Scoping Studies of Reactor Core Parameters in Support of the Abilene Christian University Molten Salt Research Reactor

Abilene Christian University (ACU) is developing a 1-MW(thermal) molten salt research reactor that will be built on the ACU campus. A conceptual reactor core model was developed to facilitate the safety analysis required for a construction permit. A series of scoping studies were performed seeking to define the reactor core design parameters subject to a variety of design requirements. A Pareto curve identifying the tradeoff between uranium and LiF-BeF₂ was determined. Within this curve, at least 250 kg of uranium and 700 kg of LiF-BeF₂ are needed, albeit for different reactor configurations and fuel salt compositions. The cylindrical reactor vessel associated with the best-performing fuel salt composition is ~130 cm in diameter, ~170 cm tall, and contains ~2.5 tons of graphite. The conversion ratio of the reactor is low and will require regular refueling. The shift in neutron spectrum observed with the changing fuel salt composition does not significantly impact reactivity loss with respect to burnup.