Microstructural evolution and mechanical hardening of Cr-coated MDA cladding under high-dose Fe ion irradiation

Mohamad, A. B.; Chen, J.*; Ioka, Ikuo*; Suzuki, Eriko; Kondo, Keietsu; Abe, Yosuke; Yamashita, Shinichiro; Okubo, Nariaki; Nemoto, Yoshiyuki; Okada, Yuji*; et al.

Journal of Nuclear Materials, 625, p.156513_1 - 156513_9, 2026/04

https://doi.org/10.1016/j.jnucmat.2026.156513

Estimation of the oxidation and hydrogen absorption behavior during simulated accidental condition of Zircaloy-4 with Cr coating formed by electrochemical plating

Kawai, Keito*; Nemoto, Yoshiyuki; Fujimura, Yuki; Kondo, Keietsu; Abe, Yosuke; Mohamad, A. B.; Pham, V. H.; Ishikawa, Norito; Ishijima, Yasuhiro; Ioka, Ikuo; et al.

Nihon Genshiryoku Gakkai Wabun Rombunshi (Internet), 24(3), p.82 - 98, 2025/08

https://doi.org/10.3327/taesj.J24.015

An accident tolerant fuel (ATF) cladding, which is more resistant to accidents than the conventional Zircaloy cladding, is under development. One of these claddings is a chromium (Cr)-coated cladding with an outer surface coated with Cr, which is expected to improve the resistance to high-temperature steam oxidation. In this study, electrochemical plating was applied to coat a Cr layer on the cladding outer surface, and its properties under accidental conditions were evaluated. In a loss-of-coolant accident (LOCA), the cladding will burst and both the outer and inner surfaces of the cladding will be oxidized. Thus, as-received Zircaloy-4 and Cr-coated claddings were tested for oxidation in high-temperature steam to investigate differences in oxidation behavior, hydrogen absorption behavior, and mechanical properties after oxidation. Oxidation tests were conducted using a thermobalance. The amount of oxidation of coated samples decreased by half compared with that of uncoated samples, indicating that the coating was effective in inhibiting oxidation. However, the hydrogen absorption of coated samples was found to be higher than that of uncoated samples. In this paper, we discuss the mechanism behind this difference in hydrogen absorption and its effect on mechanical properties.

On-going R&D program at JAEA on the accident tolerant fuels

Mohamad, A. B.; Soma, Yasutaka; Nemoto, Yoshiyuki; Abe, Yosuke; Ioka, Ikuo; Sato, Tomonori; Ishijima, Yasuhiro; Miwa, Shuhei; Nakajima, Kunihisa; Yamashita, Shinichiro; et al.

Proceedings of TopFuel 2024 (Internet), 8 Pages, 2024/10

Microstructural evolution of intermetallic phase precipitates in Cr-coated zirconium alloy cladding in high-temperature steam oxidation up to 1400C

Mohamad, A. B.; Nemoto, Yoshiyuki; Furumoto, Kenichiro*; Okada, Yuji*; Sato, Daiki*

Corrosion Science, 224, p.111540_1 - 111540_15, 2023/11

https://doi.org/10.1016/j.corsci.2023.111540

High-throughput experiments on Cr-rich particle formation in Fe-Cr-Al alloys using combinatorial samples with continuous concentration gradients

Abe, Yosuke; Mohamad, A. B.; Sasaki, Taisuke*; Yamashita, Shinichiro; Okubo, Nariaki; Ukai, Shigeharu

no journal, , 

Embrittlement due to the formation of Cr-rich embrittlement phases ( particles) is a concern in Fe-Cr-Al (ODS) alloys being developed as accident tolerant fuel cladding for light water reactors, but the compositional range of Cr and Al in which embrittlement occurs has not been determined. In this study, combinatorial samples with continuous concentration gradients were prepared by interdiffusion heat treatment of Fe-Cr-Al alloys, and high-throughput composition and hardness measurements were performed before and after thermal aging. The compositional range obtained was sufficient to determine the precipitation boundaries of the particles. Solid solution strengthening was studied from the hardness data after diffusion heat treatment, suggesting that slow cooling leads to spinodal decomposition and formation of Al precipitates. The precipitation boundary of particles was refined from the hardness data after thermal aging.

None

Ioka, Ikuo*; Mohamad, A. B.; Nemoto, Yoshiyuki; Yamashita, Shinichiro; Sato, Daiki*; Okada, Yuji*

no journal, , 

no abstracts in English

Study on coating technic to enhance accident tolerance of fuel cladding, 1; Overview of accident tolerant coating technic studies and apparatus development in JAEA

Yamashita, Shinichiro; Mohamad, A. B.; Nemoto, Yoshiyuki; Soma, Yasutaka; Ishijima, Yasuhiro; Sato, Tomonori; Ioka, Ikuo; Pham, V. H.; Miwa, Shuhei; Nakajima, Kunihisa; et al.

no journal, , 

JAEA is conducting research on various coating technologies for fuel cladding tubes aimed at improving accident resistance. In the lecture, we will introduce new equipment development at JAEA aimed at using these studies in addition to an overview of the entire project.

The Behavior of Cr-coated Zry cladding above the eutectic temperature

Mohamad, A. B.; Nemoto, Yoshiyuki; Furumoto, Kenichiro*; Okada, Yuji*; Sato, Daiki*

no journal, , 

Status of development and overview of R&D in Japan

Mohamad, A. B.; Yamashita, Shinichiro; Soma, Yasutaka; Nemoto, Yoshiyuki; Pham, V. H.; Abe, Yosuke; Ioka, Ikuo; Sato, Tomonori; Ishijima, Yasuhiro; Miwa, Shuhei; et al.

no journal, , 

High-throughput nanoindentation mapping of Alpha-Prime precipitates in ion-irradiated combinatorial FeCrAl alloys

Ukai, Shigeharu; Abe, Yosuke; Geng, D.*; Kubo, Atsushi; Sasaki, Taisuke*; Mohamad, A. B.; Fujita, Yohei*; Okubo, Nariaki; Yamashita, Shinichiro; Yu, H.*; et al.

no journal, , 

A combinatorial specimen with a continuous compositional gradient of Cr and Al in FeCrAl alloys was fabricated, and by integrating an ion irradiation with continuous stiffness nanoindentation measurement, high-throughput dataset was created. It was clarified for the first time, that alpha-prime precipitation occurs within subtle two-dimensional (Cr, Al) composition; about 5 at.% Al addition accelerates alpha-prime formation, and spinodal decomposition becomes dominant at more than 30 at.% Cr. It was also clarified that alpha-prime precipitation reaches saturation at an irradiation dose as low as 1.44 dpa (0.64 dpa).