Book Description

The irradiation creep and growth behavior of zirconium alloys has been studied during irradiation with 3.5-MeV protons. Irradiations were carried out at temperatures in the range 423 to 623 K and strain measurements were recorded up to displacement levels of 0.03 displacements per atom (dpa). In annealed materials, a significant portion of the measured strain could be attributed to the presence of dislocation loops. The measured growth strain was found to be dependent on texture, grain dimensions, network dislocation structure (cold work), and temperature. Experiments to separate the irradiation creep and growth components of the total strain revealed that irradiation growth was by far the most significant component in cold-worked zirconium-niobium alloys but that the two components were approximately equal in annealed crystal bar zirconium specimens. An investigation of transient effects revealed that no strain transient was observed when the irradiation flux was removed. The strain rate was found to be proportional to the applied stress (at low stresses) and to the damage rate.