Post quench ductility of Zirconium alloy cladding materials - 6.2 STP-2016-0088

Conference · Fri Jul 01 04:00:00 EDT 2016

OSTI ID:22788395

Mueller, A. J. ^[1]; Romero, J. E. ^[2]; Partezana, J. M. ^[1]; Pan, G.; Mitchell, D.; Garde, A. M.; Atwood, A. R. ^[2]

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1. Fuel Engineering and Safety Analysis, Westinghouse Electric Company, 1332 Beulah Road, Pittsburgh, PA 15235 (United States)
2. Fuel Engineering and Safety Analysis, Westinghouse Electric Company, 5801 Bluff Road, Hopkins, SC 29061 (United States)

The ductility of zirconium-based alloys after steam oxidation at high temperature, followed by quenching in water, is of significant interest for the nuclear industry. High temperature steam oxidation and quenching of nuclear fuel cladding occurs during postulated loss-of-coolant accidents (LOCA). The industry is currently establishing in-reactor operation limits for peak cladding temperature and time at temperature based on the measured ductile-to-brittle transition of different cladding materials, both in the as-fabricated condition and using hydrogen charging as a surrogate for in-reactor operation. Aiming to study possible differences in post-quench ductility (PQD) caused by differences in chemical composition, extensive testing has been performed on Zircaloy-4, ZIRLO{sup R} and Optimized ZIRLO{sup TM} cladding materials as a function of hydrogen content, extent of oxidation and peak cladding temperature. The results show similar ductile-to-brittle transition for the alloys studied, in spite of the differences in chemical composition, with a decrease in the extent of oxidation to reach the ductile-to-brittle transition with increasing hydrogen content. Microstructural characterization was performed to investigate the evolution of the oxygen enriched layer that appears underneath the oxide, both during the time at high temperature and during cooling. Significantly different morphologies of the oxygen enriched layer are observed with different cooling rates, particularly for alloys containing niobium. Possible mechanisms for the development of the oxygen enriched layer are discussed (authors)

• Research Organization: ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA, 19428-2959 (United States)
• OSTI ID: 22788395
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHEMICAL COMPOSITION
CLADDING
DUCTILE-BRITTLE TRANSITIONS
DUCTILITY
HYDROGEN
LOSS OF COOLANT
MICROSTRUCTURE
NIOBIUM
NUCLEAR FUELS
OXIDATION
OXIDES
OXYGEN
REACTOR OPERATION
ZIRCALOY 4