The LBB project for the new generation of WWER plants and lessons learned from the WWER 440 model 230 LBB project Original Research Article

As part of the safety enhancement of WWER-type nuclear power plants (NPPs) with model 213 and 320 reactors operated or constructed in the Czech and Slovak Republics, the leak-before-break (LBB) methodology is applied to main circulating pipe and pressuriser surge lines. The typical feature of all these NPPs is the horizontal type steam generator. The resultant effect is that the lengths of all safety significant piping are longer in comparison with standard western PWRs. For this reason the complex dynamical model is used for seismic response assessment performed as part of LBB methodology. In this paper the results of decoupling studies and the new set of experiments concerning both leak rates and accomplished diagnostics measurements are described.