Overview of the CAP1400 Reactor Hydraulic Simulation Tests

CAP1400 is the trademark of a newly designed, by Shanghai Nuclear Engineering Research and Design Institute, third generation passive PWR. To verify the hydraulic functions and to optimize the design of the CAP1400 reactor-internals, a series of simulation tests was conducted including the use a 1/6 scale replica of the CAP1400 reactor-internal model and several special-purpose models. This paper describes the design of the test models, the test setups, the results and the major conclusions from the various simulation tests. There are four major simulation tests, namely, a) the reactor-internal hydraulic test and b) the mixing test c) the flow path visualization test and d) the bypass flow tests. From these tests, the various hydraulic parameters of the CAP1400 reactor-internal design were obtained — including the pressure drop across the various flow paths inside the pressure vessel, the comparison of core inlet flow distribution with different flow distribution devices, the mixing factor between the two primary loops, the flow paths inside the pressure vessel and the flow characteristics, such as the resistance, of the bypass channels. The results of these tests were not only useful in understanding the hydraulic characteristics of the CAP1400 design and provided the bases for design optimization and future safety evaluations, but also the evidence that CAP1400 is a superior design.