Two irradiation experiments have been undertaken in OSIRIS (Saclay) and SILOE (Grenoble) reactors, in order to establish the correlation between the embrittlement of pressure vessel steels and neutron spectrum. Target fluence is 0.1 dpa for both experiments. This damage fluence corresponds to a fluence of 7.5 1019 n.cm−2 E>1 MeV (7.5 1015 n.m−2) in the case of a well moderated light water spectrum, but only 4 5 1019 n.cm−2 in the case of the specially designed SILOE irradiation location. One irradiation run is now completed, the second one is underway. This paper presents the experimental dosimetry data and irradiation parameters obtained in the preliminary qualification program, needed to assess this damage correlation.