Key upgrade completed at Darlington

July 31, 2023

Ontario Power Generation (OPG) has completed a major 10-year project to install three new emergency power generators (EPGs) at its Darlington nuclear power plant to support the continued operation of the plant for decades to come.

Darlington's new EPG2 (Image: OPG)

EPGs provide reliable backup power in case of an emergency. Each turbine/generator set and its auxiliary systems provides a standalone power plant capable of supplying 8 MWe to Darlington's emergency power system.

The upgrade to Darlington's EPGs began in 2013, with the design and installation of a new third emergency generator - EPG3 - for the station. This was completed in 2017, and was followed by replacement of the plant's two older EPGs with modern gas-turbine-driven generator sets.

The EPG life-extension project has been completed alongside the ongoing programme to refurbish Darlington's four Candu units to enable the plant to continue operating for the next 30 years. This involves 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 of Darlington's four units, and is expected to be completed for all units by the end of 2026.

"These three new emergency generators will provide reliable backup 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."

One of the retired EPGs, pictured here, will have a useful future role (Image: OPG)

One of the two decommissioned EPGs will be repurposed for use at a new training centre currently under construction in Port Hope, Ontario, where it will be used to help train future millwrights under a programme led by the Millwright Regional Council of Ontario.

Researched and written by World Nuclear News