The Kinetics of Oxidation of Zircaloy‐4 in Steam at High Temperatures

Abstract

The kinetics of oxidation of Zircaloy-4 in steam were examined under isothermal conditions from 900 ~ to 1500~C. Rate curves describing the growth of the reaction product layers, oxide-and oxygen-stabilized alpha, were obtained at 50~ intervals under carefully defined and documented experimental, conditions. The early stages of oxidation for temperatures above 1000~ were shown to be virtually ideally parabolic; below 1000~ the growth of the oxide layer was nonparabolic. Statistical evaluations of the data in terms of the rate constants and their Arrhenius parameters established the high degree of self-consistency of these measurements. The features of the experimental apparatus and techniques that were necessary to insure accurate measurements are discussed.

High Temperature Steam Oxidation Testing of Candidate Accident Tolerant Fuel Cladding Materials

“…Mass gains for Zircaloy-2 are shown in Figure 1a for reference and are consistent with prior observations [2][3][4]. Conventional 18-8 stainless steels (i.e.…”

“…Evaluations of chemical vapor deposited (CVD) SiC were conducted up to 1700°C in steam. The reaction of H 2 O with the alumina reaction tube at 1700°C resulted in Al(OH) 3 formation, which reacted with the specimen to form a liquid reaction product. This behavior was not observed at lower temperatures where gas velocity and H 2 O content showed typical effects on the reaction rate.…”

“…For conventional Zr alloy (e.g. Zircaloy)/UO 2 fuel rods, the increase in temperature when the rods become uncovered causes a well-known rapid oxidation behavior [2][3][4]. At temperatures above ~1200ºC, the self-catalytic enthalpy production from the Zr alloy cladding oxidation significantly adds to the heat production rate in the core [5] and produces significant quantities of hydrogen.…”

Oxidation kinetics of Zircaloy-4 and Zr–1Nb–1Sn–0.1Fe at temperatures of 700–1200°C

“…Since the 1960s, extensive studies were carried out to precisely evaluate the oxidation rate of Zircaloy in a high-temperature steam for a LOCA safety analysis [7][8][9][10][11][12][13][14][15][16][17]. The kinetics data showed a relatively good agreement with each other, though the kinetics by Baker-Just is generally considered to overestimate the reaction in the temperature range above 1000°C.…”

High Temperature and Pressure Steam-H2 Interaction with Candidate Advanced LWR Fuel Claddings

“…Figure 2 shows mass gain data after 8h exposures at 800°-1350°C for various alloys. The steam oxidation behavior of Zircaloy has been extensively studied [6][7][8] and will not be extensively reported here. Mass gains for Zircalloy-2 are shown in Figure 2 for reference to the more oxidation resistant alloys.…”