Development and operation of the conversion/solidification process for the CEUSP project

During the early 1960s, the U.S. Atomic Energy Commission (AEC) sponsored a test irradiation of a ThO/sub 2/-UO/sub 2/ fuel core in the Consolidated Edison Indian Point-1 Reactor at Indian Point, New York. The test generated -- 1000 kg of highly radioactive and fissile uranium (containing -- 75% /sup 235/U, -- 10% /sup 233/U, and -- 140 ppm /sup 232/U). In 1968, the AEC also sponsored reprocessing of the irradiated fuel at the Nuclear Fuel Services Plant in West Valley, New York, to recover the fissile uranium. The uranium nitrate product solution resulting from the reprocessing operations was sent to ORNL for storage. Soluble poisons (cadmium nitrate and gadolinium nitrate) were added to ensure subcriticality of this solution during its storage in a specially prepared 18,900-L (5000-gal) Thorium Reactor Uranium Storage Tank (TRUST), located at the Radiochemical Processing Plant (RPP). When no use for the uranium had become apparent after several years of storage, a project called the Consolidated Edison Uranium Solidification Program (CEUSP) was initiated in the late 1970s to solidify the material for safe long-term storage. A unique conversion/solidification process and the equipment to carry it out were conceived, developed, and operated by Chemical Technology Division personnel.