Reducing the volume of legacy waste
The largest nuclear decommissioning project in the UK at the time of construction, Evaporator D allowed continued reduction in the volume of highly active legacy waste.
- Service 1
- Service 1
Consultancy & advisory
Complex programme delivery
- Service 1
Modular design consisting of 11 in-cell modules
396 major plant items
65 nuclear class vessels
Over 21 kilometres of pipework
Pre-Construction Safety Case
Additional waste processing capacity
As part of the Nuclear Decommissioning Authority’s strategy, Evaporator D was designed to expand Sellafield’s ability to process nuclear waste material and ultimately reduce inventories at the site.
We worked with Sellafield Ltd to design and construct the new evaporator which was required to evaporate highly active raffinate produced during reprocessing of spent nuclear fuel rods. Once concentrated through evaporation, the highly active liquor produced is subsequently vitrified – immobilising the waste in a stable glass form for long term storage and eventual disposal.
- Processing of highly radioactive and very corrosive fluids
- Strictly regulated site
- Remote site access
- Located at the heart of an operating nuclear facility
- Congested site - complex design on a restricted footprint
Innovative construction methods
In order to address the challenges outlined above, our experienced team of engineers drew on expertise from within the oil & gas industry to propose a modular design pre-fabricated and tested off-site, a nuclear first at this scale.
The benefits of this modular approach include:
- Reduced schedule risk
- Minimised works adjacent to highly active facilities
- Opportunities for early operator training
- Reduced fault observations at site
- Process plant and equipment proven prior to installation
The modules, the largest of which is 27m in height, were delivered by sea, the first time in the history of the Sellafield site that this method has been used. Major temporary works were undertaken to construct a beach landing area, a bridge across the River Ehen and to widen the railway crossing to provide a delivery route onto the Sellafield site.
This extent of modularisation was novel for the client and the nuclear regulatory authorities; it was vital to work collaboratively to make this concept work effectively. The solution was to form an alliance partnership between Costain, Sellafield and other major strategic supply chain partners. One of the many success examples of this integrated team approach is the submission and approval of the Pre-Construction Safety Case in just 99 days.