Updating of a Screening Method for Assessment of Comprehensiveness of Defence in Depth and Areas for Its Applications 

Jozef Misak 

UJV Rez, a.s. (Nuclear Research Institute), Czech Republic 

Abstract: The paper describes the updated IAEA screening method for assessment of comprehensiveness of defence in depth for both existing as well as new nuclear power plants. In its first part the paper briefly summarizes the original IAEA method developed more than 10 years ago, described in the IAEA Safety Report No. 46 — Assessment of defence in depth for nuclear power plants. Further on, the need for updating the methods is justified making reference to relevant new IAEA Safety Standards and other guidance documents used for updating the method with consideration of new safety requirements and main directions in safety enhancement. Key modifications in the original IAEA method of objective trees are summarized. An example of the updated objective tree is provided and compared with the original tree. In the last part of the paper the potential areas for the use of the method areindicated. 

Key words: nuclear power plants, defence in depth, screeing method, objective trees