High-frequency structure of space-dependent neutron fluctuation spectra in a coupled-core reactor

The space dependence of neutron fluctuation spectra in a coupled-core reactor is described in terms of propagation phenomena of neutron diffusion waves from one core to two space points of observation. Analytical expressions for the spectra are derived for a reference reactor approximately representative of a coupled-core Argonaut-type reactor. Numerical calculations are carried out to illustrate the effect of the difference of two-slab core loading and ring core loading. The results of coherence function calculations provide good agreement with experimental measurements up to and including the frequency at which the real part of the cross spectra for two observation points vanishes. (author)