Language selection


External Advisory Committee on Pressure Tubes

Established on July 30, 2021, the External Advisory Committee (EAC) on Pressure Tubes was created by the Commission, under its statutory authority to establish advisory committees, to complement the expertise of Commission members, and to provide an external perspective for the benefit of Commission members in their role as decision-makers.

Its goal is to provide Commission members with objective and impartial expert advice in technical matters related to pressure tubes, notably hydrogen equivalent (Heq) exceedances and modelling.

In July 2023, 2 EAC members had their terms extended so that they could continue to provide advice and expertise with respect to pressure tubes, should it be required by the Commission.


In July 2023, the EAC provided its final report on its work, respecting the review of elevated Heq concentrations in CANDU pressure tubes and pressure tube fitness for service. The EAC found that CANDU reactors remain fit for service and that Canada’s nuclear reactors could continue to operate safely while additional work is completed.

The EAC also provided several recommendations for future advisory committees and for improving the clarity of communication.

You can read the full report here: External Advisory Committee on Pressure Tubes: Final Report

Structure and terms of reference

The EAC is guided by the principles of impartiality, fairness, timeliness, responsiveness and transparency.


  • are appointed for 2 years
  • may be from universities, science-based government departments, private consultancy firms and other institutions (e.g., international regulators, standards-setting groups)
  • a majority of the members must be based in Canada and have experience with CANDU technology

Interactions between the External Advisory Committee and the Commission were made public as Commission Member Documents posted for each hearing and/or meeting.

Read the full Terms of Reference for the EAC on Pressure Tubes

CNSC President and CEO remarks on the role of External Advisory Committee on Pressure Tubes

Former CNSC President and CEO Rumina Velshi details the role of the External Advisory Committee (EAC) ahead of the September 10, 2021, Commission hearing pertaining to the regulatory orders issued to Bruce Power and Ontario Power Generation in July 2021. The EAC will provide Commission members with supplemental expert advice on pressure tubes, hydrogen equivalent exceedances and predictive modelling.


The Commission established the External Advisory Committee on July 30, 2021, under its statutory authority to establish advisory committees, in order to complement the expertise of Commission members and CNSC specialists, and to provide external perspectives for the benefit of Commission members in their role as decision-makers.

This Committee will provide Commission members with expert information and advice related to pressure tubes, Heq exceedances, and predictive modelling.

Over the course of their two-year appointment, the Committee members will be guided by principles of objectivity, impartiality, fairness, timeliness, responsiveness and transparency.

Current members

The following EAC members were appointed for a 2-year term, effective July 30, 2021, and had their term extended for several months so that their services may be of further use to the Commission, should they be required.

Dr. Mark R. Daymond

Professor and NSERC/UNENE Senior Industrial Research Chair in Nuclear Materials, Dept. of Mechanical and Materials Engineering, Queen’s University

Education Credentials:
BSc, Physics and Theoretical Physics, University of Cambridge
PhD, Materials Science and Metallurgy, University of Cambridge

Dr. Daymond is a professor in the Department of Mechanical and Materials Engineering at Queen’s University in Kingston, Ontario.

He is an Industrial Research Chair in Nuclear Materials supported by both the Natural Sciences and Engineering Research Council and the University Network of Excellence in Nuclear Engineering. He is also a Tier 1 Canada Research Chair in Mechanics of Materials. At Queen’s University, he is the Director of the Reactor Materials Testing Laboratory, which includes a recently commissioned accelerator facility focused on irradiation and characterization of materials for nuclear power applications.

Recognized internationally, Dr. Daymond has an extensive career as a leader in materials characterization and its application to understanding mechanical properties; the use of advanced modelling to understand mechanisms operating in materials; and materials for nuclear applications. He has made contributions in several areas of research, including geo- and bio-mechanics, but with a focus on structural engineering materials.

Throughout his career, Dr. Daymond has served on various committees internationally, including the Canadian Institute for Neutron Scattering, the U.S. Advanced Photon User Source Steering Committee and the Versailles Agreement on Materials and Standards. He currently serves on a Task Force for Ontario Synchrotron Consortium. He has approximately 300 refereed journal articles published or accepted for publication.

Dr. Paul Spekkens

Retired from Ontario Power Generation

Education Credentials:
BSc (honours) Chemistry, University of Ottawa
PhD Chemistry, McMaster University

With over 44 years of experience in the nuclear industry, Dr. Paul Spekkens’ extensive career includes more than 20 years in senior management roles with Ontario Power Generation (OPG), where he was responsible for multiple projects on feeder integrity and fuel channel life extensions programs for the nuclear fleet. In addition, he was responsible for the leadership of OPG’s nuclear research and development (R&D) program for the CANDU Owners Group (COG) and a similar program for the University Network of Excellence in Nuclear Engineering (UNENE).

Throughout his career, Dr. Spekkens worked with various reactor designs, representing the CANDU fleet on a number of technical committees at the U.S. Electric Power Research Institute (EPRI) and through participation in ranking large-reactor designs from around the world.

Dr. Spekkens has served for more than 10 years on the Board of Directors for COG and the Board of Directors for UNENE, as well as representing the Canadian CANDU fleet on the EPRI Nuclear Power Council. In addition, he has spent several years representing OPG on the Institute of Nuclear Power Operations’ International Participants Advisory Committee.

Since his retirement in 2016, Dr. Spekkens has continued to be an active member in the nuclear community as a consultant for Kinectrics and as a strategic advisor for the COG Small Modular Reactor Technology Forum.

Past members

Dr. John Luxat

Professor and NSERC/UNENE Senior Industrial Research Chair, Department of Engineering Physics, McMaster University

Education Credentials:
BSc (honours) and M.Sc., Electrical Engineering, University of Cape Town
PhD, Electrical Engineering, University of Windsor

Dr. John Luxat is a resident of Dundas, Ontario, and a licensed professional engineer in the Province of Ontario.

Dr. Luxat has broad-ranging experience in nuclear reactor safety, nuclear engineering, and reactor and plant control developed during nearly 50 years in the Canadian nuclear energy field. This experience includes 32 years in the nuclear power industry prior to his appointment as a full professor and Senior Industrial Research Chair in Nuclear Safety Analysis at McMaster University in 2004.

At McMaster, he continues to conduct leading-edge research in nuclear safety, developing major nuclear research infrastructure, while training the next generation of nuclear engineers. His current areas of research focus are: severe accidents in nuclear reactors; probabilistic safety assessment and complementary risk analysis; thermal-mechanical and thermal-chemistry behaviour causing failure of reactor materials and components; and advanced nuclear reactors and small modular reactors.

Dr. Luxat has served on the Board of Directors of AECL and serves on the Board of the American Association for Structural Mechanics in Reactor Technology, the Advisory Board of Terrestrial Energy Inc. and the Advisory Board of the International Association for Structural Mechanics in Reactor Technology. He is also currently Chair of the International Nuclear Energy Academy.

Pressure tubes and their importance to nuclear power in Canada

Pressure tubes are at the heart of all CANDU nuclear power reactors in Canada. During regular nuclear power plant operation, they are exposed to high temperatures, high pressure and intense radiation, which can cause them to deteriorate. Much like with any machine, over time, nuclear reactor parts need to be tested, serviced and replaced.

For more information on pressure tubes and how the CNSC ensures they are safe to operate, visit the CNSC’s fact sheet page .

Related Links

Page details

Date modified: