Microstructural aspects of neutron embrittlement of reactor pressure vessel steels - A view from positron annihilation spectroscopy

Hardening and microstructural evolution in A533B steels under high-dose electron irradiation

“…The structure and composition of the precipitates were basically the same as those observed in commercial steels irradiated with neutrons [21,25,[28][29][30][31]. The result that no micorvoid formation occurs under electron irradiation at 290°C is also consistent with the reported results for commercial steels after neutron irradiation at near 300°C [32][33][34]. Table 3 summarizes data for Cu-rich precipitates in steels A and B at 290°C under the present electron irradiation, together with the previous neutron irradiation in which the microstructure was examined using small angle neutron scattering (SANS) measurements and 3DAP analyses.…”

Positron Annihilation Measurements on Nuclear Reactor Pressure Vessel Steels

“…At this moment this can only be attributed to inhomogeneity of the weld material. The comparison of isochronal annealing results on non-irradiated and irradiated steels (e.g., [2,3,8]) can yield valuable information about changes introduced in the steel by radiation damage.…”

Positron Annihilation Characteristics in Perfect and Imperfect Transition Metal Carbides and Nitrides

“…This is beca,use the transition metal carbides are thought to be the irradiation-induced precipitates in reactor pressure vessel steels. Precipitates formed by neutron irradiation have already been studied by PAS [18]. According to Table I the carbide precipitates in Fe could trap positrons and be observable only if they contain metal vacancies because only in that case their affinity to the positron is lower (more negative) than the iron affinity.…”