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

DISCLAIMER SUMMARYThe general purpose of the Grout Development Program is to solidify and stabilize the liquid low-activity wastes (LAW) generated at the Idaho Chemical Processing Plant (ICPP). It is anticipated that LAW will be produced from the following: 1) chemical separation of the tank f m high-activity sodium-bearing waste, 2) retrieval, dissolution, and chemical separation of the aluminum, zirconium, and sodium calcines, 3) facility decontamination processes, and 4) process equipment waste. Grout formulation studies for sodium-bearing LAW, including decontamination and process equipment waste, continued this fiscal year. A second task was to develop a grout formulation to solidify potential process residual heels in the tank farm vessels when the vessels are closed.For sodium-bearing LAW, the grouting of denitrated solids continues to be a viable process to achieve maximum volume reduction. A grout made with 35 wt% denitrated solids meets minimum strengths and leach resistance while reducing volume to 1 /5 the original volume. If volume continues to be a driving requirement, this process is the most effective.Two methods of grouting the liquid sodium-bearing LAW were found this year. The waste can be grouted if the pH is between 1 and 3 or if the pH is greater than 1 1. Both processes produce acceptable strength and leach resistance while increasing the volume by 1 1/2 times. The short-term tests look promising, but long-term tests (thermal cycling and immersion) need to be completed. If volume ceases to be a driver, these processes could become cost-effective.It was determined that the tank farm vessel process residual heels can be grouted if the heels are diluted. The heel could be diluted by repeatedly adding an equal volume of aluminum nitrate solution or water to the heel and jetting off as much solution as possible. It is recommended that premixed grout be used to displace heel so that it could be further jetted or pumped out of the tank. This method would remove as much heel as possible from the tank and leave a solid grout for tank closure.For FY-98, continued wasteform qualification is planned in the areas of compressive strength following sample immersion and thermal cycle testing. The grout formulations for both LAW and tank heels will be refined and characterized for mixture tolerances, order of addition, fluid flow, set time, cure rate, and heat of hydration. A grout pilot plant is planned for 2004 to test the equipment needed to concentrate, denitrate, and mix the grout and waste. Wasteform qualification testing is needed on full-scale disposal drums produced in the pilot plant to qualify the grout process and the grouted waste.... ACKNOWLEDGMENTS

The Idaho Nuclear Technology and Engineering Center (INTEC) is considering vitrification to process liquid sodium-bearing waste. Preliminary studies were completed to evaluate the potential secondary wastes from the melter off-gas clean up systems. Projected secondary wastes comprise acidic and caustic scrubber solutions, HEPA filters, activated carbon, and ion exchange media. Possible treatment methods, waste forms, and disposal sites are evaluated from radiological and mercury contamination estimates.iv v SUMMARYThe High-Level Waste Program is considering vitrification of the liquid sodium-bearing waste stored at the Idaho Nuclear Technology and Engineering Center which is part of the Idaho National Engineering and Environmental Laboratory. Several secondary wastes are anticipated from the melter off-gas clean up system, such as acidic and caustic scrubber solutions, HEPA filters, activated carbon, and ion exchange media. These wastes are expected to be designated as mixed low-level wastes. Initial scoping studies were completed to evaluate possible disposal paths for these wastes. The radiological and land disposal regulations as well as the individual site waste acceptance criteria were considered to anticipate treatment methods, waste forms, and disposal sites for each waste stream.

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The Idaho National Engineering and Environmental Laboratory (INEEL) is considering several optional processes for disposal of liquid sodium-bearing waste. During fiscal year 2002, immobilization-related research included of grout formulation development for sodium-bearing waste, absorption of the waste on silica gel, and off-gas system mercury collection and breakthrough using activated carbon. Experimental results indicate that sodium-bearing waste can be immobilized in grout at 70 weight percent and onto silica gel at 74 weight percent. Furthermore, a loading of 11 weight percent mercury in sulfur-impregnated activated carbon was achieved with 99.8% off-gas mercury removal efficiency.iv v EXECUTIVE SUMMARYThe Idaho National Engineering and Environmental Laboratory, specifically the Idaho Nuclear Technology and Engineering Center (INTEC) High-Level Waste Program, is to prepare the liquid sodium-bearing waste and calcined solids for eventual disposal. Several alternative treatment processes and disposal paths have been explored for these wastes. This report discusses research conducted on three process options: grouting of sodium-bearing waste following cesium removal, immobilization of sodium-bearing waste on silica gel following cesium removal, and use of activated carbon for mercury removal in the calciner or steam reformer off-gas system.During this fiscal year, the option of grouting sodium-bearing (SBW) waste was revisited to ensure the processes were still viable based on the latest flow sheets and projected SBW compositions. It was determined that the grout formulation for 70 weight percent continued to be satisfactory. New work was started for grouting of nitric acid such as that from the Liquid Effluent Treatment and Disposal Facility. Initial findings showed that 12 molar nitric acid can be grouted at 35 weight percent.Research continued on the absorption of SBW on silica gel. The process provides a simple method of solidifying the SBW for transportation or disposal. If the SBW is placed on silica gel at ambient temperatures, waste loadings of 74 weight percent can be achieved with a single addition. If the SBW and silica gel are heated more moisture and acid are driven off and waste loadings of 90 weight percent were found.If thermal methods are pursued for SBW treatment, it is proposed to use activated carbon to control mercury release in the off-gas systems. The activated carbon bed's mercury removal efficiency and breakthrough loading for the New Waste Calciner Facility were researched this fiscal year. It was found that a breakthrough loading of 11 weight percent and a removal efficiency of up to 99.8% were achievable. vi vii NOMENCLATURE Alkaline GroutA grout formulation where the waste is rendered basic (pH > 12) and mixed with a 9:1 blend of blast furnace slag and portland cement.