Job Description
At Amentum, we're not just solving problems; we're engineering the future. Our team is driven by an unyielding commitment to innovation, integrity, and collaboration, tackling some of the most significant challenges in science, security, and sustainability. If you're passionate about making a real impact and want to be part of a community that values ethical excellence, this is the place where your ambition can thrive.
Here, we believe that success comes from continuously pushing boundaries and working together to deliver on our promises. We embrace challenges with confidence and are dedicated to creating a secure and vibrant future for all.
We’ll inspire and empower you to deliver your best work so you can evolve, grow and succeed – today and into tomorrow. We offer an exciting range of opportunities to develop your career within a supportive team who always strive to do the right thing for our people, clients and communities. People are our greatest asset, and we offer a competitive package to retain and attract the best talent.
In addition to the benefits you’d expect, UK employees also receive free single medical cover and digital GP service, family-friendly benefits such as enhanced parental leave pay and free membership of employee assistance and parental programmes, plus reimbursement towards relevant professional development and memberships.
Work-life balance and flexibility is a key focus area for us. We’re happy to discuss hybrid, part-time and flexible working hours, patterns and locations to suit you and our business.
About the Opportunity
The Box Encapsulation Plant project is one of the most important construction projects at the Sellafield Site, the plant will play a vital role in Sellafield’s 100-year clean-up programme by taking nuclear waste recovered from the sites original wasteplants and encasing it in concrete so it can be stored in a modern building. The plant is primarily designed to deal with waste from the Magnox Swarf Storage Silo, one of four legacy waste plants prioritised for clean-up by Sellafield Ltd’s owner, the Nuclear Decommissioning Authority (NDA). Alongside that work, the plant will also receive certain wastes from the other three legacy waste stores, the First Generation Magnox Storage Pond, the Pile Fuel Storage Pond, and Pile Fuel Cladding Silo.
The BEP Joint Venture project will safely design and deliver a Plant and the works in accordance with the requirements of the contract to enable conditioning of wastes from the various donor plants, carried out in line with the Employer’s needs and to the satisfaction of stakeholders in the Box Encapsulation Project (BEP).
The Commissioning Engineer reporting to the Commissioning Team Leader, carries out a role to undertake delivery of assigned commissioning tasks in a safe and effective manner, in line with commissioning process requirements.
This role is specific to candidates with experience in nuclear in-cell handler testing.
The Commissioning Engineer is responsible for:
1. Execution of the arrangements for controlling, witnessing, recording and assessing the results of commissioning tests which may affect safety.
2. Delivering the commissioning work scope to an agreed strategy and plan in a timely and cost effective manner.
3. Ensuring a proactive and balanced approach to safety (nuclear, radiological, conventional and environmental) to ensure that safety is optimised during commissioning.
4. Reviewing commissioning progress and performance and taking appropriate corrective actions where necessary.
5. Managing day to day liaison with personnel to obtain any necessary permissions and minimize impact to the project
6. Review of commissioning test results.
7. Ensuring input to other project processes are incorporated, for example, design, HAZOP, risk, contract, estimating and knowledge management.
Experience & Qualifications:
8. Nuclear Mechanical systems commissioning.
9. Minimum - HNC/HND in Engineering related subject or equivalent.
10. Experience in nuclear commissioning.
11. Project management knowledge, preferably APM member.
12. Calculation production using Excel.
13. IOSH Managing Safely.
14. Relevant trade card.
15. The ability to obtain BPSS and P4 Pass is essential for continuance in the role.
Our Culture
Our values are built on a strong foundation of safety, integrity, and respect for every individual. People are at the heart of our mission, and we believe in supporting one another through a culture of care and collaboration.
We strive to create a workplace where everyone feels they belong and can thrive. Supporting mental wellbeing and fostering a sense of connection are essential to how we work.
When we embrace different perspectives and work together, we become more innovative, more agile, and more successful.
We partner with VERCIDA, for greater online accessibility please visit to view and access our roles. As a Disability Confident employer, we will interview all disabled applicants who meet the minimum criteria for a vacancy. We welcome applications from candidates who are seeking flexible working and from those who may not meet all the listed requirements for a role.
If you require further support or reasonable adjustments with regards to the recruitment process (for example, you require the application form in a different format), please contact the team.
Compensation Details:
GBP
The compensation range or hourly rate listed for this position is provided as a good-faith estimate of what the company intends to offer for this role at the time this posting was issued. Actual compensation may vary based on factors such as job responsibilities, education, experience, skills, internal equity, market data, applicable collective bargaining agreements, and relevant laws.
Benefits Overview:
Our health and welfare benefits are designed to support you and your priorities. Offerings include:
16. Health, dental, and vision insurance
17. Paid time off and holidays
18. Retirement benefits (including 401(k) matching)
19. Educational reimbursement
20. Parental leave
21. Employee stock purchase plan
22. Tax-saving options
23. Disability and life insurance
24. Pet insurance
Note: Benefits may vary based on employment type, location, and applicable agreements. Positions governed by a Collective Bargaining Agreement (CBA), the McNamara-O'Hara Service Contract Act (SCA), or other employment contracts may include different provisions/benefits.
Original Posting:
04/15/2026 - Until Filled
Amentum anticipates this job requisition will remain open for at least three days, with a closing date no earlier than three days after the original posting. This timeline may change based on business needs.
Amentum is proud to be an Equal Opportunity Employer. Our hiring practices provide equal opportunity for employment without regard to race, sex, sexual orientation, pregnancy (including pregnancy, childbirth, breastfeeding, or medical conditions related to pregnancy, childbirth, or breastfeeding), age, ancestry, United States military or veteran status, color, religion, creed, marital or domestic partner status, medical condition, genetic information, national origin, citizenship status, low-income status, or mental or physical disability so long as the essential functions of the job can be performed with or without reasonable accommodation, or any other protected category under federal, state, or local law. Learn more about your rights under Federal laws and supplemental language at .