Mechanical Engineer (Valve Specialist)

⚡️ 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.

What You'll Be Doing

As a Mechanical Engineer, specialising in Valve Engineering, you'll support all valve engineering activities for the Hinkley Point C (HPC) Project within the Joint Design Office (JDO), ensuring designs are compliant, constructible, and fit for operation in a nuclear environment.

✅ Key Responsibilities

• Provide technical clarification on valve-related deliverables required for construction, working closely with Back Office design teams (EPR-E, EDVANCE, CNEPE and valve suppliers).
• Gather, review and assess engineering inputs, design assumptions, technical specifications, equipment data sheets and supporting documentation.
• Review valve design documentation to ensure compliance with project requirements, nuclear codes and applicable standards.
• Carry out valve engineering assessments, including:
  • Functional and operational reviews
  • Assessment of operational requirements
  • Qualification and environmental requirement reviews
  • Identification and implementation of design modifications
• Manage and close valve-related technical queries and open points.
• Assess and provide technical responses to issues arising during manufacturing, testing, installation and commissioning activities.
• Review and integrate valve design modifications requested by project stakeholders following JDO handover.
• Perform engineering assessments and hand calculations to determine the feasibility and impact of proposed changes.
• Review and verify technical documentation produced by suppliers and engineering subcontractors.
• Identify opportunities to improve and optimise valve designs and associated documentation.
• Collaborate closely with system engineers, layout engineers, CAD designers and multidisciplinary teams to support valve integration across plant systems.
• Lead technical meetings and manage interfaces with a wide range of stakeholders.
• Provide subject matter expertise on valve operation, maintainability, reliability and nuclear safety requirements.

Coordination Responsibilities

Acting as the primary point of contact for valve-related queries from the HPC site, you will:

• Coordinate technical activities across multiple valve packages and systems.
• Drive alignment and consistency of technical solutions between stakeholders.
• Monitor, manage and support the resolution of valve-related open points.
• Facilitate communication between design teams, suppliers, construction teams and the client.
• Support project delivery by ensuring valve engineering activities are executed in line with project schedules, quality standards and delivery objectives.

What We're Looking For...

✅ Key Qualifications, Experience & Skills

• Degree in Mechanical Engineering, Nuclear Engineering, or a related Engineering / Science discipline.
• Experience across the valve lifecycle, including specification, design, procurement, qualification, manufacturing, installation, commissioning, or maintenance.
• Background working on complex projects within highly regulated industries such as Nuclear, Energy, Oil & Gas, Defence, Process, or Power Generation.
• Strong understanding of engineering documentation, including technical specifications, equipment data sheets, calculations, testing records and supplier deliverables.
• Ability to assess technical issues, identify practical solutions and support implementation.
• Excellent stakeholder management and interpersonal skills, with the ability to collaborate across multidisciplinary teams.
• Strong organisation, attention to detail and ability to manage multiple priorities.
• Fluent in spoken and written English, with the ability to produce clear technical documentation and present complex information to a range of stakeholders.

⭐ Desirable (but not mandatory) Experience & Skills

• Knowledge of nuclear industry codes, standards and safety requirements.
• Experience with valve sizing, actuator sizing, valve qualification, or performance assessments.
• Experience reviewing supplier documentation and managing technical interfaces with valve manufacturers.
• Knowledge of EPR design principles, the Hinkley Point C project, and associated engineering methodologies.
• Previous experience supporting construction, manufacturing, installation, commissioning, or site activities.
• Experience coordinating cross-functional engineering activities and managing complex stakeholder interfaces.
• Understanding of 2D/3D design software and engineering document management systems.
• Ability to prioritise competing demands, challenge assumptions appropriately, and understand the requirements of neighbouring disciplines.
• Proven ability to deliver commitments and meet project deadlines.
• French language skills would be advantageous.

✅ Key Competencies



We're looking for a proactive and collaborative engineer with strong communication, stakeholder management and problem-solving skills. You'll be comfortable working across multidisciplinary teams, managing competing priorities, and communicating complex technical information clearly. A commitment to quality, safety and delivering to project deadlines is essential.

Don't Meet Every Requirement? We'd Still Love to Hear From You!

We know that great engineers don't always tick every box on a job description! If you have a strong engineering background and experience in valve engineering or related mechanical systems, we encourage you to apply, even if your experience doesn't quite align with every requirement listed above.

Nuclear industry experience is also not essential. We're keen to hear from candidates from other highly regulated sectors such as Energy, Oil & Gas, Defence, Power Generation, Process Industries, Aerospace, Rail, Marine, or Heavy Manufacturing, where similar engineering principles, technical standards and safety-focused ways of working apply.

If you're looking to apply your expertise on one of the UK's most ambitious infrastructure projects, we'd be delighted to hear from you.

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

NOTICE TO CANDIDATES ON RECRUITMENT FRAUD - We are committed to safeguarding candidates from fraudulent activity associated with our recruitment process. Please note that we will never offer specialist CV writing services, request payment or ask for sensitive personal information during the recruitment process.

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.