British Nuclear Group had a requirement to produce decommissioning project mandates, for two Medium Active Tank Farms and two Low Active Effluent Treatment Plants on the Sellafield Site. The project mandate is in essence a concept scheme and associated cost and programme for decommissioning a specific plant. The objective of the project mandates was to provide a robust viable strategy for decommissioning each of the facilities and use this as the basis to produce underpinned cost, scope and schedule estimates for all future decommissioning activities. Cumbria Nuclear Solutions Limited (CNSL) was awarded the contract to develop project mandates for these facilities, through competitive tender.
CNSL developed a logical phased approach to the project that addressed the three principal elements of nuclear decommissioning design:
- 01. Understanding the start point for decommissioning
- CNSL produced specifically tailored decommissioning Plant Status Reports to define the likely status of the facilities at the start of future decommissioning. This allowed us to comprehensively record the key factors that would affect decommissioning operations, including key hazards, risks and constraints
- 02. Understanding the end point for decommissioning
- Characterising waste and desktop sentencing – CNSL carried out detailed waste and radiological activity calculations to give a complete understanding of the volume and radiological condition of the waste to be dealt with in decommissioning the plants. We used this information to determine the baseline waste product form and destination.
- 03. Developing the decommissioning scheme
- By clearly defining current plant status, waste volumes and final product form, CNSL set in place the optimum conditions to develop a robust decommissioning work breakdown structure and viable scheme. CNSL were able to use the range of design, engineering and site implementation capabilities available within the consortium to provide underpinned viable solutions and associated cost and programme estimates for all future decommissioning activities.
The key values CNSL added to the project were:
- CNSL has an unsurpassed capability and track record, developed over the last 15 years, for reviewing and understanding the status of nuclear facilities and the key factors with these plants that would affect decommissioning operations. This was essential in enabling a viable solution to be identified.
- CNSL’s wide experience at all levels of the decommissioning industry, from working with the NDA to site implementation work, gives us a unique insight into the requirements of all project stakeholders. This informed the way we approached the waste categorisation work, through ensuring it addressed the NDA’s requirements for waste inventory reporting.
- CNSL pro-active approach, including engaging with project stakeholders, ensured the mandates were completed to cost and programme and that the output exceeded the clients expectations.
- Clear, robust and auditable Multi Attribute Analysis techniques used to select appropriate waste destination and viable decommissioning scheme.
CNSL presented the draft project mandates to a senior panel within British Nuclear Group, Decommissioning. The mandates received strong positive feedback from the panel for the quality and underpinning behind the programme and cost estimates. The work undertaken by CNSL on the project mandates allowed BNGSL to demonstrate the plans, programme and lifetime costs associated with decommissioning these plants, in a manner that would withstand detailed scrutiny by the NDA and other Stakeholders.