Hydrogen permeation rate of coating zirconium hydride moderator—A prediction model

Abstract

A prediction model for hydrogen loss rate (HLR) of coating zirconium hydride at 873 K based on Wagner's model was established using gas chromatograph.A continuous and dense coating of zirconium hydride with bilayer structure was prepared by phosphation-oxidation method. The oxidation weight gain of coating zirconium hydride specimens at 873 K in a mixture atmosphere of CO 2 and He was investigated. The oxidation weight gain law was obtained by fitting Wagner's model, and the release equation of CO were further deduced.The concentration of H 2 and CO in the gas phase was measured by gas chromatograph in the closed system under the same conditions. The optimized HLR of coating zirconium hydride was obtained by deducting the amount of CO generated by the reaction of zirconium and CO 2 using the release equation of CO. Fitted by Wagner's model, the dependence between optimized HLR and reaction time was obtained, and the loss amount of hydrogen at any moment can be calculated by extrapolated and integrated, thus a prediction model was established. Based on the model, the HLR of coating zirconium hydride is 0.97% in 1 year. Highlights• A prediction model for hydrogen loss rate of coating ZrH x at 873 K was

Hydrogen Permeation Behavior of Zirconium Nitride Film on Zirconium Hydride

“…To study the hydrogen permeation behavior, the following three methods were employed: (1) permeation reduction factor (PRF) [11]; (2) vacuum thermal dehydrogenation (VTD) [20]; (3) hydrogen permeation rate (HPR) [22]. Hydrogen permeation behavior of nitride film samples prepared in nitrogen atmosphere at 800 • C was studied, and was compared with that of oxide film manufactured by in situ reaction with CO 2 [18].…”

“…Reactions that may occur during the measurement are as follows: During the experiment, the content of H 2 , CO, and CO 2 in the system were measured by gas chromatography every day, and the content of H 2 and CO were used to calculate the HPR. Details of the equipment and calculation model are presented by Qi et al [22] and Bai et al [27].…”

“…Based on the measured contents of CO and H 2 calculated by the model developed by Qi et al [22] and Bai et al [27], the hydrogen permeation rate Va (kg•m −2 •s −1 ) was calculated and is listed in Table 6.…”

“…Yan et al [21] fabricated ZrO 2 composite film by in situ reaction of urea with zirconium hydride at high temperature, resulting in a film composed of Zr, C, N, and O elements; and C-H, O-H, and N-H bonds were detected in the film, revealing that hydrogen was trapped by C, N, and O in the coating. Qi et al [22] prepared phosphating film on zirconium hydride, for which the hydrogen permeation rate of samples was measured by gas chromatography, and the hydrogen loss predicted showed a good performance.…”