Principal Mechanical Engineer (Nuclear Mechanical Handling)

COSTAIN GROUP; Manchester; On-site; GBP 70,000 - 110,000; Full time

Job summary

Costain Group is seeking a Principal Mechanical Engineer to lead design activities for nuclear projects in the UK, directing a team of engineers and designers, coordinating with delivery teams, and ensuring compliance with safety and quality standards. The role blends hands-on design with line management and budgeting responsibilities.

The position focuses on Nuclear Mechanical Handling capabilities, with responsibilities spanning from tendering to construction support, and involves a hybrid

Qualifications

• Extensive engineering design experience across the full lifecycle.
• Leadership and mentoring experience to support career development.
• Proven ability to report project data and KPIs.

Responsibilities

• Provide direct line management for engineers/designers and mentor junior staff.
• Act as single point of contact for project disciplines including budget and resource planning.
• Produce and approve engineering deliverables (calculations, scopes, specs).
• Coordinate multi-disciplinary interfaces and manage change control.
• Develop robust estimates for tenders and project changes.
• Share best practices and promote safety across the team.

Skills

Mechanical design

Project leadership

Regulatory knowledge

Nuclear handling

Education

Degree in engineering

CEng or IEng

BPSS/Security clearance readiness

Tools

Stress analysis software

Job description

Job Description

Following a number of project and long term framework wins in the Nuclear industry, including Urenco, we are seeking a Principal Mechanical Engineer to support and deliver key elements of design work on projects, primarily through the management of technical resources to deliver on company and client promises.

Costain's multi-disciplinary engineering and design team delivers comprehensive design solutions across a range of UK Infrastructure sectors - Energy, Defence & Nuclear, Water, Rail, Roads and Integrated Transport. The team covers the full project lifecycle from feasibility and concept through to detailed design and construction support. We focus on the delivery of sustainable, future ready and safe-by-design outputs with a strong constructability ethos.

Typical deliverables and activities for the Mechanical Engineering team include:

• Specifications and Datasheets for Mechanical Equipment
• Enquiry and Purchase Requisitions for Mechanical Equipment Packages.
• Technical Bid Evaluations for Mechanical Equipment Packages.
• Vendor documentation review and FAT attendance for Mechanical Equipment Packages.
• Mechanical Handling and Lifting equipment Specification and design
• HVAC & Building Services design
• Plant and Mechanical Equipment Layout
• Pumping system calculations
• Pressure Equipment design calculations and Mechanical Equipment stress analysis

As a Principal Mechanical Engineer, you will be responsible for delivering key elements of design work on projects, primarily through the management of technical resources to deliver on company and client promises.

This role requires significant technical interface management between delivery teams, driving progress, ensuring compliance and quality, and resolving complex challenges. You may act as the single point of contact for the project discipline team, hold budget and resource responsibility, and maintain line management duties while executing hands-on design production, checking, and approval.

This role will make a key contribution to development of Costain's capability in the specialist area of Nuclear Mechanical Handling to support exciting projects for a number of clients based in North and North West England.

Hybrid role typically involves working three days a week in the Manchester or in our clients office in Cheshire with a flexible approach to home working to promote wellbeing.

Responsibilities

• Technical Leadership: Provide direct line management for a group of engineers/designers, including performance reviews, upskilling, mentoring, and reward coordination with the Discipline Manager.
• Project Delivery: Act as the single point of contact for project disciplines, taking responsibility for technical compliance, quality, resource planning, and budget performance.
• Technical Review & Approval: Execute the production, checking, and approval of engineering deliverables (calculations, scopes of work, specifications) aligned with your discipline.
• Interface Coordination: Coordinate project work activities between multi-disciplinary teams, clients, and construction teams, leading meetings and managing change control.
• Estimation: Lead the development of robust estimates (scoping, hours, risks, assumptions) for tendering/project change, ensuring outcomes align with project and client targets.
• Leadership Support: Actively learn and share best practices across the team, champion safety performance. Provide technical guidance, mentoring, and support to Engineers and junior team members, and deputise for Discipline Managers when required.

Knowledge, Skills, and Experience

Essential

Extensive engineering design experience across the full engineering lifecycle (from tendering to close‑out) within a design consultancy or contractor environment.

Leadership Support and mentoring experience with the ability to support career development.

Proficient in project reporting data (KPIs, carbon tracking, change management, and risk/opportunity reporting).

Extensive working knowledge of the UK Regulatory framework associated with the discipline (e.g., CDM, PESR, Machinery Safety Regulations, ATEX).

Extensive working knowledge of relevant design codes and standards (e.g. BS EN, API, ASME, WIMES, CIBSE / ASHRAE etc).

Excellent organisation, communication, and time‑management skills with a collaborative approach.

Experience in the following specialist mechanical engineering fields:

Nuclear Mechanical Handling

Experience with the following mechanical engineering and design deliverables and activities:

• Technology Readiness Level
• Single Discipline Design Review
• Multi Discipline Design Review
• Design Justification Report
• Mechanical Handling Diagrams
• Design Proposal Drawings
• Plant and Building Layout
• Equipment Specifications and Datasheets

Desirable

• Experience with supply chain management and in site/construction environments.
• Experience in multiple sectors and an innovative approach to driving new engineering delivery methods.
• Strong working knowledge of stress analysis methods and software.
• Extensive knowledge and experience in one or more specialist areas of mechanical engineering design and delivery (e.g. wastewater pumping systems and treatment technologies, rotating or static process equipment, mechanical handling and lifting equipment, stress analysis methods and software, HVAC & Building Services design).
• Experience with Costain clients i.e. Urenco Capenhurst

Qualifications

Essential

• Degree qualified in a relevant engineering discipline (ideally 2:1 or better) or equivalent educational experience.
• Professional qualifications such as Chartered Engineer (CEng) or Incorporated Engineer (IEng) status.
• Valid safety passport or industry equivalent.
• BPSS holder, capable to obtain SC security clearance - UK Citizen or 5 years UK residency

Desirable

• Advanced technical training or post‑graduate qualifications.
• Fellowship of relevant professional body. (or working towards).
• SC security clearance holder

About Us

Costain helps to improve people's lives with integrated, leading edge, smart infrastructure solutions across the UK's energy, water, transportation and defence markets. We help our clients improve their business performance by increasing capacity, improving customer service, safeguarding security, enhancing resilience, decarbonising and delivering increased efficiency. Our vision is to be the UK's leading smart infrastructure solutions company. We will achieve this by focusing on blue chip clients whose major spending plans are underpinned by strategic national needs, regulatory commitments, legislation or essential performance requirements. We offer our clients leading edge solutions that are digitally optimised through the following five services which cover the whole lifecycle of their assets: future-shaping strategic consultancy; consultancy and advisory; digital technology solutions; asset optimisation and complex programme delivery. Our culture and values underpin everything we do.

Costain appreciate the time and effort taken when applying for one of our positions but, due to the high volume of responses, we are unable to provide individual feedback on candidates at application phase.

We do share individual feedback following an interview.

A Disability Confident employer will generally offer an interview to any applicant that disclose they have a disability and meets the minimum criteria for the job as defined by the employer.

It is important to note that in certain recruitment situations such as high-volume, seasonal and high-peak times, the employer may wish to limit the overall numbers of interviews offered to both disabled people and non-disabled people.

For more details please go to the Disability Confident website: https://www.gov.uk/government/collections/disability-confident-campaign