Evaluation of a heat exchanger performance plugged in the RCP facility

In the Pressurized Water Reactor (PWR), Reactor Coolant Pump (RCP) play an important role in the circulation of high flow rate coolant water (10m³/s) from steam generator to the reactor core and back to the steam generator. In order to evaluate the thermal hydraulic performance of the RCP, experiments have been performed in RCP test facility which was constructed in the Korea Atomic Energy Research Institute (KAERI). A heat exchanger was installed to control the loop temperature maintain a prescribed thermal margin. The strong vibration from the pump might affect to the heat exchanger causing some cracks on the surface of welding tubes. Two inspection methods which are Penetration Test (PT) and Eddy Current Test (ECT) have been applied to identify the cracks. The thermal hydraulic performance and vibration effect from the RCP can be analyzed using Computational Fluid Dynamics (CFD). The analysis results are presented in the paper. The evaluation of thermal margin of a heat exchanger was carried out using CFD. The inspection in the RCP test facility showed 25 leakage points from the tube surface by using ET technique. An evaluation of thermal margin of the heat exchanger before and after plugging the leakages as well as vibration analysis were carried out using the CFD. The analysis results showed that the thermal margin difference between initial heat exchanger and leakage plugged heat exchanger is 2.7%. It is acceptable according to the operating conditions. The mitigation of flow induced vibration can be accomplished by well design the tube sheet configuration and alignment.