Updating and Enhancing the INPRO Proliferation Resistance Methodology for Better
Sustainability Assessments

The International Project on Innovative Nuclear Reactors and Fuel Cycles (INPRO), begun in 2001, developed a methodology to assess the sustainability of nuclear energy systems. The INPRO methodology covers six key areas: infrastructure, economics, environmental impacts (particularly depletion of resources and impact of stressors), waste management, safety, and proliferation resistance. The methodology undergoes review and updating on a regular basis. The proliferation resistance (PR) area was the last area to undergo a recent update. A group of international experts, including many from the Generation IV International Form (GIF) Proliferation Resistance and Physical Protection Working Group (PR&PP), were instrumental in the update to the PR manual. The updates in the PR methodology were in streamlining the assessment process and enhancing the methodology in the user requirements for attractiveness of the nuclear energy system, as well as implementation of multiple measures to deter proliferation. These enhancements in the user requirements, criteria, and evaluation parameters, better support the nuclear community’s definition of PR by considering intrinsic features and extrinsic measurers, to improve sustainability assessments in PR for innovative nuclear energy systems. These enhancements are especially important for innovative systems that encompass advanced small modular reactors (SMRs) and microreactor designs. The outcome of a nuclear energy system assessment (NESA) in sustainability is the identification of criteria that are not met, so designs can be improved or to identify research and development needs to close the gaps, which is especially important for innovative designs.