Since 1980, the National Agency ONDRAF/NIRAS has been responsible by law for the safe management of all radioactive waste produced in Belgium, including decommissioning waste. In 1991, its responsibility was extended by Royal Decree of 16.10.91 to the field of decommissioning, its main specific assignments being: • The collection and evaluation of data (physical and radiological inventories) from nuclear plants; • The approval of decommissioning programmes, including decommissioning cost evaluations and mechanisms of funding. Already in the early 90s, ONDRAF/NIRAS started with the implementation of its own integrated data processing system, recording the physical and radiological inventories of nuclear plants and allowing the evaluation of the quantities of decommissioning materials and waste as well as of the decommissioning costs of the plants. In 1997, the law on the inventory of nuclear liabilities of 12.12.97 completed and enforced the decree of 1991, stating that the agency will: • Draw up a register specifying the location and condition of all nuclear facilities and all sites containing radioactive substances on Belgian territory; • Estimate the cost of decommissioning and cleaning up these facilities and sites; • Evaluate the availability of sufficient funds to carry out these future or ongoing operations; • Update the inventory every five years. As a result, during these last few years, ONDRAF/NIRAS had to deal with an increasing amount of decommissioning data (submission of inventories, new decommissioning plans and also a first batch of five-yearly revisions) concerning a larger diversity of facility types (enlargement of activities to “smaller” licensees, like universities, hospitals, etc). Simultaneously and consequently, ONDRAF/NIRAS faced the need to integrate a larger range of field-experienced decontamination and dismantling techniques, performed by different decommissioning companies, in order to obtain more refined and “pertinent” cost evaluations. For the same purposes, it appeared necessary to consider alternative waste processing possibilities, especially for very low-level waster arising from decommissioning activities. In 2000, ONDRAF/NIRAS started to upgrade its Decommissioning Management System (DMS) in order to enhance the quality of the database (integrity, intrinsic validity, extrinsic validity, completeness and accuracy) and simultaneously to develop the flexibility and the abilities of the evaluation functions. This paper presents and describes the latest version of the ONDRAF/NIRAS DMS (the data model, interface facilities, and the calculation and reporting possibilities) putting emphasis on experience gained and on some of the first lessons learned. The two first sections of this paper give an overview of the National Agency’s main missions and outline the information and data collection process in the framework of decommissioning and inventory. Indeed, the context in which the updated DMS was developed and the difficulties encountered during the data collection process should inform the reader about the way the upgrading of the data system has been thought out and the alternatives the National Agency had to deal with. In the third section, the main functionalities of the DMS modules are set out in concrete terms, the main modules being: • The “Inventories” module, recording their physical and radiological inventories for the sites that fall within the scope; • The “Techniques” module, integrating measurement, decontamination, dismantling and special recycling techniques, as well as their unit cost elements; • The “Waste” module, integrating standard and special waste categories, their packaging, transportation and processing possibilities, as well as their unit cost elements; • The “Nominal Forecast” module, linking an inventory to selected techniques and waste costs, associated with the “best estimate” reference calculation scenario; • The “Scenario” module, dealing with the storage and evaluation of alternative scenarios (pessimistic or optimistic ones, deferred dismantling, etc). The last section focuses on experience gained through developing the upgraded DMS and putting it into operation. Some potentialities of the upgraded DMS are also discussed.
The BR3 plant at Mol in Belgium built at the end of the fifties was the first PWR plant built outside the USA. The reactor had a small net power output (10 MWe) but comprised all the loops and features of a commercial PWR plant. The BR3 plant was operated with the main objective of testing advanced PWR fuels under irradiation conditions similar to those encountered in large commercial PWR plants. The reactor was started in 1962 and shut down in 1987 after 25 years of continuous operation. Since 1989, SCK•CEN is decommissioning the BR3 PWR research reactor. The dismantling of the metallic components including reactor pressure vessel and internals is completed and extensively reported in the literature. The dismantling of auxiliary components and the decontamination of parts of the infrastructure are now going on. The decommissioning progress is continuously monitored and costs and strategy are regularly reassessed. The first part of the paper describes the main results and lessons learned from the reassessment exercises performed in 1994, 1999, 2004 and 2007. Impacts of changes in legal framework on the decommissioning costs will be addressed. These changes concern e.g. licensing aspects, clearance levels, waste management… The middle part of the paper discusses the management of activated and/or contaminated concrete. The costing exercise performed in 1995 highlighted that the management of activated and contaminated concrete is the second main cost item after the dismantling of the reactor pressure vessel and internals. Different possible solutions were studied. These are evacuation as radioactive waste with or without supercompaction, recycling this “radioactive” grout or concrete for conditioning of radioactive waste e.g. conditioning of metallic waste. The paper will give the results of the cost-benefit analysis made to select the solution retained. The last part of the paper will discuss the end goal of the decommissioning of the BR3. In the final decommissioning plan approved by ONDRAF/NIRAS, it was mentioned that the final goal of the BR3 decommissioning will be the “green field” unless opportunities for reuse of the BR3 site will occur during decommissioning. A strategy of partial reuse of the BR3 facility is proposed and being discussed with the main stakeholders. The paper will give the present state of the discussion.
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