Verification of design characteristics of the RBMK-1500 accident confinement system Original Research Article

The reactors of the Ignalina nuclear power plant (NPP) are protected by a pressure suppression type containment which because of its specialized nature is referred to as the accident confinement system (ACS). It differs from the standard pressure suppression containments in several respects. The differences include: not all of the primary cooling circuit is enclosed; it is made up of a number of semi-interconnected compartments; it utilizes ten separate pools of water for steam condensation; and it includes a clean air venting system. The first three features are similar to the confinement system used in the VVER-440/Mod213 Soviet built PWRs; the last feature seems to be unique. Other unique aspects, at least in the Western context, are the very sparse and incomplete documentation of the design characteristics of this system and the lack of analytical verification of the ACS effectiveness. The present paper provides an overview of design data regarding the ACS of the RBMK-1500 NPPs located at Ignalina, Lithuania.