The invention relates to a device for performing a leak test on a fuel rod capsule, which contains at least one fuel rod and test gas, which device comprises a test container, which is designed to accommodate at least one fuel rod capsule and can be lowered into a pool of a nuclear plant flooded with water. According to the invention, a mass spectrometer is fluidically connected to the interior of the test container in such a way that a gas flow can be fed to the mass spectrometer in order to sense the concentration of the test gas that has diffused into the test container from the fuel rod capsule.

The invention relates to a device for performing a leak test on a fuel rod capsule, which contains at least one fuel rod and test gas, which device comprises a test container, which is designed to accommodate at least one fuel rod capsule and can be lowered into a pool of a nuclear plant flooded with water. According to the invention, a mass spectrometer is fluidically connected to the interior of the test container in such a way that a gas flow can be fed to the mass spectrometer in order to sense the concentration of the test gas that has diffused into the test container from the fuel rod capsule.

Method for long-term dry storage of spent nuclear fuel includes injecting the inert gas into a cavity formed in a cask between inner and outer lids under pressure greater than the pressure of the inert gas in the inner cavity of the cask in which the spent nuclear fuel is located. The cask contains a body with a spent nuclear fuel container placed in it, tight inner and outer lids forming a cavity into which the inert gas is pumped under pressure greater than the pressure in the inner cavity of the cask. The outer lid comprises a labyrinth hole closed with a flange and sealed with a gasket. The flange comprises an angle valve, to which at least two pressure sensors are connected. The angle valve and sensors are covered with a protective cover during long-term storage. The gasket is installed in an annular groove of the lower flange.

Method for long-term dry storage of spent nuclear fuel includes injecting the inert gas into a cavity formed in a cask between inner and outer lids under pressure greater than the pressure of the inert gas in the inner cavity of the cask in which the spent nuclear fuel is located. The cask contains a body with a spent nuclear fuel container placed in it, tight inner and outer lids forming a cavity into which the inert gas is pumped under pressure greater than the pressure in the inner cavity of the cask. The outer lid comprises a labyrinth hole closed with a flange and sealed with a gasket. The flange comprises an angle valve, to which at least two pressure sensors are connected. The angle valve and sensors are covered with a protective cover during long-term storage. The gasket is installed in an annular groove of the lower flange.

Methods and systems for detecting an individual leaking fuel channel included in a reactor. One system includes a plurality of inlet lines and a plurality of outlet lines. Each of the plurality of inlet lines feeding annulus fluid in parallel to an annulus space of each of a first plurality of fuel channels included in the reactor, and each of the plurality of outlet lines collecting in parallel annulus fluid exiting an annulus space of each of a second plurality of fuel channels included in the reactor. In some embodiments, the system also includes a detector positioned at an outlet of each of the plurality of outlet lines configured to detect moisture in annulus fluid and identify a first position of an individual leaking fuel channel, and an isolation valve positioned at an inlet of each of the plurality of inlet lines operable to stop annulus fluid from circulating through one of the plurality of inlet lines and to identify a second position of the individual leaking fuel channel.

A leakage testing device for testing leakage of a nuclear fuel assembly (18) by sipping. The device includes a collection assembly (32) that is configured to close an upper end (24A) of a cell (24) of a storage rack (22) for storing nuclear fuel assemblies discharged from a nuclear reactor (4). The closing prevents water contained in the cell from escaping via the upper end of the cell. The collection assembly is configured to collect products containing possible fission products released by a nuclear fuel assembly contained in the cell.

A leakage testing device for testing leakage of a nuclear fuel assembly (18) by sipping. The device includes a collection assembly (32) that is configured to close an upper end (24A) of a cell (24) of a storage rack (22) for storing nuclear fuel assemblies discharged from a nuclear reactor (4). The closing prevents water contained in the cell from escaping via the upper end of the cell. The collection assembly is configured to collect products containing possible fission products released by a nuclear fuel assembly contained in the cell.

A system for monitoring fissile material contents inside of a nuclear reactor can include at least a first neutron detector positioned outside a radiation shield and configured to detect a plurality of neutrons originating from the reactor core and having passed through the radiation shield, and configured to generate a first output signal, and a controller communicably linked to the first neutron detector to receive the first output signal and a power output of the nuclear reactor.

A system for monitoring fissile material contents inside of a nuclear reactor can include at least a first neutron detector positioned outside a radiation shield and configured to detect a plurality of neutrons originating from the reactor core and having passed through the radiation shield, and configured to generate a first output signal, and a controller communicably linked to the first neutron detector to receive the first output signal and a power output of the nuclear reactor.

A method and system detects failures in nuclear fuel assemblies (600). A water treatment device degasses/removes fission gases from water used in the canister (500) of a vacuum sipping device (30). A sipping procedure then detects a failure in a fuel assembly in the canister. The degassing improves a signal-to-noise ratio of the detector used during the sipping process, and improves the failure detection sensitivity of the system. Additionally and/or alternatively, gas may be recirculated through the canister water before the vacuum is applied so that fission gas concentration in the recirculating gas reaches a baseline equilibrium with the canister water. The vacuum is thereafter applied and the sipping procedure proceeds such that an increase in detected radioactivity over the baseline equilibrium indicates a leak in the fuel assembly.