A Study on Hydrogen Emission of Zirconium Hydride

The hydrogen emission of zirconium hydride at high temperature is a challenging issue for many researchers. The hydrogen emission content of zirconium hydride pins should be evaluated to confirm the application feasibility. The comparison of theory analysis and experiment data indicated that Richardson's law could offer a conservative result for calculating the hydrogen emission content of zirconium hydride pins at high temperature. Furthermore, the methods of preventing hydrogen loss should be developed for the purpose of extending the work temperature or time. The results showed that a ZrO2 layer prepared for zirconium hydride could not prevent hydrogen loss after exposure at 650 °C in an inert environment and ZrO2 transformed into Zr3O gradually due to the opposite movement of hydrogen and oxygen. Finally, a further improvement to prevent hydrogen loss was developed. The zirconium hydride with a ZrO2 layer in the cladding of He+CO2 exhibited no significant reduction of hydrogen content. It is helpful to prevent the hydrogen loss by increasing the oxygen potential on the outside of ZrO2 layer.

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A Study on Hydrogen Emission of Zirconium Hydride

Volume 2: Plant Systems, Structures, Components and Materials ◽

10.1115/icone25-67271 ◽

2017 ◽

Author(s):

Fu Xiaogang ◽

Qin Bo ◽

Ma Haoran ◽

Zhang Jinquan ◽

Long Bin

Keyword(s):

High Temperature ◽

Hydrogen Content ◽

Oxygen Potential ◽

Zirconium Hydride ◽

Theory Analysis ◽

Experiment Data ◽

Hydrogen Emission ◽

Challenging Issue ◽

Inert Environment ◽

Conservative Result

The hydrogen emission of zirconium hydride at high temperature is a challenging issue for many researchers. The hydrogen emission content of zirconium hydride pins should be evaluated to confirm the application feasibility. The comparison of theory analysis and experiment data indicated Richardson’s Law could offer a conservative result for calculating the hydrogen emission content of zirconium hydride pins at high temperature. Furthermore, the methods of preventing hydrogen loss should be developed for the purpose of extending the work temperature or time. The results showed a ZrO2 layer prepared for zirconium hydride could not prevent hydrogen loss after exposure at 923K in an inert environment and ZrO2 transformed into Zr3O gradually due to the opposite movement of hydrogen and oxygen. Finally, a further improvement to prevent hydrogen loss was developed. The zirconium hydride with a ZrO2 layer in the cladding of He+CO2 exhibited no significant reduction of hydrogen content. It is helpful to prevent the hydrogen loss by increasing the oxygen potential on the outside of ZrO2 layer.

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Effect of the Fe2O3 Addition Amount on Dephosphorization of Hot Metal with Low Basicity Slag by High-Temperature Laboratorial Experiments

Metals ◽

10.3390/met11030417 ◽

2021 ◽

Vol 11 (3) ◽

pp. 417

Author(s):

Wenkui Yang ◽

Jian Yang ◽

Yanqiu Shi ◽

Zhijun Yang ◽

Fubin Gao ◽

...

Keyword(s):

Solid Solution ◽

High Temperature ◽

Theoretical Calculation ◽

Oxygen Potential ◽

Oxygen Activity ◽

Hot Metal ◽

Rich Phase ◽

Addition Amount

In this paper, the influence of the Fe2O3 addition amount on the dephosphorization of hot metal at 1623 K with the slag of the low basicity (CaO/SiO2) of about 1.5 was investigated by using high-temperature laboratorial experiments. With increasing the Fe2O3 addition amount from 5 to 30 g, the contents of [C], [Si], [Mn] and [P] in the hot metal at the end of dephosphorization are decreased and the corresponding removal ratios increase. In dephosphorization slags, the phosphorus mainly exists in the form of the nCa2SiO4–Ca3(PO4)2 solid solution in the phosphorus-rich phase and the value of coefficient n decreases from 20 to 1. Furthermore, the oxygen potential and activity at the interface between the slag and hot metal are increased. When the oxygen potential and the oxygen activity at the interface are greater than 0.72 × 10−12 and 7.1 × 10−3, respectively, the dephosphorization ratio begins to increase rapidly. When the Fe2O3 addition amount is increased to 30 g, the ratio of the Fe2O3 addition amount to theoretical calculation consumption is around 175%, and the dephosphorization ratio reaches the highest value of 83.3%.

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Quasi-harmonic computations of thermodynamic parameters of olivines at high-pressure and high-temperature. A comparison with experiment data

Physics of The Earth and Planetary Interiors ◽

10.1016/s0031-9201(96)03174-3 ◽

1996 ◽

Vol 98 (1-2) ◽

pp. 17-29 ◽

Cited By ~ 47

Author(s):

François Guyot ◽

Yanbin Wang ◽

Philippe Gillet ◽

Yanick Ricard

Keyword(s):

High Pressure ◽

High Temperature ◽

Thermodynamic Parameters ◽

Experiment Data ◽

Comparison With Experiment

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THEORY ANALYSIS AND FOUNDATION OF THE HIGH TEMPERATURE DOT REGION OF TIRETEMPERATURE FIELD

Journal of Mechanical Engineering ◽

10.3901/jme.2004.03.150 ◽

2004 ◽

Vol 40 (03) ◽

pp. 150

Author(s):

Baoling Han

Keyword(s):

High Temperature ◽

Theory Analysis

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Microstructure and Nanoindentation Studies of Hydridated Zircaloy-4 Claddings After High Temperature Oxidation

Journal of Nuclear Engineering and Radiation Science ◽

10.1115/1.4049053 ◽

2020 ◽

Vol 7 (2) ◽

Author(s):

Petra Gávelová ◽

Patricie Halodová ◽

Daniela Marušáková ◽

Ondřej Libera ◽

Jakub Krejčí ◽

...

Keyword(s):

High Temperature ◽

Oxygen Concentration ◽

Hydrogen Content ◽

Oxygen Solubility ◽

Pressurized Water ◽

Temperature Oxidation ◽

Β Phase ◽

Significant Difference ◽

Water Reactors ◽

Increasing Temperature

Abstract Zirconium-based alloys are one of the most significant materials in thermal-neutron reactor systems. With very low neutron capture cross section, good corrosion resistance, mechanical strength and resistance to neutron radiation damage, zirconium alloys are used for fuel claddings. Cladding materials are still improved and tested in normal as well as critical reactor conditions. Zircaloy-4 (Zr-1.5Sn-0.2Fe-0.1Cr) is used for west types of light-water reactors, Pressurized Water Reactors (PWR). In our study, Zircaloy-4 cladding tubes were high-temperature oxidized in steam at the series of temperatures from 950 up to 1425 °C to simulate PWR reaching severe accident conditions. To observe the influence of hydrogen (H) diffusing from the coolant water on oxidation process, the specimens with ∼1000 ppm H were compared to the specimens with almost no hydrogen content. Wave Dispersive Spectroscopy (WDS) and nanoindentation were performed in line profiles across the cladding wall. Both methods contributed to verify the pseudobinary Zircaloy-4/oxygen phase diagram with focus on determination of phase boundaries. The increase of oxygen concentration with increasing temperature was observed. Moreover, oxygen concentration profiles and related change in nanohardness and Young's modulus showed the effect of hydrogen on the cladding microstructure. Hydrogen dissolved in metallic matrix increases the oxygen solubility in prior β-phase, the specimens with 1000 ppm H showed the higher oxygen content at almost all temperatures. As well, material hardening was observed on specimens with 1000 ppm H with significant difference in β-phase, measured on specimens exposed to lowest and highest oxidation temperature. Thus, with increasing temperature and hydrogen content, increased oxygen solubility affects the cladding ductility.

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Repair Weldability at Overlay/Base Metal Interface of Petroleum Pressure Vessel

Volume 7: Operations, Applications and Components ◽

10.1115/pvp2008-61909 ◽

2008 ◽

Author(s):

Rinzo Kayano ◽

Hiroaki Mori ◽

Kazutoshi Nishimoto

Keyword(s):

High Temperature ◽

Hydrogen Embrittlement ◽

Hydrogen Content ◽

Welding Process ◽

Pressure Vessels ◽

Cold Cracking ◽

Diffusible Hydrogen ◽

Repair Welding ◽

Crack Susceptibility

In order to extend the life of petroleum pressure vessels operated in long term, it is needed to establish the reliable repair welding technique. Weld cold cracking sometimes occurred in long-term operated petroleum pressure vessels due to hydrogen embrittlement by thermal stress and diffusible hydrogen after repair welding. The cracking was caused by the hydrogen concentration at the base meal of 2.25Cr-1Mo steel/overlaying metal of austenitic stainless steels interface during the service with high temperature and hydrogen partial pressure. The tendency was accelerated by carbide precipitation at the interface due to the post weld heat treatment (PWHT) and the operation with high temperature. That is, the crack susceptibility at the interface became markedly higher owing to the hydrogen embrittlement with metallurgical degradation by thermal embrittlement. To make clear the effect of weld thermal cycles during repair welding on the hydrogen content and weld cold cracking at the interface in the structural material of petroleum pressure vessels, the crack susceptibility was estimated by y-groove weld cracking test with varying overlay thickness and hydrogen exposure conditions. In addition, the hydrogen distribution in the material was calculated by the theoretical analysis using the diffusion equation based on activity. The crack susceptibility was raised with increase in the hydrogen content at the interface. It was concluded that the cracking could be prevented by controlling the repair welding process to reduce the hydrogen content at the interface.

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