Best Estimate Plus Uncertainty (BEPU) approach and safety margins in nuclear reactor safety

Approaches like Best Estimate Plus Uncertainty (BEPU) and concepts like Safety Margins (SM) are well established in Nuclear Reactor Safety (NRS). However continuous improvements in analytical techniques and in the sophistication of hardware products do not necessarily correspond to new industrial applications within Nuclear Power Plants (NPP) technology. The declining condition for nuclear technology also contributes to the lag between developments and applications definitely causing NPP safety at a level below the achievable level. The possibility to extend BEPU to all areas of the Final Safety Analysis Report (FSAR), so-called BEPU-FSAR is outlined in the paper. This should be combined with the Extension of the SM concept (E-SM). BEPU-FSAR techniques may be at the origin of E-SM which also will need specific monitoring hardware. All of this may open new horizons for NRS and for acceptance of NPP by the public and the decisions makers. The paper describes recent accomplishments in the areas of BEPU and E-SM.