Detection of radiation-enhanced diffusion by means of neutron-irradiated diffusion couples of Fe-Cr-Ni system

Radiation-enhanced diffusion is one of the most important parameters for the understanding and modeling the effect of radiation on materials. In this study, the averae effective interdiffusion coefficients of Ni and Cr in pure iron, an Fe-15Cr-15Ni model alloy and modified 316 stainless steel for fuel subassembley of FBR were evaluated under neutron irradiated by by using "miniature diffusion couples" which were electroplated with Ni or Cr. The miniature diffusion couples were irradiated in the experimental fast reactors JOYO at temperature ranging from 400 to 550 degrees C for 4 220 hours, to doses between 1.4 and 14 dpa. The interdiffusion was enhanced by irradiation. In poarticular, Ni diffusion increased by severaol orders of magnitude. The enhancement of diffusion depends on the point defect flux, which is affected by solute elements and the microstructure development under irradiation.