TUF Verification Against Selected RD-14 Experiments

Abstract

The advanced, two-fluid computer code TUF (Two Unequal Fluids) has been developed as part of a study of the effectiveness of Emergency Coolant Injection Systems for Ontario Hydro reactors in the event of a large Loss Of Coolant Accident (LOCA). Three experiments performed in the RD-14 thennal-hydraulics test facility at AECL-WNRE have been simulated as part of a co-ordinated verification program for the TUF code. The experiments were chosen to demonstrate both the capability of the code to capture the underlying two-fluid phenomena and the robustness and accuracy of the solution algorithms employed in the code. The following experiments were simulated: 1) A partial inventory thermosyphoning test conducted at high heated section power and high secondary side pressure. 2) A critical inlet header break with rundown of the main coolant pumps. 3) A critical inlet header break without rundown of the main coolant pumps. The paper presents an analysis of the experimental test results, concentrating on identifying the governing physical phenomena. The results obtained from the simulations of the tests using the TUF code are presented, together with a comparison to the experimental data and an evaluation of the performance of the code.