Context and challenges

The client is a major player in the nuclear industry, specialising in nuclear decommissioning and decontamination of effluent. This client needed a contingency effluent treatment plant as the existing facility had reached its designed capacity.

The contingency plant was built as an extension of the existing facility, with a link bridge to transfer maintenance equipment between plants.

Assystem was appointed to collaborate with the client’s team in delivering the detailed design for a new effluent processing plant for the removal of caesium and strontium from aqueous effluents. This included the design of mechanical handling equipment, electrical instrument and control equipment for the cells’ process, and providing support for the design of the building’s ventilation system and process cabinets.

Project scope

Assystem worked in collaboration with the client to design equipment and assist to improve the efficiency of the production process, working to a target cost contract. Assystem’s scope covered the design substantiation of the following key components of the effluent treatment plant.

  • A flask transfer bogie (with appropriate design features and methodology for recovery).
  • 2x 20Te building cranes, forklift trucks, pallet trucks, drum tipping equipment (for sand and clinoptylite) and flask lifting beams
  • Plant services (water, high and low pressure steam, CO2, condensate)
  • Roller shutter doors (standard security and fire doors)
  • Encast items (wall boxes, floor boxes, sumps and wall/floor liners and shield plugs)
  • Process cabinets (wash, steam, samplings, PH monitor, Vacuum Operated Slug Lift (VOSL), sparge air, positive breach, transducer, CO2 supply, and polyelectrolyte)
  • Vessel and tank design
  • CE&I control systems and cabinets


  • Implementation of an improved design delivery process, helping to deliver the project under budget
  • Streamlined design processes ensuring the client to hit each of its milestone design completion targets
  • Removal of interruptions and inefficiencies from the equipment design processes, enabling the client to start the preparation process of the effluent decontamination contingency plant switchover in 2025, ensuring vital safe site operations

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