Sensitivity Studies on High-Conversion Power Reactors, via Perturbation Methods and Information Conditioning

The physics of intermediate high-conversion water reactors is strongly influenced by two essentially independent phenomena:

1. a spectral shift associated with the reduced scattering performance of water, which shows an increased participation of ²³⁸U to the neutron slowdown
2. a vanishing of the thermal component of the spectrum, which is due to the huge absorption resonances of plutonium in the epithermal region.

The effects of these physical phenomena on the most important neutronic integral parameters, such as eigenvalue, voiding reactivity, and burnup, are investigated by means of the perturbation theory. A reference group structure adjusted to design requirements is also determined, via pattern recognition methods, and the most important physical trends of the parameters are presented, correlated by sensitivity coefficients and some practical applications.