Chemical Engineering Division waste management programs. Quarterly report, July--September 1974

Chemical Engineering Division waste management programs. Quarterly report, October--December 1974

“…1.~aloy hulls, with procccc selection being dependent on program objectives. 1 Processes under initial consideration are intended 1) to transform the Zircaloy into a form that no longer represents a potential pyrophoric hazard, and 2) to effect a separation and concentration of the long-lived alpha-emitting radionuclides. By * Cladding in this context comprises the short Zircaloy tube segments referred to as hulls, as well as extr·aut:!uus fuel element hardware such a~ Incone] grids and nozzles.…”

“…1 Experiments will include larger scale ZnC1 2 oxidations; these tests will also be used 1) to establish the distribution of the minor constituents (contaminants) in the system and 2) to determine whether oxide coatings on the Zircaloy inhibit or interfere with the reaction. Other pyrochemical scouting tests will examine the feasibility of 1) precipitating zirconium from a zinc solution when the concentration is above the normal solubility level (e.g., solubility at 850°C is about 12 wt %); the distribution of the contaminants between the metal phase and a salt cover (e.g., MgC1 2 -NaCl-KCl) will be examined; the salt cover also reduces the loss of metal by vaporization, .. 2) separating zirconium as the nitride from a zinczirconium melt, and 3) slagging the contaminants in Zircaloy; this requires a system near 2000°C since the melting point of zirconium is about 1850°C.…”

“…3 • 4 Conclusions on the technical and economic feasibility of adapting these developments to retention of tritium from the LLAW of a fuelreprocessing plant were offered in the preceding report in this series. 1 It was noted that information on which to base the concept was limited, and that the demonstration of the new developments has been on a small laboratory scale with feed that is not representative of LLAW.…”

“…Limitations on the information available about Cluj developments preclude estimation of the capital cost of the column, but the simplicity of its design compared to that of the Trail plant promises substantial reductions in capital costs attributed to column construction. Costs associated with mat~rialH fluw and phase rever11al, ARRumed to represent a major portion of ope:rallonal costs; were calculAted for two flow schemes: 1) For a scheme involving reduction of tritium in LLAW to 3 x lo-3 l!Ci/ml (the radiation concentration guideline for nonoccupational exposure)B and environmental dispersal of the depleted stream, the annual costs were 1.1 X l0-2 mills/kWh or $0.66/Ci retained.…”