Procedure and apparatus for determining the combustion factor of a nuclear reactor fuel assembly uses marker rod placed in assembly prior to loading into reactor core

摘要

The procedure for determining the combustion factor of a fuel rod assembly from gamma ray emission consists of introducing at least one marker rod (7) into the assembly (3) before it is loaded into the reactor core, extracting the marker rod after the assembly has spent some time in the core, and measuring its gamma ray emission in pulses per second by means of a photon detector (17) and a collimator (19) with a straight duct having one end close to the marker rod and the other adjacent to the detector. The marker rod is moved in an axial direction to enable measurements to be carried out in a series of zones along its length.