For over 30 years, we have been designing and providing equipment and running development programmes to support the nuclear decommissioning and waste management industry.
During this period, we have assembled a team whose focus and guiding principle is to find practical and fit for purpose solutions that acknowledge existing technologies whilst pushing the boundaries of innovation. The result has been practical and pragmatic solutions with numerous examples of cost savings and improved delivery on many LLW and ILW projects.
There are cost and programme benefits in the testing and development of new processes and associated equipment prior to deployment on site. We have the ideal facilities and technical expertise for conducting these trials to ensure that practical challenges and technical issues are overcome.
The Science and Technology team comprises a varied skill base, including graduate, postgraduate and PhD scientists and engineers, whose formal qualifications are enhanced by many years' experience working in the nuclear industry. This team focuses on radioactive waste management and decommissioning solutions delivered through the use of high calibre scientific and engineering expertise.
We have successfully supported numerous decommissioning and waste management campaigns by providing pragmatic, fit for purpose engineered solutions that have often been required to seamlessly integrate within larger systems.
Our engineering team typically deliver the following services to the nuclear decommissioning sector: mechanical and process concept design; underpinning technology proving trials; equipment build and evaluation; factory acceptance testing; and site installation and commissioning, including the full suite of documentation required for engineering applications implemented on nuclear licensed sites.
We have a pragmatic approach to waste management challenges and possess the capability to set up small scale trials in order to understand and replicate the processes involved. Small scale bench top development studies are a cost effective way of validating concept designs and providing confidence in developing the solution further at a larger and/or full scale.
We have the necessary understanding and techniques with which to evaluate prospective waste forms against the LLW Repository Ltd and NDA RWM acceptance criteria and possess state-of-the-art equipment to provide the full service to our clients.
Waste Retrieval and Processing
We are the market leader in radioactive waste processing, having completed many waste retrieval campaigns in the UK and processing over 2 million litres of ILW and LLW. Many of these projects have involved developing bespoke retrieval systems to meet the individual requirements and challenges of each nuclear licensed site.
To support this service, we have designed, built and operated scale and full size test mock-ups of ponds, vaults, tanks and silos. Through this work, we have developed a 'toolbox' of retrieval techniques for both wet and solid waste. This includes retrieval systems which have incorporated mixers, agitators, macerators, eductors and pumps. We have also designed, installed and operated pneumatic conveyance systems that have proved successful for the retrieval of both wet and solid waste at various sites across the UK.
In a majority of cases, we endeavour to use proven technology, whether from our own industry or elsewhere – such as the chemical, oil, gas and water industries – where the experiences of the retrieval of difficult materials from challenging environments are similar.
Waste Processing - Segregation
Many waste management strategies involve segregation of wastes with differing properties so that they can be treated independently. In order for this approach to work, it is crucial to have robust processes in place to ensure that the waste can be separated. We have had significant involvement in many large projects which have developed processes for screening, separating, size reduction and assaying.
Having retrieved the waste, conditioning is generally required to make it suitable for long term storage. We have developed techniques for waste stabilisation and volumetric reduction that can readily be applied in radiological controlled environments. In support of this approach, we have structured our development facility so that we can conduct testing to prove the most effective and practical conditioning process for each waste type.
Our structured approach to waste management and keen understanding of radioactive waste properties has led to us delivering valuable savings for many clients around the UK.
Waste Processing - Encapsulation and Grouting
We have extensive experience in cement solidification and encapsulation technologies and have been involved in the design of LLW and ILW encapsulation plant for over 30 years. In partnership with our clients, we have taken designs right through from proof of concept to inactive commissioning, site commissioning and operation.
The chemical or physical nature of certain wastes means that it is sometimes not possible to use cement for encapsulation for passive storage. We are the UK's leading expert in the use of polymers for encapsulation of radioactive waste.
Test Rig Design and Operation
The use of small and full scale test rigs allows us and our clients to identify and fix potential operational problems before they are encountered. Compared to operating within an active area on a nuclear site, the costs and timescales for development are reduced significantly.
Initially through simple test rigs, we have the capability to practically validate and underpin system designs in a cost effective manner before proceeding to the detailed design phase of the project.
As the project designs develop, we also have the in-house processes, resources and a mature supply chain to provide either full scale system mock-ups that can replicate plant or the actual plant that will be used on site. These mock-ups are invaluable in developing processes and assessing throughput, reliability, availability and maintenance (TRAM) issues that may potentially occur.
Waste Simulation and Test Material Development
One of the major challenges in providing radioactive waste management services is understanding the physical and chemical properties of the waste. At NSG, we have made huge strides in recent years in developing a range of simulants and test materials which closely represent a variety of waste streams. Our experienced team have the ability to recognise the crucial issues and challenges with specific wastes. This allows the appropriate tests to be developed, which provides relevant scientific underpinning of a proposed solution.
The challenges faced can include replicating chemical properties (e.g. pH, cement retardation, corrosion products, gas generation, etc.) and physical properties (such as rheology, particle size distribution and yield shear strength).