Nuclear energy plant digital upgrades targeted

Under guidance issued via the Nuclear Regulatory Commission (NRC), officials said the nuclear energy industry is preparing for digital upgrades to the safety-related instrumentation and control (I&C) systems.

Officials said the effort, which will involve utilities hosting 11 workshops on how to prepare required documentation, includes replacing analog controls for safety-related support systems such as chiller systems; replacing safety-related analog relays with digital relays; replacing analog controls for emergency diesel generator supporting systems and auxiliary systems such as voltage regulation; and installing safety-related circuit breakers that contain embedded digital devices.

Three years ago the Nuclear Energy Institute (NEI) formed a working group of industry experts and NRC staff to resolve key technical and regulatory issues and facilitate the implementation of I&C upgrades – noting the NRC and industry worked to produce guidance on how to bring the upgrades to fruition.

Industry directors said the May 31 regulatory issue summary document (RIS) outlines how reactor owners can use qualitative assessments to demonstrate proposed safety-related and non-safety related digital I&C modifications would have a sufficiently low likelihood of failure due to software or other issues.

The training regimen provides examples of what kinds of digital modifications and upgrades the RIS should be applied to, officials said, encouraging immediate use and implementation of the RIS in initiating digital I&C projects across the operating reactor fleet.