As-cast microstructures in U-Pu-Zr alloy fuel pins with 5-8 wt% minor actinides and 0-1.5 wt% rare-earth elements

• Published in: Materials characterization Vol. 61; no. 11
• Main Authors: Dawn E. Janney, J. Rory Kennedy
• Format: Journal Article
• Language: English
• Published: United States 01-11-2010
• Subjects: ACTINIDES; ALLOYS; FUEL PINS; metal fuels; microstructures; NUCLEAR FUEL CYCLE AND FUEL MATERIALS; NUCLEAR FUELS; RARE EARTH ALLOYS; SCANNING ELECTRON MICROSCOPY
• ISSN: 1044-5803; 1873-4189
• DOI: 10.1016/j.matchar.2010.07.012

The Idaho National Laboratory (INL) is investigating U–Pu–Zr alloys with low concentrations of minor actinides (Np and Am) and rare-earth elements (La, Ce, Pr, and Nd) as possible nuclear fuels to be used to transmute minor actinides. Alloys with compositions 60U–20Pu– 3Am–2Np–15Zr, 42U–30Pu–5Am–3Np–20Zr, 59U–20Pu–3Am–2Np–1RE–15Zr, 58.5U–20Pu– 3Am–2Np–1.5RE–15Zr, 41U–30Pu–5Am–3Np–1RE–20Zr, and 40.5U–30Pu–5Am–3Np–1.5RE– 20Zr (where numbers represent weight percents of each element and RE is a rare-earth alloy consisting of 6% La, 16% Pr, 25% Ce, and 53% Nd by weight) were arc-melted and vacuum cast as fuel pins approximately 4 mmin diameter. The as-cast pins were sectioned, polished, and examined by scanning electron microscopy. Each alloy contains high-Zr inclusions surrounded by a high-actinide matrix. Alloys with rare-earth elements also contain inclusions that are high in these elements. Within the matrix, concentrations of U and Zr vary inversely, while concentrations of Np and Pu appear approximately constant. Am occurs in the matrix and with some high-rare-earth inclusions, and occasionally as high-Am inclusions in samples without rare-earth elements.