Digital I&C System Modernization in the U.S.: Drivers, Barriers, Strategies, and Benefits

As the global community intensifies efforts to ensure reliable and strategic energy supplies, the importance of long-term operation of nuclear power plants (NPPs) has grown significantly. However, many instrumentation and controls (I&C) systems, originally designed with a lifespan of around 30 years, are now approaching the end of their operational life. While NPPs are still operating very safely, this has led to growing challenges such as equipment obsolescence and declining reliability due to aging of I&C equipment. In response, many studies have focused on digital I&C modernization, aiming to modernize aging infrastructure and leverage the advantages of digital systems.

In the United States, despite significant efforts to upgrade the I&C systems, progress has been limited, and utilities remain hesitant to move forward. Moreover, as of February 2025, 72 of the 94 NPPs in the United States are currently operating under licenses that will expire within the next 20 years, and these short remaining operating licenses brings additional concerns about the economic viability of investing in digital I&C modernization. To contemplate whether such upgrades can still deliver meaningful value at this stage, this paper examines the drivers, barriers, strategies, and benefits of digital I&C modernization, and it reviews the current status of digital upgrades in U.S. NPPs. Based on the insights gained, recommendations are presented for digital I&C modernization. This study provides stakeholders with valuable information and guidance on pursuing effective, efficient digital I&C modernization in NPPs.