Abstract: A spacer grid for PWR assemblies is characterized by curved flow channels between adjacent fuel rods and straight, essentially flat strips connecting opposite side plates of the spacer. The latter strips prevent bowing-out of the side plates during fuel assembly fabrication and during operation in the reactor. Additionally, the spacer grid allows accurate positioning of the fuel rods on a square lattice with a precisely defined pitch, and support of the rods in their spacer cells is such that rod bow will be minimized. The direction of the nozzles on the flow channels has been chosen to promote cross-flow of the coolant through the assembly.
Abstract: A method for measuring the thickness of a layer of crud containing ferromagnetic material deposited on nuclear fuel rods using eddy current lift-off (coil-to-conductor spacing) measurement by exciting a probe coil at predetermined frequency which penetrates only into the layer of crud containing the ferromagnetic material.