THE AIM OF THE PROGRAMME WILL BE TO EVALUATE THE USE OF ON-LINE NON-DESTRUCTIVE METHODS, BASED ON X RAY ABSORPTIOMETRY AND GAMMA-SPECTROSCOPY COUPLED WITH ADVANCED DATA PROCESSING TECHNIQUES, FOR THE QUALITY CHECKING AND/OR CHARACTERISATION OF VITRIFIED HLW.
PARTICULAR EMPHASIS WILL BE PLACED ON DEVELOPING AND DEMONSTRATING TECHNIQUES THAT WILL BE APPLICABLE TO FULLY ACTIVE GLASS SAMPLES. A CYLINDRICAL CONTAINER OF ACTIVE VITRIFIED WASTE PRODUCED BY THE FINGAL PROCESS IS AVAILABLE FOR THIS WORK.
RESULTING FROM THE PROPOSED PROGRAMME, WE INTEND TO DEMONSTRATE FIRSTLY THE USE OF GAMMA-EMISSION MEASUREMENTS FOR DETERMINING THE CONTENT AND DISTRIBUTION OF GAMMA-EMITTING ISOTOPES WITHIN A HIGHLY ACTIVE SAMPLE CONTAINER AND SECONDLY THE USE OF X-RAY ABSORPTIOMETRY FOR MEASURING THE LOADING OF ACTIVE GLASS.
ON COMPLETION WE AIM TO HAVE SUFFICIENT INFORMATION TO ENABLE THE DESIGN OF A PLANT INSTRUMENT TO BE UNDERTAKEN.
IT IS INTENDED THAT HARWELL COLLABORATES WITH BAM IN THE EXCHANGE OF DATA PROCESSING EXPERTISE AND HARDWARE DEVELOPMENTS, PARTICULARLY WITH RESPECT TO DETECTION SYSTEMS.
Tomography and X-ray absorptiometry have been performed on a container of vitrified high level waste produced by the FINGAL process in 1966. The studies have been carried out without recourse to specialised high activity handling facilities. Measurements were carried out by lowering the glass from a shielded container, through a measurement collar, into 1 of the original storage holes in the floor of the FINGAL plant. The tomographs showed clearly various artefacts in the glass but no cracks or voids were observed within the resolution of the technique (0.5-1 mm). The X-ray absorptiometric measurements were made using a 160 kV tube. They showed the presence of about 7% uranium. The resulting strong absorption of X-rays limited the measurements that could be made.
TASK 1. CONSTRUCTION OF THE FACILITY TO ENABLE GAMMA-EMISSION AND X -RAY ABSORPTION MEASUREMENTS TO BE CARRIED OUT ON HIGHLY RADIOACTIVE SAMPLES, PARTICULARLY THE FINGAL GLASS CONTAINER.
TASK 2. ADAPTATION AND IMPROVEMENT OF COMPUTER ALGORITHMS REQUIRED FOR THE APPLICATION OF GAMMA-EMISSION TOMOGRAPHY TO THE SAMPLE.
TASK 3. CONSTRUCTION OF AN INACTIVE SIMULANT SAMPLE CONTAINING CAVITIES TO PERMIT THE INTRODUCTION OF SEALED GAMMA-SOURCES.
TASK 4. USE THE INACTIVE SIMULANT SAMPLE TO TEST THE MECHANICAL HANDLING ASPECTS OF THE EQUIPMENT.
TASK 5. WITH THE INACTIVE SAMPLE LOADED WITH SEALED SOURCES; TEST THE MEASUREMENT AND DATA PROCESSING PARTS OF THE GAMMA-EMISSION SYSTEM.
TASK 6. CARRY OUT X-RAY ABSORPTIOMETRY ON THE INACTIVE SAMPLE.
TASK 7/8. REPEAT THE EMISSION AND ABSORPTION MEASUREMENTS, RESPECTIVELY, ON THE ACTIVE GLASS.
TASK 9. APPLY THE DEVELOPMENT FOR FINGAL GLASS SAMPLE TO SMALL (1 LITRE) SAMPLES OF CEMENTED INTERMEDIATE LEVEL WASTE AVAILABLE AT HARWELL.