High temperature oxidation of fuel cladding candidate materials in steam–hydrogen environments

Neutronic analysis of candidate accident-tolerant iron alloy cladding concepts

“…This is done by compromising coolability in the core and deposition of a large amount of enthalpy (oxidation) in addition to what is deposited by decay heat [2]. Given this understanding, an international effort is under way to examine alternate fuel cladding concepts that exhibit slower oxidation kinetics in high-temperature steam environments when compared to zirconium alloys [3][4][5].…”

High Temperature Steam Oxidation Testing of Candidate Accident Tolerant Fuel Cladding Materials

“…In contrast to Figure 2, Figure 3 shows higher magnification images of some of the more oxidation-resistant materials at 1200°-1350°C in 3.4 bar steam. Figure 3a and 3b illustrate the slower growth rate of α-Al 2 O 3 (parabolic rate constant of ~3 x 10 -12 g 2 /cm 4 s) compared to Cr 2 O 3 (3 x 10 -10 g 2 /cm 4 s) under these conditions [11]. The E-Brite alloy formed an incomplete layer of SiO 2 at the metal-oxide interface (identified by EPMA), which apparently did not slow the chromia scale growth rate [11].…”

“…Figure 3a and 3b illustrate the slower growth rate of α-Al 2 O 3 (parabolic rate constant of ~3 x 10 -12 g 2 /cm 4 s) compared to Cr 2 O 3 (3 x 10 -10 g 2 /cm 4 s) under these conditions [11]. The E-Brite alloy formed an incomplete layer of SiO 2 at the metal-oxide interface (identified by EPMA), which apparently did not slow the chromia scale growth rate [11]. Figure 3c shows that APMT continued to form a relatively thin Al 2 O 3 external scale even after 8h at 1350°C.…”

“…A broad-based study was begun to identify candidate alloys capable of forming protective thermally-grown oxide scales at temperatures of ≥1200°C for relatively short (<24 h) periods to simulate BDBA conditions. The results of this initial study, which identified the most promising alloy candidates and relevant experimental conditions for screening performance [10][11][12], are briefly described in the next section to provide the motivation for the current work.…”

“…For model binary Fe-Cr alloys, 25%Cr was needed to form a protective Cr 2 O 3 scale at this temperature. At lower Cr contents, the mass gain was greatly increased by the rapid formation of Fe-rich oxide nodules [11]. Ternary Fe-20Cr-Ni alloys illustrated the benefit of higher Ni contents on improving oxidation resistance.…”