Energy & Decommissioning

Sellafield Nuclear Site

  • Project Value £10 Million
  • Seismically Qualified Ductwork 6,000 Meters
  • Seismic Supports 41 tonnes

Sellafield has been part of the Exyte Hargreaves DNA for more than 70 years. We have contributed to all major projects at the site and our HVAC systems can be evidenced at almost all buildings at Sellafield. Our site operatives have carried out highly specialised work in some of the most challenging environments the company has experienced. Since the 1950’s we have delivered design and engineering solutions which have lowered the overall cost to Sellafield, chiefly through the design of a lighter duct system.


Completed: 2021 | Project Value: £23 million

The Box Encapsulation Project Product Store Direct Import Facility (BEPPS DIF) was a new build necessary to help treat the legacy waste streams from the Pile Fuel Cladding Silo (PFCS). The overall scope included complex High Integrity Containment systems which filter contaminated air to ensure the safety of those within the facility and surrounding areas. The project was designed to clean up one of the most hazardous buildings in Western Europe.

Exyte Hargreaves’ scope included the selection and procurement of all plant & equipment ranging from HEPA filter banks to concrete liners which transfer air through a very thick concrete slab.

The plant & equipment consisted of 11 of air handling units, 15 fans, 2 extract cabinets with associated pipe work manufactured and installed by Exyte Hargreaves. Also, 35 runs of Swagelok pipework to facilitate the DOP system which indicates when the filter media needs to be changed.

BEP will have the ability to treat silo waste, immobilise it and prepare it for long term storage on the site. The machines commenced retrieving waste in 2018 and it is estimated this could take up to 20 – 25 years.

Evap D

Completed: 2015 | Project Value: £9 million

Evaporator D (Evap D) was an additional facility to increase the current existing capacity required for the evaporation (condensing) and storage of highly active effluents produced from existing reprocessing operations at Sellafield. As Evaporator C had outlived its shelf life, the delivery of this project was essential to ensure safe nuclear reprocessing of highly active liquor.

Exyte Hargreaves supplied and installed DW144 type ductwork. This included fully welded high integrity ductwork in a variety of types and sizes (both galvanised and stainless steel). The project also included for the supply and installation of thermal and fire-rated insulation, specialist refrigerated air conditioning systems, dampers, attenuators, grilles, seismic supports and air handling units (AHUs).

B39 Paint Spray Booth

Completed: 2014 | Project Value: £1.5 million

Sellafield required a replacement spray paint booth, with dedicated ventilation system, to use in a nuclear fuel transport flask maintenance. The new unit replaced one that was obsolete and contained upgrades for compliance with legislation / safety standards.

Exyte Hargreaves supplied and installed the complete new ventilation system. We also engaged and managed key subcontractors for all associated scaffolding, civils, electrical, mechanical and instrumentation works. Installation of the ductwork system was by experienced Hargreaves Installers with appropriate security status working within radioactive areas,

The project was considered ‘fast track’ which dictated close monitoring of the project programme, extended hours and weekend working. Full traceability was maintained throughout the lifecycle of the project working to approved Inspection and Test Plans. We carried out Non Destructive weld tests and comprehensive Lifetime Quality Records were submitted on completion.


Completed: 2013 | Project Value: £16 million

Project SAV (Separation Area Ventilation) involved the replacement of legacy ventilation systems, re-routing of exhaust ductwork and the creation of new filters and a discharge stack at Sellafield. The project decommissioned the stack associated with the primary separation and head end facility, a major landmark on the site dating from the 1940’s.

The proposed decommissioning required a new stack with a large filter and fan house with ventilation re-routed around the site. Exyte Hargreaves fabricated a network of 3,000 metres of ductwork and this was installed onto existing and new high level pipe bridges.

The six ducts feeding the stack comprised up to 2,500 individual pieces of bespoke ductwork. All ductwork was fabricated in stainless steel (approximately 500 tonnes) to minimise long-term maintenance.


Completed: 2003 | Project Value: £350k

The project comprised a new extract and filtration system for the Windscale Advanced Gas Reactor (WAGR) decommissioning project at Sellafield. It provides negative pressure in the vault area and ensures complete recovery of all airborne particles during the oxy-propane cutting of the remaining reactor shell.

The plant was fully assembled off site at our Manufacturing facility in Bury. During the two-week modularisation project, materials similar in size and density to the cutting residues were introduced in controlled quantities. Coarse, medium, fine and superfine residues, down to particle sizes of 0.12 micron (less than 1/200,000 of an inch), were captured with a 100 per cent recovery rate. The plant was designed by engineers from BNFL Environmental Services and was fabricated by Hargreaves to their exact specification. The system has four stages of separation and filtration.

Contaminants first enter the plant at high speed so that particles stay suspended in the air stream. A primary momentum separator reduces air speed and forces the air around a series of baffles so the heaviest particles fall out of suspension and into a recovery vessel. Air then goes through a metal filter to arrest sparks before passing through a cyclone to remove medium and fine particles. Finally, air is drawn through HEPA filters to capture even the finest particles.

All ductwork and major plant items are stainless steel. The system includes a duplicate parallel set of separation, filtration and fan units so that extraction continues even when plant modules are serviced. The system will run continuously for the foreseeable future.

"Hargreaves has been involved in ventilation works at Sellafield for many decades. The nuclear industry has very exacting technical demands and we are pleased to meet these standards, deliver projects to schedule and have an exemplary health and safety record."

Kevin White

Managing Director (2003-2011)


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