A method for calculating a PCI margin associated with a loading pattern of a nuclear reactor including a core into which fuel assemblies are loaded according to the loading pattern is implemented by an electronic system. The fuel assemblies include fuel rods each including fuel pellets of nuclear fuel and a cladding surrounding the pellets. This method includes calculating a reference principal PCI margin for a reference loading pattern of the fuel assemblies in the core; calculating a reference secondary PCI margin for the reference pattern; calculating a modified secondary PCI margin for a modified loading pattern of the fuel assemblies in the core, and calculating a modified principal PCI margin for the modified pattern, depending on a comparison of the modified secondary PCI margin with the reference secondary PCI margin.

A nuclear-power-plant computer-based procedure display device is disposed in a main control room of a nuclear power plant, and includes a operating procedure storage unit that stores a computer-based procedure in which plant operation procedures of the nuclear power plant are divided into procedure steps and listed, a operating procedure display unit that displays the computer-based procedure, and a operating procedure display control unit that controls display of the computer-based procedure. In a case where the procedure step displayed on the operating procedure display unit is selected by an operator, the operating procedure display control unit displays an indication that the procedure step is selected, on the operating procedure display unit.

A nuclear-power-plant computer-based procedure display device is disposed in a main control room of a nuclear power plant, and includes a operating procedure storage unit that stores a computer-based procedure in which plant operation procedures of the nuclear power plant are divided into procedure steps and listed, a operating procedure display unit that displays the computer-based procedure, and a operating procedure display control unit that controls display of the computer-based procedure. In a case where the procedure step displayed on the operating procedure display unit is selected by an operator, the operating procedure display control unit displays an indication that the procedure step is selected, on the operating procedure display unit.

Disclosed are a radioisotope activity surveillance system and methods. The system includes a fuel rod assembly having a plurality of nuclear fuel rods and a target assembly having a top nozzle including an orifice plate and at least one target material rod fixedly coupled to the orifice plate. The least one target material rod is slidably disposed within the fuel rod assembly. A sensing assembly defines an opening sized and configured to receive the target assembly therethrough. The sensing assembly includes a self-powered detector assembly to detect radioisotope activity of the target rod material. Also disclosed is a method for measuring a self-powered detector signal to calculate radioisotope activity of a target assembly and a method for analyzing total activity of a desired radioisotope.

A method of measuring moisture carryover (MCO) in a nuclear reactor includes placing a first gamma detector adjacent to a steam conduit configured to transport steam generated by the core. The method additionally includes detecting a first amount of carryover gamma activity of a first quantity of sodium-24 in the steam within the steam conduit with the first gamma detector. The method also includes detecting a second amount of reference gamma activity of a second quantity of sodium-24 in a reference sample of reactor water from the core with a second gamma detector. The method further includes determining a flow rate of liquid water entrained in the steam based on the first amount of carryover gamma activity detected by the first gamma detector and the second amount of reference gamma activity detected by the second gamma detector.

A nuclear reactor protection system includes a plurality of functionally independent modules, each of the modules configured to receive a plurality of inputs from a nuclear reactor safety system, and logically determine a safety action based at least in part on the plurality of inputs; and one or more nuclear reactor safety actuators communicably coupled to the plurality of functionally independent modules to receive the safety action determination based at least in part on the plurality of inputs.

A multi-loop natural circulation experimental device under six-degree-of-freedom motion conditions and a method therefor are provided. The device includes: a six-degree-of-freedom motion simulation platform; a multi-loop main circulation loop including a serpentine pre-heater, an experimental section, two sleeve-type condensers, and a pressurized circulating pump, a voltage stabilizer and related equipment; and a cooling water system including a sleeve condenser, a plate heat exchanger, a cooling tower, a cooling fan, a cooling water tank and related equipment; and an electric heating system including a DC power supply, a low voltage power controller and a transformer. The present invention also provides an experimental method of the device.

Disclosed is a system for sensing a UF.sub.6 gas leak in a nuclear fuel manufacturing process. The system is configured to sense whether or not there is a UF.sub.6 gas leak by optically detecting UO.sub.2F.sub.2 in a solid state generated due to a reaction with outside air. This allows prevention of damage to a detection apparatus by means of sensing in a non-contact manner whether or not there is a UF.sub.6 gas leak. Further, the system extends the mechanical life of and reduces the maintenance and repair costs for the detection apparatus.

A self-powered nuclear radiation detector. The self-powered nuclear radiation detector includes a cable assembly, a temperature compensation assembly, and a metallic outer sheath. The cable assembly includes a metallic signal lead, an insulative material surrounding the metallic signal lead, and a metallic sheath surrounding the insulative material. The temperature compensation assembly includes a second metallic signal lead, a second insulative material surrounding the second metallic signal lead, and a second metallic sheath surrounding the second insulative material. The metallic outer sheath surrounds the cable assembly and the temperature compensation assembly.

A self-powered nuclear radiation detector. The self-powered nuclear radiation detector includes a cable assembly, a temperature compensation assembly, and a metallic outer sheath. The cable assembly includes a metallic signal lead, an insulative material surrounding the metallic signal lead, and a metallic sheath surrounding the insulative material. The temperature compensation assembly includes a second metallic signal lead, a second insulative material surrounding the second metallic signal lead, and a second metallic sheath surrounding the second insulative material. The metallic outer sheath surrounds the cable assembly and the temperature compensation assembly.