Some NPP’s process Dry Casks in a such a way that the entire cask produces a general area dose concern. To reduce these dose rates NPO developed a shield package that sits on the floor and shields the cask to a height of 9 feet (2.74 m). NPO is currently under contract to provide shield package with a HVL (half value layer) neutron and HVL gamma shielding factor for this application. It must allow the Dry Cask to enter on one side and exit the opposite. To keep costs down and win the project award NPO utilized its comprehensive knowledge of attenuation properties to select 4 inches (102 mm) of Borated Polyethylene as the shielding material and its engineering prowess to design a simple barn door design that allows the cask to pass through. The shielding package bolts to the floor and to overhead I–beams. In addition to the shielding package, NPO is providing a 2 over 1 seismic analysis.
