Correlations of the Steam Oxidation Rate Constant of BWR Alloy Zircaloy-2 at 800–1400 °C

Abstract

Steam oxidation experiments were conducted at 800–1400 °C with boiling water reactor alloy Zircaloy-2 strip specimens. Sample weight gain measurements were performed on the oxidized specimens before and after the test and were compared to oxygen pickup calculations using the Cathcart–Pawel correlation. The results showed that Zircaloy-2 follows the parabolic law at temperatures above 1000 °C. At or below 1000 °C, the oxidation rate was very low when compared to Cathcart–Pawel correlation and can be represented by a cubic expression. Arrhenius expressions are given to describe the parabolic rate constants at temperatures above 1000 °C and cubic rate constants are provided for temperatures at or below 1000 °C. The weight gains calculated by our Arrhenius correlations are in excellent agreement with the measured sample weight gains at all test temperatures.

Appendix A: Weight Gain Correlations for Zircaloy-4, E110, and Zircaloy-2

Weight gain correlation for PWR alloy Zircaloy-4 by Cathcart and Pawel [2]:

$$W_{g} ^{2} = 0.3622{\text{ EXP}}\left( { - 20100/T} \right)t~\;\;\hbox{for}\,1000^\circ {\text{C}} < {\text{Temp}}. \le 1500\;^\circ {\text{C}}$$

(A1)

where W_g is weight gain in g/cm2, T is temperature in K, and t is time in s.

Weight gain correlations for PWR alloy E110 by Yan et al. [18]:

$${\text{W}}_{{\text{g}}} ^{{\text{3}}} = {\text{ 3}}.1783 \times 10^2 {\text{ EXP }}\left( { - {\text{37117}}/{\text{T}}} \right){\text{ t}}~\;\;{\text{for~Temp}}. \le 1015\;^\circ {\text{C}}$$

(A2-1)

$$W_{g} ^{2} = 2.6988 \times 10^{{10}} {\text{ EXP}}\left( { - 54055/T} \right)t\;\;{\text{for}}~1015\;^\circ {\text{C}} < {\text{Temp}}{\text{.}} \le 1060^\circ {\text{C}}$$

(A2-2)

$$W_{g} ^{2} = 7.5364{\text{ EXP }}\left( { - 24760/T} \right)t\;\;{\text{for~Temp.}} > 1060\;^\circ {\text{C}}$$

(A2-3)

where W_g is weight gain in g/cm2, T is temperature in K, and t is time in s.

Weight gain correlations for BWR alloy Zircaloy-2 in this work:

$$W_{g} ^{3} = 5.885\times 10^{2} {\text{ EXP }}\left( { - 36349/T} \right)t\;\;\;{\text{for~ Temp}}.\le 1000\;^\circ {\text{C}}$$

(A3-1)

$$W_{g} ^{2} = 0.5884{\text{ EXP}}\left( { - 21428/T} \right)t\;\;\;{\text{for}}~1000\;^\circ {\text{C}} < {\text{Temp}}. \le 1400\;^\circ {\text{C}}$$

(A3-2)

where W_g is weight gain in g/cm2, T is temperature in K, and t is time in s.