The dismantling of the BR3-PWR reactor leads to the production of large masses of contaminated metallic pieces, including structural materials, primary pipings, tanks and heat exchangers. One of the main objectives is to demonstrate that we can minimise the volume of radioactive waste in an economical way, by the use of alternative waste routes, such as recycling of material in the nuclear world, free release of material in the conventional industry after melting or free release of material after thorough decontamination. The SCK•CEN launched a decontamination program with the aim to free release as much of the dismantled metallic material as possible. The selected chemical decontamination process, so-called MEDOC® (MEtal Decontamination by Oxidation with Cerium), is based on the use of cerium IV as strong oxidant in sulphuric acid with continuous regeneration using ozone. An industrial installation has been designed and constructed in close collaboration with Framatome-France. This installation started to operate in September 1999 for the treatment of the metallic pieces arising from the dismantling of the BR3 reactor. Since the installation starts up, 21 tons of contaminated material has been treated batchwise with success. Up to now, MEDOC® has been accomplished as a batch process in which the decontamination reactor is loaded with a basket containing the contaminated material. The SCK•CEN is now considering the possibility of using the MEDOC plant to decontaminate large components before cutting them, such as the BR3 -steam generator and the pressurizer. The decontamination solution will be circulated between the MEDOC plant and the steam generator during the consecutive decontamination cycles. Each cycle will comprises a decontamination step followed by a regeneration step. For the steam generator, 30 cycles are estimated to be needed to reach the free release level after melting. The decontamination studies of large components are ongoing and take into account the technical aspects, the radiological and classical safety aspects, as well as financial aspects.
The BR3 reactor was the first PWR plant installed in Europe. Started in 1962, BR3 was definitely shut down on June 30th, 1987. Used at the beginning of its life as a training device for commercial plant operators, it was also used during its whole life as test-reactor for new fuel types and assemblies. Most of the spent fuel was stored in the deactivation pool of the plant for more than 15 years. The reactor being now in decommissioning, it was decided to remove the spent fuel from the plant. After comparison of different solutions, the long term storage in dual purpose storage casks was selected in 1997. The selected CASTOR-BR3® cask is designed as a transport and storage cask for accommodating 30 spent fuel assemblies. As a type B(U) cask fitted with shock absorbers, it meets the transport requirements according to the IAEA guidelines and fulfils also the conditions for cask storage.
SCK•CEN is the Belgian Nuclear Research Centre. Founded in the mid-fifties, it has accumulated experience and know-how in all fields of the nuclear power production: in the neutronics calculation, radiation protection, waste management, fuel performance and analysis, nuclear measurements, radiochemistry, reactor technology, etc. Since 1989, SCK•CEN has launched Decommissioning activities to deal with the Technical Liabilities created by 40 years of operation. The main projects started were: • the dismantling of the BR3 PWR reactor; • the dismantling of active laboratories and the decontamination of buildings for unrestricted reuse; • the management of the waste arising from the refurbishment activities of the BR2, especially the management of the high active beryllium matrix. In 1989, the BR3 reactor, a Pressurized Water Reactor, was selected by the European Commission as one of the four pilot dismantling projects in the framework of the EC five year RTD program on dismantling nuclear installations. Through this project, SCK•CEN has built up a broad know-how in dismantling and decommissioning operations. This know how concerns the decontamination for dose rate reduction and/or free release of materials, teleoperated techniques for cutting highly activated components of a reactor, concrete decontamination techniques, characterization techniques of radioactive waste or for free release of components and development of decommissioning management and recordkeeping of material streams and of nuclear material accountancy. SCK•CEN is now actively involved in other decommissioning projects in Belgium and in expertise abroad. After giving an overview of the main achievements and the perspectives of the decommissioning of the BR3 reactor, the paper intends to present the involvement of SCK•CEN in the other decommissioning projects and to give an overview of our activities and capacities.
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.
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