SEDL / STP / STP1295-EB / STP16180S

Hydrogen Pickup and Redistribution in Alpha-Annealed Zircaloy-4

Kammenzind, BF
Bettis Atomic Power Laboratory, Westinghouse Electric Corporation, West Mifflin, PA

Franklin, DG
Bettis Atomic Power Laboratory, Westinghouse Electric Corporation, West Mifflin, PA

Peters, HR
Knolls Atomic Power Laboratory, Martin Marietta Corp., Schenectady, NY

Duffin, WJ
Bettis Atomic Power Laboratory, Westinghouse Electric Corporation, West Mifflin, PA

Pages: 33    Published: Jan 1996

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Abstract

Zircaloy-4, which is used widely as a core structural material in pressurized water reactors (PWR), picks up hydrogen during service. Hydrogen solubility in Zircaloy-4 is low, and hydrides precipitate after the Zircaloy-4 matrix becomes supersaturated with hydrogen. These hydrides embrittle the Zircaloy-4. To study hydrogen pickup and concentration, a post-irradiation nondestructive radiographic technique for measuring hydrogen concentration was developed and qualified. Experiments on hydrogen pickup were conducted in the advanced test reactor (ATR). Ex-reactor tests were conducted to determine the conditions in which hydrogen would dissolve, migrate, and precipitate. Finally, a phenomenological model for hydrogen diffusion was indexed to the data. This presentation describes the equipment and the model, presents the results of experiments, and compares the model predictions to experimental results.