News Nuclear & Defence

Actemium awarded for collaborative and innovative work at Sellafield nuclear site

We’re proud that our Actemium Design UK team are a key member of the Design Services Alliance (DSA) supply chain, an expert group of companies tasked with decommissioning Sellafield, one of the UK’s most complex nuclear sites. Our pride only grew when, earlier this summer, the team’s innovation, creativity and collaboration were honoured with three prestigious awards.

The long road to decommissioning

Located on the Cumbrian coast in Northwest England, the Sellafield site generated nuclear energy from 1956 to 2003 and reprocessed nuclear fuel from 1952 to 2022. In August 2022, it entered its decommissioning phase, shifting focus from reprocessing operations, to retrievals, remediation and the long-term storage of legacy nuclear waste. The DSA was established in 2012 to support the site’s decommissioning goals.

Decommissioning a nuclear site is one of the most challenging assignments engineers can be undertake. It requires safely and sustainable supporting numerous related projects over many years, demanding the collaboration of many trusted experts with high-level skills and knowledge. As a key delivery partner for the DSA, Actemium brings more than 40 years of experience and expertise in the nuclear sector to assist in making Sellafield safer for future generations.

Actemium’s role at Sellafield

Our Actemium Design UK engineers provide mechanical, Control, Electrical & Instrumentation (CE&I), and process engineering design services across many of the Sellafield frameworks. In addition to the DSA, these include the Infrastructure Strategic Alliance (ISA), Decommissioning Delivery Partnership (DDP), and Project and Programme Partners (PPP). Examples of these project teams include:

  •  The MSSS RIOT team is primarily responsible for improving the performance and reliability of the Silo Emptying Plant (SEP) machines used for removing legacy waste from the Magnox Swarf Storage Silo (MSSS), an aging facility that is a major challenge in the Sellafield site’s overall cleanup effort. The RIOT (Retrievals Innovation and Optimisation Tactics) team is tasked with investigating how obsolete or non-optimal equipment can be safely and efficiently replaced with minimal plant alterations. The team is also responsible for applying innovative technology to improve retrievals operations and accelerating hazard reduction in preparing for the silo’s eventual demolition.
  • The BEP team is responsible for the Box Encapsulation Plant (BEP), a key facility on the Sellafield site that processes the legacy waste retrieved from MSSS and other donor plants. Eventually, the facility will repackage this waste into more than 6,000 3-metre cubed boxes, which will then be stored in a specially built vault. Actemium Design UK has already contributed more than 470,000 hours of engineering design support to the BEP project, delivering build-to-print solutions and supporting the project through manufacture, works testing, and installation.

Progressive DSA awards for Actemium team

The Progressive Alliance annually honours teams and individuals who have excelled at collaboration and working as One Team to deliver innovative solutions. In June 2025, Actemium Design UK was recognised at the Progressive DSA Awards with three prestigious awards:

  • Lifetime Value for Money Team Award acknowledged Actemium Design UK’s RIOT team for cost-effectively supporting the MSSS retrievals programme to a high standard and showing flexibility in supporting its changing requirements — from small-scale, quick-fix improvements to more-complex and constrained longer-term improvements.
  • Contribution Team Award was presented to Actemium Design UK’s BEP team members for their impactful collaboration and dedication over more than eight years of support, consistently achieving 100% assessments on DSA’s quarterly customer feedback forms.

Progressive DSA celebrates individual achievement of Actemium’s Nurul Chowdhury

In addition, Nurul Chowdhury, a Principal Process Engineer with Actemium Design UK, was recognised for his contribution to Cavendish Nuclear’s MSSS Remediation Project. The Safe, Secure, Sustainable Site Stewardship Individual Award acknowledges his role as a project enabler thanks to his positive approach and professional conduct, including his ability to concisely and clearly explain complex information to stakeholders.

Actemium remains committed to our partnership within the DSA framework. We look forward to building on these achievements to deliver exceptional results in the future.