According to the approved NSC design sealed membrane is fitted at the junctions of the Arch eastern end wall to the Block B existing structures of Chornobyl NPP second generation main building. The membrane serves as a separation barrier between the external environment and internal radioactively contaminated space. Mounting of the membrane on the block B structure is implemented using the special metal sealing anchors.
With the purpose to install the sealing anchors, preliminary work was carried out to remove debris and, in part, the post-emergency layer of concrete to ensure a flat foundation under the anchors.
To fix the anchors in the design position in the block B covering in August 2017 complex work was started to drill holes for anchors fixing parts at the elev. +75.58, +72.10, +67.66.
In March this year these works were completed. In total 60 holes with a diameter of 400 mm were drilled in covering slabs with a drilling thickness from 600mm to 900mm.
As SIP Project Chief Engineer Mr Vladimir Kashtanov noted, "In process of holes drilling, certain difficulties arose associated with high radiation fields within the working areas, high density of reinforcement and metal in covering concrete, highly active inclusions, which led to additional labor costs and dose-costs. Completion of these works was one of the key stages of the project’s critical path".
