ALARA radiation protection applications at NPP A1 decommissioning using VISPLAN planning tool

The SCK.CEN developed during the BR3 reactor decommissioning a graphical interfaced 3D dose assessment tool aimed at the above mentioned dose optimization problems. The tool was improved further and commercialized under the name VISIPLAN 3D ALARA planning tool. The use of VISIPLAN tool at NPP A1 decommissioning was advised by EDF within the IAEA TCP SLR/4008 project missions as a component of a 3D technological chain ensuring acquisition and evaluation of digitized information leading to ALARA optimisation of the developed decommissioning working procedures (see Fig. 1). VISIPLAN license was purchased by IAEA and granted to VUJE and NPP A1 within the IAEA TCP project SLR/4008, covering also the necessary basic and advanced training (at NPP A1 real decommissioning environment), and is currently used by VUJE analysts at NPP A1 decommissioning as an ALARA tool for intervention planning and optimisation. The VISIPLAN allows a fast dose assessment for work planned in a radioactive environment. The calculations are based on a 3D model of the work place. This PC-based tool is user friendly and calculates a detailed dose account for different work scenarios defined by the ALARA analyst, taking into account worker position, work duration and subsequent geometry and source distribution changes. The VISIPLAN methodology is described. The VISIPLAN tool was applied to several ALARA studies carried out by the VUJE within development and analysis of various Work Programs for NPP Al decommissioning tasks. The applications ranged from simpler to complex ALARA planning tasks covering simple shielding applications to selection of the most suitable order of complex working procedures. Removal of inner liners from underground reservoirs 6/1 and 6/2 as well as Dismantling of pipes and components from a (hostile) 60 m corridor are described. (authors)