Principal Mechanical Engineer

Lead the Way in Nuclear Decommissioning

At Cavendish Nuclear we’re working to create a safe and secure world, together, and if you join us, you can play your part as a Principal Mechanical Engineer, at one of our key locations: Warrington (Cheshire), Hessle (East Riding of Yorkshire), or Preston (Lancashire).

The role

As a Principal Mechanical Engineer, you’ll play a pivotal role in a major civil nuclear decommissioning initiative. This project is part of a broader effort to safely dismantle and remediate legacy nuclear infrastructure, with a strong emphasis on sustainability, regulatory compliance, and environmental stewardship. You’ll be working on the integration of complex mechanical systems within a multidisciplinary team, developing innovative engineering solutions to support the safe deconstruction and long-term management of nuclear facilities.

Day-to-day, you’ll lead multidisciplinary engineering teams, oversee the delivery of complex technical solutions, and act as a key point of contact for customers, ensuring high standards of safety, quality, and performance while mentoring others and driving continuous improvement across projects.

• Lead and manage multidisciplinary engineering teams to deliver high-quality technical solutions aligned with customer requirements and project scope.
• Supervise and mentor engineers and technical specialists, ensuring effective performance, development, and adherence to engineering standards.
• Act as a key liaison with customers, fostering strong relationships and ensuring transparent communication on technical progress and delivery.
• Oversee the production, review, and approval of engineering outputs, including calculations, specifications, and reports, ensuring compliance with relevant codes and standards.
• Champion health, safety, and environmental standards across engineering activities, promoting a culture of best practice and continuous improvement.

This role is full time, 37 hours per week provides hybrid working arrangements with 3 days in the office, at one of our key locations: Warrington (Cheshire), Hessle (East Riding of Yorkshire), or Preston (Lancashire).

Essential Experience Of The Principal Mechanical Engineer

Although a benefit, nuclear experience is not essential and we welcome applicants from all highly regulated industries.

• Extensive experience leading multidisciplinary engineering teams and delivering complex technical projects within agreed scope, timeframes, and quality standards.
• Proven ability to supervise and mentor engineers and technical specialists, fostering professional development and ensuring high performance.
• Strong background in producing, reviewing, and approving detailed engineering outputs, including calculations, specifications, and technical reports.
• Demonstrated expertise in applying relevant procedures, codes, and standards to ensure compliance and technical integrity across engineering activities.
• Track record of effective customer engagement, including managing relationships, resolving technical issues, and supporting business development initiatives.

Qualifications For The Principal Mechanical Engineer

• Engineering degree (or equivalent qualification) in relevant engineering discipline, with significant demonstrable experience.

Security Clearance

The successful candidate must be able to achieve and maintain Standard (BPSS) / Security Check (SC) security clearance for this role.

What We Offer

• Generous holiday allowance.
• Matched contribution pension scheme, with life assurance.
• Access to a Digital GP, annual health check, and nutritional consultations through Aviva DigiCare+.
• Employee share scheme.
• Employee shopping savings portal.
• Payment of Professional Fees.
• Reservists in the armed forces receive 10-days special paid leave.
• Holiday Trading is a benefit that allows UK Cavendish employees to buy additional leave or to sell up to one working week of annual leave from their annual entitlement.
• ‘Be Kind Day’ enables employees to take one working day’s paid leave a year (or equivalent hours) to undertake volunteering work with their chosen organisation or registered charity.
• Excellent development opportunities and benefits package including an employee assistance programme supporting physical, mental and financial wellbeing.

Cavendish Nuclear

As a leader within the UK nuclear industry, Cavendish Nuclear, part of Babcock International Group, provides a comprehensive range of critical nuclear solutions in clean energy, defence and civil new build and decommissioning projects. Together, we’re innovating to make nuclear safer, faster and cost-effective across the nuclear energy life cycle. Your career with us could take you anywhere within Babcock International Group – from Canada, the USA to Japan. Work with us to create a safe and secure world, together.

We are a disability confident committed employer. If you have a disability or need any reasonable adjustments during the application and selection stages, please email careers@babcockinternational.com with the subject header ‘Reasonable adjustments requirement’. We’re committed to building an inclusive culture where everyone’s free to thrive. We are happy to talk about flexible working – please ask about alternative patterns of work at interview.

Closing date: 13/01/2026