RWMAC's Advice to Ministers on the Restoration of the UKAEA Dounreay Nuclear Site

5. Decommissioning

5.1 In RWMAC's view, the Dounreay Decommissioning Plan - Volume 3 of the DSRP - represents an effective overall means of setting out the manner in which decommissioning of the site is to be approached.

5.2 For the purpose of presentation, the Dounreay site has been divided into 19 zones, for each of which a zone plan has been prepared. Each zone plan contains statements of the current zone state, end-state on completion of decommissioning tasks, waste arisings, and development work (in the sense of further studies) required. Thus, the Decommissioning Plan includes much of the detail necessary to understand the key issues for Dounreay. For example, coverage of Zone 9 (the LLW pits) refers to the intention to carry out a BPEO study for managing the contents of the pits. This is, in RWMAC's view, an effective and useful form of presentation that helps to convey the vision of how restoration will affect the Dounreay site.

5.3 The zone plans are free-standing in order, inter alia, to delineate future studies accurately. However, experience of decommissioning complex sites, with many service connections that have been changed over the years, suggests that a broad-based approach is essential to the management of risk (for example, detecting unknown electrical systems still remaining live). While interdependencies between work in the various zones are identified, there is little to help understand what are seen to be the main priorities for scheduling of work between the zones. The Committee believes that these wider implications need to be brought out more clearly in the DSRP. The zone plans should then be carried forward into the DSRP's implementation.

5.4 The objectives of the Decommissioning Plan are to set out the planning, management, and implementation of decommissioning operations at Dounreay, to identify the supporting arrangements and systems needed, and to make clear the way in which decommissioning is aimed at systematic and progressive reductions in the hazards posed by individual plants and by the site as a whole.

5.5 It is argued, rightly in the Committee's opinion, that the Plan cannot be rigidly defined, as it will inevitably have to respond to actions (many outside UKAEA control) and experience gained. Decommissioning planning certainly rests on the many assumptions identified by UKAEA in the Plan. Effective delivery of the DSRP on the ground will, however, be dependent on appropriate sequencing of key projects. Where projects are central to overall delivery of the DSRP, these should be identified at the outset, a critical path defined in each case, and a contingency plan (responding to the possibility of failure on the part of other players) put in place.