UPGRADING SAFETY OF UNITS 5 AND 6 AT KOZLODUY NUCLEAR POWER PLANT WITH THE USE OF PROBABILISTIC SAFETY ASSESSMENT RESULTS AND OTHER RELEVANT STUDIES

摘要

A programme for safety upgrading of Kozloduy NPP Units 5 and 6 has been developed [1]. The experience of the existing studies (design deficiencies found during the operation), as well as the recommendations given by European and international organizations for upgrading of the units to an acceptable safety level were taken into account. The programme also includes evaluation of the economic effectiveness of the proposed solutions and modifications. The main principle for the programme development is in structuring the proposed measures in accordance with the safety functions of the systems. Another criterion for evaluation of the modifications or proposals is taken from the results of the probabilistic safety assessment (PSA) Level 1 studies already performed or recently performed with internal and external accident initiators, corrections of the Safety Analysis Report (SAR), etc. A detailed time schedule was developed for different programme measures. The programme was used as a basis for several international projects for Units 5 and 6.