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.

The invention relates to the nuclear energy field, including pressurized water reactor containment internal passive heat removal systems. The invention increases heat removal efficiency, flow stability in the circuit, and system reliability. The system has at least one cooling water circulation circuit comprising a heat exchanger inside the containment and including an upper and lower header interconnected by heat-exchange tubes, a riser pipeline and a downtake pipeline connected to the heat exchanger, a cooling water supply tank above the heat exchanger outside the containment and connected to the downtake pipeline, a steam relief valve connected to the riser pipeline and located in the water supply tank and hydraulically connected to the latter. The upper and lower header of the heat exchanger are divided into heat exchange tube sections on the assumption that: L/D≦20, L being the header section length, D being the header bore.

A nuclear reactor cooled by liquid metal incorporating a passive system for evacuation of the decay heat with a phase change material thermal reservoir and a removable thermally-insulating layer around the phase change material reservoir. A nuclear reactor incorporates an integral system that guarantees: totally passive evacuation of decay heat from the initial moment of the accident; evacuation of power via the primary containment vessel; the presence of a final cold source with a reservoir incorporating an integral exchanger divided into a plurality of parallel tubes between which a phase change material is inserted, the reservoir being surrounded by a thermally-insulating layer that can be detached in a passive manner in the event of reaching a predetermined threshold temperature.

A closed loop heat convection cooling system for nuclear reactors. The cooling system is formed outside the containment structure of the nuclear reactor and the structure of the cooling system prevents gas that is not in the closed circuit to approach the reactor within neutron radiation distance. The cooling systems has cooling assemblies that are housed in protective structures, which shield the cooling assemblies for projectile impact. Air inlet and outlet apertures are formed in the protective structures to cause outside air to be drawn into the protective structures to cool the cooling assemblies.

A closed loop heat convection cooling system for nuclear reactors. The cooling system is formed outside the containment structure of the nuclear reactor and the structure of the cooling system prevents gas that is not in the closed circuit to approach the reactor within neutron radiation distance. The cooling systems has cooling assemblies that are housed in protective structures, which shield the cooling assemblies for projectile impact. Air inlet and outlet apertures are formed in the protective structures to cause outside air to be drawn into the protective structures to cool the cooling assemblies.

A representative cooling system for a nuclear reactor control rod drive mechanism (CRDM) includes an evaporation section located within or next to the CRDM and a condensation section fluidly coupled to the evaporation section. The cooling system includes a set of heat fins coupled to drive coils in the CRDM and heat pipes that extend through the drive coils and heat fins. A fluid evaporates while in the evaporation section of the heat pipes from heat generated by the CRDM and moves out of the evaporation section into the condensation section in the heat fins. The fluid cools and condensates while in the condensation section, recirculating back into the evaporation section. This passive natural circulation cooling system reduces or eliminates the number of water hoses, piping, and other water pumping equipment typically used for cooling a CRDM thereby increasing nuclear reactor reliability and simplifying nuclear reactor operation and maintenance.

A nuclear power generation system includes a nuclear reactor that includes a reactor core fuel and a nuclear reactor vessel, the nuclear reactor vessel covering a surrounding of the reactor core fuel, shielding a space in which the reactor core fuel is present, and shielding radioactive rays; a heat conductive portion that is disposed in at least a part of the nuclear reactor vessel to transfer heat inside the nuclear reactor vessel to an outside by solid heat conduction; a heat exchanger that performs heat exchange between the heat conductive portion and a refrigerant; a refrigerant circulation unit that circulates the refrigerant passing through the heat exchanger; a turbine that is rotated by the refrigerant circulated by the refrigerant circulation unit; and a generator that rotates integrally with the turbine.

Provided herein is a liner that can be loosely inserted in process pipe to form a lined pipe and to decrease the rate of heat transfer between process fluids flowing through the liner and the process pipe. The liner provided herein can reduce applied thermal loading on the outer pipe resulting from, for example, turbulent mixing between fluids having different temperatures (with or without stratification), circumferential thermal gradients, and/or longitudinal thermal gradients. An annulus between the process pipe and liner can be at least partially filled by process fluids, thereby creating a thermal buffer to further decrease the rate of heat transfer between the fluids and the process pipe.

A printed circuit heat exchanger for use in a reactor includes a core formed from a stack of plates diffusion bonded together. The core has: a top face, a bottom face disposed opposite the top face, a first side face extending between the top face and the bottom face, and a second side face disposed opposite the first side face. The printed circuit heat exchanger includes: a plurality of primary channels defined in the core, each of the primary channels extending from a primary inlet defined in the first side face to a primary outlet defined in the second side face; and a plurality of secondary channels defined in the core, each of the secondary channels extending among at least some of the primary channels from a secondary inlet defined in the top face to a secondary outlet defined in the top face.

A printed circuit heat exchanger for use in a reactor includes a core formed from a stack of plates diffusion bonded together. The core has: a top face, a bottom face disposed opposite the top face, a first side face extending between the top face and the bottom face, and a second side face disposed opposite the first side face. The printed circuit heat exchanger includes: a plurality of primary channels defined in the core, each of the primary channels extending from a primary inlet defined in the first side face to a primary outlet defined in the second side face; and a plurality of secondary channels defined in the core, each of the secondary channels extending among at least some of the primary channels from a secondary inlet defined in the top face to a secondary outlet defined in the top face.