The UK-based Nuclear Decommissioning Ltd (NDL) consortium has won a multi million pound design contract related to the Prototype Fast Reactor Facility (PFR) decommissioning project at Dounreay in Scotland. Joint venture group NDL brings together four nuclear decommissioning businesses – James Fisher Nuclear (JFN), Shepley Engineers, React Engineering and Tetra Tech – appointed to support the clean-up and demolition of former experimental fast reactor site at Dounreay, being caried out by Dounreay Site Restoration Ltd (DSRL) on behalf of the Nuclear Decommissioning Authority (NDA).
This is the first major contract win for NDL under the Decommissioning Services Framework (DSF). The removal of irradiated fuel (IF) from site is a key goal for NDA and will significantly advance decommissioning progress on site. The consortium will be working collaboratively with DSRL to provide all scheme designs for plant, equipment and systems.
The NDL multi-discipline design team will be developing the detail scheme designs to allow DSRL to safely package and transport IF from the PFR for long term storage. This is part of the DSRL strategic plan to help accelerate the decommissioning project. JFN said on 2 June that it will be playing a key role in all aspects of engineering, project and commercial management for the programme, alongside its NDL consortium partners, together with NDL’s partners, RPS Consulting and nominated subcontract partners, Risktec and Rapid Rail.
The main objectives of the project include:
- The development of the scheme design for a facility, within the PFR reactor hall containment building, that will safely load individual IF containers into approved, shielded transport flasks ready for transfer to the storage site. The facility will ensure that all radiological aspects are assessed and proven to be ALARP (As Low As Reasonably Practical).
- Production of a developed scheme design to enable a detailed HAZOP 2 (Hazard and operability) study to be completed and accepted.
- Preparation of the scheme design for all plant items, equipment, systems and proposed techniques, including coordinated and updated proposals for structural, mechanical, process, electrical, control and instrumentation disciplines.
The PFR fast breeder reactor was primarily used to test various designs of fuel assemblies. It also supplied power to the National Grid from 1975 and generated over 9,250 gigawatts of power before it was taken offline in 1994. NDL will collaborate with DSRL to deliver a solution that will enable the safe and efficient loading and export of irradiated fuel from PFR into flasks for onward transportation.
NDL has also won a multi-million pound project related to decommissioning strategy for the Highly Active Liquor Storage and Evaporation Facility (HALSEF) at Dounreay. The NDL consortium partners will develop an integrated concept and scheme decommissioning plans for HALSEF. JNF said key to this approach will be enhanced stakeholder engagement at every stage, with NDL and DSRL working in collaboration to deliver a successful outcome. The decommissioning strategy will adopt a ‘Waste Informed Decommissioning’ approach to optimise waste streams throughout the decommissioning process, to minimise cost and required Intermediate Level Waste (ILW) storage provisions.
The HALSEF facility, which was constructed in 1955 and received its first consignments in 1958, is considered one of DSRL’s most important decommissioning challenges. The HALSEF store was designed to receive, condition and store medium and high-active raffinates (liquids separated during reprocessing) before being treated and sent to be encased and packaged at the nearby on-site cementation plant.
Tim Fox - HALSEF Project manager for DSRL said: “The scope of this project is to devise a strategy to decommission basement storage tanks and the freestanding buildings and plant above ground that service them. This will be followed by managing the waste streams so that ILW and the costs associated with its storage are minimised.” The strategy for the HALSEF plant decommissioning will cover three distinct areas and the differing waste streams they will generate.
- Medium Active Area Decommissioning Plan, which will look at the plant washings cells, the ammonium diuranate floc and the solvent storage cells;
- Evaporator Decommissioning Plan, to plan the decommissioning and post-operational clean out of all pipework and equipment of both evaporator plants and the demolition of the reinforced concrete structures; and
- The High Active Area Decommissioning Plan, to tackle the storage cells and associated furniture, plus two high active cells at ground level. These are all contained within thick, highly shielded, external walls with large, heavy gauge stainless steel tanks and complex pipework throughout.