Estimate of Cross Flow in High Temperature Gas-Cooled Reactor Fuel Blocks

Abstract

The effect of cross flow on the main coolant flow was studied at a two block test section on the model scale of 1:1. The cross flow was introduced through a wedge-shaped gap located between the two succeeding fuel blocks mentioned. The gap width varied from 1.85 to 6 mm. The entrance area for the cross flow was modified by the arrangement of blocking pieces around the circumference of the gap. The velocity distribution over the cross section of the fuel blocks and the pressure loss over the gap were measured. The experimental results allow the prediction of the flow reduction in each coolant channel of the fuel block depending on the transverse pressure gradient driving the cross flow.