Nuclear reactor corrosion and cracking tracking now possible with new approach

In a groundbreaking discovery, researchers at the Massachusetts Institute of Technology (MIT) have developed a real-time, 3D monitoring technique for corrosion, cracking, and other material failure processes inside a nuclear reactor environment. This development could lead to the design of safer and higher-performing nuclear reactors for electricity generation and naval vessel propulsion.

The research, published in the journal Scripta Materialia, was funded, in part, by the MIT Faculty Startup Fund and the U.S. Department of Energy. The team studied nickel, a material commonly used in advanced nuclear reactor alloys, and experimented with a different substrate, niobium doped strontium titanate. They prepared the sample using a process called solid state dewetting, which involves heating a thin film of the material onto a substrate until it transforms into single crystals in a furnace.

Initially, the interaction between nickel and the silicon substrate formed a new chemical compound, derailing the experiment. However, adding a thin layer of silicon dioxide between the nickel and substrate prevented the unwanted chemical reaction. This discovery was significant, as it highlighted the critical role of the substrate in strain relaxation.

The researchers then used extremely powerful X-rays to mimic neutron interactions within a material in a nuclear reactor. By keeping the X-ray beam trained on the sample for a longer period of time, they found that the strain in the material slowly relaxed, allowing for phase retrieval algorithms to accurately recover the 3D shape and size of the crystal.

This technique allows for measuring strain with a nanoscale resolution during corrosion processes. The researchers discovered they could use the X-ray beam to precisely control the amount of strain in the material, which could have implications for the development of microelectronics.

Edwin Fohtung, an associate professor at the Rensselaer Polytechnic Institute, noted the significance of the discovery for understanding how nanoscale materials respond to radiation. He emphasised that this breakthrough could pave the way for designing more resilient materials that can better withstand the stress caused by irradiation inside a nuclear reactor.

Sample preparation was carried out, in part, at the MIT.nano facilities. The exact author of the research report on real-time 3D monitoring technology for corrosion, stresses, and other material failures in a nuclear reactor environment is not specified in the available information.

Adding a buffer layer of silicon dioxide between the material and its substrate improved the sample's stability for real-time monitoring. By utilising this technique, researchers could reconstruct 3D image data on the structure of a material as it fails, providing valuable insights into the behaviour of materials under extreme conditions. This could ultimately lead to the design of safer and more efficient nuclear reactors.