increase compared to the continuum condition (atmospheric pressure). This causes the maximum allowable heat generation for rarefied condition to decrease. The three-dimensional model predicts temperature that are ~15 to 35°C lower than the two-dimensional model.