Microstructural and microchemical comparisons of AISI 316 irradiated in HFIR and EBR-II

Effects of helium content of microstructural development in Type 316 stainless steel under neutron irradiation

“…At 600 to 640°C virtually no evidence of RIS was found oyer the fluence range of 10 to 47 dpa. The compositions of n and Laves found after 47 dpa at 530 to 555°C agreed very well with simi lar data from a duplicate specimen examined by Brager and Garner, 227 as did our respective broad-beam-averaged compositional measurements. However, their observations of G phase were not confirmed in the present work.…”

“…It is also stated that "microchemical evolution" was not much affected by increased helium generation, and should therefore be similar for fusion and FBR irradiations of type 316 stainless steel. 36 ' 37 ' 227 How ever, analysis of the same data by Maziasz 319 He found that endotheraic solutions would mix more easily and exothermic solutions would resist mixing, compared to ideal solutions. Diffusion to create compositional gradients, as in spinodal decomposition, can occur if the nonideality is sufficient to make the diffusion coefficient negative.…”

Microchemical and microstructural evolution of AISI 304 stainless steel irradiated in EBR-II at PWR-relevant dpa rates

“…Second phase precipitation -There is extensive literature on t he formation of second phase precipitates (Ni 3 Si, phosphides, G-phase, carbides) in irradiated stainless steels [52][53][54][55][56][57]. In particular, γ' (Ni 3 Si) precipitates and G phase have been shown to be stable only in the presence of irradiation [58][59][60][61].…”

Neutron irradiation effects in fusion or spallation structural materials: Some recent insights related to neutron spectra

“…The slower tendency in fusion spectra to increase Mn content by (n,p) and (n,Zn) reactions was also thought to be of no real consequence. The formation in HFIR of small amounts of V from Cr in stainless steels was found by Brager and Garner [47] to be balanced by segregation of the V into various carbide phases that form in irradiated steel, once again demonstrating the role of segregation. Therefore, it has been generally assumed that stainless steels are not directly sensitive to V and Mn solid transmutants, although such a conclusion is only strictly applicable to void swelling and not to other possible damage mechanisms.…”

“…The fracture mode is intergranular in nature for the depth of one grain and transgranular beyond one grain depth [43]. in fast reactor spectra and were of only minor consequence in highly thermalized reactor spectra [46,47]. The near-total loss of the minor alloying element Mn by (n,r) reactions in HFIR was thought not to affect void swelling, although the conclusion was actually based on the behavior of a range of Mn-modified variants of 316 steel studied in the EBR-I1 fast reactor [46].…”