Principal Engineer, System Design

TerraPower LLC.; Bellevue (WA); On-site; USD 168,316 - 252,475; Full time

Benefits offered by this job

Competitive compensation

Discretionary incentive program

Medical, vision, dental

Life and disability benefits

401k plan

Generous PTO 21 days/year

Relocation assistance

Professional and educational support

Job summary

TerraPower LLC in Bellevue, Washington, seeks a Principal Engineer to support the Natrium Demonstration Project, focusing on the design and delivery of primary reactor systems. You will guide multidisciplinary teams, define requirements, and deliver critical design documentation for licensing and construction.

Join a high‑impact program advancing first‑of‑a‑kind nuclear technology, with opportunities to shape safety, reliability, and performance while collaborating across engineering, licensing,

Qualifications

• BS in Mechanical Engineering or related discipline from an accredited university.
• 15+ years of relevant experience. (Experience Level may be substituted for advanced degree.)
• Experience in designing complex structures, multi-disciplinary integration, and mechanical pressure vessel equipment.
• Strong understanding of configuration management principles and design control tools in nuclear/industrial settings.
• Experience with nuclear reactors and systems, high temperature pressure vessels, or similar systems is highly desired.
• Experience working to quality standards on design activities (ASME NQA‑1 or ISO 9001).
• Excellent technical writing, communication, and presentation skills.
• Self-starter who can coordinate and work within a design team with minimal direction.
• Ability to manage multiple objectives and design constraints.

Responsibilities

• Drive alignment across multidisciplinary engineering teams to define and refine system requirements.
• Design nuclear and industrial mechanical systems including requirements definition, analysis, specifications, and drawings.
• Develop and maintain system architecture and design documentation (e.g., DBDs, P&IDs, Interface Control Documents).
• Establish equipment design bases including regulatory criteria and performance criteria.
• Evaluate technology development needs and implement development programs for novel technologies.
• Ensure designs consider operability, maintainability, and reliability.
• Manage technical interfaces with suppliers and review deliverables.
• Prepare engineering change packages including calculations and drawings.
• Promote continuous learning and application of nuclear industry best practices.
• Interface with and support licensing activities for construction and operation licenses.
• Participate in project design reviews to verify compliance and completeness.

Skills

Technical writing

Communication skills

Presentation skills

Self-starter

Team coordination

Multidisciplinary design

Education

B.S. in Mechanical Engineering

Tools

ASME NQA-1

ISO 9001

Job description

TerraPower is a nuclear technology company based in Bellevue, Washington. At its core, the company is working to raise living standards globally through a more affordable, secure, and environmentally friendly form of nuclear energy along with innovations in medical isotopes to improve human health. In 2006, TerraPower originated with Bill Gates and a group of like-minded visionaries who evaluated the fundamental challenges to raising living standards around the world. They recognized energy access was crucial to the health and economic well‑being of communities and decided that the private sector needed to take action and create energy sources that would advance global energy deployment. TerraPower’s mission is to be a world leader in new nuclear technologies, while developing innovators and future leaders in the nuclear field. As a result, the company’s activities in the fields of nuclear energy and related sciences are yielding significant innovations in the safety and economics of nuclear power, hybrid energy and medical applications – all for significant human health benefits.

TerraPower is seeking to hire highly motivated and forward‑thinking professionals who are interested in focusing on advanced nuclear reactor research and development and influencing change within the nuclear power landscape and bringing forward the critical production of medical isotopes. TerraPower is an Equal Opportunity Employer. We do not discriminate in hiring on the basis of sex, gender identity, sexual orientation, race, color, religious creed, national origin, physical or mental disability, protected Veteran status, or any other characteristic protected by federal, state, or local law.

Principal Engineer, System Design

TerraPower, LLC. is seeking a Principal Engineer supporting the Natrium Demonstration Project. This role will support the ongoing design and delivery of the Natrium primary systems. The Natrium primary systems comprise those reactor systems responsible for heat transport, reactivity control, and containment of the reactor fuel and its coolant. You’ll collaborate with project managers, design engineers, analysts, test engineers, and other engineering specialties in a high‑performing, multi‑disciplinary environment to deliver the Natrium primary systems.

Join us in this high‑impact role to help advance a first‑of‑a‑kind nuclear reactor towards commercial development.

Responsibilities

• Drive alignment across multidisciplinary engineering teams (nuclear, thermal hydraulic, mechanical, instrumentation and controls, civil‑structural) to define and refine system requirements
• Design nuclear and industrial mechanical systems, including: requirements definition, analysis, specifications, and system drawings.
• Develop and maintain system architecture and design documentation (e.g., Design Basis Documents, P&IDs, Interface Control Documents).
• Establish equipment design bases, including: regulatory criteria, regulatory standards, functional criteria, performance criteria, and failure mode and effects.
• Evaluate technology development requirements and implement development programs for novel technologies or approaches.
• Ensure designs consider lifecycle factors including operability, maintainability, and reliability.
• Manage technical interfaces with suppliers, including review and verification of deliverables.
• Prepare engineering change packages including calculations, design reports, design drawings, and design specifications
• Promote continuous learning and application of nuclear industry best practices
• Interface with and support licensing activities needed to obtain both the construction and operating licenses for the reactor systems
• Participate in project design reviews at project milestones and periodic assessment points to verify compliance and completeness of design.

Key Qualifications and Skills

• B.S. in Mechanical Engineering or related discipline from an accredited university
• 15+ years of relevant experience
  • Experience Level may be partially substituted for advanced degree depending on position relevance
• Demonstrated experience in developing design of complex structures, multi‑discipline integration, and mechanical pressure vessel equipment.
• Strong understanding of configuration management principles, as well as knowledge of design control tools application on nuclear or similar complex industrial applications.
• Previous experience with nuclear reactors and systems, high temperature pressure vessels, or similar system design is highly desired.
• Experience working to quality standards on design activities, such as ASME NQA‑1 or ISO 9001.
• General or working knowledge of ASME BPVC Section III is highly desired.
• Professional engineering licensure is desired but not required for this position.
• Experience in originating and developing technical documentation to support system architecture is preferred.
• Excellent technical writing, communication, and presentation skills.
• Attention to detail and aspiration for technical excellence.
• Candidate must be a self‑starter and possess ability to coordinate and work within a design team with minimal direction.
• Ability to handle projects that include many competing objectives and design constraints, with ability to resolve conflicts between objectives.
• Ability to work on simultaneous tasks that require a multi‑disciplinary approach.

This position is subject to qualification requirements in accordance with ANSI/ANS 3.1. Candidates must meet the minimum education and experience criteria applicable to the role, including relevant nuclear industry experience where required. Verification of data will be part of the hiring process.

Job Functions

Job Functions are physical actions and/or working conditions associated with the position. These functions may also constitute essential functions for the job which the employee must be able to fulfill, with or without accommodation. Information provided below is to help describe the job so that the applicant has a reasonable understanding of the job duties/expectations. An applicant's ability to perform and/or tolerate these actions and conditions will be discussed and workplace accommodations may be made on a case‑by‑case basis following an individualized assessment of the applicant and other considerations, including but not limited to any governing safety standards.

• Motor Abilities: Sitting for extended periods, bending/stooping, grasping/gripping, fine motor control (hands)
• Physical exertion and/or requirements: Minimal, with ability to safely lift up to 25 pounds.
• Special Senses: Visual and audio focused work
• Work Conditions: Stairs, typing/keyboard, standard and/or sitting working environment of >8 hours/day
• Travel required 0-10%

TerraPower’s technology is controlled for export by various agencies of the U.S. Government. TerraPower must evaluate applicants who are foreign nationals (other than asylees, refugees, or lawful permanent residents) in accordance with U.S. Government export control requirements. To facilitate TerraPower’s export control reviews, you will be asked as part of the application process to identify whether you are a U.S. Citizen or national, asylee, refugee, or lawful permanent resident of the United States. Government export authorization approval times vary. Based on the business needs for a particular position, TerraPower may not consider a foreign national from a country if it is impracticable to obtain timely Government export approval.

Job details

Salary Range: $168,316 - $252,475

Any salary offered within the posted salary band is based on market data and commensurate with the selected candidate’s qualifications and experience. This range is specific to Washington State.

• Competitive Compensation
• Salary, eligible to participate in discretionary short‑term incentive payments
• Comprehensive Medical and Wellness Benefits
  • Medical
  • Vision
  • Dental
  • Life and Disability
  • Gender Affiliation Benefits
• 401k Plan
• Generous Paid Time Off (PTO)
  • 21 days of annually accrued PTO
• Generous Holiday Schedule
  • 10 paid holidays
• Relocation Assistance
• Professional and Educational Support Opportunities

The application deadline for this role is August 5, 2026