{"id":4303442,"url":"https://alion.io/job/radiant-nuclear-staff-reactor-systems-engineer","title":"Staff Reactor 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":90,"open_postings":25,"ghost_share":0,"stale_share":0.2,"repost_share":0,"time_to_fill_p50_days":76,"computed_at":"2026-11-14T05:58:10Z"}},"role":"Energy","role_family":"Energy","seniority":"staff","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":150025,"max":211838,"currency":"USD","period":"year","gross":null,"usd_annual":211838},"salary_estimate":null,"experience_years_min":10,"visa_sponsorship":false,"relocation_package":false,"has_equity":true,"technologies":[{"name":"FMEA","optional":false},{"name":"Verification & Validation","optional":false}],"status":"live","first_seen_at":"2026-11-14T00:34:40Z","employer_posted_date":"2026-11-14","last_verified_at":"2026-11-14T05:14:03Z","board_verified":true,"closed_at":null,"days_open":0,"trust":{"level":"ok","repost_count":null,"flags":[],"days_open":0},"description":"About Radiant\nRadiant is an El Segundo, CA-based company building the world's only mass-produced, transportable nuclear microreactors. The U.S. grid is under growing strain, with power demand accelerating, driving higher utility costs, rising carbon emissions, and interconnection backlogs. Radiant has a solution, transportable, on-site power. Our first reactor, Kaleidos, is 1 megawatt: small enough to be factory-built, transported by land, sea, or air, and deployed wherever power is needed. 1 MW can power 1000 homes for five years. Ship it back and we refuel for a 20 year operating life. We made energy a product that can be used for critical infrastructure like military bases, data centers, hospitals, and remote sites, as well as the commercial main street businesses that keep America running. Founded in 2020, Radiant is under contract to deliver power to the U.S. Army, Navy and Air Force and has signed pre-order agreements with Equinix, with deployments beginning in 2028.\nAbout the Role\nWe are seeking a Staff Reactor Systems Engineer to own the technical integration of a first-of-a-kind reactor. With no operating predecessor to copy and no mature supply chain, you will be the person who holds the whole machine together, making sure hundreds of design decisions across nuclear physics, thermal-hydraulics, controls, structures, materials, fuel, and licensing add up to a reactor that works safely and is delivered to customers on time.\nYou will be the technical authority for how the pieces of Kaleidos fit together: translating top-level product and safety requirements into subsystem requirements, owning interfaces, and making sure the integrated system performs, is safe, and can be built, tested, and deployed repeatably. \nAs a staff-level engineer, you will work across every engineering discipline, resolve the hardest cross-system tradeoffs, and set the systems engineering practices the team uses as Kaleidos moves from first-of-a-kind builds to scaled production. You will be instrumental in unlocking commercialization of the first mass-produced nuclear reactor.\nResponsibilities & Duties\nOwn the Kaleidos system architecture and serve as technical authority for integrated system performance, safety, and reliability.\n\nDefine and manage system budgets (e.g., thermal, mass, power, reactivity, and volume) and allocate margins across subsystems.\n\nOwn interface definitions and interface control documents between subsystems, including reactor core, primary loop, power conversion loop, shielding, controls, and structures.\n\nMaintain the technical baseline (requirements, configuration, change control, risk registers, and documentation) using lightweight processes scaled to a fast-moving startup.\n\nIdentify cross-cutting risks early and drive them to resolution before they become safety or schedule problems.\n\nDefine the verification and validation strategy and partner with Test Engineering to turn requirements into test plans, success criteria, and acceptance tests.\n\nCorrelate analysis and test results against system requirements, and drive resolution of discrepancies.\n\nSupport safety-basis and licensing or regulatory documentation as needed.\n\nMentor engineers across the organization in systems thinking, requirements quality, and interface discipline.\n\nCommunicate system status, risks, and tradeoffs clearly to engineering and program leadership.\n\nRequired Qualifications & Skills\nBachelor’s degree in engineering, physics, or a related technical discipline from an accredited institution.\n\n10+ years of professional engineering experience, including meaningful time in systems engineering, integration, testing, engineering operations, or technical leadership on complex hardware.\n\nDemonstrated experience owning requirements and interfaces for a complex system from concept through build, test, and operation.\n\nExperience leading system-level trade studies and making sound decisions with incomplete information.\n\nStrong working knowledge across several relevant disciplines, such as thermal-fluids, mechanical, structural, power systems, or controls.\n\nExperience with verification and validation, and with hazard and risk analysis methods (e.g., FMEA, FTA).\n\nDemonstrated technical leadership across multidisciplinary teams without relying on formal authority.\n\nStrong written and verbal communication, including producing clear technical documents and presenting to varied audiences.\n\nDesired Qualifications & Skills\nKnowledge of nuclear reactor design, reactor safety, or nuclear regulatory frameworks.\n\nExperience with high-temperature systems, thermodynamic power cycles, or power generation systems.\n\nExperience with configuration management and change control for hardware programs.\n\nExperience transitioning hardware from development builds to repeatable production.\n\nStartup or fast-paced hardware development experience.\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\nEligibility to work in the U.S. and ability to meet export control requirements.\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\nNuclear Engineering Certificate Program: 100% covered educational program with Penn State University, for eligible employees, to rapidly upscale into nuclear.\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 full-time 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":7380,"description_truncated":false,"requirements":{"experience_years_min":10,"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":"2026-11-14T05:14:03Z"}],"visa":[],"liveness":{"score":86,"band":"hot","label":"Hiring now","p_open":1,"p_active":0.86,"p_room":1,"age_days":0,"expected_fill_days":76,"reasons":["conf:0","win:early"],"computed_at":"2026-11-14T05:58:10Z"},"pay":{"stated_usd_annual":211838,"is_top_pay":true},"html_url":"https://alion.io/job/radiant-nuclear-staff-reactor-systems-engineer","json_url":"https://alion.io/job/radiant-nuclear-staff-reactor-systems-engineer.json","meta":{"generated_at":"2026-11-14T11:37:06Z","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":11841,"day_limit":null,"remaining_today":null,"minute_limit":300,"resets_at":"2026-11-15T00:00:00Z"}},"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":690814},"rest":"https://alion.io/mcp/rest/get_company?id=690814"},"human":"https://alion.io/catalog?offer=company.slices&for=job%2Fradiant-nuclear-staff-reactor-systems-engineer"},{"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%2Fradiant-nuclear-staff-reactor-systems-engineer"},{"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%2Fradiant-nuclear-staff-reactor-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-staff-reactor-systems-engineer\", \"note\": \"what you need it for\"}"},"human":"https://alion.io/catalog?offer=company.verify&for=job%2Fradiant-nuclear-staff-reactor-systems-engineer"}],"agent":{"mcp":"https://alion.io/mcp/jobs","mcp_open":"https://alion.io/mcp/open","next":[{"tool":"get_job","arguments":{"id":4303442}},{"tool":"search_jobs","arguments":{"company":"radiantnuclear.com","detail":"compact"}},{"tool":"match_people","arguments":{"job_id":4303442},"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. Docs: https://alion.io/developers"}}