PRACTICAL METHODS OF MEASURING DIMENSIONS FROM NEUTRON RADIOGRAPHS OF NUCLEAR-REACTOR FUEL

The importance of measuring dimensions from neutron radiographs of nuclear reactor fuel is explained. Measurements are taken using either a profile projector or a traveling microdensitometer. Neutron radiographs are made by the direct, transfer, and track-etch techniques, the last two being used for radioactive objects such as spent reactor fuel. The accuracy of these measurements was investigated during the Euratom Neutron Radiography Working Group Test Program. Measuring results are discussed for different kinds of nuclear fuel pin dimensions and 30 different combinations of recording materials. The accuracy of the measurements is assessed by calculating standard deviations between the dimensions determined from neutron radiographs and the true dimensions of a calibration fuel pin.