The Low-Activity Waste Process Technology Program at the Idaho Nuclear Technology and Engineering Center (INTEC) anticipates that large volumes of low-level/low-activity wastes will need to be grouted prior to nearsurface disposal. During fiscal year 1999, 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 on radionuclide leaching, microbial degradation, waste neutralization, and a small mockup for grouting the INTEC underground storage tank residual heels. iv SUMMARYThe general purpose of the Low-Activity Waste Process Technology Program is to solidify and stabilize the liquid low-activity wastes (LAW) 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 of the tank farm liquid sodiumbearing waste, (2) chemical separation of dissolved aluminum and zirconium calcines, and (3) facility decontamination and process equipment wastes. Grout formulation studies included cesium separated sodium-bearing waste and newly generated liquid wastes. Additional studies were completed in radionuclide leaching, microbial degradation, and pH adjustment. A small scale mockup test was completed for grouting the tank farm vessel residual heels.Initial grout formulations were developed for the cesium separated sodium-bearing waste and the projected newly generated liquid waste. The cesium separated waste would be a tranurance waste that could be sent to the Waste Isolation Pilot Plant. A waste loading of up to 70% weight percent was successfully prepared. Grout formulations of up to 47% weight percent can be prepared for one projected newly generated liquid waste. Both of these formulations utilize the waste as the liquid for the cement powders. The small lab-scale mockup test for the closure of the underground storage tank residual heels demonstrated that Savannah River reducing grout will work with the acidic heels.