ANS is committed to advancing, fostering, and promoting the development and application of nuclear sciences and technologies to benefit society.
Explore the many uses for nuclear science and its impact on energy, the environment, healthcare, food, and more.
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!
Latest Magazine Issues
Apr 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
June 2025
Nuclear Technology
Fusion Science and Technology
May 2025
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.
Ashlea V. Colton, Blair P. Bromley, Daniel Wojtaszek, Clifford Dugal
Nuclear Science and Engineering | Volume 186 | Number 1 | April 2017 | Pages 48-65
Technical Paper | doi.org/10.1080/00295639.2016.1273021
Articles are hosted by Taylor and Francis Online.
Thorium, a fertile nuclear fuel that is nearly three times as abundant as uranium, represents a long-term energy source that could complement uranium and eventually replace it. To facilitate the gradual transition from uranium-based fuels to thorium-based fuels, it may be advantageous in the near term to introduce small amounts of thorium (˂7% of the total fuel mass) into uranium-based fuels in pressure tube heavy water reactors (PT-HWRs). Downblending natural or slightly enriched uranium dioxide with thorium dioxide for fuel pellets placed at the ends of the fuel stack of a conventional 37-element fuel bundle could help reduce axial power peaking for fresh fuel, while incorporating thorium dioxide into the central element of the fuel bundle could reduce coolant void reactivity (CVR).
A series of two-dimensional lattice physics simulations was carried out as part of conceptual scoping studies to evaluate the potential performance and safety characteristics of uranium-based fuel bundles with small amounts of thorium fuel added. The simulation results were complemented by an approximate model for evaluating the potential economic characteristics. The cases studied involve modifications to fuel composition, central element materials, and the addition of thorium dioxide to the fuel stack. In addition, a set of preliminary three-dimensional MCNP simulations was performed where fuel bundles were modeled to assess the effect of thorium end pellets and graded axial enrichment on end power peaking.
Results suggest it should be possible to incorporate thorium into the fuel cycle using existing 37-element fuel bundle geometry. Advantages to incorporating thorium include a reduction in the CVR through a thorium central element, breeding of small amounts of 233U, maintaining front-end fuel costs at or below the price of natural uranium (NU) fuel, and maintaining maximum linear element ratings within 6%of those achieved using NU 37-element fuel.
