Abstract: A method of removing cesium vapor from a cover gas stream in a nuclear reactor includes the steps of oxidizing the cesium vapor in the cover gas stream to yield cesium oxide particles and removing the cesium oxide particles using a particle filter. The method yields a filtered cover gas having zero to about 2% of the cesium vapor content of the initial cover gas stream, representing a reduction of at least about 98 percent.

Abstract: 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 core, inserted into a sodium removal machine having a receiver, a cleaning vessel, and an elevator. A cleaning fluid is applied to the cleaning vessel and fuel assembly, and the fuel assembly is flushed with water while in the cleaning vessel. The cleaning vessel is at least partially submerged in the spent fuel pool during cleaning to provide passive heat removal. The cleaning vessel is lowered by an elevator into the spent fuel pool. The fuel assembly may then be loaded into a rack and/or a cask for long-term storage.

Abstract: A method of removing cesium vapor from a cover gas stream in a nuclear reactor includes the steps of oxidizing the cesium vapor in the cover gas stream to yield cesium oxide particles and removing the cesium oxide particles using a particle filter. The method yields a filtered cover gas having zero to about 2% of the cesium vapor content of the initial cover gas stream, representing a reduction of at least about 98 percent.

Abstract: 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.

Abstract: A failed fuel pin emits cesium into the primary sodium coolant and xenon into the cover gas in a reactor vessel. A pipe containing radioactive liquid sodium accepts flowing primary sodium from the reactor vessel. A radiation detector is positioned adjacent the pipe such that gamma radiation emitted from the pipe can be measured. The pipe may be isolated to increase detection limits by allowing short-lived isotopes to decay. The isotopic ratio of 137Cs/134Cs can be measured, which can be used to determine the burnup of a fuel assembly from within the core, and therefore, the failed fuel assembly can be identified based at least in part on the burnup. Further, mass spectrometry may be used to measure the ratio of a stable and unstable xenon isotope. The identification techniques may be used in conjunction to quickly identify a failed fuel assembly in-situ and during reactor operation.

Abstract: A method for replacing a cesium trap includes freezing the cesium trap which partially contains cesium and is located within a shielded cell and. The cesium trap is then decoupled and removed from the shielded cell. A second cesium trap is inserted into the shielded cell and attached to the shielded cell.

Abstract: Methods and systems for stabilizing spent fuel assemblies from sodium-cooled nuclear reactors using Zamak are described herein. It has been determined that there is a synergism between Zamak and sodium that allows Zamak to form thermally-conductive interface with the sodium-wetted surfaces of the fuel assemblies. In the method, one or more spent fuel assemblies are removed from the sodium coolant pool and placed in a protective sheath. The remaining volume of the sheath is then filled with liquid Zamak. To a certain extent Zamak will dissolve and alloy with sodium remaining on the fuel assemblies. Excess sodium that remains undissolved is displaced from the sheath by the Zamak fill. The Zamak is then cooled until solid and the sheath sealed. The resulting Zamak-stabilized spent fuel assembly is calculated to have sufficient internal thermal conductivity to allow it to be stored and transported without the need for liquid cooling.

Abstract: 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 core, inserted into a sodium removal machine having a receiver, a cleaning vessel, and an elevator. A cleaning fluid is applied to the cleaning vessel and fuel assembly, and the fuel assembly is flushed with water while in the cleaning vessel. The cleaning vessel is at least partially submerged in the spent fuel pool during cleaning to provide passive heat removal. The cleaning vessel is lowered by an elevator into the spent fuel pool. The fuel assembly may then be loaded into a rack and/or a cask for long-term storage.

Abstract: Methods and systems for stabilizing spent fuel assemblies from sodium-cooled nuclear reactors using Zamak are described herein. It has been determined that there is a synergism between Zamak and sodium that allows Zamak to form thermally-conductive interface with the sodium-wetted surfaces of the fuel assemblies. In the method, one or more spent fuel assemblies are removed from the sodium coolant pool and placed in a protective sheath. The remaining volume of the sheath is then filled with liquid Zamak. To a certain extent Zamak will dissolve and alloy with sodium remaining on the fuel assemblies. Excess sodium that remains undissolved is displaced from the sheath by the Zamak fill. The Zamak is then cooled until solid and the sheath sealed. The resulting Zamak-stabilized spent fuel assembly is calculated to have sufficient internal thermal conductivity to allow it to be stored and transported without the need for liquid cooling.

Abstract: 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.

Abstract: A method for replacing a cesium trap includes freezing the cesium trap which partially contains cesium and is located within a shielded cell and. The cesium trap is then decoupled and removed from the shielded cell. A second cesium trap is inserted into the shielded cell and attached to the shielded cell.

Abstract: A method for replacing a cesium trap includes freezing the cesium trap which partially contains cesium and is located within a shielded cell and. The cesium trap is then decoupled and removed from the shielded cell. A second cesium trap is inserted into the shielded cell and attached to the shielded cell.

Abstract: A method for replacing a cesium trap includes freezing the cesium trap which partially contains cesium and is located within a shielded cell and. The cesium trap is then decoupled and removed from the shielded cell. A second cesium trap is inserted into the shielded cell and attached to the shielded cell.