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
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!
Latest Magazine Issues
Jun 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
July 2025
Nuclear Technology
Fusion Science and Technology
Latest News
Smarter waste strategies: Helping deliver on the promise of advanced nuclear
At COP28, held in Dubai in 2023, a clear consensus emerged: Nuclear energy must be a cornerstone of the global clean energy transition. With electricity demand projected to soar as we decarbonize not just power but also industry, transport, and heat, the case for new nuclear is compelling. More than 20 countries committed to tripling global nuclear capacity by 2050. In the United States alone, the Department of Energy forecasts that the country’s current nuclear capacity could more than triple, adding 200 GW of new nuclear to the existing 95 GW by mid-century.
Kazuo Azekura
Nuclear Technology | Volume 77 | Number 3 | June 1987 | Pages 255-262
Technical Paper | Fission Reactor | doi.org/10.13182/NT87-A33965
Articles are hosted by Taylor and Francis Online.
An analysis model has been proposed to evaluate reactivity due to horizontal fast breeder reactor (FBR) core deformation in seismic events by direct three-dimensional eigenvalue calculations, which are impossible for current neutronic analysis programs. The model is based on a current-centered finite difference neutron diffusion calculation method. Macroscopic neutron reaction cross sections are defined, which take into account changes in both mesh volume and material composition. Further, the expression of vertical neutron current is modified in such a way as to take into account changes in vertical mesh interface areas. By using these macroscopic neutron cross sections and the modified expression for vertical neutron current, it is possible to calculate the effective multiplication factor of a deformed FBR core within the bounds of a finite difference diffusion calculation method using the same mesh division used for the normal nondeformed core. Computation time and computer core memory required by the presented model are almost the same as in current finite difference methods. The calculated reactivities for simple one-dimensional slab, two-dimensional slab, and three-dimensional hexagonal systems agreed within 5% of those obtained by either a finite element method or a finite difference method. The agreement was particularly good (within 2%) for cases in which fuel assembly pitches decrease around the horizontal core midplane; therefore, large reactivity is inserted.
