Navarro Research and Engineering is recruiting for a Senior Mechanical Design Engineer in Oak Ridge, TN. Navarro Research & Engineering is an award-winning federal contractor dedicated to partnering with clients to advance clean energy and deliver effective solutions for complex challenges in the nuclear and environmental fields. Joining Navarro means being a part of an exceptional team committed to quality and safety while also looking for innovative strategies to create value for the client’s success. Headquartered in Oak Ridge, Tennessee, Navarro has active programs in place across the nation for DOE/NNSA, NASA, and the Department of Defense. We are seeking a Senior Mechanical Design Engineer who specializes in designing and optimizing piping and mechanical systems within process-control environments that handle liquids or gases. This role demands extensive experience in fluid dynamics, equipment specification, and structural analysis. The successful candidate will lead innovation in system design with minimal supervision, ensuring projects meet operational, regulatory, and safety targets from conception through final realization. Key Responsibilities Lead the design, construction, and maintenance of facility piping systems, including rigorous component sizing and equipment selection (pumps, motors, heaters, blowers, valves, etc.). Model pressure, flow, and thermal effects (steady‐state and transient) using CFD, FEA, and related tools; validate piping integrity under static and dynamic loads, and perform pipe-stress/structural analyses. Develop, review, and red-line mechanical and piping drawings, plans, and specifications derived from engineering calculations; ensure compliance with codes, standards, and regulatory requirements. Plan, schedule, conduct, and coordinate detailed phases of engineering work for major projects or for entire projects of moderate scope; prepare ROMs and detailed cost estimates, compile equipment specifications, and generate procurement documentation. Participate in safety reviews, quality-assurance activities, training sessions, and regulatory audits; drive continuous improvement by integrating emerging technologies and best practices. Produce technical reports, literature reviews, and progress updates; present findings and status briefings to stakeholders and senior management. Direct the work of technical support staff and mentor junior engineers in mechanical and fluid-system design; guide troubleshooting and modifications to resolve equipment malfunctions. Perform additional related tasks as assigned. Requirements Five to twelve (5 – 12) years of mechanical design-engineering experience with a strong focus on piping and fluid systems (industrial liquid or gas processes). Demonstrated expertise in pressure-drop calculations, fluid-flow optimization, and equipment sizing/selection. Proficiency in static and dynamic piping analyses, including pipe-stress and support-structure calculations. Prior experience in highly regulated or process-driven industries (nuclear, chemical processing, oil & gas, HVAC, etc.). Familiarity with relevant codes and standards (ASME or equivalent) and proven ability to integrate them into efficient designs. Strong in fluid mechanics, thermodynamics, and materials science. Proven history of analytical, problem-solving, and project-management skills; effective oral and written communication; collaborative mindset when working with cross-functional teams. Education & Certification Bachelor’s degree in Mechanical Engineering (or a related field) from an accredited institution – or equivalent combination of education and experience. Professional Engineer (PE) licensure and/or certifications in project management or quality are advantageous but not required. Additional Requirements Ability to obtain and maintain a DOE Q-level security clearance. Due to the nature of the government contract requirements and/or clearances requirements, US citizenship is required. Navarro is an equal-opportunity employer. All qualified applicants will receive consideration for employment without regard to race, religion, color, national origin, gender, age, sexual orientation, gender identity, status as a protected veteran, or status as a qualified individual with a disability. EEO Employer/Vet/Disabled Benefits Health Care Plan (Medical, Dental & Vision) Retirement Plan (401k, IRA) Life Insurance (Basic, Voluntary & AD&D) Paid Time Off (Vacation & Public Holidays) Short Term & Long Term Disability