  Based on the earlier proposed mechanism of formation of solute-enriched
clusters in irradiated pressure vessel steels, it has been demonstrated that it
is possible to suppress this process by the method of light alloying of PVS
with a chemical element with specially selected properties such as solubility,
activity, and mobility. It is shown that it is possible to change the thermal
spike molten zone solidification mechanism and suppress the "solute drag"
leading to the formation of solute-enriched clusters. It must be noted that
such a solute-enriched cluster formation mechanism is appropriate for alloying
elements with low solubilities - it fits for B.C.C. steel-metal of PVS, but
does not for the F.C.C. austenitic steels.
