Probabilistic safety goals. Phase 2 status report

Jan-Erik Holmberg, Kim Björkman, Jukka Rossi, Michael Knochenhauer, Xuhong He, Anders Persson, Helena Gustavsson

    Research output: Book/ReportReport


    The second phase of the project, the outcome of which is described in this pro-ject report has mainly dealt with four issues: Consistency in the usage of safety goals, Criteria for assessment of results from PSA level 2, Overview of international safety goals and experiences from their use, Safety goals related to other man-made risks in society. Consistency in judgement over time has been perceived to be one of the main problems in the usage of safety goals. Safety goals defined in the 80ies were met in the beginning with PSA:s performed to the standards of that time, i.e., by PSA:s that were quite limited in scope and level of detail compared to today’s state of the art. This issue was investigated by performing a comparative review was performed of three generations of the same PSA, focusing on the impact from changes over time in component failure data, IE frequency, and modelling of the plant, including plant changes and changes in success criteria. It proved to be very time-consuming and in some cases next to impossible to correctly identify the basic causes for changes in PSA results. A multitude of different sub-causes turned out to combined and difficult to differentiate. Thus, rigorous book-keeping is needed in order to keep track of how and why PSA results change. This is es-pecially important in order to differentiate “real” differences due to plant changes and updated component and IE data from differences that are due to general PSA development (scope, level of detail, modelling issues).
    Original languageEnglish
    PublisherNordic Nuclear Safety Research NKS
    Number of pages46
    ISBN (Print)978-87-7893-238-9
    Publication statusPublished - 2008
    MoE publication typeD4 Published development or research report or study

    Publication series

    SeriesNKS Reports


    • Safety Goals
    • PSA
    • Safety Targets
    • ALARP
    • Decision criteria
    • Risk informed decision making


    Dive into the research topics of 'Probabilistic safety goals. Phase 2 status report'. Together they form a unique fingerprint.

    Cite this