Development of Flow Identification Technology for the PGSFR Thermal Fluidic Design Validation

Various experimental programs were selected for the validation of the thermal fluidic design of the PGSFR reactor system and design codes as the results of the PIRT. Among them, this study includes a core subchannel flow experiment, a reactor flow distribution test and an IHX flow characteristic test. For the assessment of the thermal margin of the core design, several essential physical parameters were identified as a result of PIRT, which are a friction coefficient, mixing factor, and pressure drop. These were considered as important parameters having significant uncertainties in the model and correlations of the core thermal design code. To identify the core subchannel flow rate and mixing characteristic, an iso-kinetic method, a wire mesh and a LIF technique were developed and optimized for the purpose of our experiment. The experimental database for the core inlet flow and outlet pressure distribution are also important for the evaluation of the core thermal margin especially for an evaluation of the clad thermal stress related to the creep. The pool side flow distribution including the pressure drop of the major flow path of the PHTS is important for the validation of the fluidic design of the reactor. The PHTS of the prototype plant was reduced to a 1/5 length scale at our test facilities with a preservation of the internal structures affecting the flow characteristics. Experimental techniques for the identification of the flow including the fuel assembly-wise inlet flow rate and outlet pressure were developed. To validate the pressure drop correlations used in the computational code for the IHX design, a test facility was designed for the flow characteristics of the shell side of the IHX with a proper scaling approach. In this paper, a brief experimental technology and facilities design for each experiment were described. The experimental database constructed in the current work will contribute to acquiring the license of the core thermal and reactor fluidic design of the PGSFR. (author)