Associate professor, University of Windsor, Windsor, Ontario
Pages: 15 Published: Jan 1979
Irradiation growth, which is defined as irradiation-induced changes in dimensions in the absence of an applied stress, is of concern both for fuel cladding and nuclear reactor structural components such as pressure tubes and calandria tubes. Many mechanistic models have been advanced to account for this phenomenon, and considerable controversy exists as to the precise mechanism. In this paper, these mechanistic models are reviewed in the light of recent electron microscope observations of the irradiation-induced damage state. It is concluded that the mechanism for growth is not as simple as was first postulated, but that there are a number of sources contributing to the overall shape change. The major sources contributing to growth of annealed materials are depleted zones, vacancy loops, and interstitial loops. For cold-worked materials, there are also contributions to the growth arising from dislocation climb, dislocation climb and glide, and relaxation of residual stresses. In order to quantify these mechanistic models, experiments are needed where accurate length measurements are made in three orthogonal directions, and detailed transmission electron microscopy and field ion microscopy are done on the same material (as the growth measurements) so as to eliminate specimen and irradiation variables.
zirconium, zirconium alloys, irradiation growth, neutron irradiation, radiation damage, electron microscopy, residual stresses, texture
Paper ID: STP38158S