System One is seeking an experienced Senior Mechanical Engineer to support the design and development of reactor structures and components for a next-generation Generation IV advanced nuclear reactor program. This role is focused on high-integrity nuclear equipment design and requires deep expertise in ASME Section III nuclear design and certification.

The Senior Engineer will work within a high-performing, multidisciplinary team of engineers and scientists developing advanced reactor systems. This role reports to the Reactor Enclosure System Component Manager and plays a critical role in design certification, licensing support, and supplier oversight.

Position Summary

The Senior Mechanical Engineer will lead and execute design solutions for reactor structures and pressure-retaining components, from requirements definition through final design. The successful candidate will be responsible for preparing, reviewing, and certifying Design Specifications (DS) and Design Reports (DR) in accordance with ASME Boiler & Pressure Vessel Code Section III, while supporting regulatory, compliance, and customer deliverables.

Key Responsibilities

• Certify Design Specifications (DS) and Design Reports (DR) for nuclear supports and/or nuclear pressure-retaining components

• Serve as Certifying Engineer, applying professional engineering judgment and signing certifications as required

• Maintain current knowledge of ASME Section III code updates, industry standards, and best practices

• Design reactor structures and components from requirements through final design

• Coordinate inputs and requirements from engineering and project teams to develop robust design solutions

• Perform scoping analyses and design calculations for alternative design options

• Interface with engineering analysis teams to support stress and mechanical evaluations

• Provide technical management and oversight of supplier activities

• Present design results at technical and formal design reviews

• Mentor junior engineers and provide technical direction to subcontractors

• Support continuous improvement and application of nuclear industry best practices

Required Qualifications & Skills

• B.S. in Mechanical Engineering or equivalent (preferred)

• Minimum 8 years of equipment/component design experience

  • Relevant M.S. degree may substitute for 2 years of experience

• Active Professional Engineer (P.E.) license (required)

• Demonstrated working experience with ASME Boiler & Pressure Vessel Code Section III

• Proven experience certifying Design Specifications and Design Reports for nuclear pressure-retaining components

• Strong understanding of ASME Section III, ASME NQA-1, and applicable NRC regulations

• Experience authoring formal design specifications

• Experience in finite element stress analysis, mechanical analysis methods, and commercial tools (ANSYS strongly preferred)

• Excellent technical writing and verbal communication skills

• Strong analytical and problem-solving skills; creative and critical thinker

• High degree of trust and integrity with the ability to communicate openly, demonstrate respect, and foster teamwork

Physical & Work Requirements

• Ability to sit and/or stand for extended periods

• Bending, stooping, grasping, gripping, and fine motor control required

• Ability to safely lift up to 25 pounds

• Repetitive work and visual/audio focused tasks

• Standard office and engineering work environment (>8 hours/day)

• Travel: 0–5%

Additional Information

• Role supports advanced nuclear reactor development programs

• Employment may be subject to U.S. export control regulations

• Candidates may be required to verify work authorization status in accordance with applicable laws