Acceptance of COTS Digital Equipment

Nuclear plant licensees and applicants do not have many options when it comes to selecting digital equipment for safety related applications. Most digital equipment used in nuclear safety related applications were not designed "from the ground up" under a nuclear quality assurance program; therefore, they must be evaluated and accepted for nuclear safety-related applications. Current process for accepting commercial of-the-self (COTS) digital equipment is based on the NRC-endorsed EPRI TR-106439 guidance that requires verification of identified critical characteristics. For verification of the dependability characteristic, this guidance requires survey of the original equipment manufacturer (OEM) design and developmental process. These surveys are not consistent and depend largely on the level of cooperation received from the OEM. In most cases, acceptance of commercial-grade digital equipment requires first-of-a-kind efforts, involving uncertainties with respect to duration, cost, and overall success. This effort is further hampered by lack of OEM involvement, driven by the fact that the nuclear market is too small to justify OEM resources necessary to support this process. Non-nuclear process industries avoid these uncertainties by deploying digital equipment certified by an independent third-party for use in systems required to accomplish safety functions. With this insight, NEI 17-06, "Guidance on Using IEC 61508 SIL Certification to Support the Acceptance of Commercial Grade Digital Equipment for Nuclear Safety Related Applications" has been developed that leverages research on the safety integrity level (SIL) certification efficacy performed by Electric Power Research Institute (EPRI). NEI 17-06 provides supplemental guidance on acceptability of the dependability critical characteristics of digital equipment during the dedicating process. NEI 17-06 has been endorsed by the NRC regulatory guide (RG) 1.250, "Dedication of Commercial-Grade Digital I&C Items for Use in Nuclear Power Plants." This panel will discuss the NRC and industry perspectives on acceptance of COTS digital equipment for nuclear safety-related applications. The emphasis for this panel is placed on current practices, approaches of dedicating entities, challenges with SIL certifying bodies, regulatory concerns with 3rd party certifying bodies, and the NRC perspectives.