Progress and Experiences From the Decommissioning of the Eurochemic Reprocessing Plant

Abstract

Belgoprocess started the industrial decommissioning of the main process building of the former EUROCHEMIC reprocessing plant in 1990, after completion of a pilot project in which two buildings were emptied and decontaminated to background levels. The remaining structures were demolished and the concrete debris was disposed of as industrial waste and green field conditions restored. The Eurochemic reprocessing plant operated from 1966 to 1974 to process fuel from power reactors and research reactors. The main building is a large concrete structure, comprising a surface area of 55,000 m2, concrete volume 12,500 m3, and 1,500 Mg of metal components. The building is divided into multiple cells. About 106 individual cell structures have to be dismantled, involving the removal and decontamination of equipment from each cell, the decontamination of the cell walls, ceilings and floors, the dismantling of the ventilation system. Most of the work involves hands-on operations under protective clothing tailored to each specific task. Tool automation and automatic positioning systems are successfully applied. In view of the final demolition of the main process building, the main process building has been divided into three parts — each part is isolated from the others. In September 2008 the eastern part of the building has been demolished. The paper presents a status overview of the decommissioning and decontamination activities at the main process building of the former Eurochemic reprocessing plant on the nuclear site of Dessel in Belgium. The specific BELGOPROCESS strategy will be highlighted, in which the decommissioning activities are carried out on an industrial scale with special emphasis on cost minimisation, the use of technology on an industrial representative scale and the specific alpha contamination of equipment and building surfaces, requiring that the decommissioning work is done with adequate protective clothing. Also specific breathing and cooling air systems have been provided to allow the operators to carry out the decommissioning tasks in acceptable working conditions.

Decommissioning of nuclear fuel cycle facilities

“…The industrial decommissioning of the main processes in the facility started in 1990 (Walthéry et al, 2009a and2009b). In 1986, it was decided not to restart the facility again and then it had to be decontaminated and decommissioned.…”

“…This therefore requires more aggressive decontamination techniques to be applied (Walthéry et al, 2009a and2009b). The preparatory work for Phase 2 requires more in-depth evaluation.…”

“…The equipment that could not be cleared, owing to the shape and inability to measure all the surface areas, were melted and released in a controlled melting facility (Walthéry et al, 2009a and2009b). The demonstration concluded that it was economically preferable to perform dry decontamination of components to clearance levels rather than waste conditioning and disposal with no prior decontamination.…”

“…Although chemical rinsing in the storage tank was regarded as successful, the dose rates were still too high to allow manual decommissioning without first performing some remote decontamination process (Walthéry et al, 2009a and2009b). During the decommissioning of the Eurochemic reprocessing facility the waste storage vessels were rinsed and decontaminated immediately after their emptying and vitrification of the content.…”

“…The Eurochemic case described in 22.6.1 (Walthéry et al, 2009a and2009b) concluded that it is useful to conduct small-scale tests with various decontamination and dismantling techniques before selecting one specific technique. It is a challenge to demonstrate quality throughout a decommissioning project ensuring that the trust built with the stakeholders is not jeopardized.…”