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.

A system for a carbon neutral cycle of gas production may include a molten salt reactor configured to generate zero carbon dioxide (CO.sub.2) emissions electricity. The system may include a desalination unit configured to receive the zero-CO.sub.2 emissions electricity from the molten salt reactor and produce a desalinated water. The system may include an electrolysis unit configured to be powered by the zero-CO2 emissions electricity generated by the molten salt reactor and generate hydrogen (H.sub.2) and oxygen (O.sub.2) from the desalinated water. The system may include an oxy-combustion unit configured to receive and combust a hydrocarbon fuel with the O.sub.2 from the electrolysis unit to produce electricity and CO.sub.2. The system may include a CO.sub.2 capture system adapted to capture the CO.sub.2 produced by the oxy-combustion unit and a catalytic hydrogenation unit configured to receive and convert H.sub.2 from the electrolysis unit and CO.sub.2 from the CO.sub.2 capture system to produce the hydrocarbon fuel.

A system for a carbon neutral cycle of gas production may include a molten salt reactor configured to generate zero carbon dioxide (CO.sub.2) emissions electricity. The system may include a desalination unit configured to receive the zero-CO.sub.2 emissions electricity from the molten salt reactor and produce a desalinated water. The system may include an electrolysis unit configured to be powered by the zero-CO2 emissions electricity generated by the molten salt reactor and generate hydrogen (H.sub.2) and oxygen (O.sub.2) from the desalinated water. The system may include an oxy-combustion unit configured to receive and combust a hydrocarbon fuel with the O.sub.2 from the electrolysis unit to produce electricity and CO.sub.2. The system may include a CO.sub.2 capture system adapted to capture the CO.sub.2 produced by the oxy-combustion unit and a catalytic hydrogenation unit configured to receive and convert H.sub.2 from the electrolysis unit and CO.sub.2 from the CO.sub.2 capture system to produce the hydrocarbon fuel.

This disclosure describes systems and methods for synthesizing UCl.sub.3 from UCl.sub.4. These systems and methods may also be used to directly synthesize binary and ternary embodiments of uranium salts of chloride usable as nuclear fuel in certain molten salt reactor designs. The systems and methods described herein are capable of synthesizing any desired uranium chloride fuel salt that is a combination of UCl.sub.4, UCl.sub.3 and one or more non-fissile chloride compounds, such as NaCl. In particular, the systems and methods described herein are capable of synthesizing any UCl.sub.3—UCl.sub.4—NaCl or UCl.sub.3—NaCl fuel salt composition from UCl.sub.4—NaCl.

This disclosure describes systems and methods for synthesizing UCl.sub.3 from UCl.sub.4. These systems and methods may also be used to directly synthesize binary and ternary embodiments of uranium salts of chloride usable as nuclear fuel in certain molten salt reactor designs. The systems and methods described herein are capable of synthesizing any desired uranium chloride fuel salt that is a combination of UCl.sub.4, UCl.sub.3 and one or more non-fissile chloride compounds, such as NaCl. In particular, the systems and methods described herein are capable of synthesizing any UCl.sub.3—UCl.sub.4—NaCl or UCl.sub.3—NaCl fuel salt composition from UCl.sub.4—NaCl.

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.

A passive nuclear reactor control device. The passive nuclear reactor control device comprises a sealed chamber, which comprises a reservoir and a tube in fluid communication with the reservoir. A molten salt is within the sealed chamber, the molten salt being a eutectic mixture of a monovalent metal halide, and a fluoride or chloride of one or more lanthanides and/or a luoride or chloride of hafnium. A gas is within the sealed chamber, and the gas does not react with the molten salt.

A passive nuclear reactor control device. The passive nuclear reactor control device comprises a sealed chamber, which comprises a reservoir and a tube in fluid communication with the reservoir. A molten salt is within the sealed chamber, the molten salt being a eutectic mixture of a monovalent metal halide, and a fluoride or chloride of one or more lanthanides and/or a luoride or chloride of hafnium. A gas is within the sealed chamber, and the gas does not react with the molten salt.

An anti-proliferation technique is disclosed to reduce the likelihood of nuclear proliferation due to the use fissionable fuel salts. The technique includes doping the fuel salt with one or more elements (referred to herein as activation dopants) that, upon exposure to neutrons such as would occur in the fuel salt when a reactor is in operation, undergo a nuclear reaction to, directly or indirectly, form highly active “protecting isotopes” (of the same element as the activation dopant or a different element). A sufficient mass of activation dopants is used so that the Figure of Merit (FOM) of the fuel salt is decreased to below 1.0 within some target number of days of fission. This allows the FOM of the fuel salt to be controlled so that the fuel becomes too dangerous to handle before to the creation of a significant amount of weaponizable isotopes.