Ignalina accident localisation system response to maximum design basis accident

Abstract

In this paper the study of the accident localisation system (ALS) of the Ignalina nuclear power plant (NPP) with RBMK-1500 reactors (large-power channel-type crater-cooled graphite-moderated reactor) wih regard to a maximum design basis accident (MDBA) is presented. The MDBA for Ignalina NPP constitutes a guillotine rupture of the maximum diameter pipe. The thermal-hydraulic and structural analyses were performed using the RELAP5, CONTAIN and ALGOR codes. The coolant mass and energy discharge source terms to the accident compartment were established using the RELAP5 code. This was then used as a source term for the long-term accident thermal-hydraulic analysis of ALS compartments employing the CONTAIN code. Results obtained by the CONTAIN calculations establish a basis for the structural analysis. A finite-element method has been used for ALS structural analysis using the ALGOR code, the results of which show that the structures of the ALS would not be breached by the pressure attained in the event of an MDBA.