THE PURPOSE OF THIS STUDY IS TO PROPOSE A CONDITIONING PROCESS SUITABLE FOR ULTIMATE STORAGE OF INCINERATED ALPHA WASTE ASHES. THE PROCESS WOULD ALSO BE APPLICABLE TO ASH CHEMICAL TREATMENT RESIDUES, BETA-GAMMA ASHES OR POWDER WASTE OF ANY ORIGIN THAT REMAINS INERT AT THE PROCESS TEMPERATURE.
A MULTIDIMENSIONAL HOT PRESSING METHOD WAS CHOSEN IN WHICH A VACUUM SEALED PRIMARY CONTAINER WITH THE WASTE ASHES IS PLACED IN AN OVEN FILLED WITH HIGH PRESSURE GAS. THE RESULTING PRODUCT IS A TYPE OF CERAMIC THAT ADHERES TO THE CONTAINER WALLS WITHOUT ANY TYPICAL VOID.
THE PROCESS HAS NOT YET BEEN APPLIED TO WASTE STORAGE. THIS STUDY IS BEING CARRIED OUT JOINTLY WITH INDUSTRIAL FIRMS WHERE ISOSTATIC PRESSES ARE AVAILABLE. THE FINAL PHASE COMPARE THE END PRODUCTS OBTAINED BY PRESSING WITH MELTED ASH PRODUCTS.
Alpha emitting solid incineration wastes are processed for 2 principal reasons: to enhance the quality of the finished product for long term storage and to reduce the total waste volume. Isostatic pressing parameters were defined using containers 36 mm in diameter, the physicochemical properties of the compacted ashes were determined using 140 mm diameter containers and industrial feasibility was demonstrated with a large, 300 mm diameter, container.
A major engineering study was also undertaken to compare the 3 known ash containment processes: isostatic pressing, melting and cement resin matrix embedding. The flowsheet, operational sequence and control principles were detailed for each process and a typical plant layout was defined in order to allow comparisons of both investment and operating costs.
1. PRODUCTION OF REPRESENTATIVE ASHES IN INDUSTRIAL PILOT FACILITIES OR UTILIZATION OF INDUSTRIAL ASHES WITH SIMILAR COMPOSITION FOR TECHNOLOGICAL FEASIBILITY TESTS.
2. DETERMINATION OF PRESSING PARAMETERS AT LABORATORY SCALE ON ACTUAL INACTIVE ASHES.
3. PRODUCTION OF INTERMEDIATE SCALE BLOCKS FROM ACTUAL INACTIVE ASHES TO DETERMINE THE PHYSICAL AND MECHANICAL PROPERTIES OF THE RESULTING MATERIAL, AND FABRICATION OF A 30 CM DIAMETER BLOCK USING INDUSTRIAL ASHES.
4. FABRICATION OF MELTED ASHES WITH OR WITHOUT PRIMARY GLASS ADDITIVES IN EXISTING CEA FURNACES.
5. PRELIMINARY DESIGN WORK FOR AN INDUSTRIAL UNIT TO ALLOW COMPARISON WITH A MELTING FACILITY.