SummaryOver several decades, site operations at what is now the U.S. Department of Energy's (DOE's) Idaho National Engineering and Environmental Laboratory have included nuclear reactor testing, reprocessing of spent nuclear fuel, and the storage, treatment, and disposal of the resultant radioactive and mixed wastes generated. Liquid, acidic, and radioactive high-level waste (HLW) and sodium bearing waste (SBW) from spent-fuel reprocessing operations have for the most part been calcined in the New Waste Calcining Facility (NWCF) and the earlier Waste Calcining Facility (WCF) to produce a dry granular waste form that is safer to store. However, about a million gallons of SBW remains uncalcined, and this liquid mixed waste, stored in tanks, does not meet current regulatory requirements for long-term storage and/or disposal. As a part of the Settlement Agreement between DOE and the State of Idaho, the tanks currently containing SBW are to be taken out of service by December 31, 2012, which requires the removal and treatment of the remaining SBW.Several potential options have been proposed for treating the SBW. Of those considered, vitrification received the highest weighted score against the criteria used. Beginning in fiscal year 2000, the INEEL HLW program embarked on a program for technology demonstration and development that would lead to conceptual design of a vitrification facility, based upon the liquid-fed melter technology, in the event that vitrification is the preferred alternative for SBW disposal. This program includes several separate activities that include, among others, waste-form development, process feed-stream design, and melter vitrification demonstration testing of the nonradioactive, surrogate SBW flowsheet. The first of the melter flowsheet tests conducted in support of INEEL's vitrification facility design is discussed below.The Pacific Northwest National Laboratory's (PNNL's) Research-Scale Melter (RSM) was used to conduct these initial melter-flowsheet evaluations. The RSM is a small (1/100-scale) joule-heated melter that is capable of processing melter feed on a continuous basis. This capability is key for:• developing/evaluating process flowsheets• characterizing relationships between feed composition and the properties of the final glass produced• establishing the fate and behavior of process effluent.This melter system's capability to produce glass in a continuous manner is also essential for estimating the behavior of a full-scale system. Moreover, the size of the RSM allows the impacts of process variables upon melter performance or glass quality to be quickly and efficiently evaluated without undue expense or waste generation.The experimental scope of this initial, 5-d, 120-h, SBW vitrification test was to evaluate the:• processing characteristics of the newly formulated SBW surrogate melter feed stream• acceptability of various SBW to glass-forming additive ratios• possible formation of a secondary sodium sulfate phase iv • effectiveness of sugar as a glass oxidation-state modifie...

SummaryOver several decades, site operations at what is now the U.S. Department of Energy's (DOE's) Idaho National Engineering and Environmental Laboratory have included nuclear reactor testing, reprocessing of spent nuclear fuel, and the storage, treatment, and disposal of the resultant radioactive and mixed wastes generated. Liquid, acidic, and radioactive high-level waste (HLW) and sodium bearing waste (SBW) from spent-fuel reprocessing operations have for the most part been calcined in the New Waste Calcining Facility (NWCF) and the earlier Waste Calcining Facility (WCF) to produce a dry granular waste form that is safer to store. However, about a million gallons of SBW remains uncalcined, and this liquid mixed waste, stored in tanks, does not meet current regulatory requirements for long-term storage and/or disposal. As a part of the Settlement Agreement between DOE and the State of Idaho, the tanks currently containing SBW are to be taken out of service by December 31, 2012, which requires the removal and treatment of the remaining SBW.Several potential options have been proposed for treating the SBW. Of those considered, vitrification received the highest weighted score against the criteria used. Beginning in fiscal year 2000, the INEEL HLW program embarked on a program for technology demonstration and development that would lead to conceptual design of a vitrification facility, based upon the liquid-fed melter technology, in the event that vitrification is the preferred alternative for SBW disposal. This program includes several separate activities that include, among others, waste-form development, process feed-stream design, and melter vitrification demonstration testing of the nonradioactive, surrogate SBW flowsheet. The first of the melter flowsheet tests conducted in support of INEEL's vitrification facility design is discussed below.The Pacific Northwest National Laboratory's (PNNL's) Research-Scale Melter (RSM) was used to conduct these initial melter-flowsheet evaluations. The RSM is a small (1/100-scale) joule-heated melter that is capable of processing melter feed on a continuous basis. This capability is key for:• developing/evaluating process flowsheets• characterizing relationships between feed composition and the properties of the final glass produced• establishing the fate and behavior of process effluent.This melter system's capability to produce glass in a continuous manner is also essential for estimating the behavior of a full-scale system. Moreover, the size of the RSM allows the impacts of process variables upon melter performance or glass quality to be quickly and efficiently evaluated without undue expense or waste generation.The experimental scope of this initial, 5-d, 120-h, SBW vitrification test was to evaluate the:• processing characteristics of the newly formulated SBW surrogate melter feed stream• acceptability of various SBW to glass-forming additive ratios• possible formation of a secondary sodium sulfate phase iv • effectiveness of sugar as a glass oxidation-state modifie...

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

Additional testing is planned in early FY-1992 to characterizethe effectivenessof a platinum catalyst in oxidizing ammonia and carbon monoxide, temperaturedependency of nitrous oxide formation, representativenessof different sample delivery systems, and catalyst life expectancy. A final report, including these results,will then be issued in March 1991 to furthe_ support design of the full-scaleNOx Abatement Project.