| dc.description | Permanent concern on the safety of nuclear installations shall be assured in order to maintain the protection of workers, individuals from the public and the environment. Safety analysis methodologies for both approaches, deterministic and probabilistic, have been developed and updated based on operational experience, investigation of past incidents or accidents, and analysis of postulated initiating events. In general terms, the main objectives of a nuclear safety study are the identification of a comprehensive list of accident initiating events, the evaluation of their impact on the installation and the assessment of the total radiological risk resulting from accidents with off-site releases.
Among all initiating events and hazards, there are external hazards that continually challenge the safety of a nuclear facility or its nearby area. In particular, seismic events represent a major contributor to the risk of a nuclear facility. Large levels of ground motion induced by earthquakes may be experienced due to the propagation of mechanical waves on the ground, caused by the displacement of tectonic plates. In this context, a seismic hazard analysis can be carried out in order to predict local acceleration levels with the associated uncertainty distribution, allowing an adequate seismic classification of plant structures, systems and components, including installations located in sites with low seismicity.
In order to estimate the risk of a nuclear installation concerning accidents induced by seismic events, a Seismic Probabilistic Safety Assessment (Seismic PSA) shall be performed. In this article, a general description of the Seismic PSA methodology is presented, with emphasis on the supporting studies for this assessment.
Finally, this study is under the scope of a master degree project at IPEN ??? CNEN/SP which intends to apply the methodology described in this article to an experimental nuclear installation containing a PWR reactor designed for naval propulsion to be installed in a low seismicity zone in Brazil. | |
