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DESTRUCTIVE AND NON-DESTRUCTIVE TESTS FOR RADIOACTIVE WASTE PACKAGES

Objective

THE OBSERVANCE OF THE WASTE ACCEPTANCE REQUIREMENTS BY QUALITY CONTROL CAN BE PERFORMED BY CHECKING THE WASTE PACKAGES USING RANDOM TESTS WHICH CAN BE EITHER DESTRUCTIVE OR NON-DESTRUCTIVE.

ONE AIM OF THE PROJECT IS TO IMPROVE THE ACCURACY OF GAMMA-SCANNING MEASUREMENTS BY TAKING INTO ACCOUNT THE DIRECTIONAL DERIVATIVE OF THE EMITTED RADIATION. THIS REQUIRES THE DEVELOPMENT AND INVESTIGATION OF THE FOLLOWING:
- TILTING GE DETECTOR - SEVERAL STATIONARY DETECTORS - HORIZONTAL MOVEMENT OF THE WASTE PACKAGE WITH RESPECT TO DETECTOR.

A FURTHER AIM IS TO DEVELOP A METHOD TO MONITOR THE PHYSICAL NATURE OF COMPACTED WASTE BY MEANS OF THE RECORDED SIZE IN COMPACTION PRESSURE. THE COMPACTIBILITY OF DIFFERENT MATERIALS, ALONE OR AS MIXTURES, WILL BE INVESTIGATED IN 180 LITER DRUMS. A PLOT OF THE SUPERCOMPACTION PRESSURE VERSUS TIME OR DISTANCE WILL BE COMPILED.
On the basis of preliminary waste acceptance requirements, quality control of radioactive waste has to be performed prior to interim storage or final disposal. The quality control can either be achieved by random tests on conditioned radioactive waste packages or by process qualification of the conditioning processes. One of the most important criteria is the activity of the radioactive waste product or packages. To get some initial information on the waste packages gamma-spectrometric measurement is performed as a nondestructive test. Besides the gamma-emitting nuclides the alpha and beta-emitting nuclides can be estimated by calculation if the waste was generated in nuclear power plants and the nuclide relations are known.
If the nondestructive determination of nuclides is not sufficient, or the nonradioactive content of the waste packages has to be identified, sampling from the waste packages has to be performed. This can best be done by air cooled core drilling. As mixed waste is not allowed for final disposal, the determination of possible organic toxic materials like polychlorinated biphenyls, dioxin and furance compounds in cemented wastes is conducted by gas chromatography-mass spectroscopy. To get more knowledge in the field of process qualification concerning supercompaction, instrumentation of the supercompaction process is investigated and tested.
IN THE AREA OF DESTRUCTIVE TESTS AIR COOLED CORE DRILLING WILL BE INVESTIGATED AND DEVELOPED FOR USE WITH CONCRETE FIXED CONDITIONING WASTE. THE PROGRAMME AIMS AT OPTIMISING THE CUTTING CONDITIONS WITH RESPECT TO THE AMOUNT OF COOLING AIR NECESSARY, THE LIFETIME OF THE CUTTING HEAD AND ELECTRONIC CONTROL OF THE DRIVING ARRANGEMENT.

TO CHECK THE CONTENT OF TOXIC ORGANIC SUBSTANCES IN CONDITIONED WASTE GC-MS INVESTIGATIONS WILL BE PERFORMED. THE INFLUENCE ON DECOMPOSITION BY THE MATRIX MATERIAL SUCH AS CEMENT AND BITUMEN WILL BE INVESTIGATED AS WELL AS THE RADIATION INFLUENCE.

FROM THE PROPOSED PROGRAMME A MORE ACCURATE MEASUREMENT OF THE GAMMA-SCAN OF WASTE MATRICES SHOULD BE OBTAINED. THIS WILL RESULT IN BETTER LOCALISATION OF RADIOACTIVITY AND A MORE EXACT CALCULATION OF THE NUCLIDE INVENTORY.

THE ABILITY TO OBTAIN SOME INFORMATION ON THE CONTENTS OF SUPERCOMPACTED PELLETS SHOULD AVOID THE OCCURENCE OF EXPLODING DRUMS CAUSED BY POOR SELECTION OF PRIMARY WASTES.

THE DEVELOPMENT AND USE OF AIR-COOLED CORE DRILLING EQUIPMENT WOULD ELIMINATE THE MANY DISADVANTAGES CONNECTED WITH WATER-COOLED DRILLING E.G. CHANGE IN CHEMICAL COMPOSITION, PHYSICAL PROPERTIES OF SAMPLES, REMOVAL OF WASTE AND PRODUCTION OF LARGE AMOUNTS OF SECONDARY WASTE.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

FORSCHUNGSZENTRUM JUELICH GMBH
Address
Wilhelm Johnen Strasse
52425 Juelich
Germany