Development of cementitious grouts for the incorporation of radioactive wastes. Part I. Leach studies

Abstract

This report mm prepared as an account ol work fporaonjd by the United State* Government Neiihci the (Anted Stales nor the United States Atomic Energy Cammsaon. nor any of the* employees, nor any of mew contractors, subcontrac tors, or Their onplo>eai. makes any warranty, express or implied, or auumes any Kajal habilitv or responsibility (or the accuracy, completeness or usefulness of any information, apparatus, product or process disclosed, or lepmtim that its us* would not mfrinaje privately owned riehts. ORNL-4962 UC-70 -Waste Management Contract No. il-7h05-eDG-26 CHEMICAL TECHNOLOGY DIVISION DEVELOPMENT OF CSME^fTEnOUS GROUTS FOR THE INCORPORATION OF RADIOACTIVE HASTES. BART I: LEACH STUDIES

Leaching Behavior of Cesium-137 in Cement-waste Composites

“…Several studies have been made on the leaching of radionuclides from cement composites using water (Sm69; Te73;Mo75). To date, too little attention has been given to t o describing the mechanism and behavior of the leaching process.…”

Laboratory stabilizations/solidification of tank sludges: MVST/BVEST

“…Cementfly ash has traditionally been the stabilizer of choice for 90 Sr, although cement alone also stabilizes 90 Sr quite well. (Laguna, 1970;McDaniel et al, 1982;Moore et al, 1975;Moore, 1976;Atkinson et al, 1986) Some contaminants are not stabilized by the high-pH environment of cementitious wasteforms, specifically, chromates and mercury in the case of the sludges discussed here. Ground, granulated blast-furnace slag (slag) effectively reduces chromates to the more insoluble cationic chromium and stabilizes ionic mercury.…”

“…(Moore et al, 1975(Moore et al, , 1976Gilliam and Loflin, 1986;Gilliam, 1986; Illite has been known as an effective selective sorbent for 137 Cs for decades. (Tamura, 1961(Tamura, , 1963Tamura and Jacobs, 1960) The gap between illite layers is apparently ideal to allow cesium ions to diffuse between the clay layers and essentially irreversibly trap these ions.…”

State of the Art Report on High-Level Waste Tank Closure

“…Since strontium behaves similarly to calcium, cement-pozzolans will also tend to tie up Sr-90 better than cement alone. Cement-fly ash has traditionally been the stabilizer of choice for Sr-90, although cement alone can stabilize Sr to some extent (Laguna 1970;McDaniel et al 1982;Moore et al 1975;Moore 1976;Atkinson et al 1986). …”

“…Over the years, illite, a clay mineral with a layered structure, has become a standard ingredient in grout formulations developed at Oak Ridge National Laboratory for stabilizing Cs-137 [Moore et al, 1975;Moore, 1976;Gilliam and Loflin, 1986;Serne, et al, 1989A and B;Tallent, et al, 1989;Huang, et al, 1994;Serne, 3t al., 1992;Sams and McDaniel, 1988]. Illite has been known as a selective sorbent for cesium for decades [Tamura, 1961;Tamura, 1963;Tamura and Jacobs, 1960;Cowser, et al, 1966;Kaplan, et al, 1999].…”