Title: SINGLE PHASE TURBULENT MIXING BETWEEN ADJACENT CHANNELS IN ROD WIT-NM F

The turbulent interchange of matter between parallel adjacent subchannels in a simulated rod bundle for single phase flow was in-vestigated to determine the effects of mass flow rate and rod spacing. The simulated rod bundle was made by placing six 1-inch diam-eter rods in a square-square array. The overall test section was 42.5 inches in length with a 16-inch entrance section, a 16-inch mixing section and a 10. 5-inch exit section. The test section was built so that several rod spacings could be investigated. Water was used as the fluid for the system and it flowed in the axial direction of the rods. The turbulent mixing was the lateral transport in the test section and was measured by using a dye tracer technique. The technique involved initially tracing one side of the test section and measuring the exit dye concentration for the initially untraced system. This result plus the subchannel mass flow rate was then used in an analytical model to calculate numerically the turbulen