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Use of the Commercial Grade Dedication (CGD) Process for Installed Commercial Grade Equipment for Safety Related Application

Abstract of the technical presentation presented at: International Symposium on Emergency Power Systems at NPPs

May 16-17, 2019

Prepared by:
Jasmina Vucetic, Technical Specialist
Jeff Stevenson, Senior Site Inspector
Canadian Nuclear Safety Commission


This presentation will focus on the application of the Commercial Grade Dedication (CGD) process, which is based on Electric Power Research Institute (EPRI) guidance and accepted by the CNSC, to qualify the already installed commercial grade standby generator in the Emergency Power Supply System (EPS), which is a safety related system.

In CANDU plants, the key design requirement for the EPS system is to provide electrical power to critical safety related loads for Design Basis Accidents (DBAs), such as Main Steam Line Break (MSLB) and/or seismic events. The emergency source of power is provided by at least two generators. These generators are referred to as DG1 and DG2 by the CNSC, and are either diesel or combustion turbine units located in a completely separate or independent location.

At one power plant, for example, DG1 was safety related while DG2 was a commercial grade trailer mounted unit installed as a non-safety power source for temporary use. This generator had initially been rented, and later was purchased without obtaining the documentation normally required to declare it nuclear grade. Following this, the licensee intended for the DG2 to become a permanent addition to the EPS, thus requiring it to provide safety-related service.

The Canadian regulator identified this deficiency of DG2 as not being a safety related power source, and the licensee was requested to correct the non–compliance. Considering the acceptable demonstrated reliability and established seismic and environmental qualification, the licensee opted to address the deficiency via the CGD process to allow retention of the existing portable generator. More details about this process will be provided in the technical paper and presentation.

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