Claims
- 1. A method for mitigating propagation of a crack in an oxided surface of a metal component submerged in water in a water-cooled nuclear reactor or associated equipment, comprising the steps of;
- injecting a solution of a compound containing a noble metal into the water in which metal component is submerged while said reactor is operating; and
- causing said noble metal compound to decompose under reactor thermal conditions to release atoms of said noble metal which incorporate in said oxided surface of said metal component.
- 2. The method as defined in claim 1, wherein said metal component is made of stainless steel.
- 3. The method as defined in claim 1, wherein said noble metal is palladium.
- 4. The method as defined in claim 1, wherein said compound is an organic, inorganic or organometallic compound of a noble metal.
- 5. The method as defined in claim 3, wherein said compound is palladium acetylacetonate.
- 6. The method as defined in claim 3, wherein said compound is palladium nitrate.
- 7. The method as defined in claim 1, wherein said compound is injected at a rate such that the concentration of said noble metal in the water of said reactor is sufficient to decrease the electrochemical potential inside a crack formed in said metal component surface to a level below the critical potential to protect against intergranular stress corrosion cracking.
- 8. The method as defined in claim 1, further comprising the step of injecting hydrogen into the water of said reactor.
- 9. The method as defined in claim 3, wherein palladium is added to said reactor water in an amount sufficient to produce a palladium concentration of up to 100 ppb.
- 10. A method for mitigating propagation of a crack in an oxided metal surface, comprising the steps of;
- filling said crack with high-temperature water in which a compound containing a noble metal is dissolved; and
- causing said noble metal compound to decompose in said high-temperature water to release atoms of said noble metal which incorporate in the oxided metal surface and deposit on the interior surfaces of said crack.
- 11. The method as defined in claim 10, wherein said metal surface is made of stainless steel.
- 12. The method as defined in claim 11, wherein said noble metal is palladium.
- 13. The method as defined in claim 10, wherein said compound is an organic, inorganic or organometallic compound of a noble metal.
- 14. The method as defined in claim 12, wherein said compound is palladium acetylacetonate.
- 15. The method as defined in claim 12, wherein said compound is palladium nitrate.
- 16. The method as defined in claim 10, wherein said compound is injected in an amount such that the concentration of said noble metal is sufficient to decrease the electrochemical potential inside said crack to a level below the critical potential to protect against intergranular stress corrosion cracking.
Parent Case Info
This application is a continuation-in-part of U.S. patent application Ser. No. 08/143,513, filed Oct. 29, 1993, and U.S. patent application Ser. No. 08/143,514, filed Oct. 29, 1993, now U.S. Pat. No. 5,448,605.
US Referenced Citations (10)
Foreign Referenced Citations (6)
Number |
Date |
Country |
0265723 |
May 1988 |
EPX |
0450440 |
Oct 1991 |
EPX |
0450444 |
Oct 1991 |
EPX |
0514089 |
Nov 1992 |
EPX |
0526160 |
Feb 1993 |
EPX |
9218665 |
Oct 1992 |
WOX |
Non-Patent Literature Citations (3)
Entry |
Derwent Publications Ltd., London, GB; AN 84-059353 & JP-A-59 016 983 (Katayama Kagaku Kogyo Kenkyush), Abstract. |
3rd Symposium on Chemical Perspectives of Microelectronics Material, Boston, USA, Nov. 30-Dec. 3, 1992, Mat. Res. Soc. Symp. Proc. vol. 282, pp. 353-358, Kowalczyk et al., "Characterization of Palladium Acetylacetonate as a CVD Precursor for Pd Metallization". |
Abernathy, C. R. et al, ed., Chemical Perspectives of Microelectronic Materials III, Mat. Research Soc. Symposium Proceedings, vol. 282, Nov. 30-Dec. 3, 1992, pp. 353-358. |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
143513 |
Oct 1993 |
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