Patent Number: 047568747
Section: claims

1. In the method for inhibiting the deposition of radioactive cobalt in a water-bearing vessel of a water-cooled nuclear reactor which comprises adding zinc ion to water entering said water-bearing vessel, the improvement in which said zinc ion contains a substantially lower proportion of the .sup.64 Zn isotope than naturally occurring zinc. 2. A method in accordance with claim 1 in which the proportion of .sup.64 Zn in said zinc ion is less than about 10%. 3. A method in accordance with claim 1 in which the proportion of .sup.64 Zn in said zinc ion is less than about 1%. 4. A method in accordance with claim 1 in which said zinc ion is substantially devoid of .sup.64 Zn. 5. A method in accordance with claim 1 in which said zinc ion is added by dissolving zinc oxide in said water. 6. A method in accordance with claim 5 in which the amount of zinc oxide dissolved is selected to achieve a concentration of about 1 to about 1,000 ppb zinc in said water-bearing vessel. 7. A method in accordance with claim 5 in which the amount of zinc oxide dissolved is selected to achieve a concentration of about 3 to about 100 ppb zinc in said water-bearing vessel. 8. A method in accordance with claim 5 in which said zinc oxide is dissolved from a member selected from the group consisting of a water-based slurry, a water-based paste and a water-based solution. 9. A method for inhibiting the deposition of radioactive material in a water-bearing vessel of a water-cooled nuclear reactor, said method comprising: adding a water-based zinc oxide paste to water entering said water-bearing vessel, the zinc in said paste containing a substantially lower proportion of the .sup.64 Zn isotope than naturally occurring zinc.  adding an aqueous solution of zinc oxide to water entering said water-bearing vessel, the zinc in said zinc oxide containing a substantially lower proportion of the .sup.64 Zn isotope than naturally occurring zinc.  adding a slurry of zinc oxide in water to water entering said water-bearing vessel, the zinc in said zinc oxide containing a substantially lower proportion of the .sup.64 Zn isotope than naturally occurring zinc. 10. A method in accordance with claim 9 in which the amount of zinc oxide in said paste is from about 25% to about 95% by weight. 11. A method in accordance with claim 9 in which the amount of zinc oxide in said paste is from about 40% to about 80% by weight. 12. A method for inhibiting the deposition of radioactive cobalt in a water-bearing vessel of a water-cooled nuclear reactor, said method comprising: 13. A method in accordance with claim 12 in which said aqueous solution is formed by passing a stream of water drawn from said water entering said water-bearing vessel through a receptacle containing solid zinc oxide retained therein. 14. A method in accordance with claim 13 in which said solid zinc oxide is a bed of zinc oxide particles. 15. A method in accordance with claim 14 in which said zinc oxide particles are sintered zinc oxide. 16. A method for inhibiting the deposition of radioactive cobalt in a water-bearing vessel of a water-cooled nuclear reactor, said method comprising: 17. A method in accordance with claim 16 in which the zinc oxide content of said slurry is from about 0.1% to about 20% by weight. 18. A method in accordance with claim 16 in which the zinc oxide content of said slurry is from about 1% to about 5% by weight. 19. A method in accordance with claim 16 in which said zinc oxide in said slurry is fumed zinc oxide. 20. A method in accordance with claim 16 in which the rate of addition of said slurry to said water is selected to produce a zinc content in the water of said water-bearing vessel of about 1 to about 1,000 ppb. 21. A method in accordance with claim 16 in which the rate of addition of said slurry to said water is selected to produce a zinc content in the water of said water-bearing vessel of about 3 to about 100 ppb.