Proceeding of ICAPP07, May 13-18, 2007
A pin power reconstruction method applicable to multigroup problems involving
square fuel assemblies is presented. The method is based on a two-dimensional semi-analytic
nodal solution which consists of eight exponential terms and 13 polynomial terms. The 13
polynomial terms represent the particular solution obtained under the condition of a twodimensional 13 term source expansion. In order to achieve better approximation of the source
distribution, the least square fitting method is employed. The eight exponential terms represent a
part of the analytically obtained homogeneous solution and the eight coefficients are determined
by imposing constraints on the four surface average currents and four corner point fluxes. The
surface average currents determined from a transverse-integrated nodal solution are used directly
whereas the corner point fluxes are determined during the course of the reconstruction by
employing an iterative scheme that would realize the corner point balance condition. The
outgoing current based corner point flux determination scheme is newly introduced. The accuracy
of the proposed method is demonstrated with the L336C5 benchmark problem
