[en] Fracture of flawed heavy section steel stuctures such as LWR pressure vessels is generally preceded by considerable plastic deformation ahead of the crack tip, thus reguiring application of elastic plastic fracture mechanics (EPFM) concepts. This holds in particular for areas with high nominal stress and strain where yielding may occur even in the absence of flaws, e.g. nozzle corner regions. One such EPFM concept is the J-integral concept, currently arousing considerable interest maninly because of its potential to yield a fracture toughness characterizing parameter from small specimen tests. However, studies aimed at verification of the applicability of this concept to actual structures are very scarce. The present study is aimed at such a verification by a combined theoretical and experimental approach for the case of through-cracks emanating from a hole in a plate. (Auth.)