TVA Sequoyah needed a way to shield the surrounding area of their reactor head while inspection work was being done. To avoid setting up scaffolding or stand alone lead blanket racks that would take up valuable floor space, NPO designed lead blanket racks that would make use of the stud holes of the reactor head flange. Posts at the bottom of each rack ran down into the stud hole and held the rack securely. The racks were slightly curved to follow the outside diameter of the flange. Lead wool blanket were then hung from the racks to create a seamless shield wall.
This was a two tiered rack designed to hold two layers of standard lead blankets with lead blankets over lapping from rack to rack to mitigate streaming. Plastic guide strips were installed along the posts as well as under the base to avoid damaging the reactor head flange.
TVA estimated approximately 1 REM of dose savings.