The Low-Activity Waste Process Technology Program anticipated that grouting will be used for disposal of low-level and transuranic wastes generated at the Idaho Nuclear Technology and Engineering Center (INTEC). During fiscal year 2000, grout formulations were studied for transuranic waste derived from INTEC liquid sodium-bearing waste and for projected newly generated low-level liquid waste. Additional studies were completed using silica gel and other absorbents to solidify sodium-bearing wastes. A feasibility study and conceptual design were completed for the construction of a grout pilot plant for simulated wastes and demonstration facility for actual wastes.iv v SUMMARYThe general purpose of the Low-Activity Waste Process Technology Program is to solidify and stabilize liquid transuranic and low-activity wastes (LAW) stored or generated at the Idaho Nuclear Technology and Engineering Center (formerly the Idaho Chemical Processing Plant). It is anticipated that LAW will be produced from the following: (1) chemical separation or ion exchange of the tank farm liquid sodium-bearing waste, (2) chemical separation of dissolved aluminum and zirconium calcines, and (3) newly generated liquid wastes, such as facility decontamination and process equipment wastes. Grout formulation studies included cesium ion exchanged sodium-bearing waste and newly generated liquid wastes. Additional studies were completed for absorbing sodium-bearing wastes, evaporation of newly generated liquid waste, and retention of mercury in grout.Grout formulations were improved for the cesium separated sodiumbearing waste and the projected newly generated liquid waste. The sodiumbearing waste following cesium ion exchange separation waste would be a tranuranic waste that could be sent to the Waste Isolation Pilot Plant. The waste loading of 70 weight percent was maintained while improving the fluid properties of the grout mix. Grout formulations of up to 35 weight percent can be prepared for dilute newly generated liquid waste. Both of these formulations utilize the waste as the liquid for the cement powders.Silica gel can be used to solidify sodium-bearing waste at up to 80 weight percent of the final dry product for a 33 percent volume reduction. The silica gel does not stabilize all hazardous metals, thus it is not a final waste form. The solid product can readily be vitrified due to the silica content and this final waste form will pass the Product Consistency Test (PCT). Alternatively, the solid product could be stored or transported later treatment.A design study was completed to determine the feasibility of newly generated liquid waste being grouted and disposed to a permitted land disposal site, such as Envirocare of Utah. The project was expanded to include cesium separated sodium-bearing waste. A conceptual design for both processes was prepared and is pending final review. The design includes a grouting pilot plant for simulated wastes and a demonstration facility for actual radioactive wastes. vi vii ACKNOWLEDGMENTS
Radioactive noble gases produced during uranium fission constitute a waste material requiring special treatment and handling techniques if releases to the environment are to be reduced or minimized. To date, treatment has been confined to short-term holdup of nuclear reactor off-gases, to allow short halflife fission products to radiolytically decay. Although the required degree or efficiency of noble gas separation and containment is not yet determined, considerable development effort has been expended on a variety of separation processes. With some separation processes, the technology is advanced sufficiently that commercial separation units are now being offered for sale. Early installations of these will be mainly at reactors where their prime advantage is a reduction in size of the holdup system required ana an increase in the holdup time for radiolytic decay. Eventually, separation processes may have to be installed at nuclear fuel reprocessing facilities to collect the long-lived krypton-85. NOBLE GAS SEPARATION The separation processes potentially applicable to removing fissionproduct noble gases from the off-gas streams include absorption in liquids (liquid air, carbon dioxide, or fluorocarbons), adsorption on charcoal or other solids, and diffusion through a selective membrane. These processes are at a variety of technological levels and each has its own particular advantage or disadvantage (summarized in Table I) w/th respect to the recovery efficiency, and each I) w/th
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