Ceramicrete(Trade Name) Stabilization of CST Resin: ITP Alternative Phase III211 Feasibility Study

摘要

The Ceramicrete(trademark) waste form is a magnesium phosphate hydrate, which211u001esets as the result of an acid-base reaction between KH(sub 2)PO(sub 4) and MgO in 211u001ethe presence of water. Based on the results of this feasibility study, this low 211u001etemperature ceramic waste form is acceptable for stabilization of cesium loaded 211u001ecrystalline silicotitanate (CST) resin. The performance objective of CST 211u001estabilization is to convert a friable powdered resin into a monolithic form to 211u001eimprove handling and storage and to reduce the waste mobility. Advantages of this 211u001etype of the CST-Ceramicrete(trademark) waste form include: room temperature 211u001eprocessing of a fluid slurry, limited off gas, flexible mix designs, rapid 211u001esetting, no free liquids, temperature tolerant and durable up to at least 90 211u001edegrees C. The Ceramicrete/220 waste form can be processed by in-container mixing 211u001eor by batch mixing. Since a trace amount of free water will be associated with 211u001ethe wet resin in the CST-Ceramicrete(trademark) waste form, radiolysis of the 211u001efree water may cause pressurization of the containers. Leaching tests were 211u001econducted to evaluate the CST-Ceramicrete(trademark) waste form performance 211u001erelative to high-level waste glass. Results were very encouraging given that only 211u001eone waste loading (50 wt. percent resin) was tested and that the leaching 211u001eprocedures were not fully optimized for a non-glass waste form. In general, the 211u001ecesium leachability per the PCT test of the CST-Ceramicrete(trademark) waste was 211u001eabout 2X more than that of the ARM glass and about 200X more than the EA glass. 211u001eFor monolithic samples (MCC-1 test), the CST-Ceramicrete(trademark) waste form 211u001eleached 4X to7X more cesium than the ARM glass. (The EA glass is not suited to 211u001emonolithic leaching.) The CST-Ceramicrete(trademark) leaching results appear to 211u001ebe independent of curing temperature over the range 24 to 90 degrees C.