Comparison of Neutronic and Thermal-Hydraulic Performance of KOMODO, NODAL3, and COBRA for Steady-State Operation of APR1400

The important challenge in preparing nuclear reactor safety parameters is in the coupled neutronic and thermohydraulic calculation since the thermohydraulic parameters of the coolant could affect the neutron flux and power distribution. For this reason, it is necessary to carry out accurate calculations for these two parameters. KOMODO is one of the open-source coupled neutronic and thermal-hydraulic (N/TH) calculation codes, while NODAL3 is an in-house coupled N/TH code owned by BRIN. On the other hand, COBRA-EN has also been widely used for steady-state thermohydraulic calculations and could be used to compare the thermal hydraulics solver performance. The APR1400 reactor core was selected under steady-state conditions, either hot zero power (HZP) or critical hot full power (HFP). The calculated core multiplication factor of our HZP model to the reference data is 100 pcm. The radial and axial power distribution calculated by KOMODO and NODAL3 agree with a maximum of 4.78% difference. For steady-state thermal-hydraulics calculations, there was a difference of 1.84% at maximum between KOMODO and COBRA-EN. The KOMODO, NODAL3, and COBRA-EN codes show consistent neutronic and thermohydraulic performance on the APR1400 steady-state calculation model.