Implementation of computation codes dedicated to the thermohydraulics analyses of the safety related system in Cernavoda NPP

The thermohydraulics deterministic analyses of the normal and abnormal transient regimes in nuclear power plants circuits required the application of dedicated computation codes. Among these codes one mentions Modular Modelling System, Mms, for thermohydraulic analyses and Pipe Network, Pantopan, for hydraulics analyses. Simulation of the operational transient and accidental regimes in NPPs is necessary to prevent occurrence of any accidental variation in the analyzed system which could endanger the NPP. The thermohydraulics analyses are performed in subsystems, systems, or the NPP as a whole depending on the development necessities required by design. Among the systems which have been already analyzed one mentions the feedwater system for the steam generators, the main condensate system, the system for storage and water purification in the spent fuel basins, the system of local air coolants, and the system of condensate supplement. The results of the hydraulics and thermohydraulics analyses were compared with the values known from Cernavoda NPP Unit 1 operation up to date, with the data of the systems performances and with the data from the Commissioning Report of Unit 1. In this paper one presents several results in some fields of application of these codes