Microstructural characterization of high burn-up mixed oxide fast reactor fuel

作者：Teague Melissa^*; Gorman Brian; King Jeffrey; Porter Douglas; Hayes Steven

来源：Journal of Nuclear Materials, 2013, 441(1-3): 267-273.

DOI：10.1016/j.jnucmat.2013.05.067

High burn-up mixed oxide fuel with local burn-ups of 3.4-23.7% FIMA (fissions per initial metal atom) were destructively examined as part of a research project to understand the performance of oxide fuel at extreme burn-ups. Optical metallography of fuel cross-sections measured the fuel-to-cladding gap, clad thickness, and central void evolution in the samples. The fuel-to-cladding gap closed significantly in samples with burn-ups below 7-9% FIMA. Samples with burn-ups in excess of 7-9% FIMA had a reopening of the fuel-to-cladding gap and evidence of joint oxide-gain (JOG) formation. Signs of axial fuel migration to the top of the fuel column were observed in the fuel pin with a peak burn-up of 23.7% FIMA. Additionally, high burn-up structure (HBS) was observed in the two highest burn-up samples (23.7% and 21.3% FIMA). The HBS layers were found to be 3-5 times thicker than the layers found in typical LWR fuel. The results of the study indicate that formation of JOG and or HBS prevents any significant fuel-cladding mechanical interaction from occurring, thereby extending the potential life of the fuel elements. Published by Elsevier B.V.

• 出版日期2013-10