Coupling of SPACE and ASTRA for Transient Analysis based on 3-Dimensional Core Simulation

In this paper, ASTRA-SPACE coupling method and test analysis results are described. Thermal-hydraulics safety analysis codes, currently used for plant transient calculation, apply point-kinetics model to its core simulation. Because point-kinetics model has the fundamental limitation of asymmetry core simulation, additional conservative assumption makes up for its limitations. However it would predict the more adverse consequences than the phenomena in the real reactor system during transient. For this purpose, the best-estimate neutron kinetics code ASTRA and the best-estimate nuclear system analysis code SPACE have been incorporated to provide a best-estimate coupled code system for performing plant transient, especially asymmetric core transient, calculation. The best-estimate neutron kinetics code ASTRA and the best-estimate nuclear system analysis code SPACE have been coupled for performing plant transient, especially asymmetric core transient, calculation. Because of the limitation of the number of channel model of SPACE and the efficiency of calculation, core node grouping has been introduced. CEAE including node grouping sensitivity, BCEAW and MSLB test analysis have been simulated with the coupled code. In conclusion, ASTRA-SPACE coupled code shows reasonable system and core behavior during transient simulation. In near future, the validation of the coupled code using MSLB benchmark problem should be conducted and its analysis methodology also will be developed.