Verification and validation

The KORSAR code verification (validation) is a sort of iterative process that includes three levels:

• separate effect validation for verifying the closure relations of the thermal-hydraulic model and demonstrating the code capability to properly represent individual physical phenomena;
• integral validation – comparison of the code results with experimental data obtained from integral thermal-hydraulic test facilities;
• code validation based on results of tests performed in actual NPPs.

The table below illustrates the amount of separate effect validation that is carried out before the release of each code version; validation results are incorporated into a verification report required for recertification of the code by Rostechnadzor.

Effect	Parameter range	Number of experiments
Interphase friction	D = 0.02 – 0.3 m P = 0.1 – 18.0 MPa  jv = 0 – 60 m/s	41
Friction loss in pipelines	D = 0.008 – 0.2 m P = 0.1 – 20.0 MPa  ro*w = 100.0 – 2500 kg/(m2s) Х = 0 – 1.0	75
Interfacial heat transfer	D = 0.01 – 0.3 m P = 0.1 – 12.3 MPa  Х = – 0.17 – 0.008	82
Wall heat transfer	D = 0.007 – 0.02 m P = 0.1 – 15.0 MPa ro*w = 30.0 – 2100 kg/(m2s) q = 0.06 – 2.2 MV/m2 Х = – 0.2 ¸ 1.5	183

The KORSAR verification and validation process is described in detail in [1, 6, 7, 8].