ANALYSIS OF FIRST-HARMONIC EIGENVALUE SEPARATION EXPERIMENTS ON KUCA COUPLED-CORE

The first-harmonic eigenvalue separation, the difference between the f undamental and the first order eigenvalues of the higher harmonic neut ron transport equations, which were measured at the Kyoto University C ritical Assembly (KUCA) has been analyzed. A method was proposed to ca lculate the first order eigenvalue based on the discrete ordinate meth od. The 3-D effect, energy group effect, mesh size effect, and transpo rt effect were investigated. Among these effects, the transport effect was significant and when it was taken into account, the calculated ei genvalue separation approached the measured value on the KUCA coupled- core.