Reactor Core Design Engineer
The job description
Tech stack. CASMO and SIMULATE core simulators, SCALE and KENO, fuel vendor design tools, Python for automation, core monitoring systems, 10 CFR 50 Appendix K methods, reload safety analysis
About the role
You will design the nuclear heart of the reactor for a fuel vendor or utility engineering organization, engineering fuel loading patterns that maximize energy output while satisfying every safety limit. The team owns core design from the first loading pattern study through final licensing approval and startup testing. You will run depletion calculations, evaluate accident scenarios, and defend your designs before internal review boards and the regulator. This role matters because the core design determines both the economics of the fuel cycle and the safety margins of the plant, and your analyses are the documented proof that both are acceptable. You will also collaborate with fuel vendors on new assembly designs, evaluating how mechanical innovations affect core physics margins. Your work will support power uprate evaluations when the utility pursues additional megawatts from the existing fleet. You will benchmark your methods against startup test data from every reload, continuously tightening the agreement between prediction and measurement. Your design reports will be written for multiple audiences, satisfying the NRC reviewer, the plant operator, and the fuel economist alike.
What you will achieve
- Deliver reload core designs meeting cycle energy targets with all safety limits satisfied and documented for NRC review.
- Complete reload safety analyses on schedule, supporting refueling outage milestones with zero licensing delays attributable to core design.
- Optimize fuel loading patterns reducing fresh fuel requirements 5 percent while preserving required shutdown margin.
- Automate design iteration workflows cutting analysis turnaround time in half across the engineering team.
- Support startup physics testing with predictions matching measured data within acceptance criteria on first attempt.
What you will bring
Must-haves
- 2 to 5 years in core design, reactor physics, or fuel engineering with production reload experience.
- Strong reactor physics fundamentals: depletion, reactivity coefficients, power distributions, and xenon behavior.
- Proficiency with core simulators such as CASMO, SIMULATE, or equivalent nodal diffusion tools.
- Experience with reload safety analysis methods and 10 CFR 50.59 or 50.90 change processes.
- Python or similar scripting skills for automating repetitive design and analysis tasks.
- Ability to defend technical work in formal design reviews and regulatory audits.
- Meticulous documentation habits producing auditable, reproducible analysis records.
Nice-to-haves
- Experience with advanced fuel designs such as accident-tolerant fuel or high-burnup programs.
- Familiarity with NRC-approved topical reports for core design methodologies.
- Knowledge of BWR or PWR specific design constraints, whichever applies to the fleet.
- Experience with core monitoring system calibration and startup test analysis.
GE Vernova
Westinghouse
X-energy
TerraPower
Constellation
Oklo