An automated system for on-line monitoring and coil diagnostics of rod position indicator (RPI) coils coil diagnostic, or RPI coil diagnostic system. The RPI coil diagnostic system performs coil diagnostics for a RPI system in a nuclear power plant. The RPI coil diagnostic system is in electrical communication with and monitors the outputs of the detector coils. The RPI coil diagnostic system measures characteristics of the detector coils that are indicative of the health of the detector coils and/or the connections between the detector coils and the RPI electronics.

An automated system for on-line monitoring and coil diagnostics of rod position indicator (RPI) coils coil diagnostic, or RPI coil diagnostic system. The RPI coil diagnostic system performs coil diagnostics for a RPI system in a nuclear power plant. The RPI coil diagnostic system is in electrical communication with and monitors the outputs of the detector coils. The RPI coil diagnostic system measures characteristics of the detector coils that are indicative of the health of the detector coils and/or the connections between the detector coils and the RPI electronics.

A fast neutron nuclear reactor contains a nuclear reactor core having an array of device locations. Some device locations in the nuclear reactor core contain fissile and fertile nuclear fuel assembly devices. One or more other device locations in the nuclear reactor core contain Doppler reactivity augmentation devices that amplify the negativity of the Doppler reactivity coefficient within the nuclear reactor core. In some implementations, a Doppler reactivity augmentation device can also reduce the coolant temperature coefficient within the nuclear reactor core. Accordingly, a Doppler reactivity augmentation device contributes to a more stable nuclear reactor core.

A fast neutron nuclear reactor contains a nuclear reactor core having an array of device locations. Some device locations in the nuclear reactor core contain fissile and fertile nuclear fuel assembly devices. One or more other device locations in the nuclear reactor core contain Doppler reactivity augmentation devices that amplify the negativity of the Doppler reactivity coefficient within the nuclear reactor core. In some implementations, a Doppler reactivity augmentation device can also reduce the coolant temperature coefficient within the nuclear reactor core. Accordingly, a Doppler reactivity augmentation device contributes to a more stable nuclear reactor core.

Reactor core and thermal neutron fission reactor has fuel rods with a composite fuel composition (each having the same uniform cross-section along their axial length), end plates at first and second ends, and intermediate support plates located along a longitudinal length of the reactor core. In a radial cross-section, the fuel rods are arranged at nodes of a hexagonal pitch arrangement, in which the nodes are in a spaced-apart arrangement and interconnected by ligaments. Openings between the nodes form part of a coolant flow path through the thermal neutron reactor core. At least two of the nodes of the hexagonal pitch arrangement are sized to allow insertion, translation, removal, or a combination thereof of auxiliary equipment, such as a target delivery system (TDS) for isotopes. Thermal neutron flux (neutrons ≤0.06 eV) is maximized for maximum neutron activation potential, which is applied to produce both commercial and research isotopes.

A fast reactor core includes a sodium plenum installed above the fuel. The sodium plenum is capable of reducing a void reactivity. During operation, a tip of a primary control rod is inserted in a core fuel region, and a tip of a backup control rod is arranged near an upper end of the sodium plenum.

Disclosed is an apparatus, system, and method for monitoring a position of a control rod disposed in a nuclear reactor vessel in a radioactive environment. A data processing unit located outside a containment structure includes a processor and a memory storing executable instructions. A nuclear reactor vessel includes a plurality of control rods proximate to the control rod and a coil stack of a plurality of control rod position indicator coils. A data cabinet mounted on the nuclear reactor vessel head inside the containment structure includes an analog multiplexer and a communication circuit. The processor executes the instructions to select a control rod position indicator coil through the analog multiplexer, pass a signal from the control rod position indicator coil through the analog multiplexer, receive the signal from the analog multiplexer through the communication circuit, and determine a position of the control rod based on the received signal.

Disclosed is an apparatus, system, and method for monitoring a position of a control rod disposed in a nuclear reactor vessel in a radioactive environment. A data processing unit located outside a containment structure includes a processor and a memory storing executable instructions. A nuclear reactor vessel includes a plurality of control rods proximate to the control rod and a coil stack of a plurality of control rod position indicator coils. A data cabinet mounted on the nuclear reactor vessel head inside the containment structure includes an analog multiplexer and a communication circuit. The processor executes the instructions to select a control rod position indicator coil through the analog multiplexer, pass a signal from the control rod position indicator coil through the analog multiplexer, receive the signal from the analog multiplexer through the communication circuit, and determine a position of the control rod based on the received signal.

The present invention relates to a nuclear reactor, more precisely a passive safety device applicable to a thermal neutron reactor and a nuclear fuel assembly equipped with the same. The nuclear fuel assembly for a thermal neutron reactor of the present invention includes multiple fuel rods; multiple guide thimbles arranged between the fuel rods; and a passive safety device including neutron absorber parts which are inserted in one or more guide thimbles.

The present invention relates to a nuclear reactor, more precisely a passive safety device applicable to a thermal neutron reactor and a nuclear fuel assembly equipped with the same. The nuclear fuel assembly for a thermal neutron reactor of the present invention includes multiple fuel rods; multiple guide thimbles arranged between the fuel rods; and a passive safety device including neutron absorber parts which are inserted in one or more guide thimbles.