Starting in 2003, Belgoprocess will proceed with the treatment and conditioning of some 200 m3 of widely varying high- and medium-level waste from earlier research and development work, to meet standard acceptance criteria for later disposal. The gross volume of primary and secondary packages amounts to 2,600 m3. The waste has been kept in decay storage for up to 30 years. The project was started in 1997. Operation of the various processing facilities will take 7–8 years. The overall volume of conditioned waste will be of the order of 800 m3. All conditioned waste will be stored in appropriate storage facilities onsite. In November 2002, a new processing facility has been constructed, the functional tests of the equipment have been performed and the start-up phase has been started. Several cells of the Pamela vitrification facility onsite will be adapted for the treatment of high-level and highly α-contaminated waste; low-level β/γ waste will be treated in the existing facility for super compaction and conditioning by embedding into cement (CILVA). The bulk of these waste, of which 95% are solids, the remainder consisting of mainly solidified liquids, have been produced between 1967 and 1988. They originate from various research programmes and reactor operation at the Belgian nuclear energy research centre SCK-CEN, isotope production, decontamination and dismantling operations. The waste is stored in 4800 primary packages, of which 700 contain 120 g (5.1012 Bq) radium. Half the radium inventory is present in 25 containers. The presence of radium in waste packages, resulting in the emission of radon gas, requires particular measurements. The total activity at the moment of production amounted to 18,811 TBq β/γ and 34.4 TBq α, with individual packages emitting up to 555 TBq β/γ and 2.2 TBq α. According to calculations, the β/γ activity has decreased to some 2,000 TBq, with individual packages up to 112 TBq. The extreme diversity of the waste is not only expressed in their radiological characteristics, but also in their chemical composition, physical state, the nature and condition of the packages. Radioactivity ranges between 0.01 mCi to 1,000 Ci per package. Some packages contain resins, Na, NaK and Al containing waste, poison rods, residues of fuel elements. Although most of the liquid waste are solidified, a small fraction — both aqueous and organic — still remains liquid. Primary packages may be plastic bags, metal boxes, wire gauze, La Cale`ne boxes; secondary packages may be steel drums and concrete containers. Solid waste may be sources, counters, nuclear fuel residues, filters, synthetic materials, metals, resins, granulates, rock, sludges, cables, glass, etc. Some 1000 primary packages are stored in a dry storage vault comprising 20 concrete cells, while 3800 primary packages are stored in some 2,000 concrete containers, on a concrete floor, surrounded by an earth bank to the height of the waste stacking and covered by a metal construction. At present, the annual production of similar waste amounts to 2 m3 divided over some 30 containers. Generally, the primary waste packages will be loaded in 80-1 drums (an average of 2 packages per drum), and compacted in a 150 ton hydraulic press. The pellets will be collected in 100 1 drums (an average of 3 pellets per drum). Low-level β/γ waste is transferred to the CILVA facility for further treatment, while the other 100-1 drums are filled up with sand and, in the case of radium-contaminated waste, tight-welded. Subsequently, the 100-1 drums are loaded into 400-1 drums and embedded into cement. Certain packages, for example solidified radium-contaminated liquids in welded metal containers, are conditioned as such in overpacks. Specific procedures will be established for the various non-standard waste, such as sources, control and poison rods, resins and filters, fuel residues. Highly active and/or heavily α-contaminated waste are transferred to the existing Pamela facility for treatment and conditioning. Ideally, gamma spectrometry measurements are carried out on the primary packages, but due to the extreme diversity of these packages, ranging from plastic bags containing cardboard to highly active steel valves, preference was given to measurements on the conditioned waste, or at least on already pre-compacted waste in the case of treatment in the 2,000 ton press of the CILVA facility. Thus tremendous problems of calibration can be largely avoided. All operations are remotely controlled. Transfers between buildings are carried out within appropriately shielded containers and secondary waste will be treated in existing facilities onsite. The new processing facility is being built partly over the dry storage vaults, in the immediate vicinity of the already covered storage area.

BELGONUCLEAIRE has been operating the Dessel plant from the mid-80’s at industrial scale. In this period, over 35 metric tons of plutonium (HM) has been processed into almost 100 reloads of MOX fuel for commercial west-european light water reactors. In late 2005, the decision was made to stop the production because of the shortage of the MOX fuel market remaining accessible to BELGONUCLEAIRE. As a significant part of the decommissioning project of this Dessel plant, about 170 medium-sized glove boxes and about 1.300 metric tons of structure and equipment outside the glove boxes are planned for dismantling. The dismantling works are expected to start in the second quarter of 2009. On account of stringent internal rules of alpha-containment during over 25 years of operation, there is no significant contamination of the plant, outside the glove boxes; that assumption has been confirmed by radiological surveys performed by independent bodies in 2001 and 2008. Therefore most of the materials outside the glove boxes that were not a priori destined for radioactive waste will be released without restriction on the basis of the applicable legal regulations in Belgium (ARBIS), along with the buildings and the plant site. In this paper, after having reviewed the different regulations in Belgium, the authors introduce the different options considered for release of materials, and the main decision criteria (process, safety aspects, radiological, etc) for the different expected types of materials (inert materials, metals, plastics, electrical cabinets and cables and electronics) are analysed. Besides the regulatory aspects, the technological and economical aspects are considered (as an example, comprehensive metal smelting is implemented, as a favourite solution because it provides with decontamination, homogeneization and volume characterization).

The alpha-contaminated solid waste generated in Belgium results from past activities in the fuel cycle (R&D + Reprocessing and MOX fabrication pilot plants) and operation of BELGONUCLEAIRE’s MOX fuel fabrication plant. After the main steps in the management of alpha-contaminated solid waste were established, BELGONUCLEAIRE, with the support of BELGOPROCESS and ONDRAF/NIRAS, started the design and construction of the T & C and interim-storage facilities for this alpha waste. The accumulated solid alpha radwaste containing a mixture of combustible and non-combustible material must be sorted and characterized. After sorting, both the accumulated and recently-generated alpha waste will be compacted and the pellets will be embedded in a cement matrix in a 400-1 drum. The commissioning of the sorting unit which includes glove boxes was completed at BP, at the beginning of year 2005; the sorting campaign of 30-1 cans has been achieved in March 2007. The paper describes the project environment and gives a short description of the used facilities; the lessons learned from the sorting campaign and from the first T/C period, will be presented, as well.

Decommissioning of nuclear facilities is a complex process involving operations such as detailed surveys, decontamination and dismantling of equipment’s, demolition of buildings and management of resulting waste and nuclear materials if any. This process takes place in a well-developed legal framework and is controlled and followed-up by stakeholders like the Safety Authority, the Radwaste management Agency and the Safeguards Organism. In the framework of its nuclear waste and decommissioning program and more specifically the decommissioning of the BR3 reactor, SCK•CEN has developed different software tools to secure the waste and material traceability, to support the sound management of the decommissioning project and to facilitate the control and the follow-up by the stakeholders. In the case of Belgium, it concerns the Federal Agency for Nuclear Control, the National Agency for radioactive waste management and fissile material and EURATOM and IAEA. In 2005, BELGONUCLEAIRE decided to shutdown her Dessel MOX fuel fabrication plant and the production stopped in 2006. According to the final decommissioning plan (“PDF”) approved by NIRAS, the decommissioning works should start in 2008 at the earliest. In 2006, the management of BELGONUCLEAIRE identified the need for an integrated database and decided to entrust SCK•CEN with its development, because SCK•CEN relies on previous experience in comparable applications namely already approved by authorities such as NIRAS, FANC and EURATOM. The main objectives of this integrated software tool are: • simplified and updated safeguards • waste & material traceability • computerized documentation • support to project management • periodic & final reporting to waste and safety authorities. The software called DASAO (Database for Safeguards, Waste and Decommissioning) was successfully commissioned in 2008 and extensively used from 2009 to the satisfaction of BELGONUCLEAIRE and the stakeholders. SCK•CEN is now implementing a simplified release of the software for the management of the decommissioning of the THETIS reactor. Its decommissioning will start in March 2013 and will be completed by the end of 2014.

BELGONUCLEAIRE has been operating the Dessel MOX plant at an industrial scale between 1986 and 2006. During this period, 40 metric tons of plutonium (HM) have been processed into 90 reloads of MOX fuel for commercial light water reactors. The decision to stop the production in 2006 and to decommission the MOX plant was the result of the shrinkage of the MOX fuel market due to political and commercial factors. As a significant part of the decommissioning project of the Dessel MOX plant, about 170 medium-sized glove-boxes and about 1.200 metric tons of structure and equipment outside the glove-boxes are planned for dismantling. The license for the dismantling of the MOX plant was granted by Royal Decree in 2008 and the dismantling started in March 2009. The dismantling works are carried out by an integrated organization under leadership and responsibility of BELGONUCLEAIRE; this organization includes 3 main contractors, namely Tecnubel N.V., the THV (‘Tijdelijke HandelsVereniging’) Belgoprocess / SCK•CEN and Studsvik GmbH and TRACTEBEL ENGINEERING as project manager. In this paper, after having described the main characteristics of the project, the authors review the different organizational and technical options considered for the decommissioning of the glove-boxes; thereafter the main decision criteria (qualification of personnel and of processes, confinement, cutting techniques & radiation protection, safety aspects, alpha-bearing waste management) are analyzed as well. Finally the progress, the feedback and the lessons learned at the end of August 2013 are presented, giving the principal’s and contractors point of view.