Nuclear fuel assembly for e.g. pressurized water reactor, has insert with inner diameter supported at fixed distance from inner diameter of instrumentation tube in segmented locations of tube, where insert centers instrument in reactor core

摘要

The assembly (20) has an elongated instrumentation tube (10) trapped between upper and lower nozzles (12, 14). The tube receives an instrument, in a core of a nuclear reactor, that remains fixed during the reactor operation. An insert i.e. spiral spring, of the tube has a narrow inner diameter in axial locations along its length, which narrows an outer diameter of the instrument. The inner diameter is supported at a fixed distance from an inner diameter of the tube in segmented locations spaced along interior and elongated dimension of the tube. The insert centers the instrument in the core.