Dounreay is now Europe's biggest nuclear site closure project – and the decommissioning of the shaft and silo, which contain untreated intermediate-level nuclear waste, is the deepest nuclear clean-up job in Europe. We are part of a consortium with CH2M and AECOM, responsible for the clean-up and remediation of the site.


That means, amongst many other things, safely retrieving waste from these two underground facilities. In total, the shaft and the silo contain around 1100m3 of waste. The 65m deep shaft was in use up until 1977 when it was damaged by a chemical explosion. Meanwhile, the silo is a shallow concrete bunker that was used as a store between 1971 and 1998.


Before we even started, our team of Process Engineers, including graduate Mohamad [link to profile], used state of the art 3D modelling software to visualise every stage of this delicate process – so that any problems or issues could be thoroughly ironed out at testing stage before any actual work begins.


It’s a hugely complex challenge: the stored waste is in a variety of sizes, shapes and forms – from solid objects to radioactive sludge and water. The waste needs to be carefully removed from each facility using specially designed cranes and grabbers. Then it will be remotely treated, conditioned, characterised and packaged for long-term storage. We’re aiming to Start waste retrieval in 2021 and expect the work to be complete by 2025.

The most important thing for me has been increasing confidence in my engineering judgement. Your studies can’t really prepare you for this – it’s about making secure and logical engineering judgements.

Mohamad, Process Engineer