Principle Engineer, Core Mechanical Test

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

Benefits offered by this job

Competitive compensation

Discretionary short-term incentive

Medical and wellness benefits

401k plan

Generous PTO - 21 days

Generous holiday schedule - 10 paid

Relocation assistance

Professional and educational support

Job summary

TerraPower LLC in Bellevue, WA seeks a Principal Core Mechanical Engineer to lead mechanical test programs for reactor core components. You will design, execute, and document validation campaigns, driving data-based decisions while ensuring safety and regulatory compliance.

Responsibilities include defining test specs, coordinating instrumentation, and mentoring engineers. Nuclear experience and strong collaboration with vendors are highly valued in this role.

Qualifications

• 12+ years of relevant engineering experience with a B.S. degree or equivalent.
• Degree in Mechanical Engineering or related technical discipline.
• Hands-on mechanical testing or system development experience.
• Strong background in mechanical system behavior: force, displacement, dynamics, vibration, and environment exposure.
• Experience in nuclear industry or regulated environment with standards such as 10CFR50 or ASME NQA-1.
• Experience coordinating with vendors or external partners for fabrication and testing.
• Ability to lead complex projects and resolve conflicting priorities.
• Proficiency with multiple engineering tools including ANSYS, SolidWorks, LabVIEW, AutoDesk, Jira/Confluence.

Responsibilities

• Lead development and documentation of mechanical test plans and validation strategies.
• Apply engineering analysis to evaluate test outcomes and identify root causes.
• Oversee complex mechanical testing campaigns from concept to final reporting.
• Define test specifications, inputs, instrumentation, and success criteria.
• Select and validate measurement instrumentation (force, displacement, strain, etc.).
• Coordinate fixture design, control systems, and lab planning.
• Lead troubleshooting and optimization of mechanical components.
• Collaborate across teams to address reactor core mechanical challenges.
• Provide vendor oversight for procurement, testing, and fabrication partnerships.
• Support safe execution of testing following TerraPower processes and regulations.
• Communicate project status and risks to leadership; mentor junior engineers.

Skills

Mechanical testing

Data analysis

Root cause analysis

Project management

Education

Bachelor's degree in Mechanical Engineering

Tools

SolidWorks

LabVIEW

AutoDesk

Jira/Confluence

Job description

Principle Engineer, Core Mechanical Test

Bellevue, Washington, United States

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 Core Mechanical Engineer

The Principal Core Mechanical Engineer will serve as a senior technical leader supporting mechanical development and validation for reactor core components and associated systems. The role includes designing and overseeing test programs, performing root‑cause investigations, coordinating vendor activities, ensuring high‑quality documentation, and driving technical decision‑making. The engineer will leverage advanced mechanical testing techniques, data analysis, and system‑level engineering to ensure the performance, reliability, and safety of mechanical systems critical to TerraPower’s reactor programs.

Responsibilities

• Lead development, execution, and documentation of mechanical test plans, design specifications, and validation strategies for reactor core mechanical systems.
• Apply quantitative, statistical, and engineering analysis techniques to evaluate test outcomes, identify root causes, and drive data‑based conclusions.
• Develop and oversee complex mechanical testing campaigns from concept through execution and final reporting.
• Translate conceptual requirements into detailed mechanical test specifications, including design inputs, instrumentation strategies, and success criteria.
• Define, select, and validate measurement instrumentation (force, displacement, strain, temperature, vibration, loading, etc.).
• Coordinate cross‑functional activities including fixture design, control system integration, and laboratory or facility planning.
• Lead troubleshooting, failure analysis, and optimization of mechanical components and systems.
• Collaborate across teams to address technical challenges related to reactor core mechanical behavior, system integration, and experimental analysis.
• Provide oversight and coordination with vendors for procurements, specialized testing, and fabrication partnerships.
• Support safe execution of mechanical testing activities while following TerraPower processes and Washington State regulations.
• Communicate project status, risks, technical outcomes, and recommended paths forward to leadership and stakeholders.
• Mentor junior engineers and contribute to developing best practices for mechanical testing and system analysis.

Key Qualifications and Skills

• 12+ years of relevant engineering experience with a B.S. degree; or equivalent experience with an advanced degree.
• Degree in Mechanical Engineering or a directly related technical discipline.
• Demonstrated hands‑on mechanical testing or system development experience.
• Strong background in mechanical system behavior including force/displacement application, structural deflection, dynamic loading, vibration/impact, and environmental exposure.
• Experience working in the nuclear industry or in a regulated environment requiring compliance with standards such as 10CFR50, ASME NQA‑1, or similar nuclear quality and safety programs.
• Experience working with large, complex mechanical systems strongly preferred.
• Experience in project management strongly preferred.
• Experience with multiple types of testing (R&D, acceptance, validation, qualification).
• Experience performing, documenting, and post‑processing mechanical experiments.
• Ability to lead complex projects with multiple technical objectives and resolve conflicts between competing priorities.
• Experience coordinating with vendors or external partners for fabrication and testing.
• Ability to operate within a lightly structured environment requiring first‑principles engineering.
• Ability to perform advanced structural analysis using ANSYS, including nonlinear behavior, dynamic loading scenarios, thermal‑mechanical coupling, and verification of complex core mechanical components; highly desired.
• Familiarity with engineering tools such as SolidWorks, LabVIEW, AutoDesk, Jira/Confluence, and Microsoft Office 365 preferred.
• High level of integrity, communication skills, and a strong desire to foster teamwork.

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 Affimation 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

Voluntary Self-Identification

For government reporting purposes, we ask candidates to