Within the framework of the safety studies in progress related to the French 900 MWe RPV structural integrity assessment, some recent developments have been proposed about the methodology used for the mechanical analyses of shallow embedded flawslocated under the cladding or in the cladding during a PTS event.A new simplified mechanical method is proposed for the analysis of shallow subclad flaws, based on two-dimensional elastic computations with a specific plasticity correction. The methodology is presented and compared to results obtained by sometwo-dimensional and three-dimensional finite element elastic and elastic-plastic computations. This methodology is validated with these comparisons. Its conservatism is reasonable.Similar work has been conducted related to the shallow flaws located in the first layer of the stainless steel cladding. A new approach is proposed, more realistic and less conservative than methodology previously used for this kind of flaw.
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