Effect of grain refinement on cracks occurring in SUS304L stainless steel under nuclear reactor operating conditions

Hirota, Noriaki; Takeda, Ryoma; Ide, Hiroshi; Tsuchiya, Kunihiko; Kobayashi, Yoshinao*

Nuclear Materials and Energy (Internet), 45, p.102009_1 - 402009_10, 2025/12

https://doi.org/10.1016/j.nme.2025.102009

Using SUS304L stainless steel, which is employed in reactor structural components, the effects of grain refinement on stress corrosion cracking occurring under nuclear reactor operating conditions were investigated. As a result, after conducting slow strain rate testing (SSRT) in air and nuclear reactor operating environments, a comparison of the tensile properties of SUS304L with the same grain size revealed that elongation significantly decreased with increasing grain size under nuclear reactor operating conditions. In SSRT conducted in air, the -value obtained from the Hall-Petch relationship was lower than the conventional values. Observations showed the absence of cracks on SUS304L with 0.59 and 1.52 m grains; however, SUS304L with larger grains exhibited rougher fracture surfaces and side cracks. Thin oxide films were formed on SUS304L with 0.59 m and 1.52 m grains, while SUS304L with coarse grains of 28.4 m or larger enabled the formation of oxide films with over 2 m thickness. CrO films were formed on SUS304L with 0.59 m, 1.52 m, and 28.4 m, while CrO and Fe based oxides were formed on SUS304L with 39.5 m and 68.6 m. Crystal orientation analysis revealed linear surface layers without cracks in the -phase for SUS304L with 0.59 m and 1.52 m. In materials with Larger grain sizes, surface irregularities and cracks were observed in the -phase. In fine-grained SUS304L, lattice diffusion caused uniform O diffusion in the -phase, resulting in the formation of a thin CrO layer that suppressed cracks. In coarse-grained SUS304L, grain boundary diffusion caused Fe oxide formation at the grain boundaries, weakening them, and supersaturated O led to the formation of thick films comprising CrO and Fe-based oxides, resulting in peeling and cracking.

Effects of grain size and PCI restraint on the rim structure formation of UO fuels

Une, Katsumi*; Nogita, Kazuhiro*; Suzaka, Yojiro*; Hayashi, Kimio; Ito, Kunio*; Eto, Yoshinori*

International Topical Meeting on Light Water Reactor Fuel Performance, 2, p.775 - 785, 2000/00

no abstracts in English

Density, porosity and grain size, 1; Unirradiated ROX fules

Yanagisawa, Kazuaki; Yamashita, Toshiyuki; Kanazawa, Hiroyuki; Amano, Hidetoshi; Muromura, Tadasumi

Journal of Nuclear Science and Technology, 36(11), p.1052 - 1063, 1999/11

https://doi.org/10.3327/jnst.36.1052

no abstracts in English

Creep rupture properties of a Ni-Cr-W superalloy in air environment

; Tsuji, Hirokazu; Shindo, Masami; Nakajima, Hajime

Journal of Nuclear Materials, 246(2-3), p.196 - 205, 1997/00

https://doi.org/10.1016/S0022-3115(97)00106-2

no abstracts in English

Computation on fuel particle size capable of being regarded as homogeneous in nuclear criticality safety analysis

Okuno, Hiroshi; Naito, Yoshitaka;

Journal of Nuclear Science and Technology, 31(9), p.986 - 995, 1994/09

https://doi.org/10.3327/jnst.31.986

no abstracts in English

Effects of UO fuel grain size on reactivity; Continuous energy Monte Carlo calculations

Sakurai, Y.*; Okuno, Hiroshi; Naito, Yoshitaka

JAERI-M 91-137, 35 Pages, 1991/09

JAERI-M-91-137.pdf:0.88MB

no abstracts in English

Effects of UO-fuel grain size on reactivity; Study by ultra-fine energy group calculations using the computer codes based on the collision probability method

Okuno, Hiroshi;

JAERI-M 91-107, 49 Pages, 1991/08

JAERI-M-91-107.pdf:1.09MB

no abstracts in English

Release behavior of cesium in irradiated(Th,U)O

Akabori, Mitsuo; Fukuda, Kosaku

Journal of Nuclear Materials, 186, p.47 - 53, 1991/00

https://doi.org/10.1016/0022-3115(91)90351-7

no abstracts in English

Preparations for revising the criticality safety handbook of Japan

Okuno, Hiroshi; Komuro, Yuichi; Naito, Yoshitaka

Proc. of the CSNI Specialist Meeting on Safety and Risk Assessment in Fuel Cycle Facilities, p.103 - 109, 1991/00

no abstracts in English

Crushing strength of fuel kernels for high-temperature gas-cooled reactors

Akabori, Mitsuo; Shiba, Koreyuki

Journal of Nuclear Science and Technology, 21(6), p.466 - 475, 1984/00

https://doi.org/10.3327/jnst.21.466

no abstracts in English