Volume reduction and salvage considerations for plutonium-contaminated ferrous metal

A survey of the literature and discussions at pertinent sites operated for ERDA disclosed an inventory exists of plutonium-contaminated metal. Reliable assay of much of the waste for plutonium content requires reliable sampling and is virtually impossible because of its heterogeneous nature. Work on assay methods, particularly nondestructive assay (NDA) techniques, continues to be monitored. Transforming the metal waste to a standard form such as an ingot or slab by melting (melt-refining) should facilitate both sampling and assay and has been selected for exploratory study. Present emphasis of work is on ferrous materials. Small-scale studies on the melt-refining of steel contaminated with plutonium are just getting started in a glove box facility. Support work on noncontaminated steel is in progress using UO2 as a stand-in for PuO2. Preliminary results in steel-melting tests without slags indicate some of the commercial fire-brick materials may be satisfactory as crucibles. UO2, added as a stand-in for PuO2 in the support work, appears to be not wetted by the molten steel and remains in the crucible when the molten steel is poured into a mold. Crucible-slag combinations are undergoing compatibility testing in the support studies. Initial work with cryolite as a slag proved very corrosive to a MgO crucible. An ultimate goal of this work is the decontamination of plutonium-contaminated metal in the light of criteria for re-use release, or disposal. (auth)