Plutonium leachability from alternative transuranic incinerator ash waste forms

• Main Authors: Neilson, R Jr, Colombo, P, Bradley, D
• Language: unknown
• Published: 2013
• Subjects: 12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; 54 ENVIRONMENTAL SCIENCES; FORMALDEHYDE; LEACHING; GEOLOGIC DEPOSITS; ALPHA-BEARING WASTES; PLUTONIUM; POLYESTERS; PORTLAND CEMENT; STYRENE; UREA; ACID CARBONATES; ASHES; BRINES; CALCIUM CHLORIDES; COMBUSTION; GROUND WATER; RADIOACTIVE WASTE DISPOSAL; RADIOACTIVE WASTE PROCESSING; SODIUM CHLORIDES; SODIUM COMPOUNDS; SOLID WASTES; WATER; ACTINIDES; ALDEHYDES; ALKALI METAL COMPOUNDS; ALKALINE EARTH METAL COMPOUNDS; AMIDES; AROMATICS; BUILDING MATERIALS; CALCIUM COMPOUNDS; CALCIUM HALIDES; CARBONIC ACID DERIVATIVES; CEMENTS; CHEMICAL REACTIONS; CHLORIDES; CHLORINE COMPOUNDS; DISSOLUTION; ELEMENTS; ESTERS; HALIDES; HALOGEN COMPOUNDS; HYDROCARBONS; HYDROGEN COMPOUNDS; LOW-LEVEL RADIOACTIVE WASTES; MANAGEMENT; MATERIALS; METALS; ORGANIC COMPOUNDS; ORGANIC NITROGEN COMPOUNDS; Carbonic acid
• Online Access: http://www.osti.gov/servlets/purl/6628351; https://www.osti.gov/biblio/6628351

Leaching experiments were conducted to determine the rate of plutonium release from Portland cement, urea-formaldehyde, and polyester-styrene waste forms incorporating incinerator ash waste. A modified IAEA leach test procedure was employing using demineralized water, simulated WIPP Brine B, simplified sodium dominated groundwater, simplified calcium dominated groundwater and simplified bicarbonate dominated groundwater leachants. The data obtained provided a good fit to a diffusion release model for semi-infinite media. This model allows the calculation of effective diffusivities for plutonium release and provides a means for the prediction of long-term plutonium releases from full-scale waste forms. The effective diffusivities determined for Portland cement and polyester-styrene waste forms varied from 1.6 x 10/sup -22/ to 3.9 x 10/sup -20/ cm/sup 2//sec. Plutonium release was more rapid from urea-formaldehyde waste forms which exhibited effective diffusivities of 2.3 x 10/sup -18/ to 1.1 x 10/sup -14/ cm/sup 2//sec. The lowest release rates were obtained for leaching in WIPP Brine B. Effective diffusivities in the range of 10/sup -22/ to 10/sup -20/ cm/sup 2//sec result in predicted fraction plutonium releases of 1.9 x 10/sup -6/ to 1.9 x 10/sup -5/ in 10/sup 5/ years (neglecting decay) from 210 liter (55 gallon drum) waste forms. As a result of the low effective diffusivities determined and for the long half-lives of TRU radionuclides, waste form stability may be the primary determinant of activity release over the time period that must be considered for TRU waste disposal.