Today, BWRs with 64 fuel rods per fuel assembly have an
average power density of about 55 kW/L. Using the parameters supplied in
Exercise 14.4, calculate how much the power density would change if the outer
diameter of the fuel rods was shrunk to 10.26 mm and the rod pitch was
reduced to 12.95. How much must the ow rate be changed so that the power-to-ow
ratio in the core remains the same? Assume that the enrichment of the fuel rods
remains the same.
Today, most BWRs use 8 × 8 fuel assemblies where the fuel
rods have an outer diameter of 11.20 mm and a rod pitch of 14.37 mm.
Suppose that the outer diameter of the fuel rods is shrunk to 10.26 mm and
the rod pitch is reduced to 12.95 so that a fuel assembly can now accommodate
100 fuel rods in a 10 × 10 array. If the enrichment of the new fuel rods
remains the same, how does this affect the overall power density of the core?