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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
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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Latest News
Argonne’s METL gears up to test more sodium fast reactor components
Argonne National Laboratory has successfully swapped out an aging cold trap in the sodium test loop called METL (Mechanisms Engineering Test Loop), the Department of Energy announced April 23. The upgrade is the first of its kind in the United States in more than 30 years, according to the DOE, and will help test components and operations for the sodium-cooled fast reactors being developed now.
Vikram Singh, Matthew R. Lish, Alexander M. Wheeler, Ondřej Chvála, Belle R. Upadhyaya
Nuclear Technology | Volume 202 | Number 1 | April 2018 | Pages 15-38
Technical Paper | doi.org/10.1080/00295450.2017.1416879
Articles are hosted by Taylor and Francis Online.
A nonlinear dynamic model for the two-fluid molten-salt breeder reactor (MSBR) system is presented. This work is partly inspired by a preliminary dynamic model of the concept studied at Oak Ridge National Laboratory (ORNL). The core heat transfer model has been revised to accurately reflect the design exemplified in ORNL-4528—the last report on the two-fluid design. A brief description of the reactor system and the effects of reactor poisons and a discussion of temperature feedback mechanisms are presented. This background information is followed by an overview of the modeling approach and a discussion of the revised lumped parametrization, along with detailed descriptions of the modeling methodology and model limitations. All equations and parameters used in the model are presented to aid in model reproduction and adaptation for other molten-salt reactor designs. Model stability is analyzed by observing the uncontrolled response to reactivity perturbations. Simulations illustrate stable behavior at all power levels investigated. Temperature-induced feedback effects lead to stable dynamics for both large and small reactivity transients. Stable and smooth changes in the various nodal temperatures are also observed. The frequency response of the system indicates no dynamics problems at all operating power levels and is consistent with the transient response. Characteristic features in the frequency response plots due to feedback effects are also discussed. Finally, the load-following capability of the MSBR system is studied for various ramp rates of the power demand in the final heat sink. The temperatures in all salt-containing parts of the system are observed to vary about an average during the load-following maneuver. It is observed that the MSBR system exhibits a self-regulating behavior, minimizing the need for external controller action for load-following operations.