SCORPIO - VVER core surveillance system

The Institutt for energiteknikk has developed the core surveillance system SCORPIO. The SCORPIO system represents a practical tool for reactor operators, which can increase the quality and quantity of information presented on core status and dynamic behaviour. This leads to an improved plant safety, as undesired core conditions are detected in an early stage and can be more easily prevented. More flexible and efficient plant operation is made possible. The system has been originally implemented on western PWRs, but since the basic concept is applicable to a wide range of reactors including VVERs a VVER version of SCORPIO has been developed and implemented in cooperation with the Nuclear Research Institute, SKODA JS a.s., CHEMCOMEX Praha a.s. and Dukovany NPP. The main differences between VVERs and typical western PWRs with respect to core surveillance requirements are outlined. The first system SCORPIO-VVER has been implemented at Dukovany NPP, where after the installation, the Site Acceptance Tests and trial operation it received a license issued by Czech nuclear regulatory SONS on September 2, 1999 for use as a Technical Specification Surveillance tool replacing the original Russian VK3 system. New approach and set of Technical Specifications is also in use at the Dukovany Plant. SCORPIO-VVER system is under operation on three Dukovany NPP Units and to be implemented on the last unit in April/May 2000. (author)