Optimization Analysis Plan for the PRO-X and NCNR Collaboration on the NNS Research Reactor Project

Published

September 29, 2026

Author(s)

Mohamed Elsawi, Carolyn Tomchik, Justin Thomas, Erik Wilson, Thad Heltemes, John Stevens, Abdullah Weiss, Osman Celikten, Jeremy Cook, Noura Elsalamouny, Thomas Newton

Abstract

The National Institute of Standards and Technology (NIST), through the NIST Center for Neutron Research (NCNR), and the U.S. Department of Energy's National Nuclear Security Administration (NNSA), through Argonne National Laboratory, are collaborating to apply the Proliferation Resistance Optimization (PRO-X) framework to the conceptual design of the proposed NIST Neutron Source (NNS) research reactor. This effort is intended to integrate proliferation resistance into early design decisions while supporting mission performance, safety, and project practicality, thereby advancing nonproliferation and reactor mission objectives together rather than treating them as competing priorities. The NNS is being developed to replace the aging National Bureau of Standards Reactor and to sustain and expand an essential national capability in neutron measurement science. The proposed facility is a 20 MW pool-type research reactor with a compact core, heavy-water reflector, cold neutron sources, thermal beam capabilities, and irradiation facilities. Because the project remains in conceptual design, this collaboration provides a timely opportunity to influence major design choices before engineering, licensing, and procurement decisions become fixed. This analysis plan establishes a structured, multi-objective approach for comparing design candidates with a baseline design. The optimization focuses on three complementary objectives: strengthening proliferation resistance by reducing the production, accumulation, accessibility, and attractiveness of special fissionable material; preserving or enhancing reactor mission performance; and maintaining adequate safety margins under representative operating conditions. The work is intended to inform design refinement and decision-making during the pre-licensing stage, not to provide final regulatory analyses. The principal areas of analysis include fuel system selection, fuel assembly design, fuel management and shuffling strategies, power-peaking mitigation, cooling-capacity rightsizing, and the configuration of key experimental capabilities. Across these areas, optimization emphasizes practical and implementable design improvements that align reactor capabilities with declared mission needs while avoiding unnecessary excess in material inventory, fissile material throughput, power, cooling capacity, or facility complexity. For NIST and NNSA stakeholders, this effort provides a clear and traceable technical basis for high-consequence design and procurement decisions. The expected outcomes include comparative assessments and decision-ready recommendations that support conceptual design refinement, strengthen future vendor engagement, and help ensure that nonproliferation objectives are incorporated directly into project requirements and acquisition planning. This collaboration is intended to strengthen the NNS project while design changes remain most feasible. By integrating proliferation resistance early and systematically with performance and safety considerations, the effort supports development of a more secure, efficient, and missioneffective reactor design that advances both national scientific capability and U.S. nonproliferation objectives. Beyond the NNS project, the PRO-X/NCNR collaboration establishes a practical, mission-driven model for future partnerships between NNSA and reactor developers, supporting NNSA's broader nonproliferation goals by demonstrating how proliferation resistance can be enhanced while supporting reactor mission performance, safety, and operational effectiveness.

Citation

Argonne National Laboratory Report

Pub Type

Others

Download Paper

https://doi.org/10.2172/17008692

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Keywords

NNS, Optimization, Reactor Design, NNSA, Pro-X, NCNR, Proliferation Resistance, LEU, Research Reactors

Citation

Elsawi, M. , Tomchik, C. , Thomas, J. , Wilson, E. , Heltemes, T. , Stevens, J. , Weiss, A. , Celikten, O. , Cook, J. , Elsalamouny, N. and Newton, T. (2026), Optimization Analysis Plan for the PRO-X and NCNR Collaboration on the NNS Research Reactor Project, Argonne National Laboratory Report, [online], https://doi.org/10.2172/17008692, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=962773 (Accessed October 14, 2026)

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