Selecting the optimum decommissioning strategy for UKAEA's redundant reactors

The United Kingdom Atomic Energy Authority has built and operated a wide range of radioactive facilities since the late 1940s for the development of weapons, reactor systems, radioisotopes, fuel and reprocessing technology. Most of these plants are now closed and a major task for UKAEA Government Division (UKAEA-GD) is to manage their decommissioning safely and at minimum cost to the UK taxpayer. Safety and economic considerations generally require that some decommissioning work is undertaken immediately after closure, and for this work to be completed as quickly as possible. For a reactor, this normally involves the removal of irradiated fuel and coolant and the reduction of the radioactive inventory by removal of non-fixed items of plant and equipment. Beyond this, there are a large number of possible options for the timing and scope of decommissioning work. This paper describes how a methodology has been developed which uses option studies to establish the minimum discounted cost strategy for the decommissioning of major facilities, using as examples the wide range of reactors which form part of UKAEA-GD's list of nuclear liabilities