As reported before, a consortium of Westinghouse Spain, the Spanish Waste Management Organisation Enresa and DBE TECHNOLOGY GmbH, supported by the local subcontractor EQE Bulgaria AD, is under contract to the Bulgarian State Enterprise for Radioactive Waste Management (SERAW) for the technical design of a near-surface repository for low level and short-lived intermediate level radioactive waste, the National Disposal Facility (NDF), at the Radiana Site adjacent to the Kozloduy Nuclear Power Plant (KNPP). A key component of the contracted work scope is the demonstration of the constructability of the NDF. As the construction start of the facility is anticipated for the spring of 2016, the current project work, led by DBE TECHNOLOGY GmbH, focuses on construction planning.
The NDF will be constructed in three phases that are separated from each other by approxi-mately 20 years. Upon completion of the first phase, the NDF will already be fully operational and capable of receiving and disposing of 6,336 waste packages. Phase 2 and Phase 3 will increase the available disposal capacity of the NDF by an additional 6,336 waste packages each. After completion of waste disposal, the facility will be decommissioned and a multilayer engineered barrier will be constructed as a protective cover.
A major initial logistical challenge of construction will be that almost 1 million m³ of soil eill have to be excavated and handled before construction work can begin. In order to minimise potential environmental impacts, the excavated soil will remain onsite to the extent possible.
Another challenge results from the requirement that the mechanical soil properties need to be improved for construction. A 5-m-thick loess-cement cushion will be constructed beneath the disposal cells, the Waste Reception and Buffer Storage (WRBS) Building. The cushion beneath the disposal cells also contains embedded structures, including the Infiltration Control Network (ICN) Galleries as well as the concrete foundation beams for the mobile roofs.
The construction planning accounts for the large volumes of soil to be excavated as well as for ensuring sufficient material supplies, especially large quantities of dry and wet cement, in terms of both quality as well as quantity. Additionally, the plan addresses the contemporaneous construction management of the auxiliary buildings and the disposal cells.
For those of you interested in learning more about this challenging project, additional details on our construction plan for the facility will be presented at the Waste Management Symposium 2016 in Phoenix. We look forward to seeing you there.