The Reactor Group of the United Kingdom Atomic Energy Authority has developed a combined technique incorporating eddy-current testing and total gamma scanning to examine irradiated fuel pins from water-cooled reactors. This ndt techniqueis for fuel pins 3–4 m long and gives information on both cladding and fuel. The eddy-current testing not only detects any defects in the cladding including hydride concentration in Zircaloy but also estimates the size of small circumferential ridges in the cladding which form at the ends of the UO 2 pellets during irradiation. The total gamma scan measures shrinkage of the fuel stack and the formation of any gaps between pellets. The simultaneous use of both methods gives additional information on interaction between the fuel and its cladding which is useful if the behaviour of fuel pins is to be understood.