In a hypothetical reactor an orificing scheme is sought such that the core is divided into two zones. Each zone produces one-half of the total reactor power. However, zone 1 contains 100 assemblies, whereas zone 2 contains 80 assemblies. It is desired to obtain equal average temperature rises in the two zones. Therefore, the flow in the assemblies of lower power production is to be constricted by the use of orificing blocks, as shown in Figure 3.1. Assume negligible pressure losses in all parts of the fuel assemblies other than the fuel rod bundle and the orifice block. The flow in all the assemblies may be assumed fully turbulent. All coolant channels have smooth surfaces