Determining axial fuel-rod power-density profiles from in-core neutron flux measurements

To find the unknown power-density profiles in the fuel rods, given the measured fluxes at various locations through the core, requires inversion of an ill-posed Fredholm integral equation. With numerical quadrature, this integral equation can be converted into a (generally, underdetermined) set of algebraic equations for the power densities at various axial positions in the fuel rods. To solve these underdetermined equations, the linear regularization method is employed. Results are presented for simulated data for a single fuel rod and for multiple rods in various configurations. This preliminary study indicates that in-core flux measurements can indeed be used to infer power-density profiles in reactor fuel rods.