scholarly journals Hydride Rim Formation in E110 Zirconium Alloy during Gas-Phase Hydrogenation

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 247
Author(s):  
Viktor Kudiiarov ◽  
Ivan Sakvin ◽  
Maxim Syrtanov ◽  
Inga Slesarenko ◽  
Andrey Lider
Keyword(s):  
Mechanical Properties ◽  
Gas Phase ◽  
Zirconium Alloy ◽  
Zirconium Alloys ◽  
Subsequent Formation ◽  
Delayed Hydride Cracking ◽  
Hydrogen Penetration ◽  
Significant Change ◽  
Hydride Cracking

The work is devoted to the study of the laws of the formation of a hydride rim in E110 zirconium alloy claddings during gas-phase hydrogenation. The problem of hydrogen penetration and accumulation and the subsequent formation of hydrides in the volume of zirconium cladding tubes of water-cooled power reactors remain relevant. The formation of brittle hydrides in a zirconium matrix firstly, leads to a significant change in the mechanical properties, and secondly, can cause the destruction of the claddings by the mechanism of delayed hydride cracking. The degree of the hydride’s effect on the mechanical properties of zirconium cladding is mainly determined by the features of the hydride’s distribution and orientation. The problem of hydride rim formation in zirconium alloys with niobium is quite new and poorly studied. Therefore, the study of hydride rim formation in Russian zirconium alloy is important and necessary for predicting the behavior of claddings during the formation of the hydride rim.

Control of hydrogen absorption by nickel films obtained upon magnetic spraying of zirconium alloy using the thermoEMF method

2020 ◽  
Vol 86 (8) ◽  
pp. 32-37
Author(s):  
V. V. Larionov ◽  
Xu Shupeng ◽  
V. N. Kudiyarov
Keyword(s):  
Magnetron Sputtering ◽  
Hydrogen Concentration ◽  
Hydrogen Absorption ◽  
Zirconium Alloy ◽  
Hydrogen Adsorption ◽  
Zirconium Alloys ◽  
Nickel Film ◽  
Protective Film ◽  
Nickel Films ◽  
Hydrogen Penetration

Nickel films formed on the surface of zirconium alloys are often used to protect materials against hydrogen penetration. Hydrogen adsorption on nickel is faster since the latter actively interacts with hydrogen, oxidizes and forms a protective film. The goal of the study is to develop a method providing control of hydrogen absorption by nickel films during vacuum-magnetron sputtering and hydrogenation via measuring thermoEMF. Zirconium alloy E110 was saturated from the gas phase with hydrogen at a temperature of 350°C and a pressure of 2 atm. A specialized Rainbow Spectrum unit was used for coating. It is shown that a nickel film present on the surface significantly affects the hydrogen penetration into the alloy. A coating with a thickness of more than 2 μm deposited by magnetron sputtering on the surface of a zirconium alloy with 1% Nb, almost completely protects the alloy against hydrogen penetration. The magnitude of thermoemf depends on the hydrogen concentration in the zirconium alloy and film thickness. An analysis of the hysteresis width of the thermoEMF temperature loop and a method for determining the effective activation energy of the conductivity of a hydrogenated material coated with a nickel film are presented. The results of the study can be used in assessing the hydrogen concentration and, hence, corrosion protection of the material.

PREDICTION OF CRITICAL TEMPERATURE FOR DELAYED HYDRIDE CRACKING IN IRRADIATED N18 ZIRCONIUM ALLOY

2010 ◽  
Vol 46 (7) ◽  
pp. 805-809
Author(s):  
Chao SUN ◽  
Jun TAN ◽  
Shihao YING ◽  
Cong LI ◽  
Qian PENG ◽  
...  
Keyword(s):  
Critical Temperature ◽  
Zirconium Alloy ◽  
Delayed Hydride Cracking ◽  
Hydride Cracking

A Comparison of Finite Element Cohesive-Zone Modelling With the Process-Zone Approach for the Prediction of Delayed Hydride Cracking

2013 ◽  
Author(s):  
Michael Martin
Keyword(s):  
Finite Element ◽  
Stress Level ◽  
Cohesive Zone ◽  
Threshold Stress ◽  
Process Zone ◽  
Zirconium Alloys ◽  
Cohesive Elements ◽  
Cohesive Zone Modelling ◽  
Delayed Hydride Cracking ◽  
Hydride Cracking

Zirconium alloys, as used in water-cooled nuclear reactors, are susceptible to a time-dependent damage mechanism known as Delayed Hydride Cracking, or DHC. Corrosion of the zirconium alloy in the presence of water generates hydrogen that subsequently diffuses through the metallic structure towards stress concentrating features such as notches or cracks. Canadian standard CSA N285.8–10 uses a process-zone modelling approach to define a threshold stress level beyond which DHC is predicted to occur. The process-zone analysis to calculate the threshold stress level generally proceeds by representing the process-zone as a crack, the length of which is determined by the superposition of stress intensity factors obtained from handbook solutions or cracked-body finite element models. Process-zone models are a subset of the more general class of cohesive-zone models and cohesive elements are available in a number of standard finite element codes. Cohesive elements can be used to simulate the process-zone response, or indeed more complex cohesive behaviour. In this paper, the stress and displacement results from finite element based cohesive-zone modelling of a sharp crack and blunt notches of various root radii are compared with analytical process-zone solutions. The cohesive-zone results are also compared with the process-zone formulation used in CSA N285.8–10. The results show that finite element based cohesive-zone analysis can be used to replicate the process-zone results. The key benefit of finite element based cohesive-zone modelling is that it provides a framework for investigating the DHC characteristics of arbitrary hydride distributions, using readily available techniques.

Critical Temperatures for Initiating and Arresting Delayed Hydride Cracking in a Zr-2.5Nb Pressure Tube

2005 ◽  
Vol 297-300 ◽  
pp. 1685-1690
Author(s):  
Young Suk Kim ◽  
Kyung Soo Im ◽  
Yong Moo Cheong
Keyword(s):  
Hydrogen Concentration ◽  
Solid Solubility ◽  
Driving Force ◽  
Stress Gradient ◽  
Zirconium Alloys ◽  
Concentration Limit ◽  
Critical Temperatures ◽  
Terminal Solid Solubility ◽  
Delayed Hydride Cracking ◽  
Hydride Cracking

The hydrogen concentration limit and critical temperatures for a delayed hydride cracking (DHC) in zirconium alloys have been reanalyzed using Kim’s DHC model that a driving force for DHC is not the stress gradient but the supersaturated hydrogen concentration or ∆C arising from a hysteresis of the terminal solid solubility on a heating and on a cooling. The DHC initiation occurs generally at the temperatures corresponding to the terminal solid solubility for precipititation (TSSP), demonstrating that the supercooling from the terminal solid solubility for dissolution (TSSD) is required to initiate the DHC. The DHC arrest temperatures correspond to the temperatures where the ∆C is reduced to zero. Therefore, we conclude that the ∆C is the driving force for the DHC and that the Kim’s DHC model is feasible.

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