Development of the Integrated IHX/Pump Component 1/4-Scale Vibration Testing

Abstract

This report summarizes the evaluation method, the development schedule and the result of the test. A conceptual design study of the Japanese sodium-cooled fast reactor (JSFR) is in progress of “Feasibility Study on Commercialized Fast Reactor Cycle Systems.” In this study we have proposed a component which integrated IHX (Intermediate heat exchanger) with primary pump into one vessel (integrated IHX/Pump) as one of advanced concepts for the plant economy. By development this component, the amount of material (steel) of the primary cooling system can be reduced and the maintenance performance of IHX can be improved. In order to confirm its feasibility, it is important to avoid the resonant vibration caused by integrating of the pump into the static IHX and to prevent excessive wear-out of the heat exchange tubes caused by contact with the tube support plates. Therefore, the vibration evaluation method has been developed and a lot of examinations were carried out to confirm the feasibility of this concept. The pump is arranged at the center of the IHX and heat exchange tubes are arranged concentrically. This component consists of the multiple cylindrical layers. Tube support plates are installed and they support the tube bundle with 0.1–0.3mm gaps. The 1/4-scale model was selected for vibration tests. The first step test with an internal vibration exciter which simulated the pump was performed, and the test with the pump installed into IHX was done. This test model has been installed at Takasago R&D center of Mitsubishi Heavy Industries, Ltd. The vibration caused by the pump was measured. As a result of data analysis, the character of frequency response was acquired. The analysis code called as “FINAS” can directly handle the vibration behavior of complex multi-cylinders with fluid between the cylinders. The eigenvalue analysis and response analysis were performed using a detailed model and the results were compared with the test results. Vibration evaluation methods of the integrated IHX/Pump have been studied. The 1/4-scale vibration test was performed and the results were compared with the analysis.

Status of Integrated IHX/Pump Development for JSFR

“…[1][2][3] Causes of tube vibrations are flow induced due to zigzag flow outside of the tubes and the pump vibration that propagates through the structure and the fluid.…”

Electromagnetic Pumps for Main Cooling Systems of Commercialized Sodium-Cooled Fast Reactor

“…So far, two main design countermeasures have been adopted for this problem. 8,9) One is having supports for the IHX and MP arranged on different floors: the lower floor for the IHX and the higher floor for the pumps to isolate pump vibrations from the IHX. The other countermeasure is a gas layer between the pump rotor and IHX tube.…”