An interesting phenomenon is observed when irra­diated alloys are tested at temperatures different from the irradiation temperature. Figure 12 shows total elongation data from cold-worked type 316 stainless steel irradiated to displacement levels of 48-63 dpa in the FFTF, where elongation is plotted
against the increment of the test temperature above the irradiation temperature.2 Although there is significant scatter in the data, the elongations below 1% obtained by test temperatures about 100 °C above the irradiation temperature are cause for concern. This phenomenon has also been observed in higher nickel alloys. The cause of this phenome­non remains elusive, pending further testing with

different holding times at various temperatures before tensile testing. Migration of interstitial solutes to moving dislocations is a candidate mechanism for this phenomenon.