Behavior under neutron irradiation of the 15-15Ti and EM10 steels used as standard materials of the phenix fuel subassembly

The present reference materials for the Phenix fuel subassembly are the CW15-15Ti for the fuel pin cladding and the martensitic steel EM10 for the wrapper. This choice is the result of the optimization of the properties playing a significant role in the design in order to increase the maximum achievable dose. The properties under consideration are the neutron induced swelling and creep which control the component deformations and the degradation of the short and long term mechanical properties during irradiation which sustain the pin integrity. In this paper are described the main macroscopic properties of these reference clad and wrapper materials and the microstructural evolution observed after irradiation in Phenix up to 100 dpa. The dpa used herein are NRTdpa. A comparison with the earlier choice of materials or with other candidates emphasizes the progress achieved