  Mechanism of solute-enriched clusters formation in neutron-irradiated
pressure vessel steels is proposed and developed in case of Fe-Cu model alloys.
We show that the obtained results are in a good agreement with available
experimental data on the parameters of clusters enriched with the alloying
elements. The suggested solute-drag mechanism is analogous to the well-known
zone-refining process. Our model explains why the formation of solute-enriched
clusters does not happen in austenitic stainless steels with fcc lattice
structure. It also allows to quantify the method of evaluation of neutron
irradiation dose for the process of RPV steels hardening.
