Applying method of electrophysical diagnostics testing of uranium nitride under irradiation

The paper studies deformation of nitride fuel at an early irradiation stage with a functional electrophysical non-destructive diagnostic method. For this purpose, we measured relative thermoelectric voltage and voltage drops on the fuel surface under irradiation. Uranium nitride tests started at the self-heating temperature, which was gradually raised to 1,500°C. Load was growing stepwise, from zero to 30 MPa. Signal structures were analyzed with discrete Fourier and wavelet transform algorithms. We build a deformation curve based on time dependence of thermoelectric voltage. The curve shows granular influence of changes in temperature and load. Accumulation of plastic strain increases internal stress until it reaches a critical point and relaxes, accompanied by spontaneous signal spikes.