Pressure tube deformation is an important aging issue in operating heavy water reactors (HWRs) and the R&D community continues to develop improved predictive models for in-reactor deformation. To progress research on this topic, a coordinated research project on prediction of axial and radial creep in pressure tubes was conducted to investigate predictive model biases when applied to different reactor units and to gain new insights into the effects of operating conditions as well as microstructure/manufacturing effects. This publication documents the work performed and the results obtained by six participating Member States’ institutes, all with currently operating HWRs. The publication summarizes various modelling and predictive approaches considered for utilization within the nuclear industry in support of operating reactors. The findings offer some direction for incorporating the intrinsic material properties into the predictive models needed for pressure tube service life management.