A method for controlling a nuclear reactor includes acquiring current values of operating parameters of the reactor; and iteratively implementing the sub-steps of generating a sequence of injection of neutron poison and/or water; calculating an evolution in at least one magnitude characteristic of the state of the core of the nuclear reactor during this given time interval using a power program, current values of operating parameters and the injection sequence considered, the evolution being calculated using a predictive model of the core of the reactor; evaluating a cost function, using the calculated evolution; repeating the generating and calculating sub-steps until a convergence criterion of the cost function is met; and repeating the acquiring and the iteratively implementing steps with a time period less than 60 minutes.

A method for controlling a nuclear reactor includes acquiring current values of operating parameters of the reactor; and iteratively implementing the sub-steps of generating a sequence of injection of neutron poison and/or water; calculating an evolution in at least one magnitude characteristic of the state of the core of the nuclear reactor during this given time interval using a power program, current values of operating parameters and the injection sequence considered, the evolution being calculated using a predictive model of the core of the reactor; evaluating a cost function, using the calculated evolution; repeating the generating and calculating sub-steps until a convergence criterion of the cost function is met; and repeating the acquiring and the iteratively implementing steps with a time period less than 60 minutes.

A stationary control rod that controls overall nuclear reactivity and axial reactivity distribution of a fuel assembly, such that power level and axial power distribution within the fuel assembly is controlled without the need for movable control rods and associated hardware. The device uses magnetic fields to control the concentration and distribution of a magneto-rheological fluid containing a material with a very high neutron capture cross section, contained in one or more enclosed thimbles placed within existing thimbles in a fuel assembly. The magnetic fields are generated from electricity produced from interactions of the radiation particles within the core, or supplied using electrical cables that attach to fuel assembly top nozzles. The electricity drives a device that encloses associated wire coil assemblies that surround different axial regions of a tube that contains the magneto-rheological fluid.

A portable apparatus for borating a continuous flow of water includes metering assemblies provided with corresponding grinders and feeders; a feeder for supplying water to the circuit; a meter and/or flow regulator for adapting the concentration of the products supplied to the water; a pumping arrangement for conveying the mixture to a mixing reactor; a reactor with a mechanical mixer; a recirculation line of the mixer; and a supply pumping arrangement, preferably forming two units in independent cages or containers, including a crane arrangement for supplying the boration products in big bags.

A portable apparatus for borating a continuous flow of water includes metering assemblies provided with corresponding grinders and feeders; a feeder for supplying water to the circuit; a meter and/or flow regulator for adapting the concentration of the products supplied to the water; a pumping arrangement for conveying the mixture to a mixing reactor; a reactor with a mechanical mixer; a recirculation line of the mixer; and a supply pumping arrangement, preferably forming two units in independent cages or containers, including a crane arrangement for supplying the boration products in big bags.

Methods of controlling the reactivity of a molten salt fission reactor. The molten salt fission reactor comprises a core and a coolant tank (101), the core comprising fuel tubes (103) containing a molten salt fissile fuel, and the coolant tank containing a molten salt coolant (102), wherein the fuel tubes are immersed in the coolant tank. The methods comprise dissolving a neutron absorbing compound in the molten salt coolant, the neutron absorbing compound comprising a halogen and a neutron absorbing element. The first method further comprises reducing the neutron absorbing compound to a salt of the halogen and an insoluble substance comprising the neutron absorbing element, the halogen being fluorine or chlorine, wherein the insoluble substance is not volatile at a temperature of the coolant during operation of the reactor. In the second method the one or more neutron absorbing compounds are chosen such that reduction of the neutron absorbing capacity of the one or more neutron absorbing compounds due to absorption of neutrons compensates for a fall in reactivity of the core in order to control fission rates in the core. Apparatus for implementing the methods are also provided.

Methods of controlling the reactivity of a molten salt fission reactor. The molten salt fission reactor comprises a core and a coolant tank (101), the core comprising fuel tubes (103) containing a molten salt fissile fuel, and the coolant tank containing a molten salt coolant (102), wherein the fuel tubes are immersed in the coolant tank. The methods comprise dissolving a neutron absorbing compound in the molten salt coolant, the neutron absorbing compound comprising a halogen and a neutron absorbing element. The first method further comprises reducing the neutron absorbing compound to a salt of the halogen and an insoluble substance comprising the neutron absorbing element, the halogen being fluorine or chlorine, wherein the insoluble substance is not volatile at a temperature of the coolant during operation of the reactor. In the second method the one or more neutron absorbing compounds are chosen such that reduction of the neutron absorbing capacity of the one or more neutron absorbing compounds due to absorption of neutrons compensates for a fall in reactivity of the core in order to control fission rates in the core. Apparatus for implementing the methods are also provided.

Provided is a secondary shutdown structure of a nuclear reactor, which uses sliding doors, and more particularly, to a secondary shutdown structure of a nuclear reactor, which uses sliding doors and is capable of shutting down a nuclear reactor reliably with a simple structure without using a boric acid solution.

Provided is a secondary shutdown structure of a nuclear reactor, which uses sliding doors, and more particularly, to a secondary shutdown structure of a nuclear reactor, which uses sliding doors and is capable of shutting down a nuclear reactor reliably with a simple structure without using a boric acid solution.

A nuclear power system includes a reactor vessel that includes a reactor core mounted therein. The reactor core includes nuclear fuel assemblies configured to generate a nuclear fission reaction. The nuclear power system further includes a chemical injection system configured to inject a chemical into the reactor vessel and remove the chemical from the reactor vessel, and a control system communicably coupled to the chemical injection system and configured to control a power output of the nuclear fission reaction. For example, the control system can determine that the power output is greater than an upper value of a range or less than a lower value of the range and, based on the determination, adjust an amount of the chemical injected into or removed from the reactor vessel by the chemical injection system to adjust the power output.