CONDITIONS FOR THE HYDRIDING OF ZIRCONIUM AND ZIRCALOY. AN INTERPRETIVE LITERATURE SURVEY
A critical review was made of ihe literature available ai Hanford Atomic Products Operation up to March 25. 1958. on the hydriding of zirconium and its alloys. A number of failures of zirconium and Zircaloy tubes and fuel element jackets are described. An hypothesis is set forth on the necessary conditions for hydriding of zirconium and its alloys. This hypothesis is necessarily based on secondary interpretation of experiments largely designed for other purposes, and is subject to modification as more direct experiments are completed. Conclusions drawn from this hypothesis should be considered as probabilities, and not as proven facts. One such conclusion is that circumstances exist where the use of Zircaloy jackets and tubes with uranium metal fuel elements could lead to hydrogen embrittlement of the Zircaloy. Uranium metal reacts with water to form considerable quantities of hydrogen. Under the proper conditions Zircaloy can pick up this hydrogen. Hydrogen concentrations greater than 100 ppm in Zircaloy start to cause hydrogen embrittlement, and very high concenirations can cause loss of all useful mechanical properties. High hydrogen contents can also impair the corrosion resistance of the metal to hot waier. Water apparently inhibits the hydriding of Zircaloy and this certainly reduces the possibility of hydriding damage in a water cooled system. However, uranium metal is an excellent dehydrating agent. Thus, dry hydrogen can form and be picked up by the Zircaloy. Once the conditions necessary for hydriding are clearly understood. it should be possible to design the fuel elements and cooling system so that hydriding probabilities are minimized. (auth) 50 references.
- Research Organization:
- General Electric Co. Hanford Atomic Products Operation, Richland, Wash.
- DOE Contract Number:
- W-31-109-ENG-52
- NSA Number:
- NSA-12-012218
- OSTI ID:
- 4336541
- Report Number(s):
- HW-55460
- Resource Relation:
- Other Information: Decl. June 19, 1958. Orig. Receipt Date: 31-DEC-58
- Country of Publication:
- United States
- Language:
- English
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