NBG-17 – An improved graphite grade for HTRs and VHTRs

NBG-18 is an established nuclear graphite grade for moderator and reflector applications in gas-cooled nuclear reactors. Prismatic-type reactors however require a material with lower maximum grain size due to the rather small spacing between cooling channels in the fuel block. With NBG-17, a suitable material is developed using same proven raw materials and process route, including vibromoulding forming process. Production process and material characteristics are described, demonstrating the general suitability for nuclear application, with irradiation tests in progress.