About the CompanyHumanity faces two critical challenges: securing reliable energy for everyone and aggressively lowering our environmental impact. Nuclear fission is the key to solving both at once, and our client is actively developing the technology to rapidly scale the deployment of nuclear fission today.This is a direct hire, permanent placement position for a client of AdAstra Talent Advisors. This position is based in El Segundo, CA. More company details will be shared during an initial call.The OpportunityAs the Sr. Nuclear Engineer, you will take end-to-end ownership of the nuclear design and safety analysis of our client’s first nuclear reactor — spanning core design and fuel cycle, reactivity control, and radiation release and dose analysis. You will advance the design from today’s working simulation models through design finalization, licensing, and first criticality, and will build the analysis tools and methods needed to do it at unprecedented speed.You will also own the highest-impact analyses and design decisions while setting the technical bar for the nuclear engineering team. Successful candidates will have previously demonstrated extreme ownership in modeling, analyzing, or de-risking complex physical systems, and will be highly motivated to power humanity with abundant, clean energy.ResponsibilitiesSupport key aspects of nuclear core design including fuel assembly design, reactivity control through burnable poisons, chemical, and mechanical shim, thermal hydraulics, and fuel cycle designOwn reactivity control design and analysis: control rod worth, shutdown margin, reactivity coefficients, chemical and mechanical shim, and transient responsePerform radiation shielding and release analysis against regulatory limitsWork closely with fluids, structures,



components and manufacturing teams to deliver a highly system-optimized and manufacturable designMaintain tight partnerships with fuel procurement supply chain including enrichment service providers and fuel assembly fabricators to ensure high manufacturability of our client’s designOwn a significant portion of the nuclear system through initial criticality, extended full power operations, and fleet-wide commercial deploymentProvide training and mentorship to junior nuclear engineers, setting the standard for technical rigor across the teamBasic QualificationsBachelor’s degree in nuclear engineering, physics, or a related technical discipline5 years of engineering experience designing, analyzing, and building complex hardwarePreferred Skills and ExperienceStrong interpersonal and collaborative skills, enthusiasm for problem solving, and desire to enable abundant clean energy5 years of experience designing and analyzing nuclear systems via professional work experience, project/research-based student experience, or a combination of bothExperience acting as a technical lead — scoping work, reviewing designs and analyses, and guiding other engineers to successful outcomesAbility to perform trade studies and make clear recommendations using first principles and engineering fundamentals even with partial informationExperience working at a nimble engineering organization or in a highly technical position that required a scrappy,



entrepreneurial manner to accomplish tasks with tight time or budget constraintsExperience with nuclear system design and analysis, including core geometry, reactivity simulations, depletion analysis, and radiation shieldingExperience with thermal hydraulics, heat transfer, and fluid flow regimesExperience designing to key regulatory standards such as 10 CFR Part 50/52/53Experience with radiation release analysis, including source term determination and dispersion analysisLogistical RequirementsOn-site in El Segundo, CAAbility to work extended hours and weekends as necessaryAbility to travel to suppliers and reactor construction sites in other states as necessaryU.S. Person RequirementRequires U.S. Person status per export control regulations (10 CFR Part 810). Candidates who are citizens of countries not on Part 810 Appendix A cannot currently be considered, even with a green card.CompensationAnnual base pay of $140,000 – $190,000, plus meaningful early-stage equityCompensation is determined by role, level, location, and alignment with market data; individual pay may varybased on job-related skills, education, experience, technical capabilities, and internal equity.Benefit HighlightsComprehensive medical, dental, and vision coverage401(k) retirement savings planPaid vacation and paid parental leaveLong-term incentives via company stock/stock options, plus an Employee Stock Purchase PlanPotential discretionary bonusesEqual OpportunityOur client is an equal opportunity employer, evaluating qualified applicants without regard to race, color, religion, gender, national origin/ethnicity, veteran status, disability status, age, sexual orientation, gender identity, marital status, mental or physical disability, or any other legally protected status.#J-18808-Ljbffr

📌 Senior Nuclear Engineer (Risaralda)
🏢 Adastra
📍 Risaralda