Abstract: Scouting experiments indicated that calcination of highly active Darex and Sulfex decladding and Purex extraction wastes will not release hazardous amounts of fission products to the atmosphere. Simulated wastes containing up to 90 curies/liter or activity were evaporated and calcined to 750°C and the off-cases passed through a condenser and a series of caustic scrubbers. Less than 0.1% of the fission products was released, of which ruthenium was 10-90%. Fission product release was lower from neutralized than from acidic wastes. Fission products were leached appreciably, 0.05% of the beta and 0.02% of the gamma, from the calcination solid with water in 96 hr.
Report documenting ongoing research and developments at the Oak Ridge National Laboratory's Gas-Cooled Reactor Project. Design Investigations: The effects on the power distribuestablished. A mathematical model was developed for studying shifting of the coolant stream as it moves along a rod in order to predict the temperatures of the parallel streams as they progress through the reactor. A fuelelement life code developed for computing the internal temperature structure, the amount of fission gas released, the internal pressure, the cladding strain when the internal pressure exceeds the coolant pressure, and the creep damage was used for comparing top-loading and inventedloading fuel programs for the EGCR. A statistical method was developed for estimating the probability that the hot spot on the EGCR fuel element will exceed a given temperature. A method of cooling the EGCR control rods was developed that will minimize diversion of coolant flow through leakage paths between graphite blocks. A preliminary design of a control rod cooled by this method was developed. Means for reducing the thermal stresses in the top head nozzles of the EGCR pressure vessel were studied. The stresses in the graphite sleeves of the EGCR fuel elements were calculated, and the maximum stress was found to be within the allowable limit. A study was made of the thermal stresses in the EGCR pressure-vessel support skirt, and a satisfactory design was developed. Procedures for removing ruthenium and cerium contamination from steel were outlined and incorporated in procedures for decontaminating the EGCR charge and service machines. Experimental information was obtained on the thermal characteristics of the specified EGCR fuel cluster. The effect of relative orientation of adjacent clusters on the heattransfer distribution in the downstream element was studied by means of mass-removal measurements on naphthalene-coated reds. Velocity distributions in the downstream element of two adjacent EGCR-type clusters ...