Zinc Vapor Trapping Using Copper-Based Materials
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TECHNICAL ARTICLE—PEER-REVIEWED
Zinc Vapor Trapping Using Copper-Based Materials Paul S. Korinko
Submitted: 4 March 2016 / Published online: 18 April 2016 ASM International 2016
Abstract As part of the development of a long range solution for zinc vapor capture, a series of experiments utilizing commercially available copper and bronze screen and bronze sheet materials were conducted. The testing used a high-vacuum system in which zinc was vaporized and condensed on the zinc getter material at various temperatures. A fixed zinc vaporization temperature was used and the zinc getter material, and consequently the condensation temperature, was varied. The testing revealed that zinc vapor was captured over a wider range of temperatures on bronze materials than on the copper screens. Keywords
Zinc Reactions Vapor phase Alloying
Introduction Gamma emitting contamination of 65Zn deposits were detected in a vacuum pumping system after a thermal treatment of irradiated components [1]. Select deposits were analyzed and it was determined that the source of the contamination was vapor deposition of small amounts of activated zinc from residual elements in the irradiated
P. S. Korinko (&) Savannah River National Laboratory, Materials Science and Technology, Aiken, SC, USA e-mail: [email protected]; [email protected]
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objects. The deposits were characterized for shape and adhesion as described [1]. A number of experiments were conducted and a method to trap zinc vapors was developed that could be used in the process piping to physically trap the zinc vapor [2]. This solution, although effective for low rates of production creates challenges at increased production rates since the gamma emitting zinc is captured in a glovebox that is designed to contain a gaseous radioactive beta-emitting material, i.e., tritium. Consequently, the facility operators requested that research be conducted to develop a solution for this problem that could be inserted into an area of the facility that is designed for high radiation isotopes in a high radiation area (HRA). The HRA provides many challenges for material and process development. The first is that there is a finite space to locate any type of trapping apparatus. In addition, no changes to the current process piping or heating could be incorporated into the developed solution. Finally, the system had to operate within the existing process pressure and temperature profiles. Other criteria were also imposed so that the quality of the product was not adversely affected by particulate or other contamination. Further, any material selected for evaluation could not absorb hydrogen to form a hydride and it had to be otherwise compatible with the process. A comprehensive review of materials was conducted and the essentially two alloy systems, copper- and cobalt-based, were compatible with the criteria [3]. A series of experiments were defined to determine the temperature conditions under which zinc vapor could be captured on copper and bronze materials. The zinc vapor
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