Dounreay Site Restoration is inviting companies to express interest in tendering for design and construction of a disposal facility for low-level radioactive waste from decommissioning the site and the adjoining Vulcan facility.
The site beside the former fast reactor gained planning permission last year for the first two vaults, with options for later phases. Each would measure 80x45m, approximately 20m deep and it is hoped to start work within 12 months of letting the contract in April 2011. A shallow groundwater catchment system and deeper excavation pumping system will be required, and the extracted water passed through a passive on-site water treatment system. Each vault is to be completed with concrete walls and floors constructed to a standard consistent with water retaining structures with a steel framework roof.
The site is located in an environmentally sensitive area so all construction activities must be carried out in a manner that minimises impact to the local environment, including noise, dust generation, ground borne vibrations and local traffic.
The site currently has constraints which exclude the use of blasting during excavations, although this constraint may be lifted by the time the contract is let. As a result, tenderers will be requested to provide costed estimates for both blasting assisted and non blasting excavation options.
All excavated material is to be stored in a waste storage area adjacent to the excavation.
The contractor will be required to obtain the appropriate CAR (groundwater abstraction) and PPC (pollution control) licences associated with groundwater abstraction and treatment as well as the operation of the rock spoil waste storage facility, and maintain these during construction of the facilities. The facilities will require a Radioactive Substance Act authorisation prior to the emplacement of waste.
The employer is progressing this authorisation by means of an environmental safety case. The contractor will be required to demonstrate that the detailed design and construction satisfies the current assumptions within the environmental safety case.
The contract will be under the NEC3 incentivised target cost conditions and will include a series of key performance indicators based on issues such as safety, waste minimisation, and stakeholder / environmental impact.
