THE ROLE OF THE OXIDATION RATE ON THE HYDRIDING OF ZIRCALOY-2 BY GASEOUS HYDROGEN. Interim Report No. 3
Work was carried out to determine the amount of water vapor required to inhibit the gaseous hydriding of Zircaloy2. The oxidation rate of Zircaloy-2 was found to be independent of H/sub 2/O pressure. However, the oxidation rate could be slowed by limiting access of water molecules to the metal surface. It was found that in every case where gaseous hydriding was observed, the oxidation rate was slowed below its normal rate due to the experimental conditions. Hydriding was never observed when the oxidation rate was normal. It was concluded the safest atmosphere forZircaloy-2 at 400 deg C (or below) is an atmosphere that will supply water (or oxygen) to the metal surface at a rate required to maintain thc oxidation rate normal for that temperature. The water concentration of the bulk gas is important only to the extent that it contributes to the rate of transpont of water to the metal surface. When the oxr-dation rate falls below the normal rate, the extent of hydriding will depend on how rapidly reaction sites become available to the hydrogen, the diffusion rate of hydrogen through the oxide, the hydrogen pressure, the mass of metal present, the temperature, and the temperature gradient in the metal. lf enough water is present to maintain the normal oxidation rate, the hydrogen pressure should be relatively unimportant. This is indicated by the available data. (auth)
- Research Organization:
- General Electric Co. Hanford Atomic Products Operation, Richland, Wash.
- DOE Contract Number:
- AT(45-1)-1350
- NSA Number:
- NSA-16-022588
- OSTI ID:
- 4836583
- Report Number(s):
- HW-67811
- Country of Publication:
- United States
- Language:
- English
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