Senior-Level Mechanical Designer; Hybrid​/Remote

Senior-Level Mechanical Designer (Hybrid/Remote)

Amentum is a global leader in advanced engineering and innovative solutions, supporting critical missions across defense, intelligence, energy, and civilian sectors. Our people are our competitive advantage, driven by purpose, collaboration, and a commitment to delivering excellence for our customers and communities. We are currently seeking a Mid-Level Mechanical Designer to support our Nuclear Projects – Oak Ridge.

Description:

As a senior-level mechanical designer, you will provide support for the design and development of HVAC, piping, and plumbing systems for industrial and government (nuclear / DOE) facilities. This role is responsible for the creation, coordination, and checking of complex 3D models and drawing packages, while working closely with mechanical engineers and multidisciplinary teams to deliver high‑quality, fully coordinated design deliverables.

The Senior Mechanical Designer serves as a technical leader within the design team, providing mentoring to junior designers and ensuring designs comply with project requirements, codes, and established quality procedures.

Key Responsibilities:

• Develop and maintain 3D models for HVAC equipment, ductwork, piping, and plumbing systems using Smart Plant 3D, AutoCAD Plant 3D, Revit, or similar tools
• Produce detailed design deliverables, including:
  • Equipment layouts
  • Duct and piping plans
  • Isometric drawings
  • Sections, and details
• Incorporate engineering design criteria, markups, and redlines into constructible models and drawings
• Coordinate designs with mechanical engineers and other disciplines (architectural, structural, electrical, process, I&C, etc.)
• Participate in interference detection and resolution (clash reviews)
• Perform peer checking and quality reviews of drawings and models created by other designers
• Ensure design outputs comply with applicable project standards, client requirements, and quality assurance procedures
• Provide direction and mentorship to junior and mid‑level designers
• Assist with task planning and workload coordination within the design team
• Support training and standardization efforts for design tools and workflows

Basic Qualifications:

• High School Diploma or GED (Associate Degree in Drafting, Design, or Engineering Technology preferred)
• 15+ years of experience in mechanical design for industrial or government facilities
• Strong experience with HVAC, piping, and plumbing layout design
• Proficiency with 3D modeling tools such as:
  Smart Plant 3D / Plant 3D / Revit.
• Ability to read and interpret engineering calculations, P&IDs, and specifications
• Experience producing fully coordinated drawing packages

Preferred
Qualifications:

In addition to the Basic Qualifications the ideal candidate might also have:

• Prior industrial, nuclear, DOE, or high‑hazard facility design experience
• Experience working under a formal quality program (ISO 9001, NQA
  1)
• Strong organizational and communication skills
• Demonstrated attention to detail and commitment to technical excellence

Work
Environment:

• Primarily office-based work in a secure engineering environment
• Amentum office location is preferred; hybrid or remote work may be available by prior agreement based on role and project requirements
• Occasional exposure to industrial facilities, which may include elevated noise levels, hazardous materials, or controlled areas
• Site visits may be required

Physical Requirements:

• Ability to sit or stand for extended periods
• Ability to lift up to 35 lbs occasionally
• Vision correctable to 20/20
• Ability to read and use computer‑aided design software effectively
• Appropriate PPE and training will be provided as required

Compliance & Eligibility Requirements:

• U.S. Citizenship required (no dual citizenship)
• Valid driver's license is required
• Ability to obtain and maintain a security clearance
• Ability to pass pre-employment background investigation and drug screening
• Willingness to work overtime or outside normal hours as needed
• Professional appearance appropriate for a customer‑facing engineering environment
• Travel required:
  
  less than 10%

Compensation Details:

The compensation range or hourly rate listed for this position is provided as a good-faith…