Nuclear Design Engineer

At Lightbridge, we’re pioneering advanced nuclear fuel technology that’s designed to make reactors safer, more efficient, and more responsive to global energy needs. Our mission is bold and we’re looking for equally bold thinkers to help us bring it to life. If you thrive at the intersection of engineering and regulatory strategy, this is your opportunity to help shape the future of clean energy.

Overview

The Nuclear Design Engineer (Junior or Senior) supports the core design and neutronics methodology development and analysis of Lightbridge Fuel for various water-cooled reactor applications. This role contributes to fuel design, analysis, licensing qualification, and commercialization through neutronics modeling, technical documentation, and collaboration with multidisciplinary teams. The scope of responsibility, technical ownership, and leadership increases with experience level.

Responsibilities

• Perform neutronics and core design analyses in support of the licensing qualification and commercialization of Lightbridge Fuel for water-cooled reactors.
• Develop, document, and maintain lattice physics and full-core neutronics models using deterministic and Monte Carlo analysis tools.
• Integrate neutronics results with thermal-hydraulics and fuel performance analyses.
• Develop and utilize software tools and workflows, including Python-based scripting, to automate analyses, post-process results, and improve efficiency.
• Explore or apply AI and data-driven techniques (e.g., machine learning, surrogate models, automated optimization) to enhance fuel design, modeling efficiency, or decision-making.
• Prepare technical calculations, reports, and licensing support documentation in compliance with quality and regulatory requirements.
• Collaborate with internal project teams, leadership, and stakeholders to meet technical, schedule, and quality objectives.
• Senior level: Lead complex analyses, resolve advanced technical challenges, review and approve technical work products, and interface with regulatory agencies, utilities, vendors, and partners.
• Senior level: Mentor and provide technical guidance to junior engineers and support engineering best practices.

 Required Experience 

• Junior Nuclear Design Engineer
  • BS in Nuclear Engineering or a closely related field.
  • 2-3 years of relevant experience in reactor analysis, core design, neutronics, or nuclear engineering.
  • Familiarity with neutronics concepts and lattice physics modeling through coursework or professional experience.
  • Exposure to deterministic and/or Monte Carlo neutronics codes.
  • Introductory experience with Python programming for analysis or data processing.
  • Strong analytical skills and ability to work effectively in a team environment.
  • Ability to access U.S. National Laboratories and pass required background checks and screenings.
• Senior Nuclear Design Engineer
  • BS in Nuclear Engineering or a closely related field plus 5+ years of relevant experience, or MS + 4+ years, or PhD + 3+ years (equivalent experience considered).
  • Proven experience performing and leading neutronics and core design analyses.
  • Proficiency with industry-standard deterministic and Monte Carlo neutronics codes.
  • Working knowledge of neutronics, thermal-hydraulics, and fuel performance, with experience integrating results across disciplines.
  • Experience developing and maintaining analysis methodologies and technical models.
  • Strong technical judgment, problem-solving ability, and written and verbal communication skills.
  • Ability to access U.S. National Laboratories and pass required background checks and screenings.

Preferred Qualification: 

• Experience with lattice physics and core design software, including:
  • CASMO/SIMULATE
  • HELIOS/PRESTO
  • SCALE/PARCS
• Experience with Monte Carlo neutronics codes such as:
  • MCNP
  • KENO
  • SERPENT
• Proficiency in Python for workflow automation, data analysis, or tool development.
• Experience or demonstrated interest in applying AI or machine learning methods to engineering analysis, optimization, or large-scale data interpretation.
• Experience developing scopes of work for neutronics analysis supporting fuel qualification, benchmarking, or core reloads.
• Experience with metallic nuclear fuels, particularly U-Zr.
• Familiarity with ASME Nuclear Quality Assurance (NQA-1) requirements.
• Experience supporting nuclear fuel licensing activities.
• Experience collaborating with utilities, national laboratories, or nuclear regulators.
• Senior level: Prior experience mentoring or training junior engineers.

Lightbridge is committed to supporting the people who power our mission. We offer a comprehensive, competitive benefits program designed to promote well-being, flexibility, and long-term growth, including:

•     Competitive salary and performance bonuses, including cash and equity awards
•     Remote-first work culture with opportunities for travel
•     100% company-paid health, dental, and vision coverage
•     401(k) with 100% company match
•     Generous time off and family care benefits
•     Up to 32 hours per year of company-covered professional development course fees

If you’re excited about contributing to work that will help shape the future of clean energy, we encourage you to apply. We look forward to learning more about you and the impact you can make at Lightbridge.