BWR corrosion experience of NSF channels

Paul E. Cantonwine, Yang Pi Lin, Dan R. Lutz, David W. White, Kevin L. Ledford

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Scopus citations

Abstract

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.

Original languageEnglish
Title of host publicationLWR Fuel Performance Meeting, Top Fuel 2013
PublisherAmerican Nuclear Society
Pages892-897
Number of pages6
ISBN (Print)9781629937212
StatePublished - 2013
Externally publishedYes
EventLWR Fuel Performance Meeting, Top Fuel 2013 - Charlotte, NC, United States
Duration: Sep 15 2013Sep 19 2013

Publication series

NameLWR Fuel Performance Meeting, Top Fuel 2013
Volume2

Conference

ConferenceLWR Fuel Performance Meeting, Top Fuel 2013
Country/TerritoryUnited States
CityCharlotte, NC
Period09/15/1309/19/13

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