Conference Proceedings Paper
INFLUENCE OF ALKALI METAL OXIDES AND ALKALINE EARTH METAL OXIDES ON THE MITIGATION OF STRESS CORROSION CRACKING IN CANDU FUEL SHEATHING
35th Annual CNS Conference - 2015 May 31 - June 3
J. Metzler (Royal Military College of Canada)
G. A. Ferrier (Royal Military College of Canada)
K. Farahani (Royal Military College of Canada)
P. K. Chan (Royal Military College of Canada)
E. C. Corcoran (Royal Military College of Canada)
This work investigates strategies to mitigate stress corrosion cracking (SCC) in Zircaloy-4 sheathing materials. The CANLUB coatings currently used in CANDU reactors contain both alkali metal and alkaline earth metal impurities, which can exist as oxides (e.g., Na2O and CaO). It is believed that when the corrosive fission product iodine reacts with these oxides, the iodine can be sequestered through the formation of an iodide (e.g.,NaI and CaI2). The subsequent O2 release may repair cracks in the protective ZrO2 layer on the sheathing,shielding the Zircaloy-4 sheathing from further corrosive fission product attack. For this investigation,O2 gas, Na2O, and CaO were separately introduced into an environment wherein slotted Zircaloy-4 rings endure mechanical stresses in iodine vapour at high temperatures. Controlled additions of O2 gas created a slight reduction in the corrosive attack on Zircaloy-4 sheathing, while the inclusion of Na2O and CaO lead to greater reductions.
Individual Conference-Paper Copies (Electronic Where Available):
- For CNS members, the first 5 copies per calendar year are free, and additional copies are $10 each.
- For non-members, the price is $25 for the first Conference-paper copy in a request, and $10 each for additional copies of papers in the same conference and in the same request.
- Contact the CNS office to order reprints.