OPG personnel inside the turbine hall at the Darlington Nuclear Generating Station.

Q1 2018

A REPORT ON CANADA’S LARGEST CLEAN ENERGY PROJECT

DARLINGTON REFURBISHMENT

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OPEN AIRLOCKS AND INSTALL SHIELDING

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REMOVE INTERFERENCES AND INSTALL WORK PLATFORM

SEVER PRESSURE TUBES AND BELLOWS

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REMOVEEND FITTINGS

INSPECT AND INSTALL CALANDRIA TUBES

REMOVE PRESSURE TUBES

INSPECT AND INSTALL FUEL CHANNELS (PRESSURE TUBES, BELLOWS AND END-FITTINGS)

REMOVE CALANDRIA TUBES

INSTALL FEEDER TUBES

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THE UNIT 2 DARLINGTON REFURBISHMENT SCHEDULE

Tetra Tech is one of more than 200 companies

across Ontario working on the Darlington

Refurbishment project. The company’s power

division, which also supports Pickering Nuclear,

provides a range of services — from engineering

and project management to scheduling and

training — using innovative 4D, virtual and

augmented reality approaches.

“The Darlington Refurbishment has opened up

new potential for our next generation of technical

staff to sit next to their peers in support of this

significant project,” said Tetra Tech’s president,

Pat Marchione. “Since the project will result in

Darlington continuing to produce economical

and clean base load power for Ontarians for an

additional three decades, ensuring that

institutional and technical knowledge is passed

along is so important.”

Passing on this knowledge — sharing lessons

learned and so improving efficiencies — is the

kind of approach that is helping the project

complete work safely, with quality, on time and

on budget.

Since joining the effort in 2013, staffing levels at

the Pickering-based company’s power division

have more than doubled, in large part as a result

of its work on the Darlington Refurbishment.

The Darlington Refurbishment, Canada’s largest clean

energy project, continues to track on time and on budget,

as Unit 2 reactor reassembly gets underway.

We experienced a successful first quarter in 2018

highlighted by arriving at the halfway mark on the Unit 2

schedule and the green lighting of Unit 3 refurbishment.

Both of these milestones serve to reinforce our

stakeholders’ confidence in our project team’s ability to

safely complete the refurbishment of all four reactors

at Darlington Nuclear on time and on budget. During

this quarter, OPG and our project partners completed

the removal of all 960 end fittings, 480 pressure tubes

and 480 calandria tubes from Unit 2. The removed

components have been shipped to OPG’s state-of-the-art

Re-Tube Waste Processing Building where they are being

prepared for long-term safe storage.

We have now begun installing new and refurbished

components in Unit 2. Other work is also underway,

including refurbishing our fuel handling equipment,

rebuilding or replacing nearly 1,000 valves and overhauling

our turbines and generators, both which help produce

electricity.

In this report, you’ll learn more about some of the

exciting milestones we’ve reached on the Darlington

Refurbishment project in our first quarter, and how we’re

delivering results for 30 more years of safe, clean and

reliable energy.

Dietmar Reiner,

Senior Vice President, Nuclear Projects

OCT 15, 2016BREAKER OPEN

PROJECT COMPLETE FEBURARY 27, 2020

SHUT DOWN REACTOR

DEFUEL REACTOR

INSTALL BARRIERS TO ISOLATE UNIT 2 FROM STATION CONTAINMENT

PRESSURE TEST

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LOAD FUEL AND REMOVE EQUIPMENT

HEAT UP AND LOW POWER TESTING

HIGH POWER TESTS AND CONNECTION TO THE GRID

Segment 4: Load Fuel, Test and Restart Reactor Segment 3: Install Reactor Components Segment 2B: Remove Reactor Components Segment 2A: Prepare for Reactor Component RemovalSegment 1: Defuel Reactor and Isolate from the Station

SEGMENT 2B DEC 17 START

SEGMENT 3 MAY 3, 2018

SEGMENT 4 AUG 7 2019 START

PROGRESS AS AT MARCH 31, 2018

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Peter Gowthorpe, Director of Laveer Engineering, third from right, receives

a plaque from Ted Gruetzner, OPG’s Vice President of Stakeholder Relations.

SEGMENT 2B DEC 17 START

REMOVE FEEDER TUBES

PROJECT PILLAR PERFORMANCEOPG’s project pillars measure the organization’s success

in maintaining high standards in worker safety, quality of

work, and adhering to schedule and overall project cost.

Here is an overview of our project pillar performance

during the first quarter of the year (January 1, 2018 —

March 31, 2018).

SCHEDULEUnit 2 remains ahead of schedule.

COSTUnit 2 refurbishment costs are slightly below plan.

The life-to-date cost for Unit 2 remains within the

approved budget.

SAFETYNo lost time injuries and three minor Medically

Treated Injuries occurred. Since Unit 2 breaker open

in Oct. 2016, 8 million hours have been worked safely.

QUALITYThere have been no quality-related events in the

quarter.

ENVIRONMENTEnvironmental performance has been excellent with

no reportable spills or infractions in Q1. Emissions are

better than target and well below all regulatory limits.

REDESIGNED TOOLSET HELPS REFURBISHMENT STAY ON TRACK

An important step in reactor disassembly is the removal of annulus spacers from six of the reactor’s fuel channels so they can be sent for

analysis. When the time came to plan for execution of the task on the

Darlington Refurbishment project, project partner Promation found

that Laveer Engineering had the expertise in retrieval tool design

and development OPG was looking for.

“Promation had the lead on the project, but felt that we could

provide the design and development required to make the project

a success,” said Peter Gowthorpe, Director of Laveer Engineering, a

custom tooling and engineering company based in Burlington, Ont.

Annulus spacers (or garter springs) play a critical role in maintaining

a gap between the pressure tube and calandria tube inside a unit’s

fuel channel, preventing contact between the two components.

Removal of these springs is intricate work, which involves collecting

the spacers by using an annulus spacer retrieval tool.

Gowthorpe said, “We’re taking lessons learned and applying them to

both projects and relationships.”

By utilizing a modified tool, the Darlington Refurbishment team

was able to safely remove 24 spacers from the fuel channels inside

Darlington’s Unit 2 reactor, ahead of schedule.

Learn more! Visit www.opg.com to watch a new Darlington

Refurbishment project video titled ‘Building Together’, which explains

what’s happening right now, during the reactor reassembly phase.

ON TRACK FOR SUCCESS

OPG and Bruce Power

signed a Memorandum

of Understanding in

2015, confirming their

commitment to ongoing

collaboration towards

improving efficiencies

in both organizations’

refurbishment programs.

A worker training in front of the full-scale replica of a reactor calandria face at

the Mock-up and Training Facility at OPG’s Darlington Energy Complex.

Even before project execution began, the Darlington

Refurbishment team sought, gathered and incorporated

industry knowledge and experience pertaining to

both nuclear and other mega-projects into its project

planning.

This information, combined with what has been learned

during refurbishment of Unit 2 — the first Darlington unit

to undergo its mid-life overhaul — is being leveraged to

ensure the safe and efficient execution of the project.

For example, a full-scale nuclear reactor mock-up was

built at the Darlington Energy Complex after operating

experience from other projects showed that schedule

and cost could be negatively impacted by a lack of

trained workers and tooling compatibility.

“The Darlington mock-up has definitely paid for itself,

allowing workers to hone their skills in a non-nuclear

environment before moving into the actual reactor,”

said OPG’s Mike Allen, Senior Vice President, Nuclear

Refurbishment. “It’s played a crucial role in this project

remaining on time and on budget.”

Knowledge gained during Unit 2’s refurbishment is

helping shape plans for Unit 3’s overhaul, set to begin

in 2020.

“We are continuous learners,” said Bill Owens, Vice

President of Unit 3 Refurbishment Execution. “That

means constantly striving to find better ways to do

what we do. And in turn, that means better value for the

province as we move forward on Canada’s largest clean

energy project.”

LESSONS LEARNED LEAD TO COST SAVINGS ON REFURBISHMENT

Pickering Mayor

David Ryan tests

virtual reality

glasses at an event

recognizing Tetra

Tech’s work on

the Darlington

Refurbishment

project, March 2018.

INNOVATION AT WORK

PLANNING FOR THE FUTURE

UNIT 3 GETS GREEN LIGHT FOR REFURBISHMENTIn February, OPG recognized reaching the halfway mark on the Unit 2 refurbishment schedule and the green lighting of

Unit 3 refurbishment at an event at the Darlington Energy Complex.

“The go-ahead to move forward with the next unit is a testament to the hard work and dedication of the Darlington

Refurbishment team,” said OPG President and CEO Jeff Lyash. “I thank OPG’s employees, the community and our many

partners across the province for the hard work that’s gone into the planning of this project.”

The Unit 3 Refurbishment team is leveraging the opportunity to incorporate lessons learned from Unit 2. Detailed planning and

engineering replications are underway and on track. Planning schedules are under development and will focus on integration

and coordination with ongoing work on Unit 2 refurbishment and across the station. Additionally, a thorough assessment of

risks and opportunities is being reviewed, including the resource challenges of undertaking two units simultaneously.

The refurbishment and continued operation of Darlington up to 2055 will contribute a total of $90 billion to Ontario’s GDP

and increase employment across the province by an average of 14,200 jobs annually, including over 2,600 jobs onsite at

Darlington. Refurbishment will also secure 3,500 megawatts of affordable, reliable and emissions-free power: the equivalent

of taking two million cars off the road.

“Darlington is an essential source of electricity in Ontario and plays a key role in our economy,” said Lyash. “The station has

delivered clean, reliable, low-cost power since 1990, and we are continuing to deliver on our commitment to complete this

project on time and on budget.”

Members of the Darlington Refurbishment project

recognize Unit 2 and Unit 3 milestones at an event,

February 2018.

WWW.OPG.COM @opgpics Ontario Power Generation@opg

Ontario Power Generation (OPG) produces almost half the electricity that Ontario homes, schools, hospitals and business rely on each day. After decades of reliable power generation, OPG’s Darlington Nuclear Generating Station is receiving a mid-life refurbishment that will benefit

Ontarians for another 30 years.

To learn more about Darlington Refurbishment, the largest clean energy project in Canada, visit our website at www.opg.com and subscribe to the Darlington Refurbishment Project Newsletter.

Have questions? Contact us at darlingtonrefurb@opg.com.

Feeder tubes manufactured by BWXT at a Whitby, Ont. warehouse prior to shipment to the Darlington Nuclear Generating Station, for OPG’s Darlington Refurbishment project.