Effects of Multiple Drying Cycles on High-Burnup PWR Cladding Alloys

Technical Report · Fri Sep 26 04:00:00 EDT 2014

DOI:https://doi.org/10.2172/1159911· OSTI ID:1159911

Billone, M. C. ^[1]; Burtseva, T. A. ^[1]; Han, Z. H. ^[1]; Liu, Y. Y. ^[1]

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1. Argonne National Laboratory (ANL), Argonne, IL (United States)

The purpose of this research effort is to determine the effects of canister/cask vacuum drying and storage on radial hydride precipitation in high-burnup (HBU) pressurized water reactor (PWR) cladding alloys during cooling for a range of peak drying-storage temperatures, internal gas pressures, and hoop stresses. The HBU PWR cladding alloys have a wide range of hydrogen contents and varying hydride morphology after in-reactor service. Radial hydrides are a potential embrittlement mechanism for HBU cladding subjected to hoop-stress loading, which may be significant during normal cask transport. Ring compression tests (RCTs), which simulate pinch-type loading at grid spacers, are used to determine cladding ductility as a function of RCT temperature and the ductile-to-brittle transition temperature (DBTT). Previous tests were conducted with pressurized and sealed cladding rodlets heated to 400°C (the NRC ISG-11, Rev. 3, limit for all fuel burnups under normal conditions of storage and short-term loading operations) and cooled slowly at 5°C/h. Following this drying-storage simulation, the DBTT for HBU M5^® decreased from 80°C to 70°C to <20°C as the peak hoop stress decreased from 140 MPa to 110 MPa to 90 MPa. Under similar drying-storage conditions, the DBTT for HBU ZIRLO™ decreased from 185°C to 125°C to 20°C to <20°C as the peak cladding hoop stress decreased from 140 MP to 110 MPa to 90 MPa to 80 MPa. These tests were conducted with a single heating-cooling cycle as simulation of the vacuum drying process with one drying cycle. (ISG-11, Rev. 3 allows <10 drying cycles, with cladding temperature variations that are less than 65°C each.)

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE Office of Nuclear Energy (NE), Nuclear Fuel Cycle and Supply Chain. Fuel Cycle Research and Development Program
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 1159911
• Report Number(s): ANL--14/11; FCRD-UFD-2014-000052; 107521
• Country of Publication: United States
• Language: English