NPO was brought on to provide shielding for Mechanical Penetrations Room No. 1 at Davis-Besse. This room featured a variety of pipe runs with many valves, bends, and reductions throughout as well as many hot spots. Using a combination of drawing information and practical measurements taken on site, NPO provided a shielding package using T-Flex Tungsten and solid lead. It took several years before the shielding package was finally installed, but it was able to be installed quickly and easily. Davis-Besse saw an average dose reduction of 50% with as high as 86% in some areas.

Modeling was done using a combination of walkdown measurements, picture references, and drawing dimensions. Because of the uncertain with some areas of the piping, T-Flex Tungsten was used. T-Flex would be able to be trimmed on-site during installation to ensure a good fit. Straight sections had solid lead pieces clad in stainless steel. All shielding was secured with steel banding.


Pictures were taken with dimensional reference next to the pipes and valves where possible


Pictures of shielding after installation