SLUDGE SURROGATE DEVELOPMENT AND VALIDATION USING CAKING FILTRATION PARAMETERS FOR A RADIOACTIVE SODIUM BEARING WASTE DERIVED SLUDGE AT THE IDAHO NATIONAL ENIGINEERING AND ENVIRONMENTAL LABORATORY

摘要

The U.S.Department of Energy is conducting remediation of eleven underground high-level nuclear waste storage tanks at the Idaho National and Engineering Laboratory.This will eventually result in one of the 300,000-gallon capacity tanks,accumulating over 70 tons of hazardous and radioactive sludge.To close this tank in an environmentally compliant manner to meet a state of Idaho/DOE legally binding agreement,the sludge has to be removed,treated,and disposed by 2012.To develop,test,and verify the design of sludge transporting,mixing,and drying processes necessary to accomplish these tasks,a highly representative surrogate for the sludge is paramount. Justification for developing a representative solid surrogate,and its corresponding chemical preparation procedure, is provided by economic factors and safety issues associated with personnel exposure to hazardous chemicals and radiation,and the high capital costs of radioactive material processing equipment and facilities. To ensure a high quality surrogate that accurately represents the unique chemical and physical properties of the actual toxic sludge,the present INEEL contractor has achitectured a novel and broad simulation strategy.This strategy includes the preparation of a solid surrogate in a manner similar to that which caused the actual waste sludge(e.g.,metathesis synthesis),and also involves a surrogate validation procedure that includes a statistical comparison of surrogate-to-real-sludge properties. The innovative strategy the INEEL contractor is presently deploying to ensure a representative and validated solid surrogate,is described to highlight the unique approach taken,in comparison to traditional solid surrogate preparations.Specifically,this strategy was pursued to ensure that test results arrived at using the solid surrogate would be transferable,and thus,scale-up tests with the surrogate could take place with high confidence that subsequent implementation of actual treatment equipment and procedures would follow directly without the typical unforeseen problems that arise after having used a poorly designed and unrepresentative surrogate.The strategy has applicability throughout the nuclear and hazardous waste industry.This is a work-in-progress that will not be completed until June 2004;however,currently available data from analyzing and testing the surrogate and actual waste sludges are presented.Included are data from constant pressure filtration studies.