Principal Reactor Physics & Neutronics Engineer

Position Summary

Senior, hands-on technical leader responsible for establishing and developing the reactor physics and neutronics capability within a growing nuclear energy organization. Provides technical leadership while remaining directly involved in engineering execution, analysis, technical problem-solving, and project delivery. This role will help establish discipline-specific standards, processes, tools, and technical practices; support multiple concurrent projects; and mentor developing engineers as the organization scales.

Functional Scope

• Reactor Physics - Apply core reactor-physics principles including neutron behavior, reactivity, flux distributions, power distributions, depletion, and feedback effects to support design, safety, and development activities.

• Neutronics Analysis - Perform and review applicable neutron-transport, deterministic, Monte Carlo, diffusion, shielding-interface, depletion, and reactivity analyses supporting reactor behavior, performance, and design decisions.

• Criticality Analysis - Evaluate fuel and material configurations, reactivity margins, moderation effects, credible abnormal conditions, and criticality-safety controls where applicable.

• Computational Modeling - Develop, execute, and maintain analytical models using appropriate reactor-physics and neutronics tools, with clear assumptions, inputs, methods, and configuration control.

• Core and Coupled-System Analysis - Lead and support evaluations of core design, fuel-loading strategies, reactivity management, core performance, and interactions with thermal-hydraulic, mechanical, materials, safety, and other engineering disciplines.

• Physics-Based Simulation - Use physics-based calculations and simulations to predict reactor performance, investigate design alternatives, assess operating scenarios, support technical decisions, and reduce technical risk.

• Verification & Validation - Verify model implementation and analytical methods; lead benchmarking, validation, uncertainty evaluation, and comparison against applicable experimental or test evidence.

• Sensitivity and Uncertainty Analysis - Assess how assumptions, modeling choices, nuclear data, and operating parameters affect analytical results, margins, and technical conclusions.

• Safety and Licensing Support - Provide reactor-physics and neutronics inputs to safety evaluations, design-basis development, licensing analyses, regulatory responses, and supporting technical documentation.

• Technical Documentation and Model Configuration - Maintain controlled calculations, model records, assumptions logs, review packages, and traceable engineering documentation under quality and configuration-management requirements.

• Technology Development Support - Bring relevant experience across reactor physics, neutronics, criticality, fuel, testing, or safety analysis to accelerate first-of-a-kind development, technical maturation, and integration.

Technical Leadership

• Serve as the senior technical resource and subject matter expert within reactor physics and neutronics.

• Lead and personally execute complex technical work across multiple nuclear projects and programs.

• Establish and maintain discipline-specific engineering standards, methodologies, procedures, and best practices.

• Lead and participate in technical reviews, design reviews, and technical decision-making.

• Identify and resolve complex multidisciplinary engineering issues while maintaining appropriate technical rigor.

Engineering / Technical Execution

• Develop, perform, and review reactor-physics and neutronics analyses supporting nuclear engineering, advanced-reactor development, test activity, and safety-related technical programs.

• Develop and apply computational models for neutron transport, criticality, reactivity, shielding, depletion, fuel behavior, and related physics evaluations using approved methodologies.

• Support evaluation of measured, experimental, benchmark, or test data and comparison against analytical predictions.

• Perform sensitivity, uncertainty, verification, validation, and benchmarking activities.

• Support design development, technical decision-making, safety evaluations, and licensing activities as required.

• Maintain controlled calculations, packages, model configurations, assumptions, methods, and supporting technical documentation.

Team & Capability Development

• Help establish and grow the discipline capability within the organization.

• Mentor and provide technical guidance to junior and early-career personnel.

• Support technical assessment of future team members.

• Develop repeatable technical practices and workflows that support continued organizational growth.

• Promote knowledge transfer, accountability, and continuous technical development.

Technical Governance

• Ensure technical activities align with applicable nuclear-industry codes, standards, regulations, quality requirements, and company procedures.

• Support engineering quality, configuration management, document control, and change-control practices.

• Ensure technical work is appropriately developed, reviewed, documented, and controlled.

• Incorporate technical risk management into engineering decision-making.

• Support corrective actions and continuous-improvement initiatives.

Cross-Functional Collaboration

• Partner with engineering leadership, project leaders, systems engineering, and adjacent technical disciplines.

• Collaborate with quality, safety, licensing/regulatory, testing, manufacturing, supply chain, and project-delivery functions.

• Support multidisciplinary technical integration across concurrent projects.

• Interface with suppliers, manufacturers, laboratories, engineering partners, and other external stakeholders as required.

Safety & Quality

• Champion a strong nuclear safety culture and disciplined engineering execution.

• Promote quality-focused technical work and risk-informed decision-making.

• Maintain technical rigor while operating effectively in a fast-moving, evolving organization.

Required Qualifications

• Master's degree in Nuclear Engineering, Engineering Physics, Physics, or closely related discipline required; PhD preferred.

• Approximately 10+ years of relevant technical experience, unless discipline-specific requirements indicate otherwise.

• Demonstrated hands-on technical experience within reactor physics and neutronics.

• Experience leading complex technical work, projects, workstreams, or engineering teams.

• Experience within the nuclear industry, national-laboratory environment, research reactor, naval nuclear, advanced-reactor program, or another highly regulated, safety-critical engineering environment.

• Strong technical problem-solving, engineering judgment, and decision-making capability.

• Ability to operate successfully within a growing organization where processes and capabilities are still being developed.

• Demonstrated adaptability, comfort with ambiguity, hands-on ownership, and ability to contribute immediately in a lean, entrepreneurial organization.

Preferred Qualifications

• Experience in nuclear engineering, advanced reactors, reactor operations, fuel-cycle work, national-laboratory programs, nuclear safety analysis, or adjacent regulated technical environments.

• Experience establishing or improving technical processes, standards, and organizational capability.

• Experience mentoring or developing junior technical personnel.

• Experience supporting multidisciplinary or matrixed engineering organizations.

• Professional Engineer registration, Chartered Engineer status, or equivalent credential where applicable.

Core Competencies

• Reactor Physics

• Neutronics

• Criticality Analysis

• Computational Modeling

• Verification & Validation

• Technical Leadership

• Technical Governance

• Nuclear Safety Culture

• Quality Assurance

• Cross-Functional Collaboration

• Team Development