VERIFICATION OF DESIGN CHARACTERISTICS OF THE RBMK-1500 ACCIDENT CONFINEMENT SYSTEM

The reactors of the Ignalina nuclear power plant (NPP) are protected b y a pressure suppression type containment which because of its special ized nature is referred to as the accident confinement system (ACS). I t differs from the standard pressure suppression containments in sever al respects. The differences include: not all of the primary cooling c ircuit is enclosed; it is made up of a number of semi-interconnected c ompartments; it utilizes ten separate pools of water for steam condens ation; and it includes a clean air venting system. The first three fea tures are similar to the confinement system used in the WER-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 inco mplete documentation of the design characteristics of this system and the lack of analytical verification of the ACS effectiveness. The pres ent paper provides an overview of design data regarding the ACS of the RBMK-I500 NPPs located at Ignalina, Lithuania.