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[en] Minimising contaminated waste is a top priority in decommissioning projects in the nuclear sector. In the area of building decontamination, efficient processing of all affected concrete ceilings, walls and floors is essential and quickly results in a surface area of several thousand square metres to be processed. Decontamination is mainly carried out by using milling machines, e. g. rotary cultivators. Within the scope of a research project (BMWI, ZIM, funding code: KF2286004LL3) the project partners Karlsruher Institut fuer Technologie (KIT) and Contec Maschinenbau and Entwicklungstechnik GmbH (Alsdorf/Sieg) investigated the influence of the geometry of the cutting tools on concrete removal. This article shows results from the test program conducted at the Institute for Technology and Management in Construction (TMB) of the KIT, Department of Deconstruction of Conventional and Nuclear Structures.
[en] Two methods have been proposed for more precise determination of the cutting forces when using tools with different wear at the rear surface: in one, the actual contact is taken into account; in the other (proposed by Zorev), it is ignored. In the present work, these methods are compared.
[en] Westinghouse capitalizes more than 30 years of experience in the cutting of internal components of reactor and their packaging in view of their storage. Westinghouse has developed and validated different methods for cutting: plasma torch cutting, high pressure abrasive water jet cutting, electric discharge cutting and mechanical cutting. A long feedback experience has enabled Westinghouse to list the pros and cons of each cutting technology. The plasma torch cutting is fast but rises dosimetry concerns linked to the control of the cuttings and the clarity of water. Abrasive water jet cutting requires the installation of costly safety devices and of an equipment for filtering water but this technology allows accurate cuttings in hard-to-reach zones. Mechanical cutting is the most favourable technology in terms of wastes generation and of the clarity of water but the cutting speed is low. (A.C.)
[en] The chip formation in turning by cutting inserts with balls at the front surface is considered. Chip samples are shown. The use of such cutting inserts is found to decrease vibration in the lathe and to improve the final surface quality.
[en] A few states started in the early forties/fifties the first development of nuclear technologies. Some of them now own a great amount of nuclear installations which entirely fulfill their assignment. In some cases, the life time of the nuclear power plants which were scheduled for approximately 30 years have been extended by more than 50%, the other ones as well as fuel production and enrichment plants, experimental or research reactors, will have to be dismantled in the near future. The decommissioning of those installations is definitely one of the twenty first century challenge. It is differently managed depending on the countries and their energetic and development policies, their financial consideration, the availability of qualified engineers or specialized companies to handle such projects. The final aim of decommissioning is to recover the geographic site in its original condition. A real cooperation is existing in between the people involved in different countries through different types of conferences and meetings during which the main subjects are: - The safety of the operators during all the phases of decommissioning operations. - Restrictions and dimensioning of the required equipment - Storage and waste management - Elaboration of procedures for recording all different steps and processes. Some of the techniques are described in this paper without being exhaustive. (author)
[en] The fuel element on a support is perpendicular to the cut edge, it is maintained by clamps and between 2 cuttings it is advanced of the wanted length. The ends are cut with a cutter for ends and evacuated separately. The pencils are cut inside a cavity for containment and evacuated through an opening
[fr]L'element, place sur un support, presente sa section transversale a la coupe. Il est comprime au moyen d'au moins un serre-flanc et entre deux coupes, le(s) serre-flanc(s) est (sont) desserre(s), l'element est alors avance de la longueur voulue. Les embouts coupes avec un moyen de coupe des embouts tombent dans un moyen d'evacuation des embouts fixe. Les crayons sont coupes a l'interieur d'une cavite de facon a y etre confines, ladite cavite est munie d'une ouverture basse permettant d'evacuer et diriger les crayons coupes