Canada and the Republic of Korea have a long history of nuclear cooperation, which began in the 1970s when Korea selected CANDU® technology as part of its strategy to diversify reactor technologies and strengthen energy security
Construction of Wolsong Unit 1, Korea’s first CANDU reactor, began 50 years ago in 1976, with commercial operation commencing in 1983. In July 2011, Wolsong 1 was connected to the grid after an 839‑day outage for retubing, becoming the first CANDU 6 reactor to be successfully retubed.
Following Wolsong 1’s success, Korea reaffirmed its commitment to CANDU technology by signing contracts for Wolsong Units 2, 3, and 4 in the early 1990s. These units entered commercial operation between 1997 and 1999, marking a transition toward greater Korean industrial participation and technology transfer. This period helped establish Korea Hydro & Nuclear Power Co., Ltd. (KHNP), and predecessor KEPCO entities, as a globally respected CANDU operator with growing domestic capability supported by Canadian expertise.
Today, Canada and the Republic of Korea are entering a period of renewed strategic alignment across advanced industries, energy security, and clean energy transformation. At the centre of this engagement is nuclear power, supported by increasingly deep cooperation between Candu Energy, an AtkinsRéalis company, and KHNP.
In an era of heightened geopolitical uncertainty, this long-standing partnership is taking on renewed strategic value and importance, supported by five decades of trust between Canada and the Republic of Korea. Recent exchanges related to Wolsong’s continued operation, life extension planning, and broader bilateral engagement point to a collaboration that is moving from intent to execution, with tangible benefits for operators, supply chains, and national energy objectives on both sides.
A Broader Strategic Context: Canada–Korea Engagement
Nuclear cooperation between Canada and Korea is unfolding within a wider framework of active bilateral engagement. Senior level discussions and commercial exchanges have intensified in recent months with a Canadian trade mission in March and ongoing defence-adjacent collaboration. AtkinsRéalis, Candu Energy’s parent company, signed a tripartite agreement with Hanwha Ocean and LIG Defense & Aerospace. This agreement builds on a Memorandum of Understanding signed in April to establish a collaboration framework for the potential development of defence infrastructure in Canada.
Together, these engagements reflect a deliberate effort to build on a long and successful nuclear partnership, deepening long-term multi sector collaboration and reinforcing trusted industrial ties between the two countries beyond individual projects.
Within this context, nuclear stands out as a foundational capability, supporting energy security, industrial competitiveness, and decarbonization goals that both countries are pursuing at scale.
The strength of the Candu Energy–KHNP partnership lies in its complementarity. Candu Energy brings decades of successful CANDU life extension and retubing experience, while KHNP offers world-class nuclear operations, disciplined project execution, and a mature domestic supply base. Together, they provide a low‑risk, execution‑ready model for extending asset value while maintaining the highest safety standards.
Wolsong Units 2, 3, and 4: From Continued Operation to Retube Execution
Engagement related to the continued operation and long-term sustainability of Wolsong Units 2, 3, and 4 has progressed constructively at both the executive and working levels. Since March, Candu Energy and KHNP teams have been meeting regularly, including multiple face‑to‑face sessions, to align on technical, regulatory, and execution considerations associated with a future retube.
Most recently, a KHNP team visited Canada in late May as discussions progressed toward more practical and implementation-focused planning. A central focus of these engagements was the supply chain for key components and tooling, with both parties working collaboratively to identify and address critical challenges to accelerate overall execution.
At the heart of these discussions is the value of leveraging Candu Energy’s extensive life extension experience, including end‑of‑pressure‑tube-life management, retubing execution, and long-term asset stewardship. Canada’s approach to licensing based on effective full‑power hours (EFPH) and long‑term operating frameworks offers an alternative to more rigid, date‑based licensing constructs. For Korea, alignment with internationally proven life‑extension and continued‑operation practices could unlock additional operating value while maintaining the highest safety standards.
Crucially, collaboration is now extending beyond policy and regulatory dialogue. Both sides are actively reviewing supply chain readiness, execution models, and delivery sequencing, signaling a transition from conceptual alignment to implementation planning where Candu Energy’s retube experience and KHNP’s operational excellence are highly complementary.
Importantly, continued operation and retubing also preserve critical nuclear skills on both sides of the partnership, ensuring workforce readiness for future projects in Korea and internationally.
Wolsong Unit 1: A Strategic Option for Energy Security and Decarbonization
In parallel, restarting Wolsong Unit 1 is a compelling opportunity: the unit has already undergone major refurbishment, including successful retubing, and could quickly restore a proven source of reliable, large scale clean baseload power to meet Korea’s rising industrial energy demand, particularly POSCO’s steelmaking transition.
A demonstration plant is under construction to commercialize HyREX, POSCO’s proprietary hydrogen reduction ironmaking technology, despite not yet having sufficient clean baseload power to support operations at scale. In this context, Wolsong Unit 1 represents an immediate and viable option capable of delivering the reliability, scale, and emissions free electricity required for hydrogen‑enabled steel production.
From an energy systems perspective, the restart of Wolsong 1 presents a clear win‑win‑win:
- For Korea: strengthened energy security and industrial competitiveness
- For industry: firm, clean power to enable hydrogen production and maintain global leadership in low carbon steel
- For the environment: meaningful emissions reductions through nuclear-enabled decarbonization.
POSCO has expressed interest in a commercial framework under which it would fund the restart and ongoing operation of the unit, subject to feasibility, regulatory approval, and government decision making.
From Intent to Execution
Taken together, recent developments demonstrate steady, relationship-driven progress. Continued operation and retube discussions for Wolsong 2/3/4 are active and increasingly execution focused. Feasibility work for a Wolsong 1 restart is advancing in support of decarbonization and hydrogen production. Engagement is broad and multi-layered, encompassing a wide range of stakeholders and levels of collaboration, while the broader Canada–Korea strategic partnerships continue to provide depth and long-term optionality beyond the nuclear sector alone.
For Candu Energy and KHNP, this collaboration combines proven CANDU life extension expertise with world-class nuclear operations, creating a platform for safe, reliable, and economically compelling solutions to some of the most pressing energy challenges facing industrial economies today.
As both countries navigate energy transition, industrial decarbonization, and geopolitical uncertainty, the Candu–KHNP partnership at Wolsong offers a compelling model – one grounded in technical excellence, proven execution, and long-term strategic trust. This collaboration is not only about sustaining existing nuclear assets, but also about demonstrating how trusted nuclear collaboration can enable secure, low‑carbon energy systems for decades to come.
Written by:
Gary Rose, Executive Vice-President, Nuclear Canada and President Candu International, Inc, Candu Energy Inc., an AtkinsRéalis Company
Maura McDonald, Vice-President, Key Account & Stakeholder Management, Candu Energy Inc., an AtkinsRéalis Company
