Ontario Power Generation (OPG) has installed three new emergency power generators (EPGs) at its Darlington NPP, completing a key 10-year project to support life extension of the plant. Each turbine/generator set and its auxiliary systems provides a standalone power plant capable of supplying 8 MWe to Darlington's emergency power system providing backup power in case of an emergency.

The EPG life-extension project and ongoing Darlington Refurbishment project will make possible 30 more years of operation. The work involved replacing two older generators with modern gas-turbine-driven generator sets and installing an additional third generator set.

The work began in 2013 with the design and installation of EPG3, an all-new third emergency generator for the station, which was completed in 2017. This was followed by the design and replacement of EPG2 in 2020, and finally the design and replacement of EPG1.

“These three new emergency generators will provide reliable back-up power to the Darlington Nuclear station to the end of the plant’s life, ensuring the safety of the station as well as community,” said Yousif Dweiri, Manager for the EPG replacement project at OPG. “The project overcame the challenges of COVID-19, and involved multiple local vendors and material suppliers, while providing hundreds of trades jobs over the years.”

The EPG2 turbine generator will now be used to help train future millwrights. It will be installed at the Millwright Regional Council of Ontario’s (MRCO) new Port Hope Millwright Training Centre when its construction is finished. In particular, Indigenous participants of OPG’s Indigenous Opportunities Network and recent Indigenous graduates of MRCO’s Introduction to Millwrighting programme will develop their skills using the repurposed equipment.

The EPG life-extension project was undertaken in parallel with the ongoing programme to refurbish Darlington's four Candu reactors to extend operation of the plant for 30 years. This requires defuelling, disassembling and reassembling each reactor in a high-precision operation, during which thousands of components are inspected and replaced. The work has now been completed for two units, and is expected to be completed for all four by the end of 2026. Unit 3 returned to service earlier in July and unit 2 in 2020. Darlington Refurbishment is a CAD12.8bn ($9.7bn) clean energy project that began in 2016 after nearly a decade of planning and preparation.

Image: Darlington's new emergency power generators (courtesy of OPG)