Apparatuses for reducing or eliminating Type 1 LOCAs in a nuclear reactor vessel. A nuclear reactor including a nuclear reactor core comprising a fissile material, a pressure vessel containing the nuclear reactor core immersed in primary coolant disposed in the pressure vessel, and an isolation valve assembly including, an isolation valve vessel having a single open end with a flange, a spool piece having a first flange secured to a wall of the pressure vessel and a second flange secured to the flange of the isolation valve vessel, a fluid flow line passing through the spool piece to conduct fluid flow into or out of the first flange wherein a portion of the fluid flow line is disposed in the isolation valve vessel, and at least one valve disposed in the isolation valve vessel and operatively connected with the fluid flow line.

Apparatuses for reducing or eliminating Type 1 LOCAs in a nuclear reactor vessel. A nuclear reactor including a nuclear reactor core comprising a fissile material, a pressure vessel containing the nuclear reactor core immersed in primary coolant disposed in the pressure vessel, and an isolation valve assembly including, an isolation valve vessel having a single open end with a flange, a spool piece having a first flange secured to a wall of the pressure vessel and a second flange secured to the flange of the isolation valve vessel, a fluid flow line passing through the spool piece to conduct fluid flow into or out of the first flange wherein a portion of the fluid flow line is disposed in the isolation valve vessel, and at least one valve disposed in the isolation valve vessel and operatively connected with the fluid flow line.

A handling device for a nuclear fuel assembly includes a body; gripping means capable of cooperating with a fuel assembly so as to grasp or release the assembly; control means for controlling the gripping means capable of controlling the gripping means between a grasping position and a releasing position of the assembly, and vice versa; suction means capable of generating a suction of a cooling gas through the handling device and through the assembly when it is grasped by the device. A handling assembly for a nuclear fuel assembly, comprising: a handling device, a receiving support capable of receiving a fuel assembly and capable of cooperating with the handling device.

A handling device for a nuclear fuel assembly includes a body; gripping means capable of cooperating with a fuel assembly so as to grasp or release the assembly; control means for controlling the gripping means capable of controlling the gripping means between a grasping position and a releasing position of the assembly, and vice versa; suction means capable of generating a suction of a cooling gas through the handling device and through the assembly when it is grasped by the device. A handling assembly for a nuclear fuel assembly, comprising: a handling device, a receiving support capable of receiving a fuel assembly and capable of cooperating with the handling device.

A cooling air amount adjustment device of a concrete cask is provided. The device includes at least one of an air outlet port opening level adjustment mechanism and an air inlet port opening level adjustment mechanism which are adapted to automatically perform adjustment to reduce a flow rate of a cooling air when a temperature of the cooling air at an air outlet port is lower than an adjustment reference temperature, and adjustment to increase the flow rate of the cooling air so as to restore the flow rate of the cooling air when the temperature of the cooling air at the air outlet port is higher than the adjustment reference temperature.

A cooling air amount adjustment device of a concrete cask is provided. The device includes at least one of an air outlet port opening level adjustment mechanism and an air inlet port opening level adjustment mechanism which are adapted to automatically perform adjustment to reduce a flow rate of a cooling air when a temperature of the cooling air at an air outlet port is lower than an adjustment reference temperature, and adjustment to increase the flow rate of the cooling air so as to restore the flow rate of the cooling air when the temperature of the cooling air at the air outlet port is higher than the adjustment reference temperature.

Apparatuses for reducing or eliminating Type 1 LOCAs in a nuclear reactor vessel. A nuclear reactor including a nuclear reactor core comprising a fissile material, a pressure vessel containing the nuclear reactor core immersed in primary coolant disposed in the pressure vessel, and an isolation valve assembly including, an isolation valve vessel having a single open end with a flange, a spool piece having a first flange secured to a wall of the pressure vessel and a second flange secured to the flange of the isolation valve vessel, a fluid flow line passing through the spool piece to conduct fluid flow into or out of the first flange wherein a portion of the fluid flow line is disposed in the isolation valve vessel, and at least one valve disposed in the isolation valve vessel and operatively connected with the fluid flow line.

Apparatuses for reducing or eliminating Type 1 LOCAs in a nuclear reactor vessel. A nuclear reactor including a nuclear reactor core comprising a fissile material, a pressure vessel containing the nuclear reactor core immersed in primary coolant disposed in the pressure vessel, and an isolation valve assembly including, an isolation valve vessel having a single open end with a flange, a spool piece having a first flange secured to a wall of the pressure vessel and a second flange secured to the flange of the isolation valve vessel, a fluid flow line passing through the spool piece to conduct fluid flow into or out of the first flange wherein a portion of the fluid flow line is disposed in the isolation valve vessel, and at least one valve disposed in the isolation valve vessel and operatively connected with the fluid flow line.

System for storing radioactive materials comprising: —a canister (4) containing radioactive waste; —a container (C), provided with a casing (1), a base (2) and a cover (3), and a passive helicoidal convection-based ventilation system provided with: lower air inlets (5); an area (6) of air circulation between the canister (4) and the inner surface of the container (C), and upper air outlets (7); the inlets (5) and outlets (7) have a decreasing variation of section in the direction of air circulation, are curved and facing an oblique direction with respect to the radial direction of the container, the air between said inlets (5) and outlets (7) describing an upward helicoidal path around the capsule or canister (4).

A nuclear reactor is configured with an intermediate coolant loop for transferring thermal energy from the reactor core for a useful purpose. The intermediate coolant loop includes a bypass flowpath with an air heat exchanger for dumping reactor heat during startup and/or shutdown. A fluidic diode along the bypass flowpath asymmetrically restricts flow across the bypass flowpath, inhibiting flow in a first flow direction during a full power operating condition and allowing a relatively uninhibited flow in a second direction during a startup and/or shut down low power operating condition.