PROSIR - Probabilistic Structural Integrity of a Pressurised Water Reactor (PWR) Pressure Vessel, was a round robin exercise with the primary objective to issue some recommendations of best practices when performing probabilistic analysis of a reactor pressure vessel (RPV). Another objective was to try to understand what the key parameters are in this type of approach. Following an NEA CSNI round robin activity proposal, 16 participants from 9 countries (the United States, Japan, Korea with 5 participants, Sweden, Germany, the Czech Republic, Spain, France with 4 participants and the European Commission) were involved in the round robin.
In this report, the PROSIR project is summarised in a structured way and additional remarks are included to emphasise some parts of the project. Also included is a sensitivity analysis, which provides an understanding of the key driving parameters in the analysis and also discusses the effect of the assumed fracture toughness representation within PROSIR. Finally, the report provides some suggestions and recommendations regarding future probabilistic benchmarking.
The results of the probabilistic benchmark evaluations show large differences between participants in certain cases. The reasons for this wide difference are in most cases related to unclear problem definitions, differences in treatment of stresses in K-solutions, and user errors. Some of the biggest differences were provided by participants with the least experience in conducting deterministic and probabilistic fracture mechanics analyses.