Cold Spray EMAT continuous monitoring system for real-time structural health monitoring

As made evident by multiple publications by experts from the U.S. Department of Energy from 2014 through 2018, welded stainless-steel Dry Storage Canisters used for spent nuclear fuel storage are experiencing severe stress corrosion cracking, especially in the welds’ heat-affected zone. In 2016, there were 2777 Dry Storage Canisters deployed across the country, and approximately 200 more are added every year. With each Canister containing more Cesium-137 than Chernobyl released in the atmosphere, a microscopic crack could release enough radioisotopes to risk the environment and human health. Several researchers have attempted to develop permanent ultrasonic monitoring solutions for this sort of applications, although with limited success. The project aims to develop the first prototype of a cold-spray Electro Magnetic Acoustic Transducer (EMAT) magnetostrictive sensor for on-site corrosion and crack propagation monitoring on Dry Storage Canisters, with minimum disruption and human intervention. Patented solution (#20180156758) tackles state-of-the-art limitations using cold-spray bonding to create a permanent magnetostrictive patch that does not rely on mechanical bonding and new sensors featuring permanent and pulsed magnets. Phase I will seek to assess the performance of portable low-pressure cold-spray instruments with different powder-pressure-propellant configurations, and the feasibility to produce uniform patches on components that are flat, round, or have complex geometries using a manual gun, and test the effect of generating ultrasound with Electro Magnetic Acoustic Transducer (EMAT) in said instances. Ultimately, the project will determine the suitability of the manual magnetostrictive patches for application to Dry Cask Storage, and prepare sensor and instrumentation options. The market for spent nuclear dry storage casks in the Americas is set to rise to over $1-billion by 2020. Canada and the US represent more than Half of Dry Cask Demand (62%) and the global nuclear market is also quite considerable. Few countries are making any meaningful progress on facilities for permanent storage of this nuclear waste—only Sweden and Finland are expected to see underground repositories for radioactive waste completed in the 2020s.Despite a clear and beneficial impact in the nuclear sector, this might be the smallest market for the technology. Permanent sensors would be of immediate application at any industrial facility: The biggest limitation of existing ultrasonic sensors, whether they are piezoelectric or magnetostrictive, is that they require mechanical coupling to the component. This mechanical coupling is inherently subject to failure and is not a reliable nor practical solution for long-term monitoring. The technology tackles these limitations providing a permanent metallurgical bond between patch and target surface that will not degrade or deteriorate. Cold-spray would also permit the use of guided waves to inspect areas that are not accessible. The biggest application could be chime rings on storage tanks in the oil & gas and chemical sectors. Lastly, results of the project will provide a significant boost in terms of nuclear-safety, preventing and reducing the amount of radioactivity leaks and their hazardous impact in the environment and human health.