Atomic Energy of Canada Limited

About AECL

Executive Team

Fred Dermarkar

Fred Dermarkar

President and CEO

Read Bio

Fred Dermarkar is AECL’s President and CEO. He was first appointed in February 2021 for a term of three years and re-appointed in 2024 for another term of three years.

Prior to joining AECL, Fred was President and CEO of the CANDU Owners Group, where he led the not-for‐profit organization to advance collaboration between CANDU nuclear reactor operators worldwide.

Fred has been working in the Canadian nuclear industry for close to 40 years. Throughout his career, he has occupied a variety of key technical and senior leadership positions at Ontario Power Generation in support of the design, commissioning, operation and refurbishment of its CANDU reactors.

Fred has received the Canadian Nuclear Association’s Ian McRae award in recognition of his substantive engineering contributions, leadership and positive influence on the Canadian nuclear industry and the advancement of nuclear energy in Canada, and the Nuclear Excellence Award from the World Association of Nuclear Operators (WANO) in recognition of his contributions to Ontario Power Generation’s overall post-Fukushima response.

As President and CEO of AECL, Fred is leading the organization in its oversight role, seeing that the priorities of Government are delivered safely and efficiently under the Government-owned, Contractor-operated model.

Fred holds a bachelor’s degree in mechanical engineering from the University of Toronto and is a registered professional engineer in the Province of Ontario.

Thomas Assimes

Vice-President, Business
Operations, Chief Financial Officer

Read Bio

As Vice President, Business Operations & CFO, Thomas leads AECL’s finance organization and is responsible for financial operations, reporting, treasury, business services, information technology, corporate finance, controls, risk management, compliance and reporting. He is also responsible for providing strategic leadership of financial management and business initiatives within AECL and financial oversight of the contract with CNL.

Thomas has over 30 years of executive experience in both the private and public sectors. Prior to joining AECL, Thomas held various executive leadership roles in finance at the Montreal Port Authority, CDPQ Infra (a wholly-owned subsidiary of the Caisse de dépôt et placement du Québec), and BC Hydro where he was involved in the successful development, financing and procurement of some of Canada’s largest infrastructure projects.

Thomas has significant international experience, including working as Chief Financial Officer of Olympia Odos S.A., a Public-Private Partnership in Athens Greece, and in banking as Vice-President, Global Trade Finance with TD Securities in Montreal. He holds a BEng in mechanical engineering from McGill University and an MBA from the University of Western Ontario’s Richard Ivey School of Business.

Headshot of Jason Cameron

Jason Cameron

Vice-President, Indigenous and Stakeholder Relations


Read Bio

In his role as Vice-President, Indigenous and Stakeholder Relations, Jason leads on all of AECL’s communications and public affairs functions and works to strengthen the organization’s approach to reconciliation with Indigenous communities and Nations. Jason is also responsible for government and international relations.

For 23 years, Jason has worked across many areas of nuclear regulation at the Canadian Nuclear Safety Commission (CNSC), including nuclear material accountancy, international safeguards, import and export controls, and nuclear security. Most recently, Jason was the Vice-President, Regulatory Affairs and Chief Communications Officer for the CNSC. In this position, he led strategic and regulatory policy functions, including the CNSC’s approach to reconciliation, as well as their internal and external communications programs.

Grant Gardiner

Executive Vice-President Strategy and Business Development


Read Bio

As Executive Vice-President Strategy and Business Development, Grant provides strategic leadership for AECL which includes establishing and implementing strategic plans as well as pursuing and integrating strategic business initiatives. These include leading the implementation of AECL’s corporate strategy, the exploitation and oversight of AECL’s CANDU reactor and other intellectual property as well as AECL’s ESG efforts. Grant also works closely with AECL’s President & CEO to assist with the overall management of the organization, including responsibility for AECL’s legal function under the leadership of the General Counsel & Corporate Secretary.

Between 2015 and 2022, Grant was Vice-President, General Counsel & Corporate Secretary for AECL, representing the organization in all matters of law, legal policy and contract interpretation as well as being a member of the Executive team. Grant was admitted to the Ontario Bar in 1993 and has extensive experience leading organizations and their Boards of Directors through complex legal, governance and compliance landscapes, having served at the general counsel and corporate secretary level for more than 20 years.

Prior to joining AECL, Grant was Senior Vice-President, General Counsel & Corporate Secretary of Nordion, where he led the company through a divestiture of its Target Therapies business and the sale of Nordion. Grant has also previously served as Vice-President, Associate General Counsel, as well as Corporate Secretary, for BlackBerry, and has held leadership roles at other companies such as Cognos Inc. and JDS Uniphase. He holds a Bachelor of Business Administration from the University of Prince Edward Island, an L.L.B. from Osgoode Hall Law School and an ICD.D designation from the Institute of Corporate Directors.

Headshot of Jason Cameron

Amy Gottschling

Vice-President, Science, Technology and Commercial Oversight

Read Bio

As Vice-President, Science, Technology & Commercial Oversight, Amy is responsible for overseeing the performance of Canadian Nuclear Laboratories’ nuclear science and technology projects and programs for the Government of Canada, as well as commercial science and technology projects for third-party customers. 

Prior to joining AECL, Amy was the Vice-President of Radioactive Materials and Chemistry Services at Kinectrics Inc, where she managed a portfolio encompassing research and development, radioactive waste processing and decommissioning planning, radiochemistry, tritium technologies, and medical isotopes. 

Amy has held increasingly management-focused roles at Kinectrics since 2009, transitioning to a leadership role as Vice-President in 2018. Amy successfully completed the International Senior Nuclear Plant Manager Executive Leadership Programme from the World Association of Nuclear Operators WANO and Ontario Power Generation in 2019.   

She holds a BSc and PhD in chemistry and nuclear from Western University in London, Ontario. 

Kathleen Heppell-Masys

Kathleen Heppell-Masys 

Vice-President, Nuclear Operations Oversight

Read Bio

As Vice-President, Nuclear Operations Oversight, Kathleen is responsible for the oversight of CNL activities related to site operations and infrastructure, including nuclear, health, safety, security, and environment operations.

Prior to joining AECL, Kathleen worked with the CNSC for 16 years. In 2009, she was appointed as their Director General of the Directorate of Safety Management and was later appointed as the Director General of the Directorate of Security and Safeguards. In these roles, she was responsible for the development of nuclear regulatory policies and for the technical regulatory oversight of nuclear safety, nuclear security, and emergency management of Canada’s nuclear facilities.  She oversaw the implementation of Canada’s non-proliferation policy, including its non-proliferation controls regime for the import and export of nuclear technology, material, and equipment, and she ensured Canada met its International Nuclear Safeguards obligations. She also worked with National Defence as a Senior Nuclear Specialist, and which was preceded with extensive work experiences with the Canadian Armed Forces as an Aerospace Engineering Officer for the engineering and maintenance of military aircrafts and facilities.

She holds a B.Eng (Fuels and Materials) and a Masters (Nuclear Engineering) from the Royal Military College of Canada in Kingston, Ontario.

David Hess

Senior Procurement and Contracting Executive


Read Bio

As Senior Procurement and Contracting Executive, David (Dave) is responsible for leading the competitive procurement process to renew the contract for the management of Canadian Nuclear Laboratories under AECL’s Government-owned, Contractor-operated model.

Dave has over 25 years of experience in strategic contracting oversight and management through various senior positions with AECL and the United States Federal Government. Between 2015 and 2022, Dave was AECL’s Lead Contracting Officer with responsibility for oversight of the performance of the Contractor and CNL in the management and operation of AECL’s sites.

Prior to joining AECL, Dave headed up a Contracting Office for the Department of Energy’s Office of Environmental Management where he was responsible for the management and oversight of federal contracting staff that provided acquisition and contract management support to fifteen Department of Energy sites, encompassing the negotiation, award and management support of multi-billion dollar complex acquisitions for large-scale environmental management projects.

Prior to that, Dave served as the Lead Contracting Officer for the National Nuclear Security Administration’s multi-billion dollar design, construction and operations contract for a nuclear fuel processing facility that converts excess weapons-grade plutonium into fuel for commercial nuclear reactors. Dave also served in various Lead Contracting Officer positions for the Naval Air Systems Command, during which time he supported the V-22 Osprey and Air Combat Electronics major weapon system programs. Dave holds a Bachelor of Science Degree in Finance from Northern Illinois University and is certified as a Level III Acquisition Professional.

Alastair MacDonald

Vice-President, Decommissioning
and Waste Management

Read Bio

As Vice President, Decommissioning and Waste Management, Alastair ensures that program and contract objectives are met with respect to CNL’s activities to manage AECL’s decommissioning and waste management responsibilities, as well as capital projects to revitalize the Chalk River Laboratories. Oversight areas include: facilities decommissioning, waste management, land remediation and infrastructure investments.

Alastair has over 30 years of experience in the nuclear industry and has worked at sites in the United States and United Kingdom. Most recently, he was responsible for a complex nuclear packaging and transport project at Dounreay, as part of his role with the United Kingdom’s Cavendish Nuclear Ltd.

Graeme Williamson

Lead Contracting Officer


Read Bio

As Lead Contracting Officer, Graeme is responsible for overall day-to-day oversight of the performance of the Contractor and CNL in the management and operation of AECL’s sites. Graeme works with the organization and subject matter experts to assess CNL’s performance in accordance with annual performance measures, including ensuring all contract deliverables are timely, complete and satisfactory, and compliant with all terms and conditions, and make fee determinations as per the contract. Graeme’s responsibilities also include oversight of CNL’s planning documents, including annual and long-term plans.

Between 2015 and 2022, Graeme served as AECL’s Chief Strategy and Planning Officer where he was responsible for all of AECL’s strategy, risk management, planning and reporting activities, and government relations, both domestic and international, as well as for the oversight of CNL’s planning documents. Prior to joining AECL, Graeme had 15 years’ experience with the Government of Canada, including its Central Agencies. Immediately prior to joining AECL, Graeme played a critical role in the restructuring of AECL at Natural Resources Canada, including both the divestiture of AECL’s commercial reactor division and the transformation of its nuclear laboratories from a government organization to a Government-owned, Contractor-operated (GoCo) model.