Author: Mehran Moalem
Publisher:
ISBN:
Category :
Languages : en
Pages : 640
Book Description
High Temperature Corrosion of Zircaloy-4 in Steam-hydrogen Mixtures
High-temperature Oxidation of Zircaloy in Hydrogen-steam Mixtures. [PWR ; BWR].
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Oxidation rates of Zircaloy-4 cladding tubes have been measured in hydrogen-steam mixtures at 1200 to 1700°C. For a given isothermal oxidation temperature, the oxide layer thicknesses have been measured as a function of time, steam supply rate, and hydrogen overpressure. The oxidation rates in the mixtures were compared with similar data obtained in pure steam and helium-steam environments under otherwise identical conditions. The rates in pure steam and helium-steam mixtures were equivalent and comparable to the parabolic rates obtained under steam-saturated conditions and reported in the literature. However, when the helium was replaced with hydrogen of equivalent partial pressure, a significantly smaller oxidation rate was observed. For high steam-supply rates, the oxidation kinetics in a hydrogen-steam mixture were parabolic, but the rate was smaller than for pure steam or helium-steam mixtures. Under otherwise identical conditions, the ratio of the parabolic rate for hydrogen-steam to that for pure steam decreased with increasing temperature and decreasing steam-supply rate.
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Oxidation rates of Zircaloy-4 cladding tubes have been measured in hydrogen-steam mixtures at 1200 to 1700°C. For a given isothermal oxidation temperature, the oxide layer thicknesses have been measured as a function of time, steam supply rate, and hydrogen overpressure. The oxidation rates in the mixtures were compared with similar data obtained in pure steam and helium-steam environments under otherwise identical conditions. The rates in pure steam and helium-steam mixtures were equivalent and comparable to the parabolic rates obtained under steam-saturated conditions and reported in the literature. However, when the helium was replaced with hydrogen of equivalent partial pressure, a significantly smaller oxidation rate was observed. For high steam-supply rates, the oxidation kinetics in a hydrogen-steam mixture were parabolic, but the rate was smaller than for pure steam or helium-steam mixtures. Under otherwise identical conditions, the ratio of the parabolic rate for hydrogen-steam to that for pure steam decreased with increasing temperature and decreasing steam-supply rate.
High-Temperature Oxidation of Zircaloy in Hydrogen-Steam Mixtures
Author: HM. Chung
Publisher:
ISBN:
Category : Alloys
Languages : en
Pages : 17
Book Description
Oxidation rates of Zircaloy-4 cladding tubes have been measured in hydrogen-steam mixtures at 1200 to 1700°C. For a given isothermal oxidation temperature, the oxide layer thicknesses have been measured as a function of time, steam supply rate, and hydrogen overpressure. The oxidation rates in the mixtures were compared with similar data obtained in pure steam and helium-steam environments under otherwise identical conditions. The rates in pure steam and helium-steam mixtures were equivalent and comparable to the parabolic rates obtained under steam-saturated conditions and reported in the literature. However, when the helium was replaced with hydrogen of equivalent partial pressure, a significantly smaller oxidation rate was observed. For high steam supply rates, the oxidation kinetics in a hydrogen-steam mixture were parabolic, but the rate was smaller than for pure steam or helium-steam mixtures. Under otherwise identical conditions, the ratio of the parabolic rate for hydrogen-steam to that for pure steam decreased with increasing temperature and decreasing steam supply rate. The smaller parabolic rates in the hydrogen-steam mixtures indicate that, under the test conditions, a considerable amount of hydrogen was dissolved in Zircaloy during oxidation and, as a consequence, oxygen transport in both the oxide and alpha-phases was slower than in the corresponding phases produced in pure steam or helium-steam mixtures. The findings are discussed in relation to some reported high-temperature transport characteristics of oxygen ions in the oxide formed in hydrogen-steam mixtures. For smaller steam supply rates (sufficiently small but still larger than the "steam starvation" limit), significantly smaller linear oxidation rates were observed in the hydrogen-steam mixture, which indicates that the oxidation rate was limited either by the gaseous transport of the steam molecules or as a result of chemical reaction between the chemisorbed oxygen on the zirconium oxide surface and the gaseous hydrogen molecules. This phenomenon of "hydrogen blanketing" is discussed in relation to fuel rod heatup in a degraded-core-accident situation.
Publisher:
ISBN:
Category : Alloys
Languages : en
Pages : 17
Book Description
Oxidation rates of Zircaloy-4 cladding tubes have been measured in hydrogen-steam mixtures at 1200 to 1700°C. For a given isothermal oxidation temperature, the oxide layer thicknesses have been measured as a function of time, steam supply rate, and hydrogen overpressure. The oxidation rates in the mixtures were compared with similar data obtained in pure steam and helium-steam environments under otherwise identical conditions. The rates in pure steam and helium-steam mixtures were equivalent and comparable to the parabolic rates obtained under steam-saturated conditions and reported in the literature. However, when the helium was replaced with hydrogen of equivalent partial pressure, a significantly smaller oxidation rate was observed. For high steam supply rates, the oxidation kinetics in a hydrogen-steam mixture were parabolic, but the rate was smaller than for pure steam or helium-steam mixtures. Under otherwise identical conditions, the ratio of the parabolic rate for hydrogen-steam to that for pure steam decreased with increasing temperature and decreasing steam supply rate. The smaller parabolic rates in the hydrogen-steam mixtures indicate that, under the test conditions, a considerable amount of hydrogen was dissolved in Zircaloy during oxidation and, as a consequence, oxygen transport in both the oxide and alpha-phases was slower than in the corresponding phases produced in pure steam or helium-steam mixtures. The findings are discussed in relation to some reported high-temperature transport characteristics of oxygen ions in the oxide formed in hydrogen-steam mixtures. For smaller steam supply rates (sufficiently small but still larger than the "steam starvation" limit), significantly smaller linear oxidation rates were observed in the hydrogen-steam mixture, which indicates that the oxidation rate was limited either by the gaseous transport of the steam molecules or as a result of chemical reaction between the chemisorbed oxygen on the zirconium oxide surface and the gaseous hydrogen molecules. This phenomenon of "hydrogen blanketing" is discussed in relation to fuel rod heatup in a degraded-core-accident situation.
High-temperature Oxidation of Zircaloy-4 in Steam and Steam-hydrogen Environments
Author: J. T. Prater
Publisher:
ISBN:
Category : Oxidation
Languages : en
Pages : 22
Book Description
Publisher:
ISBN:
Category : Oxidation
Languages : en
Pages : 22
Book Description
Zirconium in the Nuclear Industry
Author: R. B. Adamson
Publisher: ASTM International
ISBN: 0803109350
Category : Creep
Languages : en
Pages : 832
Book Description
Publisher: ASTM International
ISBN: 0803109350
Category : Creep
Languages : en
Pages : 832
Book Description
Energy Research Abstracts
ERDA Energy Research Abstracts
French Activity on High Temperature Corrosion in Water Vapor
Author: Sébastien Chevalier
Publisher: Trans Tech Publications Ltd
ISBN: 3038263826
Category : Technology & Engineering
Languages : en
Pages : 206
Book Description
Increased clarity in our understanding of water vapor effects on oxidation is resulting from our recognition that multiple mechanisms are possible, and that distinctions must be drawn between situations where, on the one hand, molecular oxygen accompanies water vapor, and on the other, it does not, and instead free hydrogen can be present. It is a pleasure to welcome the contributions of this new book to this important field. Whilst the existence of a substantial French research effort in the area has been well known, the scale and extent of the effort comes as something of a surprise. The reason for this is apparent in the reference lists provided at the end of each chapter: much of the work is simply not available in the readily accessed literature. The book performs an important service in bringing these results to the attention of the wider research community. Overall, the book succeeds well in its aim of presenting an integrated view of water vapor effects on high temperature corrosion. Its organization into chapters concerned with different alloy classes is appealing, and the contents should prove useful to many readers.
Publisher: Trans Tech Publications Ltd
ISBN: 3038263826
Category : Technology & Engineering
Languages : en
Pages : 206
Book Description
Increased clarity in our understanding of water vapor effects on oxidation is resulting from our recognition that multiple mechanisms are possible, and that distinctions must be drawn between situations where, on the one hand, molecular oxygen accompanies water vapor, and on the other, it does not, and instead free hydrogen can be present. It is a pleasure to welcome the contributions of this new book to this important field. Whilst the existence of a substantial French research effort in the area has been well known, the scale and extent of the effort comes as something of a surprise. The reason for this is apparent in the reference lists provided at the end of each chapter: much of the work is simply not available in the readily accessed literature. The book performs an important service in bringing these results to the attention of the wider research community. Overall, the book succeeds well in its aim of presenting an integrated view of water vapor effects on high temperature corrosion. Its organization into chapters concerned with different alloy classes is appealing, and the contents should prove useful to many readers.