Theoretical investigation of the MTC noise estimate in 1-D homogeneous systems

Paper in proceeding, 2000

Two possible reasons of the MTC underestimation by noise analysis are investigated: the deviation from point-kinetics of the reactor response, and the effect of randomly distributed (both in time and in space) noise sources. The strong deviation of the MTC noise estimate from its actual value is found to be mainly due to the heterogeneous structure of the temperature noise. The spatial heterogeneous temperature noise distribution gives both a smaller (space independent) reactivity effect, and a smaller (space dependent) cross-power spectrum density between neutron and temperature noise, in comparison with homogeneous noise sources, on which the MTC definition relies.