Senior Mechanical Engineer - Welding & Fabrication

• ️ About Assystem

At Assystem, our mission is to accelerate the energy transition worldwide. Our 8,000 Switchers blend historical engineering expertise with cutting-edge digital technologies to drive this change. Join us in revolutionizing the energy sector and making a significant global impact.

Why Join the Community of Switchers?

Be part of one of the top three largest nuclear engineering companies globally. At Assystem, you’ll contribute to groundbreaking projects that push the boundaries of innovation and engineering excellence. Join a community committed to driving forward the future of energy.

JOB DESCRIPTION

Job Purpose / Overview

The successful applicant will play a key role within the Nuclear Power Plant Project’s Technical Branch, working as part of a team that tackles critical, cross‑discipline design issues and engages with multidisciplinary specialists. This role provides exposure to a broad range of technical topics across the project, driving timely resolution of technical issues, strengthening engineering delivery, and proactively reducing key project engineering risks.

Contextual Information

As part of the project’s Technical Directorate and based on site alongside the Construction Team, the team manages site‑based queries during construction, installation, and commissioning. It also leads the closure of post‑handover open points arising from site activities or, by exception, upstream of handover or from subsequent design NCRs.
The team is responsible for addressing Nuclear Safety Category 3 and 4 site queries as part of the Intelligent Customer role, under a Technical Delegation of Authority from the Project’s Design Authority. Within this structure, the Technical Branch also delivers Category 1 and 2 changes with support from the wider business.

The team additionally oversees design changes and configuration management throughout construction, installation, and commissioning, maintaining control of non‑permanent design information and As‑Built records.

Framework & Boundaries

• Build strong, sustainable relationships across SMEs, Technical Authority, Operations, Responsible Designer, Project Managers, Contract Managers, and Construction/Installation contractors.
• Collaborate closely with Operational teams to resolve complex technical issues.
• Produce high‑quality technical reviews, justification papers, and formal judgement documents.
• Protect the integrity of the nuclear safety case for all safety‑impacting changes.
• Oversee and provide surveillance of design changes delivered by Operational teams and the Responsible Designer.
• Represent the client with clear, risk‑informed decisions that consider wider project impacts.
• Apply UK regulatory and construction requirements across all design and delivery activities.
• Embed ALARP through practical, evidence‑based implementation.
• Champion innovation to improve efficiency, quality, safety, and delivery.
• Work constructively with internal and external regulators to ensure technical compliance and nuclear safety.
• Leverage specialist nuclear services to maintain technical excellence and delivery confidence.
• Act as custodian of the Nuclear Baseline, upholding SQEP standards and safety justification integrity.

Principal Accountabilities

• Be an organised, proactive communicator able to engage clearly with a wide range of stakeholders.
• Provide oversight and approval for Nuclear Safety Category 3 changes.
• Lead joint Task Forces for Nuclear Safety Category 2 changes.
• Collaborate across teams to deliver high‑quality technical outcomes and uphold safety‑critical standards.
• Actively contribute in meetings to drive constructive, delivery‑focused discussions and timely decisions.
• Support the development and rollout of standardised technical solutions for recurring construction, installation, and commissioning challenges.
• Demonstrate a growth mindset, resilience, adaptability, and a willingness to learn.
• Recognise your own knowledge boundaries and seek guidance when needed.
• Proactively identify where you can add value in resolving complex engineering problems.
• Apply sound engineering judgement consistently.
• Work effectively both as part of a team and autonomously when required.
• Take a pragmatic, practical approach to developing solutions.
• Resolve high‑complexity or high‑risk technical issues and contribute to safety‑case substantiation where required.
• Be a competent user of Microsoft software.
• Interpret complex technical information, understand its impact on plant performance, and communicate it clearly to stakeholders.

MY PROFILE

✅ Essential Requirements

• Degree (or equivalent) in Mechanical or Materials Engineering
• Strong experience working within a highly regulated industry
• Demonstrable evidence of problem‑solving and stakeholder management
• Excellent communication skills and strong initiative to drive results
• Understanding of civil, electrical, and mechanical interfaces on a construction site
• Strong written and verbal English communication skills
• Hands‑on experience with onsite engineering

• Desirable Qualifications & Experience

• Understanding of welding in site and fabrication environments (Including CSWIP Certification)
• Chartered Engineer status (or equivalent)
• Previous experience within the Nuclear Industry
• Experience working in engineering design
• Knowledge of EPR building, plant, and systems
• Safety Case experience and understanding of Nuclear Safety Categorisations
• Knowledge of Technical French is an advantage

Why Apply?

Join Assystem and become a key player in delivering critical nuclear projects that shape the future of energy. Embrace this opportunity to excel in a dynamic environment where your expertise and leadership will drive global innovation.

Your Benefits Package

Hybrid Working – Flexibility to work from home and the office
️ 25 Days Annual Leave + Bank Holidays
Buy & Sell Holiday – Make your time off work for you
8% Company Pension Contributions
️ Income Protection & 3x Salary Death-in-Service Cover
Competitive Sick Pay – Support when you need it
Healthcare Cash Plan – Claim back on dental, optical & more
Free Digital Gym Access – Expert-led fitness classes
Exclusive Discounts – Restaurants, days out & top brands
24/7 Employee Support Line – Mental health, financial & legal help
Cycle to Work Scheme – Save money & go green
Free Flu Jabs & Eye Test Vouchers
Paid Professional Membership Fees
❤️ Volunteer Days – Make a difference on company time

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.

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.