relap5–relap3d.ppt

Development of a RELAP5-3D thermal-hydraulic model for a Gas Cooled Fast Reactor D. Castelliti, C. Parisi, G. M. Galassi, N. Cerullo (San Piero A Grado Nuclear Research Group ) DIMNP – University of Pisa - ITALY Contents Introduction ETDR Thermal-Hydraulic Nodalization Main Results Steady State Transient Conclusions Introduction [1/3] GCFR, a Gen IV system developed by a wide international consortium (NNC, CEA, CIRTEN, Framatome, JRC-IE, NRG, PSI, Univ. of Delft, etc.) Huge efforts required for testing materials, component, plants layout Need to have a testing facility ? ETDR Need to have numerical tool and a model for proposed experimental analyses Introduction [2/3] Different features of GCFR system vs. present NPPs technology Helium coolant Direct Brayton cycle Fast Neutron Flux Fuel geometry Introduction [3/3] Proposed ETDR layout as testing facility for GCFR system: Testing start-up and demo cores (different temperatures ranges) Testing fuel and structural materials Analyzing system dynamic behavior Asses Codes Qualification ETDR TH Nodalization [1/2] ETDR TH Nodalization [2/2] Core modeled by two hydraulic channels Average channel Hot channel MULTID component used for MHX for an improved estimation of Heat Transfer Coefficient (HTC not imposed) Blower modeled by PUMP component? use of benchmark homologous curves Heat structures simulated for all components Model qualified according to benchmark data Qualification [1/2] - Volume-Height Curve Qualification [2/2] - Steady State Results LOFA Results [1/7] - Blower Velocity LOFA Results [2/7] - Primary pressure LOFA Results [3/7] - DHR mass flow - helium side LOFA Results [4/7] – DHR mass flow – water side LOFA Results [5/7] - Hot channel Clad temperature LOFA Results [6/7] - Power trend in DHR HX (provided run-down curve) LOFA Results [7/7] Two transient-cases analyzed provided run-down curve calculated run-down curve DHR Valves open in 170 s from LOFA in 1st case, and in 600 s in 2nd case Second