Nuclear Mechanical Engineer

Oak Ridge National Laboratory; Oak Ridge (TN); On-site; USD 110,000 - 140,000; Full time

Benefits offered by this job

Medical and retirement plans

Flexible work hours

Relocation assistance

Life Insurance

Wellness Programs

Job summary

Oak Ridge National Laboratory is seeking a Nuclear Mechanical Engineer to advance thermal-hydraulic analysis for HFIR isotope production targets and related tooling. You will lead modeling efforts, evaluate coolant flow, heat loads, and margins, and contribute to safety documentation while collaborating with scientists and engineers across disciplines.

Applicants should have a strong background in nuclear-related thermal analyses and experience with CFD tools, COMSOL, ANSYS, and programming for

Qualifications

• BS in Mechanical, Nuclear, Chemical Engineering, Materials Science, or related field with 4+ years of experience or advanced degree with 2 years.
• Moderate knowledge of thermal and mechanical performance of materials in nuclear systems.
• Experience performing moderately complex thermal hydraulic calculations.
• Experience with engineering modeling and simulation using listed tools.

Responsibilities

• Develop models and computational strategies to assess HFIR Isotope Production target design.
• Contribute to design of radioisotope production targets to optimize coolant flow and thermal performance.
• Develop and document integrated thermal-hydraulic evaluations for target/experiment hardware; define coolant paths and heat loads; assess off-normal conditions.
• Produce and review safety basis calculations and ensure compliance with safety requirements.
• Participate in post-irradiation examination activities to validate models.
• Develop capabilities for enhanced thermal analysis of targets.
• Prepare peer-reviewed articles, reports, and presentations for sponsors and the technical community.
• Engage in professional societies and standards development.

Skills

Thermal hydraulics

Engineering modeling

CFD tools

Python

Education

Bachelor's in Mechanical/Nuclear Engineering

Tools

COMSOL

ANSYS

STAR-CCM+

MATLAB

Python

Job description

Overview

Oak Ridge National Laboratory (ORNL) is seeking a Nuclear Mechanical Engineer with experience in the analysis of heat transfer and fluid flow in nuclear systems to provide support in the development of novel radioisotope production targets and enhanced tools for analysis.

You will work with scientists, engineers, and technicians to develop thermal and fluid flow models for HFIR isotope production targets. A successful candidate will be capable of leading efforts to achieve isotope production objectives, including HFIR target design, qualification, fabrication, irradiation, and post-irradiation chemical processing. The work is performed under exacting quality standards and in accordance with conduct of operations requirements for nuclear facilities, requiring strong technical judgment, attention to detail, and the ability to work efficiently under demanding schedules.

Excellent communication and interpersonal skills are essential, as success in this role depends on collaborating effectively across multidisciplinary teams and building productive working relationships with a diverse group of technical staff.

Supporting the largest radioisotope production and research portfolio within the Department of Energy (DOE) Office of Science for Isotope R&D and Production, as well as extensive isotope production programs for the DOE Office of Nuclear Energy and National Nuclear Safety Administration, this position will grant you the opportunity to work with rare nuclear materials, and the unique facilities at ORNL, including the High Flux Isotope Reactor (HFIR) and the Radiochemical Engineering Development Center (REDC), as you help guide the strategic growth of our isotope production enterprise.

This role includes developing and documenting analyses consistent with the type of thermal‑hydraulic evaluation used for in‑vessel nuclear experiments, including establishing bounding heat loads, coolant flow paths, thermal margins, and credible off‑normal conditions; producing and reviewing calculation packages suitable for internal review and incorporation into facility safety/operability documentation.

Major Duties / Responsibilities

• Work as part of a multi‑disciplinary team to develop appropriate models and computational strategies to assess HFIR Isotope Production target design.
• Contribute to the design of radioisotope production targets to optimize coolant flow and thermal performance.
• Develop and document integrated thermal‑hydraulic evaluations for target/experiment hardware-define coolant flow paths (flow splits, pressure drops, velocities) and heat loads/temperatures across the operating envelope; assess credible off‑normal conditions (e.g., reduced flow/blockage, control or operator errors, post‑trip/low‑flow heat removal), demonstrate margin to applicable thermal limits (saturation/incipient boiling/CHF as required), and evaluate hydraulic stability risks (flow‑induced vibration, loose parts/debris transport), using calculations and/or flow testing to support conclusions and required mitigations.
• Produce and review/independently check safety basis calculations to rigorous quality standards documenting the performance of radioisotope production targets within HFIR and demonstrating compliance with applicable facility safety basis and experiment/target review requirements.
• Participate in post‑irradiation examination activities necessary to validate computational models.
• Develop capabilities for enhanced thermal analysis of radioisotope production targets.
• Prepare peer‑reviewed journal articles, reports, and presentations for sponsors and the technical community.
• Serve in professional societies and standards development committees.
• As a member of the ORNL scientific community, you will be expected to commit to ORNL's Research Code of Conduct.
• Deliver ORNL's mission by aligning behaviors, priorities, and interactions with our core values of Impact, Integrity, Teamwork, Safety, and Service. Promote equal opportunity by fostering a respectful workplace – in how we treat one another, work together, and measure success.

Basic Qualifications

• BS in Mechanical Engineering, Nuclear Engineering, Chemical Engineering, Materials Science, or similar field, and a minimum of four years of related experience or an advanced degree with two years' experience is required. Work towards an advanced degree with relevant research may be applied towards this experience requirement.
• Moderate knowledge of thermal and mechanical performance of materials in nuclear systems.
• Experience performing moderately complex thermal hydraulic calculations.
• Demonstrated experience with engineering modeling and simulation, including the use of COMSOL, ANSYS (Fluent, CFX, or Mechanical), STAR‑CCM+, RELAP or other hydraulic system codes, and MATLAB or Python for data reduction, automation, and model development.

Preferred Qualifications

• Thermal‑structural knowledge and understanding how it relates to and intersects with thermal‑hydraulic calculations.
• Familiarity with developing/using flow test data (test planning, instrumentation, data reduction, uncertainty) to support hydraulic evaluations.
• Experience in research and development with established publication record.
• Demonstrated ability to organize and lead tasks and/or projects.
• Excellent written and oral communication skills.

Additional Qualifications

• Motivated self‑starter with the ability to work independently and to participate creatively in collaborative teams across the laboratory.
• Ability to function well in a fast‑paced research environment, set priorities to accomplish multiple tasks within deadlines, and adapt to ever changing needs.

Special Requirements

• Visa sponsorship is not available for this role.
• Provide at least two references.

Benefits

• Medical and retirement plans
• Flexible work hours
• On‑site fitness, banking, and cafeteria facilities
• Prescription Drug Plan
• Dental Plan
• Vision Plan
• 401(k) Retirement Plan
• Contributory Pension Plan
• Life Insurance
• Disability Benefits
• Generous Vacation and Holidays
• Parental Leave
• Legal Insurance with Identity Theft Protection
• Employee Assistance Plan
• Flexible Spending Accounts
• Health Savings Accounts
• Wellness Programs
• Educational Assistance
• Relocation Assistance
• Employee Discounts

Relocation

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.

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.