Hybrid analysis of the simplified boiling water reactor using RAMONA-4B and CASMO-3 computer codes

An analysis of the simplified boiling water reactor (SBWR) is carried out u sing the reactor analysis computer program RAMONA-4B in an operational tran sient scenario, a turbine trip with failure of all the bypass valves. The S BWR model represents the vessel's internal components, such as flow areas, diameters, and volumes. The one-quarter-core neutron parameters are calcula ted with the CASMO-3 transport theory lattice physics computer program. The three-dimensional representation of the reactor core uses some standard fu el design parameters, such as a wide central water rod, 8 X 8 lattice, gado linium rods, etc. The thermal-hydraulic equations ape solved with the RAMON A-4B computer program in a closed loop inside the reactor vessel and in 184 parallel channels (including bypass) in the core. Finally, the hue-phase coolant and neutronic parameters are calculated in s teady state and during the turbine trip transient. The results obtained com pare fa vorably with the standard safety analysis report data.