Density, Porosity and Grain Size, (II) Irradiated ROX Fuels to Burn-up of 28%FIMA

• Published in: Journal of nuclear science and technology Vol. 36; no. 12; pp. 1153 - 1159
• Main Authors: YANAGISAWA, Kazuaki, YAMASHITA, Toshiyuki, KANAZAWA, Hiroyuki, AMANO, Hidetoshi, MUROMURA, Tadasumi
• Format: Journal Article
• Language: English
• Published: Tokyo Taylor & Francis 01.12.1999; Atomic Energy Society of Japan
• Subjects: Applied sciences; burn-up; density; Energy; Exact sciences and technology; Fuels; gas bubble swelling; grain growth; grain size; JRR-3M; Nuclear fuels; PIE; porosities; Preparation and processing of nuclear fuels; ROX fuels; Grain size; Uranium Oxides; Swelling; Radiation effect; Nuclear fuel; Porosity; Microstructure; Density; Plutonium Oxides; Irradiated nuclear fuel
• ISSN: 0022-3131; 1881-1248
• DOI: 10.1080/18811248.1999.9726310

The irradiation of ROX fuels to a burn-up of 28%FIMA in JRR-3M was made. Obtained results from post-irradiation examinations are: 1. The fuel bulk density of the ROX-SZR decreased by irradiation from 4.6g/cc (82%TD) to 3.4g/cc (61%TD), while that of the ROX-ThO 2 also decreased from 5.2g/cc (83%TD) to 3.4g/cc (55%TD). 2. The porosity of the ROX-SZR increased from 18 to 39%, while that of the ROX-ThO 2 also increased from 17 to 46%. The increase of porosity, that is, the unconstrained gas bubble swelling in the present case might be attributed to the agglomeration of pores, where Al 2 O 3 and PuAl 11 O 18 of ROX components took an important role. 3. The rate of unconstrained gas bubble swelling was estimated to be 0.8%ΔV/V per 1%FIMA for the ROX-SZR and 1%ΔV/V per 1%FIMA for the ROX-ThO 2 , respectively. For UO 2 , it was about 1%ΔV/V per 1%FIMA. Hence, with respect to the rate of unconstrained gas bubble swelling between the ROX fuels and UO 2 , the difference was insignificant. 4. The average grain size of the ROX-SZR increased from 2 to 6 μm, while that of the ROX-ThO 2 increased from 2 to 4 μm. A grain growth occurred slightly.