The early earthquake warning system of the Armenian Nuclear Power Plant

Fridrikh Arakelyan, Hrahat Hakobyan
Atomenergyseismicprojects Institute, Yer. HEPS-2, Razdan Canyon, Yerevan, 375015, Armenia.
Tel. : +374-2 58 06 49, Fax: +374-2 15 18 05

To increase the operation reliability, and prevent secondary effects of earthquakes which may result in significantly more damage and casualties than those caused by the devastation of regular buildings and structures, a system of industrial anti-seismic protection has been created and is in operation at the Armenian Nuclear Power Plant (ANPP). It automatically triggers the appropriate protection means of the ANPP when the ground acceleration exceeds a certain value (margin).

The system has a substantial disadvantage: a signal from a seismic sensor triggers emergency protection at the moment of impact on the plant, which is conditioned by the location of the seismic sensors immediately next to the ANPP site. To eliminate this shortcoming an early earthquake warning system is planned, which is to be organised at the ANPP. The peculiarity of the system consists of the transmission of a seismic signal via radio waves, from registration points located at a certain distance from the plant, to the emergency protection system. Due to the difference in the velocities of seismic and radio waves, the radio waves reach the plant tens of seconds earlier than the seismic waves. This is of crucial importance for the increase in the reliability of the plantís operation, because the start and initial stages of emergency shutdown will take place during the normal phase of operation.