NUREG/CR.


Book Description




Long-Term Irradiation Growth in Zirconium Alloys


Book Description

This paper reviews the experimental research program on irradiation growth in zirconium alloys performed by the United Kingdom Atomic Energy Authority between 1975 and 1988. The original technological objectives of the program, key aspects of rig and test specimen design, experiments aimed at improving fundamental understanding of the growth process, and key final results on long-term growth behavior are described. Our recollections of the program are given in relation to the understanding of irradiation growth mechanisms that prevailed at the beginning and end of the research program.




Irradiation Creep and Growth in Zirconium During Proton Bombardment


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.