Analysis of First-Harmonic Eigenvalue Separation Experiments on KUCA Coupled-Core

Abstract

The first-harmonic eigenvalue separation, the difference between the fundamental and the first order eigen-values of the higher harmonic neutron transport equations, which were measured at the Kyoto University Critical Assembly (KUCA) has been analyzed. A method was proposed to calculate the first order eigenvalue based on the discrete ordinate method. The 3-D effect, energy group effect, mesh size effect, and transport effect were investigated. Among these effects, the transport effect was significant and when it was taken into account, the calculated eigenvalue separation approached the measured value on the KUCA coupled-core.

KEYWORDS:

• first-harmonic eigenvalue separation
• fundamental eigenvalue
• first-order eigenvalue
• discrete ordinate method
• measurement
• KUCA reactor
• coupled-core
• analysis
• three-dimensional effect
• energy group effect
• mesh site effects
• transport effects