Safe on-line refurbishment of separation plants for metal fuel

Plants and related facilities dedicated to Magnox fuel reprocessing at Sellafield were developed during the late 1950s, with construction and commissioning phases carried out during the early 1960s. The major facilities in the reprocessing route, housed in separate buildings, are as follows: pond storage, fuel decanning plant, chemical separation plant, uranium finishing, plutonium finishing, effluent treatment plants. The plants have operated successfully since the commissioning phase, with reprocessing rates of some 1,000 to 1,600 tons of uranium per year. The paper describes on-line refurbishment, concentrating on the following aspects: (1) selection of new equipment for installation in an existing chemical plant; (2) installation of new plant and equipment in an operating plant with minimum loss of production while meeting onerous new and significant safety requirements; (3) upgrading of an operating plant to meet new and more demanding criteria for radiological protection; and (4) establishments of the best approach to decommissioning and removal or redundant equipment within an operating plant