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.
Explore membership for yourself or for your organization.
Conference Spotlight
2026 Annual Conference
May 31–June 3, 2026
Denver, CO|Sheraton Denver
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
Dec 2025
Jul 2025
Latest Journal Issues
Nuclear Science and Engineering
December 2025
Nuclear Technology
Fusion Science and Technology
November 2025
Latest News
Deep Fission to break ground this week
With about seven months left in the race to bring DOE-authorized test reactors on line by July 4, 2026, via the Reactor Pilot Program, Deep Fission has announced that it will break ground on its associated project on December 9 in Parsons, Kansas. It’s one of many companies in the program that has made significant headway in recent months.
G. Ivan Maldonado, Paul J. Turinsky, David J. Kropaczek,Geoffrey T. Parks
Nuclear Science and Engineering | Volume 121 | Number 2 | October 1995 | Pages 312-325
Technical Paper | doi.org/10.13182/NSE95-A28567
Articles are hosted by Taylor and Francis Online.
The computer code FORMOSA-P (Fuel Optimization for Reloads Multiple Objectives by Simulated Annealing—PWR) has been developed to address pressurized water reactor (PWR) in-core nuclear fuel management optimization. Until recently, the optimization objectives available to the user included minimization of relative power peaking throughout the cycle, maximization of the end-of-cycle reactivity, and maximization of region-average discharge burnup. In addition, during an optimization, various core attributes (including the preceding objectives) can be optionally activated as constraints via penalty functions or to directly reject sampled loading patterns that violate established design limits. The underlying theoretical framework that enables the accurate and efficient calculation of objective and constraint values within the FORMOSA-P code is its higher order, nodal generalized perturbation theory (GPT) neutronics model. The utility of the FORMOSA-P code has been extended to include a traditionally out-of-core decision variable, namely, the fresh (i.e., feed) reload fuel enrichment. This is accomplished by formulating the feed enrichment as a GPT variable that can be adjusted concurrently with changes in the core loading pattern to enforce a target cycle length. This provides a reload designer with the capability to minimize feed enrichment during an in-core optimization while enforcing all other constraints (e.g., power peaking limit, cycle energy requirement, degree of eighth-core power tilt, discharge burnup limit, and moderator temperature coefficient limit).