DETAILED STANDARDIZED DECOMMISSIONING PARAMETERS CALCULATION FOR LARGER TECHNOLOGICAL AGGREGATES AND RELEVANT BUILDINGS IN NUCLEAR POWER PLANTS USING THE OMEGA CODE

摘要

The computer code OMEGA was developed for evaluation and optimisation of decommissioning project planning. It implements the standardised cost structure PSL (Proposed Standardised List) developed by IAEA, OECD/NEA, EC [1], as the universal structure for calculation and optimisation of decommissioning scenarios. Dismantling of technological systems especially in radiation ambient is the most important among decommissioning activities. The document concentrates on dismantling activities in controlled area of NPP buildings and the principles of standardised calculation structure generation for these activities. It presents the principles of calculation for larger technological aggregates (LTA) i.e. complex primary systems such as reactor steam generators, refuelling machines and suchlike. It includes examples of system oriented approach dismantling and sets of typical dismantling activities. LTA which are situated in controlled area have typical attributes such as contamination of technological surfaces, induced volume radioactivity of materials [2] (due to influence of high neutron fluxes during operational period of reactor) resulting into high dose rates of their components. Dismantling of LTA requires to use specialized dismantling techniques ensuring protection of personnel from high radiation with consideration of ALARA principle [4], [9]. The significant techniques being used for these activities are remote dismantling techniques ensuring negligible exposure hazard for service personnel. The extent of remote activities usage depends on local conditions for dismantling such as decommissioning equipment category, dose rates and other, local working conditions. These factors determine the selection of dismantling techniques for particular system of working place.