Initial examination of fuel compacts and TRISO particles from the US AGR-2 irradiation test

Journal Article · Sat Oct 21 00:00:00 EDT 2017 · Nuclear Engineering and Design

DOI:https://doi.org/10.1016/j.nucengdes.2017.09.017· OSTI ID:1435300

Hunn, John D.  ^[1]; Baldwin, Charles A. ^[1]; Montgomery, Fred C.  ^[1]; Gerczak, Tyler J.  ^[1]; Morris, Robert Noel  ^[1]; Helmreich, Grant W.  ^[1]; Demkowicz, Paul ^[2]; Harp, Jason ^[2]; Stempien, John ^[2]

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1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
2. Idaho National Lab. (INL), Idaho Falls, ID (United States)

Post-irradiation examination was completed on two as-irradiated compacts from the US Advanced Gas Reactor Fuel Development and Qualification Program’s second irradiation test. These compacts were selected for examination because there were indications that they may have contained particles that released cesium through a failed or defective SiC layer. The coated particles were recovered from these compacts by electrolytic deconsolidation of the surrounding graphitic matrix in nitric acid. The leach-burn-leach (LBL) process was used to dissolve and analyze exposed metallic elements (actinides and fission products), and each particle was individually surveyed for relative cesium retention with the Irradiated Microsphere Gamma Analyzer (IMGA). Data from IMGA and LBL examinations provided information on fission product release during irradiation and whether any specific particles had below-average retention that could be related to coating layer defects or radiation-induced degradation. A few selected normal-retention particles and six with abnormally-low cesium inventory were analyzed using X-ray tomography to produce three-dimensional images of the internal coating structure. Four of the low-cesium particles had obviously damaged or degraded SiC, and X-ray imaging was able to guide subsequent grinding and polishing to expose the regions of interest for analysis by optical and electron microscopy. Additional particles from each compact were also sectioned and examined to study the overall radiation-induced microstructural changes in the kernel and coating layers.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1435300
• Journal Information: Nuclear Engineering and Design, Vol. 329, Issue C; ISSN 0029-5493
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
High-temperature gas-cooled reactor (HTGR) fuel
Tristructural isotropic (TRISO) particles
Post-irradiation examination (PIE)
Cesium release
SiC failure