Principal Mechanical Engineer

Assystem; Helensburgh; Hybrid; GBP 45,000 - 65,000; Full time

Job summary

Assystem in the United Kingdom is seeking an experienced Mechanical Engineer to support the Client Design Authority, focusing on mechanical design and reliable infrastructure systems. You will produce and review design packages, define performance and safety requirements, and support compliant operations.

The role is primarily remote with 1–2 days per month at the client site in Helensburgh, offering exposure to nuclear-grade projects and opportunities to work across a multi-disciplinary team

Qualifications

• Broad mechanical engineering experience with knowledge of pumps, cranes, HVAC, pressure systems, or diesel generators.
• Experience in the nuclear sector or another highly regulated/high-hazard industry is desirable but not essential.
• Ability to develop practical, innovative, and cost-effective engineering solutions for plant and infrastructure modifications.
• Good understanding of British and international engineering design standards.
• Strong analytical skills with evidence-based decision making using technical data.
• Excellent written and verbal communication skills with stakeholders.
• Well organised with the ability to manage priorities and deadlines.
• Essential: HNC (or equivalent) in a relevant engineering discipline.
• Essential: Strong understanding of design intent for mechanical infrastructure in a regulated industry.
• Desirable: IEng status or equivalent experience.
• Desirable: Degree in Mechanical Engineering or related discipline.

Responsibilities

• Produce and review high-quality infrastructure design packages and technical specifications.
• Define reliability, performance, and operational requirements for infrastructure systems.
• Assess maintenance and work control procedures to support safe operations.
• Evaluate design, material condition, ageing mechanisms, and asset suitability to support operation.
• Promote safety, security, and compliance culture across activities.
• Act as an intelligent customer ensuring safety-related contracts and deliverables meet requirements.

Skills

Mechanical design

Pumps

HVAC

Diesel generators

Regulatory standards

Stakeholder engagement

Education

HNC in engineering

IEng status

BEng/MEng in Mechanical Engineering

Job description

Job Description

We are looking for an experienced Mechanical Engineer to support the technical capability of the Client Design Authority (DA). This role will be suited to engineers with experience in Mechanical Design, although candidates experienced in Mechanical Installation or Maintenance are also welcomed.

Responsibilities

• Produce and review high-quality infrastructure design packages and technical specifications.
• Define reliability, performance, and operational requirements for infrastructure systems.
• Assess maintenance and work control procedures to support safe and effective operations.
• Evaluate infrastructure design, material condition, ageing mechanisms, and asset suitability to support continued facility operation.
• Promote a strong safety, security, and compliance culture across all activities.
• Act as an intelligent customer, ensuring safety-related contracts and technical deliverables meet contractual and regulatory requirements.

Qualifications

• Broad mechanical engineering experience, with knowledge of systems such as pumps, cranes, HVAC, pressure systems, or diesel generators.
• Experience in the nuclear sector or another highly regulated/high-hazard industry is desirable but not essential.
• Ability to develop practical, innovative, and cost-effective engineering solutions for plant and infrastructure modifications.
• Good understanding of British and international engineering design standards.
• Strong analytical skills with the ability to make informed, evidence-based decisions using a range of technical data.
• Excellent written and verbal communication skills, with the ability to engage effectively with stakeholders.
• Well organised, with the ability to manage priorities and deliver work to agreed timescales.
• (Essential) HNC (or equivalent qualification/experience) in a relevant engineering discipline.
• (Essential) Strong understanding of the design intent for mechanical infrastructure within the nuclear sector or a similar highly regulated industry.
• (Desirable) Incorporated Engineer (IEng) status, or equivalent experience.
• (Desirable) Degree (or equivalent qualification/experience) in Mechanical Engineering or a related discipline.

Benefits

• The Group is currently ranked third in the world for nuclear engineering.
• A dynamic career management policy to enable employees to progress through five business lines: operations, project, technical, sales and support functions.
• Opportunities to work on exciting, global projects.
• Access to an employee assistance programme with free mindfulness, health, wellbeing resources and a confidential support line available 24/7 via phone or text.
• Discount vouchers for days out and restaurants, eye test and glasses vouchers, cycle to work scheme, free flu jabs.

Additional Information

• Umbrella contractor or permanent staff.
• Requires sole UK national with SC clearance.
• Mainly remote working with 1–2 days per month at client site in Helensburgh.

Security & Export Control

• These restrictions mean that factors such as your nationality, any nationalities you may have previously held, and your place of birth can restrict the roles you are eligible to perform within the organisation.
• All applicants must at a minimum achieve Baseline Personnel Security Standard. Many roles also require higher levels of National Security Vetting where applicants must typically have 5 to 10 years of continuous residency in the UK depending on the vetting level required for the role, to allow for meaningful security vetting checks.

We are committed to equal treatment of candidates and promote, as well as foster all forms of diversity within our company. We believe that bringing together people with different backgrounds and perspectives is essential for creating innovative and impactful solutions. Skills, talent, and our people’s ability to dare are the only things that matter. Bring your unique contributions and help us shape the future.