In this month’s issue of Power Engineering, Nancy Spring wrote an editorial on digital safety systems for nuclear power plants. She basically berates NRC for taking so long to approve digital technology for use in reactor protection systems and engineered safeguard protection systems at the Oconee Nuclear Power Plant. The technology for Oconee will utilize Areva’s Teleperm XS. Nancy makes the point that nuclear plant digital safety technologies are common everywhere but the US and that the Oconee approval will hopefully break the logjam.
There are many reasons why having digital technologies in nuclear plants is important. Consequently, as a nuclear engineer that managed the EPRI Nuclear Plant Instrumentation and Diagnostics Program for 5 years, I was involved in helping get digital technologies ready for use in nuclear plants. However, that was before concerns about cyber security emerged. I believe the nuclear industry’s digital upgrade programs have not adequately addressed cyber security.
Late last year, the French, English, and Finnish regulators expressed concern in the mixing of safety and control in the Areva Teleperm XS. The issues centered primarily on ensuring the adequacy of the safety systems used to maintain control of a plant if it goes outside normal conditions, and their independence from the control systems used to operate the plant under normal conditions. There also have been control system cyber incidents with the Teleperm T3000 in non- nuclear plant applications which is an issue because the Teleperm T3000 is used for nuclear plant balance-of-plant applications.
The unintended cyber incidents at Browns Ferry and Hatch (these were not Teleperm systems) demonstrate that cyber security has not been adequately understood or addressed. Additionally, there has been at least one instance in a non-nuclear facility where safety systems have been impacted by cyber. The nuclear industry has not been a leader in control system cyber security and has had minimal participation in non-nuclear cyber security activities. It is one thing to use cyber-sensitive technology in balance-of-plant applications which can affect plant reliability (FERC 706B) but will not cause a core melt; it is a totally different to use cyber-sensitive technology in safety applications that can either cause or not prevent a core melt scenario.
I believe digital systems can be used in safety systems in nuclear plants if adequate cyber security considerations are addressed throughout the life cycle including in the development phase. This requires a better understanding of the unique issues associated with control system cyber security and the issues associated with mixing safety and control. It also requires nuclear personnel participation with non-nuclear industries that have much more experience in control system cyber security and have been actively involved in addressing digital safety systems.
Joe Weiss
