In conjunction with a pressurized water reactor (PWR) and a pressurizer configured to control pressure in the reactor pressure vessel, a decay heat removal system comprises a pressurized passive condenser, a turbine-driven pump connected to suction water from at least one water source into the reactor pressure vessel; and steam piping configured to deliver steam from the pressurizer to the turbine to operate the pump and to discharge the delivered steam into the pressurized passive condenser. The pump and turbine may be mounted on a common shaft via which the turbine drives the pump. The at least one water source may include a refueling water storage tank (RWST) and/or the pressurized passive condenser. A pressurizer power operated relief valve may control discharge of a portion of the delivered steam bypassing the turbine into the pressurized passive condenser to control pressure in the pressurizer.

A method of handling spent nuclear fuel assemblies immerses the spent nuclear fuel assemblies in water in a relatively short time period when compared to traditional methods. A spent nuclear fuel assembly is removed from a nuclear reactor, an inert gas is applied to the fuel assembly, moisture content in the inert gas is gradually increased as it is applied to the fuel assembly, and the fuel assembly is immersed in water. The fuel assembly is immersed relatively quickly, within about 2 hours or less, which improves safety and allows normal processing and handling equipment to care for the fuel assembly. The fuel assembly may then be loaded into a cask for long-term storage and/or disposal.

A nuclear reactor includes a heat exchanger that transfers thermal energy from a primary reactor coolant to a secondary coolant. The heat exchanger is a compact plate heat exchanger and more than one heat exchanger may be spaced about the reactor vessel. A plurality of heat exchangers may be spaced vertically, radially, and/or circumferentially about the reactor vessel. A first heat exchanger may be in fluid communication with a second heat exchanger. Two or more heat exchangers may share a thermal load and therefore share thermal stresses. The heat exchanger may have a third fluid flow path and a third fluid. The third fluid may be used to remove fission products, be used for leak detection, create an oxidation layer to inhibit migration of activation products, and/or provide additional heat transfer.

A curvilinear electromagnetic pump is configured to follow a curve, such as by coupling multiple linear pump segments together that are offset by an angle with respect to each other. The curvilinear electromagnetic pump can curve within two dimensions, or within three dimensions. The curvilinear electromagnetic pump allows for more efficient arrangement of components and systems within a nuclear reactor vessel and allows a significantly reduced reactor vessel height as compared to a linear pump arranged vertically. The curvilinear electromagnetic pump may follow the curvature of the reactor vessel wall and may be entirely disposed near the bottom of the reactor vessel.

Power generation systems, such as nuclear power generation systems, are described herein. A representative power generation system includes a heat source, a heat pipe, and a thermophotovoltaic cell. The heat pipe includes a first region and a second region. The first region is positioned to absorb heat from the heat source, and the second region is positioned to radiate at least a portion of the absorbed heat away from the heat pipe as thermal radiation. The thermophotovoltaic cell is positioned to receive the thermal radiation from the second region of the heat pipe and to convert at least a portion of the thermal radiation to electrical energy. The power generation system can further include another heat pipe positioned to remove waste heat from the thermophotovoltaic cell.

A circuit arrangement, in particular for a safety I&C system of a nuclear power plant, keeps a proven diagram-centric project-specific engineering approach known from CPU-based systems while reaping the benefits of FPGA technology. To this end, the circuit arrangement includes: a generic FPGA with a plurality of logic blocks, and at least one dedicated PLD which operates as an application-specific switch-matrix for the logic blocks.

A method, system, and apparatus for the thermal storage of energy generated by multiple nuclear reactor systems including diverting a first selected portion of energy from a portion of a first nuclear reactor system of a plurality of nuclear reactor systems to at least one auxiliary thermal reservoir, diverting at least one additional selected portion of energy from a portion of at least one additional nuclear reactor system of the plurality of nuclear reactor systems to the at least one auxiliary thermal reservoir, and supplying at least a portion of thermal energy from the auxiliary thermal reservoir to an energy conversion system of a nuclear reactor of the plurality of nuclear reactors.

A method and apparatus for maintaining or establishing a readiness state in a fuel cell backup system of a nuclear reactor system are disclosed. A method includes maintaining a readiness state of a fuel cell system within a set of readiness parameters, the readiness parameters a function of a characteristic of the nuclear reactor system. Another method includes monitoring a nuclear reactor system characteristic and, responsive to the monitored nuclear reactor system characteristic, establishing a readiness state of a fuel cell system. An apparatus includes a fuel cell system associated with a nuclear reactor system and a fuel cell control system configured to maintain a readiness state of the fuel cell system. Another apparatus includes a fuel cell system associated with a nuclear reactor system, a nuclear reactor characteristic monitoring system, and a fuel cell control system configured to establish a readiness state of the fuel cell system.

A nuclear power plant control system (3) is provided with detection units (30a to 30d) which detect phenomena that occurs in a nuclear power plant for each of four systems, a trip control device (20) which starts, in the case where a signal that indicates an occurrence of the phenomenon is input from at least a predetermined number of signal lines out of signal lines of two systems, processing corresponding to the phenomenon, and majority circuits (50a and 50b) which are provided for each signal line of the two systems and each output, in the case where the phenomenon is detected by N or more detection units out of the detection units (30a to 30d), a signal that indicates an occurrence of the phenomenon to a corresponding signal line.

A device for separating a shielding slab for a heavy water reactor according to an embodiment includes: a body; a circular rail installed on at least one side of the body; and a decommissioner for decommissioning a shielding slab installed on the circular rail and installed on an inner wall of a heavy water reactor, wherein the decommissioner includes a decommission head moving on the circular rail, a separator installed in the decommission head and separating and desalinizing the shielding slab, and a gripper installed in the decommission head and gripping the separated shielding slab.