UK Innovation and Additive Manufacturing within the Nuclear Decommissioning Supply Chain
Posted on 09/01/2019
The UK nuclear sector is a diverse one, with a significant focus on the country’s nuclear legacy and the inherent issues of decommissioning hazardous sites. The Nuclear Decommissioning Authority (NDA) has overall responsibility for a multi-billion-pound sub-sector of the industry with the remit of “ensuring the safe and efficient clean-up of the UK’s nuclear legacy” across 17 sites in the UK. The work involves decommissioning and demolishing all buildings, as well as treatment and disposal of associated waste, both radioactive and conventional. Viridian Consultants is a micro SME based in North Wales, which has been operating for more than 15 years and has been developing innovative equipment solutions for more efficient, safer sampling collection and analysis in contaminated or potentially contaminated areas.
By far the largest site in the UK is Sellafield, where Viridian Consultants has been very active specifically with regard to addressing the problems and issues the team has experienced around contamination and characterisation, which is a lengthy and expensive process, with huge safety implications around the risks of exposure.
A New Concept
The impetus behind the firm’s ViridiScope project was to make this process safer, faster and more cost efficient. The specific idea, based on the team’s scientific knowledge and experience, was to use a very small, low power laser beam to safely and easily collect a small sample from a potentially contaminated surface. However, to prove the idea they needed funding, which initially came through Innovate UK for a one-year feasibility study in 2013.
John Williams, Viridian’s Technical Director, had seen lasers were being used for cleaning applications, with the ability to gently remove dirt, grime and pollution without damaging the article that was being cleaned. He elaborated: “For our application, we were interested in removal and capture, a methodology that required removal by laser, transferral from the site in real time, and safe capture without human contact (or risk of contact). I’d actually been doing this in a lab for years, so I knew it was conceptually possible, but what I wanted to find out was if it was possible to scale up in industrial environments, with transfer possible over greater distances from removal to capture.”
The ViridiScope sampling head device combines a number of vital features that have been cleverly designed and developed to minimise the disposal load, with the emphasis always on safety.
The core components are: a laser, focused on the sample area via an optical fibre, control and interlocks to collect the sample and keep it sealed, a vacuum pump to draw the sample through a nylon transport tube to a filter pod where it is collected, before being automatically transferred for final analysis.
John explains how he first started working with Kevin Quigley, the founder of Quigley Design in Shrewsbury: “At the very beginning I had nothing but an idea and a vague notion of how to go about it. My background was in science and analysis techniques, my engineering skills were limited and while I love figuring these things out, I knew I needed someone with good design and engineering skills. Kevin has exactly the right skill set — and patience — and together we have figured it out.”
The sampling head itself has evolved through a series of design iterations to fulfil the brief and at every stage 3D printing has speeded up the process and enabled further development. It is the sampling head concept that enables the whole ViridiScope product, which includes sample removal, transfer and capture, with further options for analysis, either in-situ or remotely using existing scientific analysis instrumentation.
Product Development and Production
The additive manufacturing process that has been used throughout the product development process was Selective Laser Sintering (SLS) with nylon material, a material that the nuclear industry is comfortable with, is well understood and has a tried and tested disposal route.
The iterations of the ViridiScope have evolved to result in a multi-component sampling head that can be operated directly by hand or remotely sent up walls and onto ceilings (up to 20 m in height) to fire the laser and collect samples safely, cleanly and quickly. It swiftly became apparent that the front end of the sensor head, touching the (potentially) contaminated area, had to be easily disposable, while the “brains” and therefore expensive part of the device, containing the optics and sensors, needed to be re-usable and thus protected. These levels of disposability make the ViridiScope both safe and efficient, as well as dramatically increasing the speed with which sample areas can be tested while reducing waste and the costs associated with disposal.
The design and development of the filter devices where the sample is collected for testing now ensures that there is zero human contact through innovative seals that prevent any dust particles from the sample escaping. Between the release of the sample from the surface to the machine where it will be analysed there is zero human contact.
According to Kevin: “I have used 3D printing for many years for proving concepts and testing functionality. We have used a variety of processes, as required, some in-house but mostly through buying in parts from service providers. We have also bought in end-use parts at low volumes as the capabilities of the processes have improved. However, this project is the first time I have bought in production parts in bulk volumes, more than 1000 parts at a time. It has been eye-opening to say the least.”
“The fact that the part was designed for the 3D printing process (SLS) from the beginning was definitely a plus. This would not have been possible with injection moulding or machining, and it meant that we could keep adapting and improving the design without incurring additional costs for each iteration.”
Manufacturing this device using conventional plastic processes would literally take years longer and be cost prohibitive. John believes the project would not have got past the concept stage if 3D printing had not been an option for the actual production of the designs, or without an intelligent designer that fully understood the 3D printing process.
Unsurprisingly, the development of these products has got stakeholders in the nuclear industry very excited, to the point where five complete systems, together with all the spares of sampling heads and collection pods have been through production using 3D printing and have been deployed across five nuclear sites within tight deadlines to meet their demands.
In recognition of its success, Viridian Consultants most recently received the Minister’s SME award, which acknowledged the company’s value, flexibility and innovation. The company is testament to how collaboration across the supply chain can maximise the skill sets within each tier to bring innovative products to market. It is also a striking example of how additive manufacturing can enable the development of a truly innovative product, right through to production.