Abstract: A spacer grid welding fixture comprises a frame sized to receive an assembled spacer grid comprising a first set of parallel straps and a second set of parallel straps oriented orthogonally to the first set of parallel straps, the first and second sets of parallel straps interlocked together by slots cut into the straps. A first set of grid engagement bars is placed on a first side of the spacer grid with each grid engagement bar arranged parallel with the straps of the first set of parallel straps and engaging the straps of the second set of parallel straps. A second set of grid engagement bars is placed on an opposite second side of the spacer grid with each grid engagement bar arranged parallel with the straps of the second set of parallel straps and engaging the straps of the first set of parallel straps.

Abstract: A spacer grid welding fixture comprises a frame sized to receive an assembled spacer grid comprising a first set of parallel straps and a second set of parallel straps oriented orthogonally to the first set of parallel straps, the first and second sets of parallel straps interlocked together by slots cut into the straps. A first set of grid engagement bars is placed on a first side of the spacer grid with each grid engagement bar arranged parallel with the straps of the first set of parallel straps and engaging the straps of the second set of parallel straps. A second set of grid engagement bars is placed on an opposite second side of the spacer grid with each grid engagement bar arranged parallel with the straps of the second set of parallel straps and engaging the straps of the first set of parallel straps.

Abstract: A spacer grid welding fixture comprises a frame sized to receive an assembled spacer grid comprising a first set of parallel straps and a second set of parallel straps oriented orthogonally to the first set of parallel straps, the first and second sets of parallel straps interlocked together by slots cut into the straps. A first set of grid engagement bars is placed on a first side of the spacer grid with each grid engagement bar arranged parallel with the straps of the first set of parallel straps and engaging the straps of the second set of parallel straps. A second set of grid engagement bars is placed on an opposite second side of the spacer grid with each grid engagement bar arranged parallel with the straps of the second set of parallel straps and engaging the straps of the first set of parallel straps.

Abstract: A spacer grid welding fixture comprises a frame sized to receive an assembled spacer grid comprising a first set of parallel straps and a second set of parallel straps oriented orthogonally to the first set of parallel straps, the first and second sets of parallel straps interlocked together by slots cut into the straps. A first set of grid engagement bars is placed on a first side of the spacer grid with each grid engagement bar arranged parallel with the straps of the first set of parallel straps and engaging the straps of the second set of parallel straps. A second set of grid engagement bars is placed on an opposite second side of the spacer grid with each grid engagement bar arranged parallel with the straps of the second set of parallel straps and engaging the straps of the first set of parallel straps.

Abstract: A spacer grid welding fixture comprises a frame sized to receive an assembled spacer grid comprising a first set of parallel straps and a second set of parallel straps oriented orthogonally to the first set of parallel straps, the first and second sets of parallel straps interlocked together by slots cut into the straps. A first set of grid engagement bars is placed on a first side of the spacer grid with each grid engagement bar arranged parallel with the straps of the first set of parallel straps and engaging the straps of the second set of parallel straps. A second set of grid engagement bars is placed on an opposite second side of the spacer grid with each grid engagement bar arranged parallel with the straps of the second set of parallel straps and engaging the straps of the first set of parallel straps.

Abstract: A spacer grid welding fixture comprises a frame sized to receive an assembled spacer grid comprising a first set of parallel straps and a second set of parallel straps oriented orthogonally to the first set of parallel straps, the first and second sets of parallel straps interlocked together by slots cut into the straps. A first set of grid engagement bars is placed on a first side of the spacer grid with each grid engagement bar arranged parallel with the straps of the first set of parallel straps and engaging the straps of the second set of parallel straps. A second set of grid engagement bars is placed on an opposite second side of the spacer grid with each grid engagement bar arranged parallel with the straps of the second set of parallel straps and engaging the straps of the first set of parallel straps.

Abstract: A process chamber is configured to contain a work piece in a controlled atmosphere and to perform a process that emits pyrophoric particulates. A closed recirculating loop connected with the process chamber recirculates gas defining the controlled atmosphere through the process chamber. A filter in the closed recirculating loop captures the generated pyrophoric particulates in the recirculating gas. A valve set has a work configuration defining the closed recirculating loop including the connection of the process chamber with the filter, and a filter regeneration configuration in which the filter is blocked off from the process chamber and is connected with an exhaust. A work piece is loaded into the process chamber. With the valve set in the work configuration, the process is performed on the loaded work piece. Thereafter, regeneration gas containing oxygen is delivered to the filter with the valve set in the regeneration configuration.

Abstract: A pedestal plug is sized to fit into a cladding of a nuclear fuel rod. A lower end plug is sized and shaped to plug the lower end of the nuclear fuel rod. One of the pedestal plug and the lower end plug includes a protrusion and the other of the pedestal plug and the lower end plug includes a hollow region into which the protrusion fits. In one embodiment the pedestal plug is a hollow cylindrical pedestal plug and the protrusion is disposed on the lower end plug. The protrusion disposed on the lower end plug suitably press fits into the hollow cylindrical pedestal plug. In a method of assembling a fuel rod of a nuclear reactor, the pedestal plug and the lower end plug are press fit together, and after the press fitting the lower end plug is welded to a cladding of the fuel rod with the pedestal plug disposed inside the cladding.

Abstract: A process chamber is configured to contain a work piece in a controlled atmosphere and to perform a process that emits pyrophoric particulates. A closed recirculating loop connected with the process chamber recirculates gas defining the controlled atmosphere through the process chamber. A filter in the closed recirculating loop captures the generated pyrophoric particulates in the recirculating gas. A valve set has a work configuration defining the closed recirculating loop including the connection of the process chamber with the filter, and a filter regeneration configuration in which the filter is blocked off from the process chamber and is connected with an exhaust. A work piece is loaded into the process chamber. With the valve set in the work configuration, the process is performed on the loaded work piece. Thereafter, regeneration gas containing oxygen is delivered to the filter with the valve set in the regeneration configuration.