Pacific Northwest National Laboratory (PNNL) is advancing nondestructive evaluation (NDE) technologies to support the safe operation and long-term reliability of nuclear power reactors across the United States. By using advanced sensing and imaging techniques, researchers are enabling the inspection of critical reactor components without causing damage, helping detect hidden flaws and monitor material health throughout a plant's operational life.
Drawing parallels to medical imaging technologies such as ultrasound and X-rays, PNNL's NDE methods allow researchers to examine steel and concrete structures for defects that would otherwise remain undetected. The work supports a nuclear fleet that generates nearly 20% of the nation's electricity, reinforcing the role of NDE in maintaining reactor safety and operational reliability.
For nearly five decades, PNNL has partnered with the U.S. Nuclear Regulatory Commission (NRC) to address inspection challenges across the country's nuclear fleet. Through confirmatory research, the collaboration has expanded inspection capabilities, produced more than 250 technical reports and peer-reviewed journal articles, and contributed to updates in the American Society of Mechanical Engineers (ASME) Boiler & Pressure Vessel Code. These developments have enabled wider adoption of modern ultrasonic inspection techniques and digital technologies for both existing reactors and next-generation nuclear systems.
The laboratory's NDE research spans a range of inspection technologies, including ultrasound, laser ultrasound, eddy current testing, and X-ray computed tomography. While some researchers focus on advancing sensing technologies and inspection physics, work conducted for the NRC is centered on confirmatory research that provides the technical foundation required for regulatory licensing decisions.
PNNL also manages an NRC-owned library containing hundreds of nuclear-related components and samples, including materials recovered from cancelled nuclear plants. Many of these samples contain fabricated defects, allowing researchers to validate inspection methods under realistic conditions without manufacturing new components or removing materials from operating reactors.
The laboratory's inspection capabilities are further supported by dedicated radiography, ultrasonic, electromagnetic, and cable aging facilities, including the ARENA cable and motor test bed. These facilities enable researchers to evaluate how materials and components perform under the high temperatures, radiation exposure, and corrosive environments found inside nuclear reactors.
"Our program has evolved alongside advances in inspection technology," said Katie Wagner, manager of PNNL's Nuclear Regulatory programs. "For example, cast austenitic stainless steel, or CASS, was once considered uninspectable. Our work for the NRC helped demonstrate that, with modern NDE methods, this material can be inspected reliably, giving the NRC the technical foundation for evaluating and approving the regulatory framework for CASS inspections."
In addition to inspection validation, PNNL is applying modeling, simulation, artificial intelligence (AI), and automated data analysis to improve inspection efficiency. Researchers are evaluating AI-based tools that analyze conventional ultrasonic inspection data, allowing inspectors to identify significant indications more quickly while reducing inspection time and minimizing reactor shutdown periods.
"We're evaluating an AI tool to screen data from traditional NDE ultrasonic data analysis and flag the most important signals," Jacob explained. "Inspectors can then focus only on the relevant data, which is expected to significantly cut inspection time and shorten plant shutdowns, keeping reactors online longer and providing more power to the grid."
As the nuclear industry moves toward advanced reactor technologies and additive manufacturing, PNNL is also evaluating inspection methods for new materials and manufacturing processes. Researchers are assessing NDE techniques capable of inspecting components produced through additive manufacturing while developing durable sensors designed for long-term monitoring in increasingly demanding reactor environments.
"Additive manufacturing is the future for nuclear power, and we suspect it will play a strong role with advanced reactor designs, but it is important to demonstrate that the new materials and components developed with new manufacturing methods can be inspected," Jacob said.
The laboratory's multidisciplinary NDE team includes physicists, materials scientists, inspectors, signal processing specialists, radiographers, and AI experts working together to address emerging inspection challenges. Their efforts are supported by advanced laboratory infrastructure and a comprehensive component library dedicated to nondestructive testing research.
"PNNL's work plays a key role in the NRC's efforts to ensure U.S. nuclear power plants use effective non-destructive examinations of their safety systems," said Stephen Cumblidge, a materials engineer in the NRC's Office of Nuclear Reactor Regulation. "We're confident in the procedures and methods validated by PNNL research."
Building on research that began in 1976, PNNL and the NRC continue to advance NDE technologies that support the safety and reliability of the U.S. nuclear power fleet. From validating advanced inspection methods to integrating AI into ultrasonic analysis and evaluating inspection strategies for future reactor designs, the collaboration continues to strengthen the role of nondestructive evaluation in nuclear infrastructure.
"We've built this capability together over decades," said Wagner. "The NRC funds the work, PNNL invests in the people, and together our staff are helping support the U.S. nuclear fleet one report, inspection, or NDE breakthrough at a time."
Reference: https://www.azom.com/news.aspx?newsID=65585
