Darlington Nuclear Generating Station (DNGS) meets about 17% of Ontario's electricity needs.
DNGS features four CANada Deuterium Uranium (CANDU) reactors.
The mid-life refurbishment of the nuclear power plant is expected to be completed by 2025. Image courtesy of Ontario Power Generation Inc.
The Global Assessment Report and Integrated Implementation Plan for the refurbishment project, submitted in December 2013, is expected to be reviewed in 2014. Image courtesy of Ontario Power Generation Inc.

Darlington Nuclear Generating Station (DNGS) is located in Clarington, within the Regional Municipality of Durham, in the Province of Ontario. The nuclear power plant (NPP) meets about 17% of Ontario’s electricity needs, producing approximately 31 million megawatt hours of electricity annually. The plant is owned and operated by Ontario Power Generation (OPG).

The mid-life refurbishment of DNGS will enable the nuclear power plant to generate 3,500MW of electricity for an additional 25-30 years. The project is currently in the definition phase, which is expected to last until 2015. The execution phase of the project will commence in 2016 and be completed by 2025.

The announcement to proceed with the planning for the refurbishment of the power plant was made by OPG in February 2010. The project’s environmental assessment and integrated safety review (ISR) reports, which were submitted to the Canadian Nuclear Safety Commission (CNSC) in December 2011, were approved in March 2013 and July 2013, respectively.

OPG submitted the Global Assessment Report and Integrated Implementation Plan in December 2013, expected to be reviewed in 2014.

Contracts worth up to $1.5bn have been awarded as of early 2014. The project is expected to generate approximately 6,000 direct and indirect jobs.

History of DNGS

Trianel Kohlekraftwerk Lünen (TKL) developed the 750MW hard coal-fired power plant at Lünen, Germany.

DNGS comprises four CANada Deuterium Uranium (CANDU) reactors with a combined net power output of 3,512MW.

The four reactors were commissioned from 1990 to 1993. The power plant site in Ontario also houses the Darlington Waste Management Facility (DWMF) for dry storage of spent nuclear fuel from the station.

Refurbishment project details

The refurbishment project involves the replacement of major plant components, including the fuel channels, calandria tubes and feeders, steam generators, turbine generators, fuel handling systems and other ancillary plant equipment. Up to 480 pressure tubes and calandria tubes, and 960 feeder pipes for each of the four reactors will be removed and replaced as part of the project.

The reactors will each be refurbished with planned outage. Unit 2 will be refurbished from 2016 to 2019, Unit 1 will be refurbished from 2019 to 2022, Unit 3 will be refurbished from 2021 to 2024 and Unit 4 will be refurbished from 2022 to 2025. The DWMF will also be expanded to accommodate the additional fuel waste during and after the refurbishment.

Environmental and safety approvals, engineering studies, infrastructure development and integrated project planning will be completed as part of the definition phase.

Preliminary refurbishment works

Construction of the Darlington Energy Complex, to assist the refurbishment project, started in July 2011. It is located within the Clarington Energy Park, adjacent to the DNGS. The construction of the complex was completed in January 2013.

“Facilities within the new building include an advanced training centre, a full-scale mock-up reactor facility and a tool testing facility.”

Facilities within the new building include an advanced training centre, a full-scale mock-up reactor facility and a tool testing facility. The building also comprises an office space for 450 staff, a public information centre and a 70,000ft² warehouse. The facilities are being used to train the staff during the definition phase in order to prepare them for the execution phase.

A number of improvement works are also currently underway at the site, which include the installation of new municipal water and sewer connections, new water main lines for domestic use and fire control, sanitary pumping stations, additional electrical distribution facilities and a new heavy water storage and drum handling facility.

Contractors and suppliers

A contract worth more than $600m for the project’s retube and feeder replacement (RFR) was awarded to a joint-venture comprising Aecon Industrial and SNC-Lavalin (the SLN-Aecon JV) in March 2012. Aecon will provide the construction and fabrication services, while SNC-Lavalin will carry out the specialty tooling and engineering activities.

A €265m (approximately $366m) contract for the refurbishment of the four steam turbines and generator units, including ancillary equipment, was awarded to Alstom in April 2013. GE Hitachi Nuclear Energy Canada will carry out the refurbishment of the fuel handling system.

Technical and contract support services for the project are being provided by AMEC and Worley Parsons, while the Independent Oversight Advisors for the Ontario-based nuclear power station include CALM Management Consulting and Burns & McDonnell.

The Darlington Energy Complex was constructed by McKay-Cocker Construction. The architect and engineer for the support building is Aecom, who is also involved in assisting OGP in gaining the planning and environmental approvals for the project.

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