New Technique Designed To X-Ray and “Map” Cracks In Metallic Tubing

Metallic tubing is critical in transporting water coolant to steam generators within nuclear power plants but Alloy-600, a high-strength nickel-based alloy, is susceptible to intergranular stress corrosion cracking leading to costly failure at many plants.

To combat this issue, a team of researchers has designed a new technique to essentially x-ray and “map” cracks and potential crack areas among Alloy 600.

According to Stewart McIntyre, an emeritus professor in the Department of Chemistry at the University of Western Ontario in London, Canada, “Failures of Alloy 600 are preceded by mechanical strains, but the location of this type of strain is often a tiny area only a few microns wide, which has been mechanically damaged by a physical process like a micro scratch or a chemical process such as rapid local corrosion.”

It is essential to identify tiny areas under local tensile stresses, because these stresses can lead to issues, most notably pulling a material apart at the boundary between two metal grains.

McIntyre and his team are using an extremely small x-ray beam to locate potential problem areas under local tensile stresses, resulting in them being able to “map” or determine where strains may eventually crack.