Principal Mechanical Engineer

Amentum; Stockton-on-Tees; Hybrid; GBP 55,000 - 75,000; Full time

Job summary

A leading engineering firm in Stockton-on-Tees is looking for a Principal Mechanical Engineer to support nuclear fleet transformation. The role involves delivering mechanical design solutions, collaborating with various stakeholders, and ensuring compliance with regulations. Ideal candidates will hold an engineering degree, have experience in regulated industries, and proficiency in CAD software. This position offers competitive benefits and flexible work arrangements.

Benefits

Competitive salary

Medical cover

Enhanced parental leave

Professional development reimbursement

Qualifications

• Chartered status or working towards it (e.g., IMechE, MIET) is preferred.
• Experience with technical drawings (BS EN 8888) and P&ID.
• Knowledge of UK Nuclear Regulatory processes is desirable.

Responsibilities

• Own technical challenges, develop strategies, and implement solutions.
• Deliver technical analysis and design solutions.
• Produce and review design documents, specifications, and calculations.

Skills

Mechanical design solutions

CAD software proficiency

Technical analysis

Experience in regulated industries

Experience with American codes

Education

MEng, MSc, BEng, or BSc in Mechanical Engineering

Tools

AutoCAD

Inventor

Creo

SolidWorks

Job description

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Principal Mechanical Engineer, Stockton-on-Tees

Client: Amentum

Location: Stockton-on-Tees, United Kingdom

Job Category: Other

EU work permit required: Yes

Job Reference: 0ece7f8cbe58

Job Views: 25

Posted: 12.08.2025

Expiry Date: 26.09.2025

Job Description:

We’ll inspire and empower you to deliver your best work so you can evolve, grow, and succeed - today and into tomorrow. We offer an exciting range of opportunities to develop your career within a supportive and diverse team who always strive to do the right thing for our people, clients, and communities.

People are our greatest asset, and we offer a competitive package to retain and attract the best talent. In addition to the benefits you’d expect, UK employees also receive free single medical cover and digital GP service, family-friendly benefits such as enhanced parental leave pay and free membership of employee assistance and parental programmes, plus reimbursement towards relevant professional development and memberships. We also give back to our communities through our Collectively program which incorporates matched-funding, paid volunteering time, and charitable donations.

About the Opportunity

Amentum is recruiting a Principal Mechanical Engineer to join our Energy business, supporting UK nuclear fleet transformation and new small modular reactor developers. Our work covers Licensing, New Build, Generation, Life Extension, and Defueling, with demand across the nuclear sector.

Your role involves managing and delivering mechanical design solutions to meet project goals, working closely with Operations and Engineering Managers to maximize value. The position can be based at one of our Energy offices (Newcastle, Warrington, Glasgow, Gloucester, Stockton, Bristol, or Knutsford), with flexible working arrangements considered.

Responsibilities:

• Own technical challenges, develop strategies, and implement solutions with stakeholders.
• Deliver technical analysis and design solutions.
• Produce and review design documents, specifications, and calculations.
• Collaborate with international SMR developers for regulatory assessments.
• Justify design decisions to the ONR.
• Fulfill CDM responsibilities.

Minimum Qualifications:

• MEng, MSc, BEng, or BSc in Mechanical Engineering or relevant field.
• Experience in heavy infrastructure, nuclear, or regulated industries.
• Chartered status or working towards it (e.g., IMechE, MIET).
• Experience with American codes and designing pumps, valves, heat exchangers, tanks, filters, HVAC equipment, and authoring datasheets.
• Proficiency with CAD software (AutoCAD, Inventor, Creo, SolidWorks).
• Experience with technical drawings (BS EN 8888) and Piping & Instrumentation Diagrams.
• Familiarity with safety cases in industrial environments.
• Knowledge of UK Nuclear Regulatory processes is desirable.

Our Culture

We prioritize safety, integrity, inclusion, and diversity. We support a culture of caring, positive mental health, and belonging. We promote inclusion and diversity through our policies and partnerships, including VERCIDA, and are a Disability Confident employer. We welcome applications from candidates seeking flexible working or who may not meet all listed requirements.