CRYOGENIC WASHOUT OF SOLID ROCKET PROPELLANTS

Abstract

Cryogenic washout (U.S. Patent No. 5025632) is a process using liquid nitrogen (LN2) as a washout medium to remove propellant from within solid rocket motors. The process is environmentally clean and produces dry, size-reduced particles that are well suited for disposal or for reuse in applications such as commercial explosives. A prototype cryogenic washout facility has been constructed for washout of Minuteman II Stage 3 solid rocket motors under a contract with the U.S. Air Force. Design support testing on a bench-scale system has been completed. Workup and subscale safety tests are in progress. The design support testing included laboratory and bench-scale testing on Hazard Class 1.1 and 1.3 propellants. The laboratory tests established that essentially no change in the sensitivity of the test propellants occurred between ambient and cryogenic temperatures. This paper describes prototype equipment design and presents a summary of the testing performed.