[en] Irradiation may induce substantial evolution in mechanical behaviour of steels, these evolutions being favourable or unfavourable, depending on the phenomena considered and on the type of mechanical damage. Effects of irradiation are listed as well as their influence on the mechanical behaviour of the stainless steel to be considered for the internals of PWRs. Considering all the possible effects, it can be shown that loss of ductility is a major one. We have proposed to study on a practical case the possible damaging modes that may be due to this reduction in allowable strain. In the particular geometry of a screw, submitted to an axial load, it is shown that failure by loss of ductility must be envisioned but only in the core, and for strain controlled loadings. (orig.)