What value is there in a Mock-up to support Decommissioning? Part 4

In this 7 part series, guest author David Loughborough delves into the topic of mock-ups and their role in decommissioning today.
Physical mock-up for boom testing at VNS UK assembly site (pedestal access)

Confirming the solution

The Windscale Advanced Gas Cooled Reactor (WAGR) Pressure Vessel and Insulation (PV&I) decommissioning project provides another early example of the use of a mock-up. Around 1998, a full-scale physical mock-up was constructed for a small part of the project. While there was some debate about whether 3D modelling techniques could have been used instead, the benefits established in the previous projects, as mentioned earlier, were compelling. 

The approach proved to be cost effective for several reasons

  1. Confirming the solution; The mock-up served as a tangible way to validate the proposed decommissioning solution. 
  2. It provided verification of multiple clearances in various scenarios, providing valuable insights into potential challenges and solutions. 
  3. ‘Quick’ adjustments: The ability to make quick minor adjustments to the final design before entering the contaminated area was a significant advantage. It minimised risks and streamlined the overall project execution. 

The mock-up consisted of a wooden ILW waste box and a wooden internal rack, representing the shielded container, and stainless-steel internals for positioning the cut sections of the WAGR pressure vessel and insulation.  All very simple and cost effective in demonstrating that the methodology would work.

The practice of using mock-ups for complex decommissioning operations, particularly those involving hazardous areas requiring renovation, recovery or decommissioning became standard practice. This was especially true in situations where access and visibility were limited, or where unknown factors needed to be addressed and validated through the development and testing of operational and recovery scenarios. 

Mock-ups provided a tangible and practical means to assess and refine these critical processes enhancing safety, efficiency and client and regulator confidence in decommissioning projects. 


With nearly 40 years of experience in the nuclear industry, David Loughborough has made significant contributions to various aspects of the field. His journey began in 1985 as a graduate at AERE Harwell, following an apprenticeship and earning a degree. In the 1980s, he worked on the circular filter development program, and during this time, he built his first mock-up of an MOD facility to demonstrate an accident scenario safety feature.

Throughout the 1990s, David managed projects at Harwell, Amersham International, and AWE. His expertise expanded to include leading teams at Dounreay, focusing on design, reactor maintenance, and decommissioning. He then went on to work for renowned organisations such as Jacobs, AREVA (now ORANO), and Veolia, where he served as the Managing Director of VNS UK, the UK Nuclear arm of Veolia.

David's contributions extend beyond his project management roles. He has actively participated in British and European standards committees for nuclear ventilation and filtration. He has also published papers on his decommissioning projects and has shared insights on training and developing project managers. In recognition of his exceptional work, he was awarded the APM's PM of the Year in 1995.

Most recently, David has developed a comprehensive training program aimed at supporting non-nuclear engineers, designers, and project managers as they transition into the nuclear industry. This program provides a thorough introduction to the nuclear industry's history and current practices, equipping professionals with the knowledge and skills required to excel in their roles.