Disclosed embodiments include nuclear fission reactor cores, nuclear fission reactors, methods of operating a nuclear fission reactor, and methods of managing excess reactivity in a nuclear fission reactor.

Disclosed embodiments include nuclear fission reactor cores, nuclear fission reactors, methods of operating a nuclear fission reactor, and methods of managing excess reactivity in a nuclear fission reactor.

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.

The invention concerns a liquid metal-cooled fast-neutron nuclear reactor (1), comprising a system (2) for removing at least part of both the nominal power and the residual power of the reactor, which ensures, at the same time: removal of the residual power in a totally passive manner from the initial instant of the accident; removal of the heat through the primary vessel; implementation of a final cold source (container with PCM) other than the sodium/air or NaK/air heat exchangers used in the prior art.

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, and any movement, such as through seismic forces, transmits an equal direction and magnitude to the control elements and the reactor core, thus inhibiting the opportunity for differential movement.

A closed-vessel molten salt reactor (cvMSR) is described herein. A cvMSR may comprise a suspended container, such as a metallic container, within a trench surrounded by a concrete enclosure and a concrete cover having a number of channels. The suspended container may be hollow and a solution of fissile materials and salt materials may be provided within the suspended container. The solution may be capable of undergoing a chain reaction nuclear fission process once a threshold temperature is reached. Heat generated by the solution may heat a fluid surrounding the suspended container. The heated fluid may be transported, through the number of channels of the concrete cover, to an external location where the heated fluid may be used in distributing heat and/or electricity generation.

A liquid metal cooled nuclear reactor incorporates a fully passive decay heat removal system with a modular cold source. The system which simultaneously ensure decay heat removal in a completely passive way from the moment an accident starts; heat removal through the primary vessel; and reduction in the risk of chemical interaction between sodium (or NaK) and the material acting as the final cold source. The presence of the final cold source provides an improvement over sodium/air or NaK/air exchangers that are used in the prior art.

A liquid metal cooled nuclear reactor incorporates a fully passive decay heat removal system with a modular cold source. The system which simultaneously ensure decay heat removal in a completely passive way from the moment an accident starts; heat removal through the primary vessel; and reduction in the risk of chemical interaction between sodium (or NaK) and the material acting as the final cold source. The presence of the final cold source provides an improvement over sodium/air or NaK/air exchangers that are used in the prior art.

A nuclear reactor includes a reactor container, a reactor core, a control drum assembly, a hot channel, a heat exchanger and a main pump. The reactor container contains a coolant; the reactor core is arranged at a lower middle part of the reactor container; the control drum assembly is arranged on an outer periphery of the reactor core, and includes control drums arranged at intervals along a peripheral direction of the reactor core; the hot channel is arranged in the reactor container and located above the reactor core. The hot channel has a bottom hermetically connected to the control drum assembly and a top hermetically connected to an inner top surface of the reactor container. The hot channel has a hot pool passage for the coolant to pass through. The heat exchanger is arranged in the reactor container and located on an outer periphery of the hot channel.

A nuclear reactor includes a reactor container, a reactor core, a control drum assembly, a hot channel, a heat exchanger and a main pump. The reactor container contains a coolant; the reactor core is arranged at a lower middle part of the reactor container; the control drum assembly is arranged on an outer periphery of the reactor core, and includes control drums arranged at intervals along a peripheral direction of the reactor core; the hot channel is arranged in the reactor container and located above the reactor core. The hot channel has a bottom hermetically connected to the control drum assembly and a top hermetically connected to an inner top surface of the reactor container. The hot channel has a hot pool passage for the coolant to pass through. The heat exchanger is arranged in the reactor container and located on an outer periphery of the hot channel.