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.

Modeling of the P2M past fuel melting experiments with the FEMAXI-8 code

Mohamad, A. B.; Udagawa, Yutaka

Nuclear Technology, 210(2), p.245 - 260, 2024/02

https://doi.org/10.1080/00295450.2023.2185061

Chemical interaction between Sr vapor species and nuclear reactor core structure

Mohamad, A. B.; Nakajima, Kunihisa; Miwa, Shuhei; Osaka, Masahiko

Journal of Nuclear Science and Technology, 60(3), p.215 - 222, 2023/03

https://doi.org/10.1080/00223131.2022.2092227

Fundamental research program on zircalloy with accident tolerance

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

no journal, , 

Japan Atomic Energy Agency (JAEA) has launched fundamental researches on zircalloy with accident tolerance since 2019. The main purposes of the fundamental researches are to deepen the understanding of the zircalloy behavior under long-term normal operation or Loss of Coolant Accident (LOCA), beyond design basis accident (B-DBA) and severe accident (SA) conditions, and to support the implementation of Cr-coated zircalloy which is being developed by Japanese vendor. JAEA has also been conducted basic technology developments which is necessary for the understanding of the behavior of accident tolerant coated-zircalloy under normal operation, LOCA, B-DBA and SA conditions. For example, the ion irradiation technique combined with light water reactor (LWR) coolant conditions is being developed to simulate the normal operation condition. In addition, to understand LOCA phenomena, the results obtained from the LOCA test are implemented in the machine learning to understand in more detail the cladding fracture and ballooning. Furthermore, a separate effect test, such as the high temperature oxidation test, is also carried out. The fission product release during the B-DBA and SA are also included in the research program. The research results obtained by using these basic technologies will be integrated and implemented into the fuel performance analysis code to predict the fuel performance under reactor operating conditions.

Updating fission product chemistry database based on recent investigation in Fukushima-Daiichi Nuclear Power Station, 1; Overview of fundamental study related to fission product chemistry

Miwa, Shuhei; Nakajima, Kunihisa; Karasawa, Hidetoshi; Rizaal, M.; Luu, V. N.; Mohamad, A. B.

no journal, , 

no abstracts in English

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.

Technical basis development for the introduction of ATF cladding materials into existing light water reactors

Mohamad, A. B.; Chen, J.*; Ioka, Ikuo; Yamashita, Shinichiro

no journal, , 

no abstracts in English

The Transition of protective coating to no-longer protective coating of Cr-coated Zry cladding in high temperature steam oxidation

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

no journal, , 

Study on coating technic to enhance accident tolerance of fuel cladding, 2-1; Overview of accident tolerant coating technic studies and apparatus development in JAEA

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

no journal, , 

JAEA is promoting the characterization of various coating tubes as part of fundamental research that contributes to the practical application of coated fuel cladding aiming at improving accident tolerance. In this presentation, overall outline, the new test equipment under construction, and highlight results of the vapor oxidation characteristic evaluation test for coated claddings will be presented.

None

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

no journal, , 

no abstracts in English