Patent Number: 042960746
Section: claims

1. A method of decladding an assembly comprising an element selected from the group consisting of uranium, thorium and mixtures thereof, clad in stainless steel, zirconium or a zirconium alloy consisting essentially of zirconium and containing minor amounts of nickel, chromium, tin, iron and combinations thereof; said method comprising: perforating the cladding material to expose the selected element;  reacting said selected element with hydrogen at a temperature of from 450.degree. C. to 680.degree. C. and a hydrogen pressure of from 360 to 1400 torr for a time sufficient to form a hydride of substantially all of the selected element;  increasing the temperature to a range of from about 700.degree. C. to 900.degree. C. to dehydride the selected element to reduce it back to its elemental form;  separating the cladding material from the selected element; and  recovering the selected element in a friable particulate readily comminutable form. 2. The method of claim 1 wherein the selected element is hydrided and dehydrided from two to four times. 3. The method of claim 1 wherein the selected element is hydrided and dehydrided at least three times. 4. The method of claim 1 wherein in the hydriding step the selected element is thermally cycled between the temperatures of from 450.degree. C. to 680.degree. C. 5. The method of claim 1 wherein the selected element is reacted with hydrogen at a temperature within the range of from about 500.degree. C. to 650.degree. C. and at a hydrogen pressure of about 760 torr. 6. The method of claim 1 wherein the selected element is a mixture of thorium and uranium.