Effects of Irradiation on the Microstructure of U-7Mo Dispersion Fuel with Al-2Si Matrix

Journal Article · Fri Jun 01 00:00:00 EDT 2012 · Journal of Nuclear Materials

DOI:https://doi.org/10.1016/j.jnucmat.2012.01.013· OSTI ID:1039711

Keiser, Jr, Dennis D; Jue, Jan-Fong; Robinson, Adam B; Medvedev, Pavel; Gan, Jian; Miller, Brandon D; Wachs, Daniel M; Moore, Glenn A; Clark, Curtis R; Meyer, Mitchell K; Finlay, M Ross

The Reduced Enrichment for Research and Test Reactor program is developing low-enriched uranium U-Mo dispersion fuels for application in research and test reactors around the world. As part of this development, fuel plates have been irradiated in the Advanced Test Reactor and then characterized using optical metallography (OM) and scanning electron microscopy (SEM) to determine the as-irradiated microstructure. To demonstrate the irradiation performance of U-7Mo dispersion fuel plates with 2 wt% Si added to the matrix, fuel plates were tested to medium burnups at intermediate fission rates as part of the RERTR-6 experiment. Further testing was performed to higher fission rates as part of the RERTR-7A experiment, and very aggressive testing (high temperature, high fission density, high fission rate) was performed in the RERTR-9A, RERTR-9B and AFIP-1 experiments. As-irradiated microstructures were compared to those observed after fabrication to determine the effects of irradiation on the microstructure. Based on comparison of the microstructural characterization results for each irradiated sample, some general conclusions can be drawn about how the microstructure evolves during irradiation: there is growth of the fuel/matrix interaction layer (FMI), which was present in the samples to some degree after fabrication, during irradiation; Si diffuses from the FMI layer to deeper depths in the U-7Mo particles as the irradiation conditions are made more aggressive; lowering of the Si content in the FMI layer results in an increase in the size of the fission gas bubbles; as the FMI layer grows during irradiation more Si diffuses from the matrix to the FMI layer/matrix interface, and interlinking of fission gas bubbles in the fuel plate microstructure that may indicate breakaway swelling is not observed.

• Research Organization: Idaho National Lab. (INL), Idaho Falls, ID (United States)
• Sponsoring Organization: DOE - NA
• DOE Contract Number: DE-AC07-05ID14517
• OSTI ID: 1039711
• Report Number(s): INL/JOU-11-21725; JNUMAM; TRN: US1202237
• Journal Information: Journal of Nuclear Materials, Vol. 425, Issue 1 - 3; ISSN 0022-3115
• Country of Publication: United States
• Language: English

Related Subjects

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
BUBBLES
COMPARATIVE EVALUATIONS
DISPERSION NUCLEAR FUELS
ENRICHED URANIUM
FABRICATION
FISSION
FUEL PLATES
IRRADIATION
METALLOGRAPHY
MICROSTRUCTURE
PERFORMANCE
RESEARCH AND TEST REACTORS
SCANNING ELECTRON MICROSCOPY
SWELLING
TEST REACTORS
TESTING
URANIUM
URANIUM-MOLYBDENUM FUELS
irradiation testing
nuclear fuel
research reactor
uranium molybdenum alloy