RERTR

RERTR stands for Reduced Enrichment for Research and Test Reactors. It is an international program dedicated to promoting the use of low-enriched uranium (LEU) fuel and converting research and test reactors away from highly enriched uranium (HEU). The program aims to reduce the proliferation risk associated with HEU while maintaining reactor performance, safety, and fuel supply for scientific, medical, and industrial research. It began in 1978 as a cooperative effort led by national laboratories in the United States and has since expanded to involve a broad network of governments, reactor operators, fuel suppliers, and international organizations, including the International Atomic Energy Agency (IAEA).

A central objective of RERTR is to facilitate the conversion of existing reactors to LEU fuel and to prevent future installations from using HEU whenever feasible. The program coordinates research, development, and technical assistance to support conversion projects, including the design and qualification of LEU fuels, irradiation testing, licensing support, and information sharing among participants. It also addresses regulatory, safety, and supply-chain considerations that affect conversion timelines and outcomes.

Technical activities under RERTR have included the development of high-density LEU fuels and related fuel-cycle technologies, such as uranium-molybdenum alloys and other advanced fuel forms, aimed at matching or exceeding the performance of HEU fuels for various reactor types. The program emphasizes safety, performance, cost, and regulatory compliance throughout the conversion process.

RERTR has contributed to the global transition of many research and test reactors from HEU to LEU, reducing reliance on weapons-usable materials in civilian facilities. It continues to support ongoing conversions, fuel qualification, and international collaboration to address remaining technical and regulatory challenges.