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Defence in Depth Side Event



A very successful side event was held during the 56th IAEA General Conference entitled “Challenges and New Considerations in the Defence in Depth Concept for Safety Provision of Nuclear Power Plants”. A large audience attended the event demonstrating the strong interest in this important topic in the international nuclear community.
The objective of the event was to present new considerations and promote discussion with senior international experts on the issues that need to be addressed and directions for the further development of the Defence in Depth (DiD) concept and its practical application. A panel discussion was preceded by short presentations by panelists from the United Kingdom, Slovakia, and the IAEA.
Organized by the Safety Assessment Section of the Nuclear Installation Safety Division, the event was presented under the umbrella of the Nuclear Safety and Security Department’s Nuclear Safety Action Plan. Following an introduction by Mr. Javier Yllera, Acting Head of the IAEA’s Safety Assessment Section, Ms. Irina Kuzmina, IAEA Expert in Probabilistic Safety Assessment, set the stage for discussion by proving and overview of the DiD Safety Concept for NPPs – its concept and objectives, historical development and the different levels of DiD. Mr. Jozef Misak, Senior Safety Assessment Expert from Slovakia subsequently highlighted the approach for comprehensive assessment of DiD provisions based on IAEA Safety Report Series #46. Nigel Buttery, Senior Expert from EDF, UK then discussed the application of DiD in the United Kingdom from a utility perspective.
To conclude, Ms. Kuzmina delivered a very informative presentation on challenges and new considerations in the DiD concept, a topic which included DiD levels in conjunction with accident sequence frequencies, the independence of DiD levels, and the concept of ‘Extended Design Basis’ and DiD.
From the presentations and discussions it can be concluded that Defence in Depth is, without a doubt, a valid and robust concept for providing safety of nuclear installations. However, there are developments internationally that may assist in a more holistic and consistent application of this safety concept, e.g. a more explicit consideration of accident sequence frequencies while deciding on whether an accident is ‘practically eliminated’ or not.
Several recommendations for future activities were provided by the participants. Specifically, it was mentioned that further effort should be pursued to improve safety assessment tools and methods to assess compliance with DiD along with providing more clear and robust criteria for compliance assessment, a more consistent and uniform terminology, and more focused training for newcomer countries. It was also suggested that the IAEA should consider developing a guidance document on robust application of the DiD concept to further assist in ensuring the safety of present and future nuclear power plants.
This side event proved to be very useful in highlighting the strong interest of Member States for DiD Concepts and in indicating areas for further emphasis needed at the international level.
The session was recorded and will be made available on our Multimedia Module for all GSAN registered users.
Presentations made during the event can be found below.

 Side Event Videos

Overview of DiD Safety Concepts for NPPs in IAEA Publications


IAEA's Guidance on Defence in Depth 



  You can find more videos of this Side Event in our Multimedia Section!

  Only for registered users. Register here.




1 DiD-SideEvent_ObjectivesLevels_fin-1.pdfSide Event Objectives1 DiD-SideEvent_ObjectivesLevels_fin-1
2_GC 2012 Side event DID Misak Rev 1.pdfIAEA's Guidance on Defence in Depth Assessment2_GC 2012 Side event DID Misak Rev 1
3_IAEA DiD presentation_Nigel_UK.PDFApplication of Defence in Depth in the UK - a utility perspective3_IAEA DiD presentation_Nigel_UK
4_DiD-SideEvent_NewConsiderChallenges_Fin-5.pdfChallenges and new considerations in the DiD Concept4_DiD-SideEvent_NewConsiderChallenges_Fin-5
Agenda_DiD Side Event GC56.pdfSide Event AgendaAgenda_DiD Side Event GC56