A sealed and thermally insulated tank arranged in a bearing structure (1) to contain a fluid, said tank comprising walls fixed to said bearing structure, a tank wall having a primary sealed barrier, a primary insulating barrier, a secondary sealed barrier and a secondary insulating barrier, the tank comprising a through-element arranged through the tank wall, in which tank the tank wall around the through-element comprises: secondary insulating blocks arranged on the wall of the bearing structure around the through-element and being covered by a first sealed layer forming the secondary sealed barrier, a circular plate arranged parallel to the tank wall at the same level as the first sealed layer forming the secondary sealed barrier, a second sealed layer (723a-d) fixed in a sealed manner straddling the first sealed layer and the circular plate all around the circular plate.