Systems and methods for providing a molten salt reactor are described. While the systems can include any suitable component, in some cases, they include a graphite reactor core that defines an internal space, with multiple fuel wedges being received in the internal space, and with the wedges each defining a fuel channel extending from a first end to a second end of each of the wedges. In some cases, the reactor further includes a fuel pin rod that defines an internal fuel conduit and that is disposed between at least two of the wedges. In some cases, the reactor core defines a fuel ingress port and a fuel egress port. In some such cases, the reactor core is rotatably received within a reactor housing such that the ports are configured to become at least one of more occluded and less occluded as the reactor core rotates. Other implementations are described.

A nuclear reactor is designed to couple the load path of the control elements with the reactor core, thus reducing the opportunity for differential movement between the control elements and the reactor core. A cartridge core barrel can be fabricated in a manufacturing facility to include the reactor core, control element supports, and control element drive system. The cartridge core barrel can be mounted to a reactor vessel head. Thus, any movement, such as through seismic forces, transmits an equal direction and magnitude to the control elements and the reactor core. This arrangement reduces the opportunity for differential movement between the control elements and the reactor core.

Configurations of molten fuel salt reactors are described that allow for active cooling of the containment vessel of the reactor by the primary coolant. Furthermore, naturally circulating reactor configurations are described in which the reactor cores are substantially frustum-shaped so that the thermal center of the reactor core is below the outlet of the primary heat exchangers. Heat exchanger configurations are described in which welded components are distanced from the reactor core to reduce the damage caused by neutron flux from the reactor. Radial loop reactor configurations are also described.