{"id":3249382,"url":"https://alion.io/job/radiant-nuclear-senior-fluid-systems-engineer","title":"Senior Fluid Systems Engineer","company":{"id":690814,"name":"Radiant Nuclear","domain":"radiantnuclear.com","url":"https://alion.io/company/radiantnuclear","size_band":"201-500","is_staffing_agency":false,"employer_type":"direct","is_intermediary":false,"listed_via":null,"ats_vendor":"Ashby","truth_index":{"grade":"A","score":88,"open_postings":26,"ghost_share":0,"stale_share":0.5,"repost_share":0,"time_to_fill_p50_days":53,"computed_at":"2026-11-01T06:10:25Z"}},"role":"Industrial Engineering","role_family":"Industrial Engineering","seniority":"senior","employment_type":"full_time","work_mode":"on_site","remote_scope":null,"remote_scope_basis":null,"remote_working_hours":null,"hiring_geo_confidence":"structured","locations":["El Segundo, United States"],"countries":["US"],"hiring_countries":[],"hiring_countries_total":0,"salary":{"min":158000,"max":219450,"currency":"USD","period":"year","gross":null,"usd_annual":219450},"salary_estimate":null,"experience_years_min":5,"visa_sponsorship":false,"relocation_package":false,"has_equity":true,"technologies":[{"name":"FMEA","optional":false},{"name":"MATLAB","optional":false},{"name":"Python","optional":false}],"status":"live","first_seen_at":"2026-10-12T20:44:33Z","employer_posted_date":"2026-10-12","last_verified_at":"2026-11-02T01:48:08Z","board_verified":true,"closed_at":null,"days_open":20,"trust":{"level":"ok","repost_count":null,"flags":[],"days_open":20},"description":"About Radiant\nRadiant is an El Segundo, CA-based startup building the world’s first mass-produced, portable nuclear microreactors. Rising energy demand is straining the U.S. grid and driving up utility costs, emissions, and interconnection backlogs. Radiant decentralizes energy, producing power close to where it’s used. Its first reactor, Kaleidos, is a factory-built, 1-megawatt, fail-safe microreactor that can be transported by land, sea, or air and runs up to 5 years without refueling. Deployed locally without a decade-long build or permitting fight, Kaleidos provides independent power for critical infrastructure like military bases, data centers, hospitals, and remote sites. Founded in 2020, Radiant is under contract to deliver power to the U.S. Army, Air Force, Navy, and has pre-order agreements with Equinix, with deployments beginning in 2028.\nAbout the Role\nRadiant is seeking a highly motivated Senior Fluid Systems Engineer to own critical Kaleidos fluid systems from preliminary design through build and production. These systems include the primary loop subsystems and power conversion loop, serving to convert heat from the reactor core into electrical power. You will be responsible for the following: trade studies, component selection, thermal hydraulic analysis, piping design, vendor selection, assembly, and testing. You will have an instrumental impact of fueling the first new commercial reactor design in over 50 years by 2026.\nResponsibilities & Duties:\nOwn end-to-end engineering of fluid systems and components, including compressors, valves, and heat exchangers.\n\nPerform complex thermal and fluids analysis to drive design decisions, verify system performance, and ensure structural integrity using first-principle hand calculations and finite element tools.\n\nPerform trade studies to optimize system and meet program requirements.\n\nDevelop and execute manufacturing/assembly instructions and test plans.\n\nCreate and manage a Bill-Of-Materials (BOM).\n\nFind and develop suppliers for all components.\n\nOwn subassembly design, manufacturing, and test schedules.\n\nOwn risk analysis (FMEA) for subsystems.\n\nCollect requirements, provide expertise and feedback to engineers in other functional areas via clear, constructive communication.\n\nRequired Qualifications & Skills :\nBachelor’s degree from an accredited institution in Mechanical, Materials, Aeronautical, Civil or Structural Engineering.\n\nExperience with fluid system architecture design.\n\n5+ years of experience in designing, building, and testing fluids systems.\n\nProficient knowledge in fluid dynamics and thermodynamics.\n\nProficient knowledge of heat exchanger design and analysis methods.\n\nDesired Qualifications & Skills :\nKnowledge of thermodynamic power cycles.\n\nPrior experience with designing piping system for thermal growth using hand calculations and FEA tools.\n\nExperience with process piping design and testing codes, such as ASME B31.3 and ASME PCC-2.\n\nPrior experience with fluid system modeling via Matlab/Python.\n\nExperienced in design for manufacturability and ramping up hardware build in a production environment.\n\nExperienced in designing and operating test stands.\n\nTakes extreme ownership of work and a high degree of responsibility.\n\nExcellent communication across multidisciplinary teams.\n\nPrior nuclear experience in not required for this role.\n\nAdditional Requirements:\nMust be willing to work extended hours and weekends as necessary to accomplish our mission.\n\nMust work 100% onsite at El Segundo HQ.\n\nBenefits and Perks\nStock: Substantial incentive stock plan for all full-time employees.\n\nMedical: 100% up to base silver level plan for employee + 50% dependents, offers up to Platinum plans.\n\nOne Medical: Sponsored memberships for employees and their dependents.\n\nVision: 100% top tier plan coverage + 50% for dependents.\n\nDental: 100% top tier plan coverage, orthodontia extra, 50% for dependents.\n\nVoluntary life, accident, hospital, critical illness, commuter and FSA/HSA are offered as employee contributed benefits.\n\n8-weeks of paid parental leave for all parents. Additional paid pregnancy leave for CA employees.\n\nDaily catered lunch. Free snacks and drinks.\n\nFlexible PTO policy. Remote workday allocation.\n\nCompany and team-bonding events, happy hours and in-person camaraderie.\n\nBeautiful El Segundo headquarters close to the Pacific Ocean.\n\nTotal Compensation and Benefits\nRadiant compensates people for impact and invests in those who continue to raise the bar. Radiant’s new hire compensation package includes base salary, substantial equity grants, and comprehensive health benefits. Total compensation and level are determined through a rigorous evaluation of interview performance, experience, education, and qualifications, and are designed to support continued growth as scope, responsibility, and impact expand at Radiant.\nThe best of today’s advanced reactor builders don’t wait for job postings. They join the winning team. If that’s you, contact us directly for immediate opportunities: .\nWe are an equal opportunity employer and all qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity or expression, pregnancy, age, national origin, disability status, genetic information, protected veteran status, or any other characteristic protected by law.\nThis position involves access to technology that is subject to U.S. export controls. Any job offer made will be contingent upon the applicant’s capacity to serve in compliance with U.S. export controls.","description_format":"text","description_chars":5616,"description_truncated":false,"requirements":{"experience_years_min":5,"management_years_min":null,"team_size_min":null,"manages_managers":false,"education":{"level":"bachelor","optional":false},"security_clearance":false,"languages":[]},"benefits":["Equity","Parental leave"],"hiring_locations":[],"hiring_excludes":[],"relocation_offered":false,"industries":["Nuclear Energy"],"lifecycle":[{"event":"open","at":"2026-10-25T20:13:25Z"}],"visa":[],"liveness":{"score":57,"band":"ok","label":"Likely open","p_open":1,"p_active":0.631,"p_room":0.9,"age_days":19,"expected_fill_days":53,"reasons":["conf:0","stale_co","velocity","win:mid"],"computed_at":"2026-11-01T06:10:25Z"},"pay":{"stated_usd_annual":219450,"is_top_pay":true},"html_url":"https://alion.io/job/radiant-nuclear-senior-fluid-systems-engineer","json_url":"https://alion.io/job/radiant-nuclear-senior-fluid-systems-engineer.json","meta":{"generated_at":"2026-11-02T03:31:16Z","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":5265,"day_limit":null,"remaining_today":null,"minute_limit":300,"resets_at":"2026-11-03T00:00:00Z"}},"offers":[{"id":"company.slices","title":"One company in depth, by slice","status":"live","price":{"credits":0.02,"usd":0.002,"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":690814},"rest":"https://alion.io/mcp/rest/get_company?id=690814"},"human":"https://alion.io/catalog?offer=company.slices&for=job%2Fradiant-nuclear-senior-fluid-systems-engineer"},{"id":"market.stats","title":"A market slice: pay, demand and time to fill","status":"live","price":{"credits":1,"usd":0.1},"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%2Fradiant-nuclear-senior-fluid-systems-engineer"},{"id":"job.search","title":"Open jobs by role, technology, place, pay and visa","status":"live","price":{"credits":0.02,"usd":0.002},"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%2Fradiant-nuclear-senior-fluid-systems-engineer"},{"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/radiant-nuclear-senior-fluid-systems-engineer\", \"note\": \"what you need it for\"}"},"human":"https://alion.io/catalog?offer=company.verify&for=job%2Fradiant-nuclear-senior-fluid-systems-engineer"}],"agent":{"mcp":"https://alion.io/mcp/jobs","mcp_open":"https://alion.io/mcp/open","next":[{"tool":"get_job","arguments":{"id":3249382}},{"tool":"search_jobs","arguments":{"company":"radiantnuclear.com","detail":"compact"}},{"tool":"match_people","arguments":{"job_id":3249382},"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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