On the sites of Belgoprocess several thousands of drums containing conditioned legacy waste are stored. A significant number of these waste packages are 220 litre drums containing radioactive waste embedded into inactive bitumen. Most of the radioactive waste in these drums was generated during the development and production of MOX-fuels and the operation of the Eurochemic reprocessing plant. The current state of a number of these packages is no longer acceptable for long term storage. In order to make the waste packages acceptable for interim storage a repackaging process was developed. The process involves the repackaging of the waste items into 400 or 700 litre waste drums and a non-destructive gamma-ray assay (NDA) measurement performed on the new package. The aim of the NDA measurement is to detect significant quantities of fissile material in order to demonstrate compliance with the operational limits of the storage building. Since the waste items are destined for geological disposal, there is no specific need for a detection limit in the order of milligrams of plutonium as required for surface disposal. To meet this NDA requirement Babcock International Group supplied, calibrated and commissioned an open geometry system from its HRGS product range. The DrumScan® HRGS Solo assay system was delivered to the Belgoprocess site in 2009 after completing a series of factory acceptance tests performed in the UK. In May 2009 after successful completion of the site acceptance tests performed in Belgium, the system has been undergoing extensive testing and validation by Belgoprocess in order to demonstrate acceptance and compliance to the Belgian Radioactive Waste Agency, NIRAS/ONDRAF. After a careful evaluation of the qualification file, NIRAS/ONDRAF approved the system for operational measurements at the end of 2010. This paper provides a detailed description of the NDA requirement, calibration methodology, system validation tests and overall measurement performance of the system.
Belgoprocess started the industrial decommissioning of the main process building of the former Eurochemic reprocessing plant in 1987. In 2008 the eastern part was torn down and in 2010 the central part of the building was removed. The demolition of the third and last part is planned in 2014. At that point the area will be restored to brown field conditions. During the 25 years of decommissioning the Eurochemic installations a lot of effort has been invested in improving the efficiency. The Belgian decommissioning policy is based on maximizing effort for decontamination with the goal of unconditional release and minimization of nuclear waste. As a result a number of installations have been implemented that reduce the processing costs, increase the output of decontamination and increase the speed of release measurements. • The abrasive blasting installation is used to remove a thin layer from metal components and concrete objects. • The concrete crushing and sampling installation is used as the final measurement before unconditional release of concrete debris. • The concrete spec installation is used to separate the contaminated part from the non contaminated part of concrete debris. As the end of the decommissioning project is approaching the time is right to look back and evaluate the course of the project. Looking back what were the key decisions during the project, what were important milestones and what could or should have been done differently knowing what we know now.
Belgoprocess is capable of processing almost every type of low and medium level radioactive waste and thereby covering a large segment from the back-end of the nuclear fuel cycle. Waste from numerous producers is treated and conditioned into a stable end product. Such processes lead inevitably to the generation of a large number of different waste streams. Each of these streams is uniquely defined by its radiological and physicochemical characteristics. From regulatory point of view and in order to select appropriate processing and conditioning techniques it is essential to characterize each of these waste streams. Because of the labour-intensive nature of the work and to keep a trustworthy traceability, Belgoprocess has decided to automate this task as far as possible. Therefore it has developed a system that seamlessly integrates waste-accounting and radiological characterization into one system. The use of generic methodologies, isotope vectors and a measurement database makes it possible to characterize most waste packages without elaborate knowledge of radiological characterization. A nuclear engineer develops generic methodologies and defines isotope vectors and appropriate measurements. These combinations are documented in procedures and used by the waste-accounting team to characterize the waste packages. The whole system is designed and programmed in such a way that it offers maximum flexibility and traceability. For example, changes in characterization of the previously processed and conditioned waste will propagate through the system until the changes reach the end product. This kind of systematic approach to radioactive waste characterization is found to be very fruitful.
Incineration of low active waste is the most efficient way to obtain high volume reduction factors. Although the initial scenario for processing low active alpha suspected waste (α-activity ≤ 400MBq/m3) in Belgium was supercompaction, incineration was eventually chosen for various benefits concerning volume reduction as well as the elimination of organic compounds improving the long term performance. This specific type of waste is often contaminated with for example mercury, requiring special attention in the treatment of both off-gas en waste water. In this paper it is shown that the CILVA incinerator of Belgoprocess N.V. has a high efficiency to combine both incineration and supercompaction of such types of waste.
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