Naslov
Update of System Failure Probabilities for NPP Krško Shutdown PSA

Autori
Vuković, Igor ; Vrbanić, Ivan ; Bašić, Ivica

Vrsta, podvrsta i kategorija rada
Radovi u zbornicima skupova, cjeloviti rad (in extenso), stručni

Izvornik
Proceedings of the 5th International Conference on Nuclear Option in Countries with Small and Medium Electricity Grids / Pevec, Dubravko ; Debrecin, Nenad - Zagreb : Hrvatsko nuklearno društvo, 2004

Skup
5th International Conference on Nuclear Option in Countries with Small and Medium Electricity Grids

Mjesto i datum
Dubrovnik, Hrvatska, 16.05.2004. - 20.05.2004

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
PSA; shutdown

Sažetak
The potential for common cause failures in systems that perform critical functions has been recognized as very important contributor to risk associated with operation of nuclear power plants. Consequentially, modelling of common cause failures (CCF) in fault trees has become one among the essential elements in any probabilistic safety assessment (PSA). Detailed and realistic representation of CCF potential in fault tree structure is sometimes very challenging task. This is especially so in the cases where a common cause group involves more than two components. During the last ten years the difficulties associated with this kind of modelling have been overcome to some degree by development of integral PSA tools with high capabilities. Some of them allow for the definition of CCF groups and their automated expanding in the process of Boolean resolution and generation of minimal cutsets. On the other hand, in PSA models developed and run by more traditional tools, CCF-potential had to be modelled in the fault trees explicitly. With explicit CCF modelling, fault trees can grow very large, especially in the cases when they involve CCF groups with three or more members, which can become an issue for the management of fault trees and basic events with traditional non-integral PSA models. For these reasons various simplifications had to be made. Speaking in terms of an overall PSA model, there are also some other issues that need to be considered, such as maintainability and accessibility of the model. In this paper a comparison is made between the two approaches to CCF modelling. It is based on a fault tree from a full-scope Level 1 PSA model for internal events, which had originally been developed by a traditional PSA tool and later, transferred to a new-generation PSA tool with automated CCF modelling capabilities. The aspects and issues described above are discussed in the paper.

Izvorni jezik
Engleski

Znanstvena područja
Elektrotehnika

POVEZANOST RADA