The Thermal Hydraulic Test of the MEGAPIE Cooling System and System Code Validation

The MEGAPIE project undertaking in Paul Scherrer Institute (PSI) aims at design, building, operating and decommissioning a 1 MW liquid-metal spallation target. The design and manufacturing phases are almost finished. The target and the required ancillary systems were installed on a test facility called MEGAPIE Integral Test Stand (MITS). The cooling system is among the ancillary systems being tested. A series of thermal hydraulic tests were conducted for testing the main functions of the cooling system. These tests were focused on obtaining data about the system's stability, cooling capacity, and the transient responses. The consistency of the data was checked by comparing the heat balance between the input and output power of each heat exchanger (HEX) in the system. The main flow in the target can only be determined by the thermal balance because the built in flow meter did not work properly. The steady state pump speed, flow rates, and overall heat transfer coefficients (OHTC) of the whole cooling system were measured and analyzed for characterization of the system. Those results were used to refine numerical model of the system. A special version of RELAP5/Mod3.2.2 implemented with the fluid properties of LBE was used for the simulation study. Twomore » cases of 'beam trip' transients were simulated and compared with test results. The agreements were good in both cases and the main features of the transients were captured by the RELAP5. This was the first step of validating RELAP5 model. (authors)« less