Radiation Protection and Shielding Analysis of the Versatile Test Reactor

The Versatile Test Reactor (VTR) is currently under development by the U.S. Department of Energy. It will provide very high fast neutron flux irradiation capabilities that are currently unavailable in the United States. Given the increasingly large number of advanced reactor concepts being pursued in recent years, this irradiation testing capability will be essential to support maturation of these designs. Radiation protection is an important part of the VTR design. High neutron fluxes can pose a challenge for radiation protection of the structures and equipment near the reactor core. This paper provides a summary on the status of the radiation protection considerations and shielding analysis performed for VTR under a nominal operating condition. The main radiation sources identified and examined in the study are applicable only under this operating condition. The paper focuses on three areas of radiation protection and shielding: secondary sodium activation in the intermediate heat exchanger, air activation in the reactor vessel auxiliary cooling system, and dose rate above the head access area due to primary sodium activation. VTR design and development are continuously progressing, and as such, the shielding considerations discussed in this paper will evolve alongside the overall VTR design.