Inside the steam generators of CANDU nuclear power plants, a divider plate separates the hot leg from the cold leg. Dozens of bolts hold this divider plate together, and these bolts trap hot particles that are a major source of radiation during inspections. NPO designed magnetic shielding designed to fit around each bolt. Since it is impractical to physically install the shielding by hand, each piece had an embedded steel loop for a hooked tool. The shield at the end of the tool would be able to be put in place from a safe distance. First, the open piece would be installed to shield around the bolt, then the closed piece would stack on top of that one to shield the face of the bolt. Both pieces were light enough to make installation with the hook and pole tool easy. The plant was able to reduce the 14,000 mRem/hr (140,000 μSv/hr) dose rate down to 700 mRem/hr (7,000 μSv/hr) inside the boilers.
