Exploration on Parallel Operation of LOCA Surveillance System in Daya Bay NPP

LOCA Surveillance System（LSS） in Daya Bay NPP is facing the problems of aging parts,unavailable spare parts leading to unstable work and the frequent failures,and the modification and upgrading of the whole LOCAL system is demanded.To verify the basic function and performance of the new system and at the same time to avoid any effect on the normal operation of the old system,the new and old systems of LSS for Unit 2 are operated in parallel in Daya Bay NPP.This paper describes the design solution of the new and old LSS parallel operation,then the required function tests for the parallel operation are conducted to verify the function and performance of the new system.The expected requirement of the parallel operation is satisfied.