The Nordic PSA Group (NPSAG) has undertaken to develop a piping reliability parameter handbook for use in risk-informed applications that involve the consideration of structural integrity of piping systems. The scope of the handbook is to establish high quality reliability parameters that account for the Nordic and worldwide service experience with safety-related and non-safety-related piping systems in a consistent and realistic manner. The report aims to demonstrate the complete workaround process including modeling approaches.
While the work to develop the handbook was finalised at the beginning of 2010, the planning for its preparation has been underway for fifteen years. An important step towards the handbook development project was the SKI SLAP (SKI LOCA Affected Pipes) database work. This research project started in 1994 and the very first goals was to investigate possibilities for deriving pipe failure rates and rupture probabilities from service experience with piping components in commercial nuclear power plants, as an alternative to probabilistic fracture mechanics.
The SLAP database was handed over to the OECD Nuclear Energy Agency in late 90-ies when the international cooperative effort through the OECD begun to maintain and further develop the event database (called OPDE) which have provided the necessary input to the work with the Reliability Data Handbook for Piping Components in Nordic Nuclear Power Plants (the R-Book).
The first phase of the R-Book project in 2003 was initiated by the stakeholders when it was evident that LOCA frequencies are treated in a non-consistent manner between Nordic NPP utilities.