Regulatory activities related with the modification of the frequency of the programmed stoppings of the Argentine nuclear centrals

The mandatory character documentation of the Argentinean nuclear power stations in Embalse and Atucha I, required the realization of a programmed stoppings every twelve months to execute that settled down in the maintenance and surveillance programs for each installation. Nucleoelectrica Argentina S.A., in it character of Responsible Entity of the operation of these power stations, requested to the Argentinean Nuclear Regulatory Authority, in 2003 and 2005 respectively, the authorization to change the period of the repetitive tests and of the preventive maintenance of the systems related with the safety, to extend them from twelve to eighteen months. The mentioned applications were founded in economic aspects and in inclining to a decrease in the doses of the workers that perform in the activities that are carried out in the programmed stops. The adopted position by the Nuclear Regulatory Authority to decide on these applications was based on the result of diverse evaluations that included the use of the Probabilistic Analysis of Safety specific of each power station, the operative experience resultant of the execution of the preventive maintenance program, and of the results of the repetitive tests and of the inspections in service. The regulatory decisions were different in each case. Indeed, the Embalse nuclear power station was authorized by the Regulatory Authority to modify from twelve to eighteen months the period among the realization of the repetitive tests and of the preventive maintenance, conditioned to the execution of some specific regulatory requirements. On the other hand, the Atucha I nuclear power station was not authorized to modify this period. In this presentation that is detailed the acted by the Nuclear Regulatory Authority in both cases, the used analysis tools, and the foundation of the adopted decisions. (Author)