Patent Number: 047675721
Section: description

EXAMPLE 1 Stainless steel piping from a nuclear power plant, contaminated to the extent that it has a cobalt 60 equivalent specific activity of about 80 Bq/g is smelted together with a cast iron of the type usually used for the production of transport vessels in accordance with the aforementioned U.S. patents, in an amount of 25% by weight of the radioactive residue and 75% of the customary cast iron composition. Transport and storage vessels, as described in the aforementioned U.S. patents, are then cast from the resulting melt. The radiation added to the environment as a result of the residue incorporated in the container structure is minimal and the container structure is found to have a greater shielding capacity for radiation than a virgin cast iron without the radioactive residue. EXAMPLE 2 A concrete containment vessel for a nuclear power plant reactor is broken up into gravel-size particles by crushing and used as a aggregate in place of an equivalent amount of gravel in concrete which is then placed to form a radiation shielding wall. Here again the contribution of radiation to the environment is minimal when the radioactive aggregate has a cobalt 60 specific activity of 50 Bq/g.