SYMPOSIA PAPER Published: 30 January 2015
STP154320130008

Performance and Property Evaluation of High-Burnup Optimized ZIRLO™ Cladding

Source

Optimized ZIRLO™ cladding has been exposed to burnup levels exceeding 70 GWd/MTU, significantly higher than the licensed burnup in the United States of 62 GWd/MTU, in an effort to evaluate the performance margins of Optimized ZIRLO cladding during irradiation to high burnups. Extensive poolside and hot-cell post-irradiation examination (PIE) have been performed on the high-burnup rods. Based on poolside PIE, Optimized ZIRLO-clad fuel rods have demonstrated 40 % lower in-reactor corrosion compared to ZIRLO®-clad fuel rods, at burnups over 70 GWd/MTU. The oxide thickness of Optimized ZIRLO cladding is less than 70 μm for modified fuel duty index (MFDI) over 1000 and burnups over 70 GWd/MTU. The Optimized ZIRLO-clad fuel rods have shown excellent in-reactor dimensional stability, and similar diametral creep to ZIRLO-clad fuel rods. Detailed examinations were conducted on the high-burnup Optimized ZIRLO-clad rods in the hot cell, including length measurement, eddy current (EC) oxide-thickness measurement, profilometry, visual inspection, metallography, scanning electron microscopy (SEM), transmission electron microscopy (TEM), ring tensile testing, axial tensile testing, and hot vacuum extraction hydrogen measurements. Hot-cell examinations confirmed the low corrosion and low growth and also revealed the high ductility of these high-burnup Optimized ZIRLO-clad rods. TEM examination on samples taken from the deformed region of the axial tensile test samples relates dislocation channeling behavior to the ductility of Optimized ZIRLO alloy. Metallography and SEM examinations reveal the layered structure of the oxide layer. Poolside and hot-cell PIE results from the high-burnup Optimized ZIRLO-clad rods are discussed in the paper.

Author Information

Pan, G.
Westinghouse Electric Company, Hopkins, 29061, US
Garde, A., M.
Westinghouse Electric Company, Hopkins, 29061, US
Atwood, A., R.
Westinghouse Electric Company, Hopkins, 29061, US
Price: $25.00
Contact Sales
Related
Reprints and Permissions
Reprints and copyright permissions can be requested through the
Copyright Clearance Center
Details
Developed by Committee: B10
Pages: 1–21
DOI: 10.1520/STP154320130008
ISBN-EB: 978-0-8031-7580-8
ISBN-13: 978-0-8031-7529-7