An assessment of TRAC-PD2 refill calculations based on Creare countercurrent flow tests

An important step in computer code development is the assessment of code capabilities through comparison of calculated results with experimental data A number of Creare countercurrent flow tests were simulated with the Transient Reactor Analysis Code (TRAC)-PD2 code to assess the emergency core coolant (ECC) lower plenum penetration and refill predictive capabilities. The tests examined in this study indicate a prediction of complete bypass and delivery at countercurrent steam flows where these phenomena occurred experimentally. Steam flows leading to partial delivery experimentally did not always lead to partial delivery in the calculations, however. A number of parameters can potentially effect TRAC refill calculations. Sensitivity studies indicate the TRAC results are most sensitive to droplet Weber number variations that affect interfacial shear and heat transfer rates. The condensation model also affects calculations with subcooled ECC liquid