The Start-up Test of Mechanical Sodium Pump installed in STELLA-1

Testing at the high temperature sodium environments is more expensive and time consuming because of difficulties of operating and maintaining of sodium experimental facilities. Consequent upon those problems, water is often selected as a surrogate test fluid because its important hydraulic properties such as a density and a kinematic viscosity are not only very similar to that of the sodium but also it is cheap, easily available and easy to handle. SFR NSSS System Design Division of Korea Atomic Energy Research Institute (KAERI) is performing a development and demonstration of sodium technology using various sodium experimental facilities, especially STELLA-1. STELLA-1 (Sodium inTegral Effect test Loop for safety simuLation and Assessment) is a large-scale separated effect test facility for demonstrating the thermal-hydraulic performances of major components such as a Sodium-to-Sodium heat exchanger (DHX), Sodium-to-Air heat exchanger (AHX) of the decay heat removal system, and mechanical sodium pump of the primary heat transport system (PHTS). The result of start-up test, most of the instruments and components except for flow control valve are functionally work. Also, we confirmed that performance test of mechanical sodium pump is unable at the high flow rate with lower RPM because pressure drops of pump performance test loop are bigger than the pump head of some cases. To confirm the safety and operability of major components in the sodium-cooled fast reactor (SFR), demonstration of component performance should be carried out before its installation in reactor. So, in order to estimate the hydraulic behavior of the mechanical sodium pump, the performance tests of the model pump with water environment was carried out using a pump vender's experimental facility. Also, to compare the hydraulic characteristic of model pump with water and sodium, the performance test of model pump with sodium environment were performed using STELLA-1. The present paper describes start-up test procedure and results of mechanical sodium pump with sodium environment. There is no experience of operating of mechanical pump with sodium environment in domesticity. So, there are many trial and errors for start-up test of the mechanical sodium pump at rated RPM. The start-up test of mechanical sodium pump with sodium was successfully performed