Neutronics Analyst

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The Neutronics Analyst supports the dynamic modeling/analysis and helps to validate neutronics codes. The Neutronics Analyst will be responsible for the reactor core design/development and analysis, taking into consideration coupled neutronics, thermo-fluid dynamics, and fuel cycle aspects for nuclear energy reactors.


• Develop and implement Verification, Validation and Uncertainty Quantification (VVUQ) plans for codes and models for nuclear reactor design and analysis.
• Provide inputs to Mechanistic Source Term (MST), Probabilistic Risk Assessment (PRA), and System Engineering personnel on nucleonic aspects, including nuclear materials properties, requirements, nuclear boundary conditions, and processes.
• Perform High temperature gas-cooled reactor (HTGR) core neutronics design, reactivity, feedback, and safety analyses.
• Perform criticality and shielding design and considerations for fresh and spent fuel
• Develop and validate fission product release models and software
• Determine radionuclide release from fuel to Reactor System and within the helium pressure boundary (HPB) and Helium Purification System during normal operation
• Assess external and airborne radionuclide source terms and dose rates for the X-energy Reactor shielding design and radiological zoning purposes
• Be cognizant of related work being performed in the international engineering community
• Be cognizant of related neutronics tests and experiments being performed for similar, relevant systems internationally
• Contribute to planning and executing experiments/tests to satisfy Design Data Needs
• Provide technical feedback and advice to diverse multi-functional technical groups


• Think critically and reflectively
• Create and synthesize knowledge
• Demonstrate critical engineering and scientific skills
• Strong Initiative/Self Starter
• Team Player & able to work with diverse groups
• Highly motivated

Minimum Qualifications

• Must be a U.S. Citizen
• Must be eligible to apply for and possess a U.S. security clearance with either the Dept. of Defense or the Dept. of Energy
• PhD in Nuclear Engineering from a US accredited university or equivalent years’ experience
• Demonstrated expertise with Unix operating systems
• At least five years of experience with High Performance Computing (HPC) clusters
• Desired expertise with C++ and/or Fortran90 programming languages and scripting experience (using Perl or Python)
• High temperature gas cooled reactor experience highly recommended

Minimum Experience/Knowledge

• Able to perform physics code development and perform multi-scale, multi-physics modeling of the physics characteristics of HTGRs
• Knowledge of MCNP, RELAP, VSOP; deterministic and stochastic neutron transport and fuel performance techniques highly recommended
• Knowledge of Predictive Capability Maturity Model (PCMM) and VVUQ is highly recommended.
• Willingness to gain thorough understanding of legacy HTGR modelling codes (e.g., VSOP, TINTE, MGT system of codes), as appropriate.
• Able to effectively communicate results and analytical findings verbally and in writing.

X Energy, LLC is committed to hiring and retaining a diverse workforce. We are proud to be an Equal Opportunity Employer and making decisions without regard to race, color, religion, creed, sex, sexual orientation, gender identity, marital status, national origin, age, veteran status, disability, or any other protected class. We welcome the employment of women, minorities, veterans, and individuals with disabilities in our workforce. If you are in need of special assistance, please contact our Human Resources Department. X Energy, LLC participates in eVerify.

To Apply by Email: [email protected]