Development of Fuel Clad Materials for High Burn-up Operation of LWR

Abstract

Oxide dispersion strengthening (ODS) steels have been considered to be very promising for fuel clad materials for high burn-up operation of light water reactor and super critical water reactor. For improving the corrosion resistance, increasing chromium concentration, which often resulted in degradation of mechanical properties and thermal embrittlement, has been required. In this work, the effects of aluminum addition on the mechanical properties of high chromium ODS steels have been investigated. Various ODS steels which have 14 ∼ 22 wt% Cr concentrations were made by mechanical alloying method. In order to evaluate the mechanical properties and the effect of thermal aging, a miniaturized Charpy V notch test and tensile test were performed before and after aging. 1) The addition of Al resulted in the decrease in anisotropy of tensile properties, although it reduced the tensile stress. 2) The impact properties of 19Cr-ODS steel are improved by the addition of Al.

Effects of neutron irradiation on the tensile properties of high-Cr oxide dispersion strengthened ferritic steels

“…It is well known that the corrosion resistance in high-temperature water diminishes significantly with decreasing chromium concentration below 13% [6][7][8][9][10][11][12]. In order to improve corrosion resistance in super critical pressurized water (SCPW), high-Cr-ODS steels have been developed [7][8][9][10][11][12][13]. However irradiation embrittlement caused by the Fe-Cr phase decomposition under neutron irradiation is a critical issue for high-Cr steels.…”

Oxide Dispersion Strengthened Steels for Advanced Blanket Systems

“…As for the effects of the other alloying elements than Cr, it was also shown that an addition of Al is effective to reduce the weight gain of the ODS steels and the effect becomes significant with decreasing Cr content from 19 to 15 wt.% [47,48]. The estimated corrosion layer thickness as a function of temperature and Al contents is shown in Fig.…”

“…The previous research on the chemical analysis and XRD measurements of the corrosion layer revealed that the layer of Al-free 15Cr-ODS steels consists of three parts, Fe 2 O 3 outer layer, Fe 3 O 4 middle one and (Fe, Cr) 3 O 4 inner one, after the test for 300 h at 510 • C in SCPW dissolved with 8 ppm oxygen [49]. In the Al-added ODS steels, a thin alumina layer was formed at the most inner region of the multi-corrosion layers [47][48][49]. Fig.…”

Corrosion resistance of high-Cr oxide dispersion strengthened ferritic steels in super-critical pressurized water

“…The ODS steels developed for SFR fuel cladding material contain 12% chromium at most. It is well known that the corrosion resistance in high-temperature water reduces significantly with decreasing chromium concentration below 13% [6][7][8][9][10][11][12]. Thus, the most critical issue for the application of ODS steels to the watercooling solid breeder fusion blanket is to improve their corrosion resistance in super critical pressurized water (SCPW) environment.…”

“…In our previous work [7][8][9][10][11][12][13], it was reported that the addition of chromium (>13 wt%) and aluminum (4.5 wt%) to the ODS steels were very effective in suppressing the corrosion in a SCPW (783 K, 25 MPa) environment. Addition of aluminum also improves the Charpy impact property of the high Cr ODS steels.…”