REVIEW OF ZIRCALOY-2 AND ZIRCALOY-4 PROPERTIES RELEVANT TO N.S. SAVANNAH REACTOR DESIGN
Information on zircaloy technology, with specific emhasis on environmental conditions similar to those present in the reactor core of the N. S. Savannah is discussed. ata on mechanical and corrosion properties, radiation effects, and other pentinent subjects are given. Out-of-pile data relevant to Zircaloy-2 structural components in the N. S. Savannah core show a yield strength of ~20,000 psi for annealed material, a creep rate of <10/sup -5/%/hr at 15,000 psi, and corrosion of only a few mils in 20 years. The principal effects of radiation exposure are increased mechanical strength and decreased uniform elongation. Brittle fracture does not occur, however, because reductions in area permit local plastic deformation. The corrosion rate is increased by radiation exposure (less than a factor of 5), but even at the increased rate metal loss is insignificant. Except for hydrogen pickup, Zircaloy-4 exhibits essentially the same properties as Zircaloy-2. Excessive hydrogen content, with resulting precipitation of ZrH/sub 2/, causes embrittlement of Zircaloy-2. The pickup of hydrogen by Zircaloy-2 is about three times that of Zircaloy-4. On the basis of the available information, Zircaloy-4 appears to be adequate for use as the material of construction for the fuel element containers in the advanced core for the N. S. Savannah. Zircaloy-4 is recommended over Zircaloy-2 because of its lower hydrogen pickup. Recommendations for 20-year service life cannot be made with complete confidence, however. because of the necessary extrapolations of data. Hairline cracks in Zircaloy-2 sometimes occur during fabrication of the metal that are not always detected by present inspection methods. (auth)
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- US Atomic Energy Commission (AEC)
- DOE Contract Number:
- W-7405-ENG-26
- NSA Number:
- NSA-16-025760
- OSTI ID:
- 4827123
- Report Number(s):
- ORNL-3281
- Resource Relation:
- Other Information: Orig. Receipt Date: 31-DEC-62
- Country of Publication:
- United States
- Language:
- English
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