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Senior Thermal Hydraulics Analyst (Casual)

Date: Sep 1, 2021

Location: Oak Ridge, TN, US, 37830

Company: Oak Ridge National Laboratory

Requisition Id 6306 


The Nuclear Safety and Experiment Analysis (NSEA) Group within the Research Reactors Division (RRD), Neutron Sciences Directorate (NScD) seeks applications for a Senior Thermal Hydraulics Analyst position at the High Flux Isotope Reactor. We are seeking a highly motivated senior reactor analyst who is comfortable working in a team environment, with collaboration at all levels, disciplines, and diverse cultural backgrounds both inside and outside the organization. The successful candidate should have a strong background in nuclear reactor analysis and a broad level of knowledge and experience in (1) nuclear heat transfer and fluid dynamics topics relevant to the HFIR,  (2) development of the power-flow safety envelope for research reactors like HFIR, and (3) analysis of technical uncertainties in the fuel manufacturing, aluminum and water properties, heat transport correlations, and operational variables of the HFIR.  The successful candidate will serve as a senior analyst/advisor  to support the HFIR NSEA Group in planning, developing, and executing upgrades to the HFIR legacy thermal-hydraulic analyses (both steady state and transient) that support current operation,  with a goal of increasing the existing safety margin expressed in the current safety basis.   The successful candidate may also serve as a senior analyst/advisor to the HFIR-SENSe program and the HFIR LEU Program if needed.


Major Duties and Responsibilities:

  • Perform high-quality reactor modeling, simulation, and thermal-hydraulic (T-H) analysis activities to support the nation’s most versatile research reactor.
  • Provide relevant input to assist the NSEA Manager and Team Leads to support application of modern analysis tools and methods to upgrade of the HFIR T-H safety basis.
  • Provide support to apply best estimate plus uncertainty or advanced probabilistic uncertainty methods to the HFIR T-H safety basis.
  • Collaborate on projects, such as the high-enriched uranium to low-enriched uranium fuel conversion project and the HFIR-SENSe project, as needed.
  • Collaboratively work with the RRD NSEA Nuclear Safety and Experiments staff; others within RRD (e.g., Systems Engineering, Operations); and other ORNL directorates and divisions to support RRD and ORNL T-H safety missions, as needed.
  • Thoroughly document and present work performed to meet HFIR T-H upgrade deliverables.
  • Prepare and review publications to document reactor analysis and modeling for HFIR T-H upgrades and associated research programs.
  • As a member of the ORNL scientific community, you will be expected to commit to ORNL's Research Code of Conduct. Our full code of conduct, and a statement by the Lab Director's office can be found here:


Basic Qualifications:

  • Ph.D. degree in nuclear engineering, mechanical engineering, engineering physics, or a related technical field with 25 or more years of relevant experience
  • Possess a strong reactor analysis background in thermal-hydraulics, as demonstrated through university professorship research, publications, and/or work experience
  • Must be organized, detail-oriented, and sensitized to a nuclear safety culture
  • Demonstrated results-oriented problem-solving skills and a willingness to apply those skills to a variety of engineering problems
  • Excellent communication skills, including verbal, presentation, and writing skills
  • Capability to successfully function both independently and in small-to-moderate size teams


Preferred Qualifications:

  • Ph.D. degree with 25 or more years of relevant experience
  • Experience modeling and analyzing research reactors with both analytical approaches and with software, such as HSSHTC, COMSOL, and RELAP
  • Experience and knowledge of the multi-physics reactor engineering framework, including the interplay between reactor neutronics, thermal-hydraulics, thermal-structural interaction, fluid dynamics, fluid transient analysis, material property variations, and accident analysis
  • Ability to set priorities to accomplish multiple tasks with varying requirements and deadlines
  • Experience with LINUX or LINUX-like environments and scripting/computer languages, such as MATLAB, Python, and Fortran
  • Familiarity and experience with 10 CFR 830 Subparts A and B and the Reg. Guide 1.70 Chapters 4 and 15 T-H analysis frameworks.

Other Job Requirements:

This position requires the ability to obtain and maintain a DOE “L” clearance. 


This position is a Workplace Substance Abuse program (WSAP) testing designed position which requires passing a pre-placement drug test and participation in an ongoing random drug testing program in which employees are subject to being randomly selected for testing. The occupant of this position will also be subject to an ongoing requirement to report to ORNL any drug-related arrest or conviction or receipt of a positive drug test result.

This is a causal part-time position.


About Our Directorate:
The Neutron Sciences Directorate (NScD) at Oak Ridge National Laboratory (ORNL) operates the High Flux Isotope Reactor (HFIR), the United States’ highest flux reactor-based neutron source, and the Spallation Neutron Source (SNS), the world’s most intense pulsed accelerator-based neutron source.  Together these facilities operate 30 instruments for neutron scattering research, each year carrying out in excess of 1,000 experiments in the physical, chemical, materials, biological and medical sciences for more than 3,000 visiting scientists.  HFIR also provides unique facilities for isotope production and neutron irradiation.  To learn more about Neutron Sciences at ORNL go to

Benefits at ORNL:
UT-Battelle offers a quality benefits package, including a matching 401(k), contributory pension plan, paid vacation, and medical/dental plan options.  Onsite amenities include a credit union, medical clinic, cafeteria, and fitness facilities.

Moving can be overwhelming and expensive.  UT-Battelle offers a generous relocation package to ease the transition process.  Domestic and international relocation assistance is available for certain positions.  If invited to interview, be sure to ask your Recruiter (Talent Acquisition Partner) for details.

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This position will remain open for a minimum of 5 days after which it will close when a qualified candidate is identified and/or hired.

We accept Word (.doc, .docx), Adobe (unsecured .pdf), Rich Text Format (.rtf), and HTML (.htm, .html) up to 5MB in size. Resumes from third party vendors will not be accepted; these resumes will be deleted and the candidates submitted will not be considered for employment.

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ORNL is an equal opportunity employer. All qualified applicants, including individuals with disabilities and protected veterans, are encouraged to apply.  UT-Battelle is an E-Verify employer.

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