Available post-irradiation examination techniques to evaluate the CANDU fuel performance

As part of the collaboration under the Romania - Canada Memorandum for Co-operation in research and development of nuclear energy and technology, a load following test has been devised to demonstrate the load following capability of CANDU-6 fuel within the established design envelope for operating powers. A 37-element CANDU-6 fuel bundle element fabricated by AECL was irradiated in the TRIGA 14 MW(th) material testing reactor at the Institute for Nuclear Research (INR) in Pitesti, Romania. The load following cycle consisted of 200 daily cycles from 100% power to 50% power within the reference overpower envelope for fuel in a CANDU-6 reactor. Full power operation was 57 kW/m Element Linear Power. The paper provides the results got by post-irradiation examination of the fuel element in the INR hot cells. The following techniques were used: - Visual inspection and photography by periscope; - Profilometry; - Axial gamma scanning; - Fuel element puncturing and fission gas analysis; - Metallographic and ceramographic examinations by optical microscopy; - Burn-up measurement by mass spectrometry using the 235U depletion method. (authors)