19 research outputs found
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Evaluation of destructive methods for managing decontamination wastes
Results are discussed of a laboratory evaluation of destructive methods for processing chemical decontamination wastes. Incineration, acid digestion and wet-air oxidation are capable of degrading decontamination reagents and organic ion-exchange resins. The extent of destruction as a function of operating parameters was waste specific. The reagents used in the testing were: EDTA, oxalic acid, citric acid, picolinic acid and LND-101A
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Release of organic reagents from solidified decontamination wastes
In order to provide technical information needed by the US Nuclear Regulatory Commission to evaluate the adequacy of near-surface disposal of decontamination wastes, Brookhaven National Laboratory has measured the release of organic reagents from solidified simulated decontamination wastes. The waste streams consisted of either mixed-bed ion-exchange resins or anion exchange resins equilibrated with EDTA, oxalic acid, citric acid, picolinic acid or simulated LOMI decontamination reagent. These simulated resin wastes were solidified in either cement or vinyl ester-styrene. Samples were tested by a fixed interval leach procedure or according to the standard ANS 16.1 procedure. The leachability indices, which were calculated as prescribed in ANS 16.1, varied with leach period for some of the composites tested. 4 references, 6 figures, 2 tables
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Leachability of decontamination reagents from cement waste forms
Brookhaven National Laboratory, in order to provide technical information needed by the US Nuclear Regulatory Commission to evaluate the adequacy of near-surface disposal of decontamination wstes, has begun to study the leachability of organic reagents from solidified simulated decontamination wastes. Laboratory-scale cement waste forms containing EDTA, picolinic acid or simulated LOMI decontamination reagent were leach tested. Samples containing an organic reagent on either mixed bed ion-exchange resins or anion exchange resins were tested. A fixed interval leach procedure was used, as well as the standard procedure ANS 16.1. The leachability indices measured for the release of the acid from resin/cement composites are: 10.1 for EDTA on mixed bed resins; 9.1 for picolinic acid on mixed bed resins; 9.2 for picolinic acid on anion exchange resins; 8.8 for picolinic acid in forms containing simulated low oxidation metallic ion (LOMI) reagent on mixed bed resins and 8.7 for picolinic acid in forms containing simulated LOMI reagent on anion exchange resins. The leachability indices measured varied with leach time and the data indicate that the release mechanism may not be simply diffusion controlled. 5 references, 2 tables
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The effect of cure conditions on the stability of cement waste forms after immersion in water
We investigated the effects of curing conditions on the stability of cement-solidified ion-exchange resins after immersion in water. The test specimens consisted of partially depleted mixed-bed bead resins solidified in one of three vendor-supplied Portland I cement formulations, in a reference cement formulation, or in a gypsum-based binder formulation. We cured samples prepared using each formulation in sealed containers for periods of 7, 14, or 28 days as well as in air or with an accelerated heat cure prior to 90-day immersion in water. Two cement formulations exhibited apparent Portland-cement-like behavior, i.e., compressive strength increased or stabilized with increasing cure time. Two cement formulations exhibited behavior apparently unlike that of Portland cement, i.e., compressive strength decreased with increasing cure time. Such non-Portland-cement-like behavior is correlated with higher waste loadings. The gypsum-based formulation exhibited approximately constant compressive strength with cure time. Accelerated heat cures may not give compressive strengths representative of real-time cures. Some physical deterioration (cracking, spalling) of the waste form occurs during immersion