Remote Removal and Installation of Sr-90 Hot Cell Liner

DDES was tasked with the removal of the Sr-90 hot cell floor lining. The polypropylene plastic liner had degraded from years of high beta field bombardment causing failure of the material. The project scope required the damaged floor be removed and replaced without disassembling the cell. Our staff designed tooling and equipment that could be used to remove the existing cell floor using the hot cell manipulators only. The team installed a remote camera to guide operations which could not be seen through the leaded glass viewing window. The project team cut the entire floor into small sections so that they could be loaded into shielded was containers inside the cell. A total of 14 Curies of contaminated liner was removed and transferred without any release of contamination.

Once the floor liner was removed a set of five large panels were fabricated based on the interior dimensions of the cell and the capacity of the attached transfer cell. These panels were placed and sealed with FDA approved adhesive to provide an impermeable layer to contain any potential future radioactive liquid spills. DDES came up with a 6 inch by 6 inch tile design which was layered over the impermeable layer of polypropylene. Each of these tiles were keyed together to provide a smooth working surface and so individual tiles could be changed out using the manipulators if they were ever damaged in the future. This eliminated the potential for the project to have to be repeated years from now.

This approach reduced the volume of high activity radioactive waste by an order of magnitude. It also reduced personnel exposures to high dose rate materials by employing remotely operated tooling and keeping the hot cell shielding in place. We often have requests to design, beta test and then implement innovative approaches to solve complex health physics and waste management issues.