THE UK DEPARTMENT OF ENVIRONMENT (DOE) HAS INDICATED THAT THE OVERALL QUALITY ASSURANCE PROGRAMME FOR THE MANAGEMENT OF RADIOACTIVE WASTES WILL PROBABLY INVOLVE THE QUALITY CHECKING (QC) OF FULL-SCALE WASTE PACKAGES. DOE-FUNDED PROGRAMMES HAVE THEREFORE BEEN SET UP TO ESTABLISH THE AVAILABILITY OF DESTRUCTIVE (DT) AND NON-DESTRUCTIVE (NDT) TEST METHODS FOR BOTH ENCAPSULATED INTERMEDIATE LEVEL (ILW) AND LOW LEVEL (LLW) WASTE PACKAGES. THIS RESEARCH PROGRAMME (JOINTLY FUNDED BY CEC/DOE) WAS DESIGNED TO AUGMENT THE SCOPE OF THE ABOVE PROGRAMMES.
THE OBJECTIVES OF THE PROJECT ARE:
- TO PROVIDE EXPERIMENTAL DATA ON THE DESTRUCTIVE SAMPLING AND ANALYSIS OF ENCAPSULATED ILW
- COMPARISON WITH SIMILAR EUROPEAN CEC-FUNDED PROGRAMMES
- TO PROVIDE EXPERIMENTAL DATA ON NDT EXAMINATION OF LLW PACKAGES.
THE RESULTS WILL BE USED AS INPUT TO THE DESIGN OF FACILITIES IN THE UK FOR QC OF BOTH ILW AND LLW PACKAGES.
A sampling rig was designed, fabricated and used to develop techniques for the destructive sampling of cemented simulated waste using remotely operated equipment. An engineered system for the containment of cooling water was designed and manufactured and successfully demonstrated with the drum and coring equipment mounted in both vertical and horizontal orientations. The preferred in cell orientation was found to be with the drum and coring machinery mounted in a horizontal position.
Small powdered samples can be taken from cemented homogeneous waste cores using a hollow drill vacuum suction technique with the preferred subsampling technique being to discard the outer 10 mm layer to obtain a representative sample of the cement core. An estimate of the beta-emitter content of cemented waste packages can be obtained by a combination of nondestructive and destructive techniques.
THE WORK PROGRAMME CONSISTS OF SEVEN TASKS:
1. TO IDENTIFY AND DEVELOP TECHNIQUES WHICH MAY BE USED FOR THE EXTRACTION OF MATERIAL FROM WASTE PACKAGES BY CORING TECHNIQUES.
2. TO COMPARE THE CONCLUSIONS FROM THE CORING PROGRAMME WITH THOSE FROM SIMILAR CEC PROGRAMMES (KFA, WEST GERMANY; CEA/CEN-CADARACHE, FRANCE; AND SCK/CEN MOL, BELGIUM).
3. TO PREPARE TEST PIECES AND REPRESENTATIVE SAMPLES FROM THE EXTRACTED CORES IN TASK 1 FOR CHEMICAL AND PHYSICAL ANALYSES.
4. TO ASSESS THE IMPORTANCE AND RELEVANCE OF CHANGES TO THE SAMPLE ARISING FROM MODIFICATIONS ENGENDERED BY THE CORING PROCESSES.
5. TO DEVELOP RAPID, NON-LABOUR INTENSIVE METHODS FOR THE DISSOLUTION OF POWDERED SAMPLES OF CEMENTED INTERMEDIATE LEVEL WASTE.
6. TO INVESTIGATE THE USE OF BETA/GAMMA CORRELATIONS AS AN AID TO DETERMINING THE RADIONUCLIDE INVENTORY OF CEMENTED INTERMEDIATE LEVEL WASTE.
7. TO ASSESS THE POTENTIAL OF X-RAY VIDEO IMAGING TECHNIQUES FOR THE DETERMINATION OF SPATIAL DISTRIBUTION AND PARTIAL IDENTIFICATION OF THE CONTENTS OF DRUMMED LOW LEVEL WASTE.