The 4-years European project ATLAS+ (Advanced Structural Integrity Assessment Tools for Safe long Term Operation) has been launched in June 2017. One of its objectives is to study the transferability of material ductile properties from small scale specimens to large scale components and validate some advanced tools for structural integrity assessment.
The study of properties transferability is based on a wide experimental program which includes a full set of fracture experiments conducted on conventional fracture specimens and large scale components (mainly pipes).
Three materials are considered in the program: a ferritic steel WB36 typical from secondary feed water line in German PWR reactors, an aged stainless steel austenitic weld representative of EPR design and a typical VVER austenitic dissimilar weld (DMW).
This paper describes preparation, realization, fractographic expertise and analysis of large scale tests performed on the ferritic steel WB 36 (15NiCuMoNb5). These large scale tests consisted of four point bending tests on piping’s conducted at room temperature. Two configurations of cracks (shape, size and location) were tested. With the first configuration (FP1), with a through wall crack, a large ductile tearing was obtained. For the second configuration (FP2), with an external semi-elliptical crack, cleavage was obtained after a limited ductile tearing.