CKTI-Vibroseism (CVS) has proposed a new approach in evaluation of a safety state of nuclear power plants (NPPs) subjected to seismic or other extreme dynamic events of a natural and malevolent origin. The approach is named as RTSS (Real Time Safety System) and uses state of the art practice in a safety and structural mechanical analysis of NPP’s structures, systems and components. The RTSS proposal was formulated first time in August 2010 at the IAEA EBP/ISSC meeting in Vienna.

The initiation point for developing of RTSS were lessons learned from Kashiwazaki-Karima NPP seismic event happened on July 17, 2007 when losses due to a shutdown of all 7 Units of the plant has achieved several billions dollars. To mitigate such negative consequences RTSS allows to make a fast real time risk analysis of structures, systems and components included in a safe shutdown equipment list (SSEL) using actual time history external event’s input.

RTSS allows providing for operator an actual safety state of the main structures, systems and individual components in terms of probability of failure of safety systems, core damage or radiation release probability. Using RTSS operator will obtain comprehensive data to make a weighted and cost effective decision concerning shut down of the plant or to extend plant’s operation during and after impact. RTSS has some essential technical advantages in comparison with usual NPP’s seismic safe shutdown systems based on peak acceleration, cumulative absolute velocity (CAV) or other damage indicating parameters (DIPs). RTSS gives an opportunity to prevent enormous losses due to unjustified shutdown of the plants subjected to external events of different origins.