Naslov
The Large Minimal Cut Sets Compact Representation with Binary Decision Diagrams

Autori
Reni Banov ; Zdenko Šimić

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

Izvornik
HND2022 Conference Proceedings / Vrbanić, Ivan ; Šadek, Siniša ; Trontl, Krešimir - Zagreb : Hrvatsko nuklearno društvo, 2022

ISBN
978-953-48100-3-3

Skup
13th International Conference of the Croatian Nuclear Society

Mjesto i datum
Zadar, Hrvatska, 05.06.2022. - 08.06.2022

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Probabilistic Safety Assessment (PSA), Fault Tree Analysis (FTA), Binary Decision Diagrams (BDD), Minimal Cut Sets (MCS)

Sažetak
As from the beginning of the application of the fault tree analysis in nuclear energetics it became obvious, that a more accurate insight into the reliability of the observed system relies on the understanding of the complete or, at least, the most significant parts of failure sets (minimal cut sets MCSs). However, the determination of MCSs turns out complex even with very simple systems modelled by a coherent fault tree, dealing with at least two basic problems. The first, being the time complexity of algorithms employed for the determination of the complete or partial set of MCSs, while the latter problem relates to a space complexity of the same sets recording. More recently, binary decision diagrams (BDDs) have been developed, enabling indirect recording of fault trees by applying indicator variables for the component failure state within the system. This state is commonly presented by means of the Bernoulli random variable for basic component associated events, i.e., in the way that the component is associated with the probability of the occurrence of a failure event. Such association establishes a link between the logical function presented by a coherent fault tree model and the probabilistic safety assessment (PSA) model. Now, a qualitative and quantitative analysis on a fault tree model may be carried out with BDDs by applying known algorithms for the determination of minimal disjunctive normal form of the logical function presented by the coherent fault tree, which represents the logical recording of a set of minimal cuts. Thus, not only do BDDs show (under the condition of an appropriate variable order) an acceptable time complexity for the implementation of algorithms for determining MCSs but also enable a compact recording of complete or partial sets of MCSs singled out in that way. The exceptional compactness of minimal cut set recordings gained by the BDDs technique makes it possible to ensure the recording of a complete set of MCSs. The accessibility of the complete set of MCSs by means of BDDs allows accurate calculations from a probabilistic model. The results indicate compactness of recordings (mostly 1015 MCSs or more are being recorded), hence, this technique facilitates the recording of MCSs for fault tree models of the most complex events such as core damage, which have been described typically with more than 1000 basic events.

Izvorni jezik
Engleski

Znanstvena područja
Matematika, Elektrotehnika, Računarstvo

POVEZANOST RADA