{"id":939561,"url":"https://alion.io/job/terrapower-principal-engineer-safety-methods-2","title":"Principal Engineer, Safety Methods","company":{"id":10977,"name":"TerraPower","domain":"terrapower.com","url":"https://alion.io/company/terrapower","size_band":"501-1000","is_staffing_agency":false,"employer_type":"direct","is_intermediary":false,"listed_via":null,"ats_vendor":"Greenhouse","truth_index":{"grade":"B","score":80,"open_postings":31,"ghost_share":0,"stale_share":0.806,"repost_share":0,"time_to_fill_p50_days":31,"computed_at":"2026-11-12T10:38:37Z"}},"role":"Industrial Engineering","role_family":"Industrial Engineering","seniority":"lead","employment_type":"full_time","work_mode":"on_site","remote_scope":null,"remote_scope_basis":null,"remote_working_hours":null,"hiring_geo_confidence":"structured","locations":["Bellevue, United States"],"countries":["US"],"hiring_countries":[],"hiring_countries_total":0,"salary":{"min":140021,"max":181845,"currency":"USD","period":"year","gross":null,"usd_annual":181845},"salary_estimate":null,"experience_years_min":8,"visa_sponsorship":false,"relocation_package":true,"has_equity":false,"technologies":[{"name":"ASME NQA-1","optional":false},{"name":"RELAP5","optional":false},{"name":"SAS","optional":false}],"status":"live","first_seen_at":"2026-05-21T22:37:32Z","employer_posted_date":"2026-11-11","last_verified_at":"2026-11-13T01:13:53Z","board_verified":true,"closed_at":null,"days_open":175,"trust":{"level":"stale","repost_count":1,"flags":["stale"],"days_open":174},"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.”\nTerraPower 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. \nPrincipal Engineer, Safety Methods\nThis role supports the development, enhancement, and deployment of plant-scale thermal-hydraulic analysis methods and models for the Natrium reactor. Reporting to the Manager, Plant Thermal Hydraulics Methods, the principal engineer supports the creation, improvement and qualification of advanced system-level modeling approaches that enable accurate, robust prediction of plant behavior across operational and transient scenarios.\nThe position requires expertise in system-level thermal-hydraulics, thermal-fluids behavior, computational methods, and scaling analysis supporting benchmarking computational models against experimental data.\nResponsibilities\nSupport verification, validation, and uncertainty quantification activities for plant scale thermal-hydraulic analysis tools.\nDevelop and execute code assessment plans, including validation matrices, test selection, and quantitative comparison methodologies.\nPerform scaling analysis to evaluate the applicability of test data to reference system conditions, including assessment of similarity criteria and scaling distortion.\nInterpret and apply experimental data from separate effects and integral test facilities to support model validation and closure of technical gaps.\nDefine validation needs, develop test requirements, and collaborate closely with test engineering teams to ensure alignment between model gaps and experimental programs.\nDocument V&V methodologies, model assumptions, validation results, and uncertainty analyses for internal design processes and regulatory submittals.\nCollaborate with multidisciplinary teams to support plant design, safety analysis, and licensing workflows.\nApply and improve TerraPower’s SQA and NQA1 modeling quality practices and ensure traceability and configuration control of analysis inputs, models, and results.\nMentor junior engineers in system modeling, validation methodologies, and best practices in code assessment.\nKey Qualifications and Skills\nDegree in Mechanical, Nuclear, Chemical Engineering, or similar field, with 8 plus years in the field of system-level thermal-hydraulic analysis and code assessment for nuclear or complex energy systems.\nDemonstrated experience in code assessment, including model-to-test comparison, validation metric development, and uncertainty quantification.\nHands-on experience working with experimental thermal-hydraulic data, including data analysis, uncertainty evaluation, and comparison against system-level predictions.\nProficiency with system analysis tools (e.g., RELAP5-3D, TRACE, SAS, or equivalent) applied to plant-scale transient and steady-state evaluations.\nStrong foundation in thermal-fluid and reactor system behavior considerations relevant to advanced reactor designs.\nExperience performing scaling analysis to ensure appropriate translation test-scale phenomena, including application of similarity criteria and detailed scaling distortion impact qualifications.\nExperience developing validation strategies, defining data needs, and coordinating with experimental programs.\nExperience with SQA and NQA-1 quality assurance practices for modeling workflows is highly preferred.\nStrong analytical thinking, clear technical communication, and the ability to manage multiple validation tasks in parallel.\nThis 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.\n\nJob Functions:\nJob 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.\nMotor Abilities: Sitting for extended periods, bending/stooping, grasping/gripping, fine motor control (hands)\nPhysical exertion and/or requirements: Minimal, with ability to safely lift up to 25 pounds.\nRepetitive work: Prolonged\nSpecial Senses: Visual and audio focused work\nWork Conditions: Stairs, typing/keyboard, standard and/or sitting working environment of >8 hours/day\nTravel required 0-10%\nTerraPower’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.\nJob details\nSalary Range: $140,021 - $181,845\n\nAny 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.\nJob Type: Full-time\nBenefits:\nCompetitive Compensation\nSalary, eligible to participate in discretionary short-term incentive payments\nComprehensive Medical and Wellness BenefitsMedical\nVision\nDental\nLife and Disability\nGender Affirmation Benefits\n\nParental Leave\n401k Plan\nGenerous Paid Time Off (PTO)21 days of annually accrued PTO\n\nGenerous Holiday Schedule10 paid holidays\n\nRelocation Assistance\nProfessional and Educational Support Opportunities\nTerraPower Career and Benefits information: https://www.terrapower.com/contact-us/careers/","description_format":"text","description_chars":7932,"description_truncated":false,"requirements":{"experience_years_min":8,"management_years_min":null,"team_size_min":null,"manages_managers":false,"education":null,"security_clearance":false,"languages":[]},"benefits":["401k plan","Parental leave","Relocation assistance"],"hiring_locations":[{"name":"United States","iso":"US","kind":"country"}],"hiring_excludes":[],"relocation_offered":true,"industries":["Nuclear Energy","Nuclear Engineering"],"lifecycle":[{"event":"open","at":"2026-09-15T16:34:59Z"},{"event":"close","at":"2026-09-30T10:40:43Z"},{"event":"reopen","at":"2026-10-05T23:13:16Z"},{"event":"close","at":"2026-10-19T09:51:03Z"},{"event":"reopen","at":"2026-10-19T21:19:49Z"},{"event":"close","at":"2026-11-11T08:51:28Z"},{"event":"reopen","at":"2026-11-11T18:58:59Z"}],"visa":[],"liveness":{"score":7,"band":"cold","label":"Long shot","p_open":1,"p_active":0.247,"p_room":0.28,"age_days":174,"expected_fill_days":31,"reasons":["conf:4","stale_co","win:tail","crowd:"],"computed_at":"2026-11-12T10:38:37Z"},"pay":{"stated_usd_annual":181845,"is_top_pay":true},"html_url":"https://alion.io/job/terrapower-principal-engineer-safety-methods-2","json_url":"https://alion.io/job/terrapower-principal-engineer-safety-methods-2.json","meta":{"generated_at":"2026-11-13T03:14:07Z","cache_seconds":300,"methodology":"https://alion.io/methodology","terms":"https://alion.io/terms","contact":"https://alion.io/contact","api":"https://alion.io/developers","about":"Alion is a live layer of people, companies and AI agents: who they are, whether they are real and active right now, what they do and how to work with them, readable by people and by agents and paid per call.","catalog":"https://alion.io/catalog.json","usage":{"tier":"crawler_verified","counted_by":"address","units_charged":1,"used_today":6779,"day_limit":null,"remaining_today":null,"minute_limit":300,"resets_at":"2026-11-14T00:00:00Z"}},"offers":[{"id":"company.slices","title":"One company in depth, by slice","status":"live","price":{"credits":0.1,"usd":0.01,"plus_per_slice":{"credits":0.05,"usd":0.005}},"unit":"per company, plus each slice with data","note":"the employer in depth","call":{"mcp_tool":"get_company","arguments":{"id":10977},"rest":"https://alion.io/mcp/rest/get_company?id=10977"},"human":"https://alion.io/catalog?offer=company.slices&for=job%2Fterrapower-principal-engineer-safety-methods-2"},{"id":"market.stats","title":"A market slice: pay, demand and time to fill","status":"free","price":{"credits":0,"usd":0},"unit":"per slice","note":"pay, demand and time to fill for this role and place","call":{"mcp_tool":"market_stats"},"human":"https://alion.io/catalog?offer=market.stats&for=job%2Fterrapower-principal-engineer-safety-methods-2"},{"id":"job.search","title":"Open jobs by role, technology, place, pay and visa","status":"live","price":{"credits":0.1,"usd":0.01},"unit":"per posting in a list","note":"similar open postings","call":{"mcp_tool":"search_jobs"},"human":"https://alion.io/catalog?offer=job.search&for=job%2Fterrapower-principal-engineer-safety-methods-2"},{"id":"company.verify","title":"Is this company real and active right now","status":"pilot","price":null,"unit":"per company","request":{"url":"https://alion.io/catalog/request","method":"POST","body":"{\"offer\": \"company.verify\", \"for\": \"job/terrapower-principal-engineer-safety-methods-2\", \"note\": \"what you need it for\"}"},"human":"https://alion.io/catalog?offer=company.verify&for=job%2Fterrapower-principal-engineer-safety-methods-2"}],"agent":{"mcp":"https://alion.io/mcp/jobs","mcp_open":"https://alion.io/mcp/open","next":[{"tool":"get_job","arguments":{"id":939561}},{"tool":"search_jobs","arguments":{"company":"terrapower.com","detail":"compact"}},{"tool":"match_people","arguments":{"job_id":939561},"note":"people open to offers who fit this vacancy"}],"note":"The same data through MCP tools: https://alion.io/mcp/open needs no sign-in (compact searches, postings, people); https://alion.io/mcp with an Alion account has everything. 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