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Title: CHEMICAL PROCESSING TECHNOLOGY QUARTERLY PROGRESS REPORT, JULY-SEPTEMBER 1962

Technical Report ·
DOI:https://doi.org/10.2172/4157103· OSTI ID:4157103

Aqueous zirconium fuel processing studies, directed at adapting the hydrofluoric acid process to continuous dissolution-complexing in order to increase the capacity of the ICPP process, resulted in two successful approaches to the complexing-feed adjustment step. Continuous in-line adjustment (conversion of uranium(IV) to uranium(VI) necessary for extraction) was accomplished in one minute or less at approximately 90 deg C; surges of dissolver product from the operating dissolver up to 1.9 times the flow sheet rate did not inhibit the oxidation of the uranium at this temperature. Batchwise mixing in air of dissolver product solution with complexer solution oxidized the uranium within two minutes at 23 deg C or higher. Further studies of continuous zirconium dissolution indicated that precipitation of uranium at the acid inlet can be a problem, probably because of local concentration gradients of free HF, which result in conditions of low uranium solubility. Control of dissolver acid composition by electrical conductance measurement appeared possible due to the linear relationship of conductance with acid concentration. Aluminum alloy dissolution rates in nitric acid were found to vary significantly, depending on the type and amount of alloying agent. Silicon, nickel, and copper in the alloy significantly decreased the dissolution rate. Batch dissolution times for standard test coupons ranged from 14 minutes for a high purity aluminum to 1400 minutes for an alloy containing 2.9 percent silicon. In the electrolytic dissolution of Nichrome in a bench-scale basket dissolver, the substitution of titanium for niobium as the anode basket material significantly reduced the contact resistance. Current interruption due to contact failure was essentially eliminated, and contact resistance on the titanium was sufficiently low that increasing solution resistance due to acid depletion became a major contributor to current decline as dissolution progressed. The indirect solution-contact electrolytic dissolution principle was further studied, producing data on electrode corrosion, power consumption, and gas generation on noble metal electrodes using both direct and alternating current. A second dual component analyzer, msking use of density-conductivity measurements on the dissolver effluent, was shown to give an accurate measure of the acid and dissolved metal concentrations. Chemicalirradiation tests of insulating materials for use in electrolytic dissolvers were completed. Alumina ceramic was the only material tested that showed little or no change at dose levels of 10/sup 10/ r; plastic materials with varying degrees of resistance are reported. Studies on waste treatment methods indicated the successful application of either ion exchange resins or locally available soil material to the removal of low concentrations of Cs/sup 137/ and Sr/sup 90/ from ICPP fuel storage basin effluent. The workability of a meltfreeze process for separation of aluminum nitrate from fission products, aimed at a 200-fold reduction in volume of ICPP generated wastes, was demonstrated in a singlestage laboratory unit. Pertinent solubility and density measurements were made and the operating diagram applicable to a multistage process is presented. Preliminary experiments on impregnation of calcined alumina with molten sulfur appeared to be favorable from the standpoints of leach resistance, particle immobilization, and heat transfer. Operation of the Demonstrational Waste Calcining Facility further confirmed the applicability of process control methods developed in pilot plant operations to the DWCF, and demonstrated that these methods provide an ample degree of control over processing conditions. With this assurance of operability of the unit, plans are being made for a run spiked with radioactive Na/sup 24/ as the next test. Key processing conditions, which were selected for this run, include operation at 400 deg C bed temperature, control to an amorphous bed, and return of the primary cyclone fines directly to storage with the bed product.

Research Organization:
Phillips Petroleum Co. Atomic Energy Div., Idaho Falls, Idaho
Sponsoring Organization:
US Atomic Energy Commission (AEC)
DOE Contract Number:
AT(10-1)-205
NSA Number:
NSA-18-005415
OSTI ID:
4157103
Report Number(s):
IDO-14599
Resource Relation:
Other Information: Orig. Receipt Date: 31-DEC-64
Country of Publication:
United States
Language:
English