Safety assessment of Temelin NPP

History of peaceful use of nuclear energy, despite of all necessary emphasis on operation safety, is accompanied by a series of accidents, some of which left indelible trace in minds of wide public and so led to changes in the comprehension of nuclear safety and in the access to its preservation. Because the consequences of possible nuclear power plant accident have always serious social impacts, it is most desirable to define all possibly risks, to quantify probability of their formation and in this way to gain the possibility to prevent them effectively and efficiently. This work is dedicated to approve or to disapprove that the KARS method is practically applicable for evaluation of nuclear power station operation safety. The work objective is to evaluate events and risks associated with the operation of a particular nuclear facility by the KARS method and critically evaluate obtained results and the used method as such. The work is divided into theoretical and practical part. Theoretical part includes basic information necessary for correct understanding of the chosen data processing procedure and subsequent interpretation of the gained results. A brief overview of basic concepts relating to the nuclear safety, the safety culture and the emergency preparedness, including their definitions is given in this section of the work. For the evaluation of obtained results it is useful to make familiar with basic concepts of the NPP safety evaluation, PSA and the stress tests. Obviously, it is necessary to describe the KARS method and to define the concept of quality of human performance with regard to the obtained results. The risk analysis by the KARS method was carried out in the four consecutive steps: 1. Data collection for the risk analysis. 2. Data processing by the use of the KARS method. 3. Interpretation of the obtained results. 4. Comparison of the obtained results with the available data. The particular risks for the construction of the risk correlation table were based on the analysis of activities of individual members of the emergency and technical support center on the basis of managing documentation for each function. In the emergency instructions these risks are either named or the action to manage them are determined. Subsequently these risks are further more specify according to the operational documentation used for solving abnormal and emergency conditions or solving of severe accidents. Determination of the risk correlation seems to be subjective and requires a considerable degree of professional insight into the analyzed issues. The risk analysis was processed according to the procedure that was laid down by Ing. Stefan Pacinda, Ph.D. Each risk taken into consideration in this analysis is briefly described within the interpretation of obtained results. The coefficients of activity with the biggest value were found for these risks: human error, earthquake, plane crash, terrorist threat, errors in operating and managing documentation and fire. The coefficients of passivity with the biggest value were found for these risks: human failure, serious damage to health, ecological disaster, components malfunctions, radiation accident, nuclear material integrity damage and control system malfunctions. Comparison of the risks that were postulated in the stress tests and the risks that were considered in this analysis indicate that the ETE NPP emergency response was prepared to be able to cope these risks. Results of this analysis showed that the essential element for the safe operation of nuclear power plants is qualified, well selected and systematically trained staff. In light of the experience acquired during elaboration of this work I have concluded that the KARS method can be used for nuclear safety evaluation only in a limited way