A multi-step approach for evaluation of pipe impact effects

A flexible procedure was developed for evaluation of interactions resulting from postulated high-energy line breaks inside containment. The procedure includes steps of increasing sophistication. It starts with inexpensive energy dissipation assessments for very safe interactions and proceeds to 3-D non-linear dynamic analyses when warranted. The simplest approaches allowed qualification of 80% of interactions at Garona NPP. The implementation of the procedures proposed here, combined with detail safety analyses of the plant, permitted qualifying all resulting interactions without imposing plant design changes