Volume conservation during irradiation growth of Zr-2.5Nb

Dimensional changes are reported in three dimensions for cold-worked Zr-2.5 Nb pressure tube material irradiated to a fast fluence of 174 x 10(24) nm(-2), E > 1 MeV at a nominal temperature of 250degreesC. The observed dimensional changes in the longitudinal and transverse directions (up to similar to1.2% and similar to-0.5%, respectively) are consistent with earlier data at 280degreesC and 310degreesC, and the previously reported negative temperature dependence. The observed growth in the radial direction is negative (up to similar to0.7%). Initially, there is a small volume increase (0.05-0.1%) but this gradually decays to < 0.05% and the long term rate of volume change is negligible, within the accuracy of the measurement, demonstrating that the phenomenon observed is, indeed, irradiation growth. (C) 2004 Elsevier B.V. All rights reserved.