Abstract: Alternative designs for a modular test reactor are presented. In one aspect, a molten fuel salt nuclear reactor includes a vessel defining a reactor volume, the vessel being open-topped and otherwise having no penetrations. A neutron reflector is provided within the vessel and displacing at least some of the reactor volume, the neutron reflector defining a reactor core volume. A plurality of heat exchangers are contained within the vessel above the neutron reflector. A flow guide assembly is provided within the neutron reflector that includes a draft tube draft tube separating a central portion of the reactor core volume from an annular downcomer duct. Fuel salt circulates from the reactor core volume, through the heat exchangers, into the downcomer duct and then back into the reactor core volume.

Abstract: Alternative designs for a modular test reactor are presented. In one aspect, a molten fuel salt nuclear reactor includes a vessel defining a reactor volume, the vessel being open-topped and otherwise having no penetrations. A neutron reflector is provided within the vessel and displacing at least some of the reactor volume, the neutron reflector defining a reactor core volume. A plurality of heat exchangers are contained within the vessel above the neutron reflector. A flow guide assembly is provided within the neutron reflector that includes a draft tube draft tube separating a central portion of the reactor core volume from an annular downcomer duct. Fuel salt circulates from the reactor core volume, through the heat exchangers, into the downcomer duct and then back into the reactor core volume.

Abstract: A simple nuclear reactor in which most of the reflector material is outside of the reactor vessel is described. The reactor vessel is a cylinder that contains all of the fuel salt and a displacement component, which may be a reflector, in the upper section of the reactor vessel. Other than the displacement component, the reflector elements including a radial reflector and a bottom reflector are located outside the vessel. The salt flows around the outside surface of the displacement component through a downcomer heat exchange duct defined by the exterior of the displacement component and the interior surface of the reactor vessel. This design reduces the overall size of the reactor vessel for a given volume of salt relative to designs with internal radial or bottom reflectors.

Abstract: Designs for a low power, fast spectrum molten fuel nuclear reactor that can be used to advance the understanding of molten salt reactors, their design and their operation are described. Furthermore, the designs described may be adapted to extra-terrestrial use as described herein for use as a low-gravity, moon-, Mars-, or space-based power generator. These low power reactors include a reactor core volume defined by a radial neutron reflector enclosed in a reactor vessel, in which heated fuel salt flows from the reactor core through a duct between the radial neutron reflector and the reactor vessel and back into the reactor core. Heat generated from the fission in the reactor core is transferred from the molten fuel through the reactor vessel to a coolant, in the case of an experimental design, or directly to an extra-terrestrial environment, in the case of an extra-terrestrial design.

Abstract: A nuclear fuel element for use in water-cooled nuclear power reactors and an improved multilayered silicon carbide tube for use in water-cooled nuclear power reactors and other high temperature, high strength thermal tubing applications including solar energy collectors. The fuel element includes a multilayered silicon carbide cladding tube. The multilayered silicon carbide cladding tube includes (i) an inner layer; (ii) a central layer; and (iii) a crack propagation prevention layer between the inner layer and the central layer. A stack of individual fissionable fuel pellets may be located within the cladding tube. In addition, a thermally conductive layer may be deposited within the cladding tube between the inner layer of the cladding tube and the stack of fuel pellets. The multilayered silicon carbide cladding tube may also be adapted for other high temperature, high strength thermal tubing applications including solar energy collectors.

Abstract: A nuclear fuel element for use in water-cooled nuclear power reactors. The fuel element includes a multilayered silicon carbide cladding tube. The multilayered silicon carbide cladding tube preferably includes an inner layer and a central layer. Also, in one embodiment, the ends further include hermetically sealed end caps. The cladding tube is sized to receive a stack of individual fissionable fuel pellets. In one embodiment, the fuel pellets comprise a mixture of thorium oxide and plutonium oxide.