Reactor Engineer Jobs in Ontario (NOW HIRING)

Mechanical Engineer (Advanced Manufacturing & Reactor Hardware)

Work Location: Waterloo, ON (5 days/week - Mon-Fri)

About Canadian Strategic Missions Corp. (CSMC)
Canadian Strategic Missions Corporation is building the capabilities that will shape Canada's future in space, defence, and energy. We focus on developing dual use systems that address critical challenges here on Earth while enabling sustained human activity beyond it.

Ina short time, CSMC hasestablishedreal momentum. Wehave secured significant government investment to advance next generation micro nuclear reactors in partnership with leading institutions, alongside expanding a portfolio of technologies designed for remote environments, national defence, and future space missions. These efforts reflect a broader ambition to deliver reliable power and critical infrastructure where it matters most.
Our work is grounded in close collaboration with government and guided by a clear sense of purpose: to build sovereign capability at a time when it has never been more important. We care deeply about execution, long term impact and earning the trust required to deliver systems that will service Canada and its allies for decades.

CSMC is a company for builders. We are a group of people drawn to hard problems, meaningfulimpactand the opportunity to shape systems that matterata national and global scale. We are building a team that thrives in ambiguity, values execution, and is motivated by mission and impact.

About the Role

CSMC is seeking a highly capable Mechanical Engineer to support the design, development, fabrication, and qualification of advanced reactor hardware and other mission-critical mechanical systems.

This role is not focused on supporting mature production lines. Instead, you will work from first principles to determine how complex hardware should be designed, manufactured, assembled, inspected, tested, and scaled. You will collaborate closely with engineering, suppliers, fabricators, and manufacturing partners to bring hardware from concept through prototype and into production readiness.

The ideal candidate combines strong mechanical engineering fundamentals with deep practical knowledge of fabrication, welding, machining, materials selection, and manufacturing processes. You should be comfortable evaluating multiple manufacturing approaches, identifying technical risks, and developing practical solutions for high-integrity hardware operating in demanding environments.

This position is ideal for someone who thrives in fast-moving environments, brings structure to ambiguity, and enjoys building complex hardware from the ground up.

Key Responsibilities

Mechanical Design & Hardware Development

• Design and develop pressure-boundary components, welded assemblies, structural systems, and mechanical hardware.
• Translate engineering requirements into practical, manufacturable hardware solutions.
• Create engineering drawings, specifications, manufacturing packages, and technical documentation.
• Perform design trade studies considering manufacturability, cost, performance, quality, and schedule.
• Apply Design for Manufacturing (DFM) and Design for Assembly (DFA) principles throughout hardware development.
• Support design reviews and technical decision-making activities.

Manufacturing Development

• Develop manufacturing strategies for pressure vessels, welded structures, machined parts, and mechanical assemblies.
• Evaluate manufacturing routes including:
  • Plate rolling
  • Forming
  • Machining
  • Welding
  • Heat treatment
  • Casting
  • Forging
  • Cladding
• Determine which operations should be performed internally versus outsourced.
• Develop manufacturing work instructions, build procedures, and fabrication documentation.
• Design or support the development of tooling, fixtures, and assembly methods.

Welding, Fabrication & Pressure Systems

• Support development of pressure-boundary and structural hardware.
• Work directly with fabricators and suppliers to ensure manufacturability and weldability.
• Participate in weld design reviews and fabrication planning activities.
• Support development of inspection, testing, and qualification programs.
• Ensure fabrication approaches align with applicable codes, standards, quality requirements, and safety expectations.

Prototype Builds & Testing

• Support fabrication, assembly, integration, and qualification of prototype hardware.
• Develop testing plans and validation strategies.
• Troubleshoot fabrication, assembly, and performance issues.
• Analyze test results and implement design improvements.
• Support first-article inspections and manufacturing readiness reviews.

Supplier & Program Support

• Identify and qualify suppliers, fabricators, machine shops, and manufacturing partners.
• Collaborate with procurement and supply chain teams on supplier selection and technical evaluations.
• Support manufacturing readiness, process capability development, and supply chain qualification activities.
• Participate in technical reviews with external partners and stakeholders.

Continuous Improvement & Quality

• Identify manufacturing risks and implement mitigation plans.
• Lead structured root-cause investigations and corrective actions.
• Support quality initiatives including:
  • PFMEA
  • Control plans
  • NCR investigations
  • Process qualification activities
• Analyze production and test data to identify bottlenecks, variability, and improvement opportunities.

Required Qualifications

• Bachelor's degree in Mechanical Engineering.
• Minimum 4 years of experience designing and developing fabricated or welded mechanical systems.
• Strong knowledge of manufacturing processes including:
  • Welding
  • Machining
  • Fabrication
  • Forming
  • Mechanical assembly
• Experience working with:
  • Low-alloy steels
  • Carbon steels
  • Stainless steels
  • Aluminum alloys
• Strong understanding of:
  • GD&T
  • Tolerance stack-ups
  • Materials selection
  • Manufacturing drawings
  • Design documentation
• Experience working directly with machine shops, weld shops, fabricators, and industrial suppliers.
• Ability to develop hardware and manufacturing solutions from first principles.
• Strong problem-solving, communication, and project execution skills.
• Ability to work effectively in a fast-paced, multidisciplinary engineering environment.

Preferred Qualifications

• Experience designing pressure vessels, pressure piping, boilers, reactors, or pressure-boundary systems.
• Familiarity with:
  • ASME BPVC
  • ASME Section III
  • ASME Section VIII
  • Pressure equipment design and fabrication
• Experience in:
  • Nuclear
  • Aerospace
  • Defence
  • Automotive
  • Heavy industrial equipment
  • Energy systems
• Experience supporting hardware development from concept through fabrication and testing.
• Familiarity with welding procedures, weld qualification, and NDE processes.
• Experience with manufacturing qualification and production readiness programs.
• Knowledge of PFMEA, process validation, and quality management systems.
• Experience working in startup, R&D, prototype development, or growth-stage engineering organizations.
• Professional Engineer (P.Eng.) designation or eligibility for registration is considered an asset.

Why Join CSMC

CSMC is building technologies that will shape Canada's future in energy, space, and national security. You'll join a team of engineers, scientists, and missiondriven builders who care deeply about solving hard problems that matter. We move quickly, support each other, and take pride in doing work that has real impact. Along the way, you'll have access to competitive compensation, benefits, and equity, and the chance to grow with a company that values ownership, curiosity, and technical excellence.

Employment Eligibility
CSMC works withhighly sensitivenuclear, defence, and aerospace technologies, and all roles require eligibility for federal security screening and compliance with controlled goods and export regulations. Candidates must be legally authorized to work in Canada, able to obtain andmaintainGovernment of Canada security clearance, and eligible to meet foreign affiliation and export control requirements. These conditions aremandatoryBona Fide Occupational Requirements and reflect the need to securely develop and protect nationally significant capabilities.