Principal Nuclear Engineer SME

Leidos' Analysis Solutions business area is seeking a highly accomplished Principal Nuclear Engineer Subject Matter Expert (SME) to support critical national security missions in Reston, Virginia. This role offers the opportunity to apply advanced nuclear engineering expertise to some of the nation's most challenging counterproliferation and nuclear survivability problems. The successful candidate will lead technical assessments of foreign nuclear weapons infrastructure, reverse engineer protective hardening measures, and identify vulnerabilities across facilities, processes, and supply chains. This unique position combines computational physics, engineering analysis, and all-source intelligence methodologies to deliver actionable insights that strengthen national security. As part of a multidisciplinary government-contractor team, you will conduct in-depth analysis of above-ground and underground facilities, associated equipment, and operational processes to develop innovative, mission-focused solutions. Work is performed in a fast-paced, high-impact environment within a secure government facility. Primary Responsibilities Technical Leadership & Subject Matter Expertise Serve as the organization's recognized expert in nuclear engineering, nuclear effects, and counterproliferation analysis. Provide technical leadership, mentorship, and strategic guidance across complex national security initiatives. Counterproliferation & Defense Analytics Conduct high-fidelity technical reverse-engineering assessments of domestic and foreign facilities, stockpiles, supply chains, and production processes. Evaluate vulnerabilities and develop analytical insights that support defense and intelligence community partners. Nuclear Hardness & Survivability Analyze the effects of nuclear weapons on facilities, infrastructure, equipment, and operational workflows. Develop protective design criteria using physics-based modeling of radiation environments, electromagnetic pulse (EMP), and other nuclear effects. Threat Modeling & Simulation Employ advanced multi-physics modeling and simulation tools to assess structural, thermal, electronic, and operational degradation resulting from weapons effects. Perform quantitative analyses that inform survivability and resilience strategies. All-Source Intelligence Integration Leverage and synthesize GEOINT, SIGINT, OSINT, and other intelligence sources to assess foreign nuclear capabilities, technological development paths, and operational timelines. Translate fragmented technical information into defensible, evidence-based assessments. Intelligence Reporting & Briefings Produce high-quality technical reports, assessments, and executive briefings. Present findings, methodologies, and recommendations to senior government stakeholders and technical review boards. Required Education, Skills, and Experience Security Requirements Active TS/SCI clearance with an in-scope SSBI required. Must be eligible to obtain a polygraph; active TS/SCI with polygraph preferred. U.S. Citizenship required. Education & Experience Master's degree with 15+ years of relevant experience, or Doctorate with 13+ years of relevant experience. Technical Expertise Recognized authority in advanced nuclear technologies, scientific principles, and engineering concepts. Extensive experience with nuclear weapon production, fabrication, storage, deployment, and supply-chain logistics. Demonstrated expertise in assessing vulnerabilities within nuclear-related facilities, stockpiles, and supply chains, and developing mitigation strategies. Deep understanding of fault-tree analysis, hazard analysis, and risk assessment methodologies. Advanced knowledge of the nuclear fuel cycle, nuclear weapon effects, radiation damage mechanisms, and electromagnetic shielding architectures. Experience developing and executing physics-based simulations using tools such as MCNP, SCALE, ORIGEN, and COMSOL, supplemented by data analytics and modeling in Python, MATLAB, and/or C++. Analytical & Communication Skills Ability to develop sound technical judgments from incomplete or ambiguous information. Experience defending analytical conclusions and communicating uncertainty under rigorous peer review. Exceptional written and verbal communication skills, with the ability to engage senior leaders, intelligence professionals, and technical stakeholders. Preferred Qualifications Military, Department of Defense, or Department of Energy experience. Familiarity with ICD 203 (Analytic Standards) and ICD 206 (Sourcing Requirements). Experience with protective design methodologies and survivability requirements for sensitive nuclear facilities. Advanced understanding of EMP and other non-kinetic nuclear effects. If you're looking for comfort, keep scrolling. At Leidos, we outthink, outbuild, and outpace the status quo — because the mission demands it. We're not hiring followers. We're recruiting the ones who disrupt, provoke, and refuse to fail. Step 10 is ancient history. We're already at step 30 — and moving faster than anyone else dares. Original Posting: June 10, 2026 For U.S. Positions: While subject to change based on business needs, Leidos reasonably anticipates that this job requisition will remain open for at least 3 days with an anticipated close date of no earlier than 3 days after the original posting date as listed above. Pay Range: Pay Range $154,050.00 - $278,475.00 The Leidos pay range for this job level is a general guideline only and not a guarantee of compensation or salary. Additional factors considered in extending an offer include (but are not limited to) responsibilities of the job, education, experience, knowledge, skills, and abilities, as well as internal equity, alignment with market data, applicable bargaining agreement (if any), or other law. Leidos Leidos is an industry and technology leader serving government and commercial customers with smarter, more efficient digital and mission innovations. Headquartered in Reston, Virginia, with 47,000 global employees, Leidos reported annual revenues of approximately $17.2 billion for the fiscal year ended January 2, 2026. For more information, visit Pay and Benefits Pay and benefits are fundamental to any career decision. That's why we craft compensation packages that reflect the importance of the work we do for our customers. Employment benefits include competitive compensation, Health and Wellness programs, Income Protection, Paid Leave and Retirement. More details are available here. Securing Your Data Leidos will never ask you to provide payment-related information at any part of the employment application process. And Leidos will communicate with you only through emails that are sent from a Leidos.com email address. If you receive an email purporting to be from Leidos that asks for payment-related information or any other personal information, please report the email to View email address on click.appcast.io. Commitment and Diversity All qualified applicants will receive consideration for employment without regard to sex, race, ethnicity, age, national origin, citizenship, religion, physical or mental disability, medical condition, genetic information, pregnancy, family structure, marital status, ancestry, domestic partner status, sexual orientation, gender identity or expression, veteran or military status, or any other basis prohibited by law. Leidos will also consider for employment qualified applicants with criminal histories consistent with relevant laws.