Abstract: Combustible, solid radioactive waste, such as paper, plastics, rubber, cloth and wood, are reduced in volume to an ash residue using pyrohydrolysis, a method which combines pyrolysis of the waste in a vessel at temperatures in the range of 500.degree. to 700.degree. C. and gasification of residual carbon with superheated steam. Pressures of 1.0 to 3.5 MPa are used with steam flows in the range 4 to 50 grams/second/cubic meter so that carbon containing components of the waste are removed as gaseous decomposition products in the form of carbon monoxide and hydrogen leaving an ash residue.

Abstract: In pressurized water-cooled nuclear reactors, the formation of deposits on surfaces in the core of the reactor, e.g. on fuel sheaths, is suppressed by maintaining in the circulating pressurized water, a high concentration of ammonia ranging from about 120 to about 200 mg NH.sub.3 /kg water. Crevice corrosion of the fuel sheaths is avoided, even under localized boiling conditions, since the pH never attains a corrosively high level. The crevice corrosion danger with lithium can be reduced by replacing part of the lithium with ammonia.