TY - GEN
T1 - BWR corrosion experience of NSF channels
AU - Cantonwine, Paul E.
AU - Lin, Yang Pi
AU - Lutz, Dan R.
AU - White, David W.
AU - Ledford, Kevin L.
PY - 2013
Y1 - 2013
N2 - NSF is a zirconium alloy with nominally 1%Nb, 1%Sn, and 0.35%Fe that is being considered as a channel material by Global Nuclear Fuel (GNF). The reason NSF is a candidate channel material is that it exhibits a high resistance to fluence gradient-induced bow compared to Zircaloy-2 and Zircaloy-4. Although there is extensive experience with corrosion of Zr-Nb alloys (ZIRLO™ and M5) in PWR conditions, the predominant experience of Zr-Sn-Nb-Fe alloys under boiling water conditions has been in Russian reactors. The purpose of this paper is to review the corrosion performance of GNF NSF channels. Long term autoclave testing (ASTM G2 conditions) of NSF with either an etched surface or a pre-oxidized surface condition indicates that the relative corrosion resistance of NSF is slightly less than Zircaloy-2 but better than Zircaloy-4. Hot-cell measurements of oxide thickness for general in-reactor corrosion (where susceptibility to shadow corrosion is low) follows the trend observed in autoclave testing. At bundle exposures of 50 GWd/MTU, the in-reactor corrosion thickness of Zircaloy-4 was found to be ∼70 μm while NSF was ∼30 μm and Zircaloy-2 was between 10 and 20 μm. In addition, visual observations indicate the severity of shadow corrosion also follows the same trend. Zircaloy-4 was the most susceptible to oxide blisters indicative of shadow corrosion, followed by NSF and then Zircaloy-2. Based on the evidence presented herein, the corrosion rate of NSF in typical boiling water conditions is lower than Zircaloy-4 but slightly greater than Zircaloy-2: thus adequate for BWR channels.
AB - NSF is a zirconium alloy with nominally 1%Nb, 1%Sn, and 0.35%Fe that is being considered as a channel material by Global Nuclear Fuel (GNF). The reason NSF is a candidate channel material is that it exhibits a high resistance to fluence gradient-induced bow compared to Zircaloy-2 and Zircaloy-4. Although there is extensive experience with corrosion of Zr-Nb alloys (ZIRLO™ and M5) in PWR conditions, the predominant experience of Zr-Sn-Nb-Fe alloys under boiling water conditions has been in Russian reactors. The purpose of this paper is to review the corrosion performance of GNF NSF channels. Long term autoclave testing (ASTM G2 conditions) of NSF with either an etched surface or a pre-oxidized surface condition indicates that the relative corrosion resistance of NSF is slightly less than Zircaloy-2 but better than Zircaloy-4. Hot-cell measurements of oxide thickness for general in-reactor corrosion (where susceptibility to shadow corrosion is low) follows the trend observed in autoclave testing. At bundle exposures of 50 GWd/MTU, the in-reactor corrosion thickness of Zircaloy-4 was found to be ∼70 μm while NSF was ∼30 μm and Zircaloy-2 was between 10 and 20 μm. In addition, visual observations indicate the severity of shadow corrosion also follows the same trend. Zircaloy-4 was the most susceptible to oxide blisters indicative of shadow corrosion, followed by NSF and then Zircaloy-2. Based on the evidence presented herein, the corrosion rate of NSF in typical boiling water conditions is lower than Zircaloy-4 but slightly greater than Zircaloy-2: thus adequate for BWR channels.
UR - http://www.scopus.com/inward/record.url?scp=84902340151&partnerID=8YFLogxK
M3 - Conference contribution
AN - SCOPUS:84902340151
SN - 9781629937212
T3 - LWR Fuel Performance Meeting, Top Fuel 2013
SP - 892
EP - 897
BT - LWR Fuel Performance Meeting, Top Fuel 2013
PB - American Nuclear Society
T2 - LWR Fuel Performance Meeting, Top Fuel 2013
Y2 - 15 September 2013 through 19 September 2013
ER -