Compton Imaging Tomography for In-Situ NDE of Nuclear Reactor Materials

The DOEs Office of Nuclear Energy is seeking to develop innovative methods for nondestructive examination (NDE) of key nuclear reactor structures, systems, and components (SSCs). The degradation of nuclear power plants (NPPs) impacts NPP reliability, availability, and even safety of operation. Many current NPPs have been operating for over 40 years, which places considerable stress on SSCs that are normally considered to have high reliability. In particular, degradation of NPP cables is considered one of the top six most serious safety concerns of aging NPP operation. Each NPP contains over 1000 km of cables, which are often located in conduits or tight spaces and therefore are inaccessible for visual inspection. Nonintrusive inspection (without disconnection) of such cables presents a major challenge. Physical Optics Corporation (POC) proposes to develop an innovative high-resolution Compton Imaging Tomography for In-Situ NDE of Nuclear Reactor Materials (TSUNAMI), primarily aimed at detecting nuclear power plant cabling degradation. It can also be optimized for detection of weld defects and piping degradation and cracking, and also early material fatigue and stress cracking. TSUNAMI is based on a high-resolution version of Compton imaging tomography recently pioneered by POC, and providing precise three-dimensional reconstruction of the internal structure of a tested object (nuclear power plant material structures, systems, and components (SSCs)) by using acquired multiple two-dimensional Compton scattered X-ray images of each cross section of the object. In contrast to conventional radiography, the TSUNAMI requires only one-sided access to components, and has no limitations on their sizes, internal structures, and geometries. The proposed TSUNAMI will allow fast, inexpensive NDE of SSCs for degradation of the contemporary and future nuclear power plant (NPPs). TSUNAMI can also be used by reactor operators in combination with traditional NDE methods (such as ultrasound or eddy current) to provide more complete characterization of reactor components. In addition to the NDE of key nuclear reactor components and material structures, the TSUNAMI (with slight modifications) can also address an NDE market that is of direct and significant benefit to a large number of industries. A one- sided industrial TSUNAMI-based system is considered a high priority for many types of NDE, from current and future nuclear reactor structures to gas turbines, pipelines, aircraft, spacecraft, heavy machines, bridges, etc. Once TSUNAMI is developed, a completely novel market niche and market shift toward industrial tomography systems could occur for in situ one-side NDE of large nonuniform metallic alloy/ceramic/composite structures with complicated geometries.