TRANSPORT AND REDUCTION POSSIBILITIES DURING TPBAR EXTRACTION
In light of the discovery of the activated zinc 65 in the TEF process piping, a discussion of potential sources and mechanisms for the production of this species has been initiated. A suspected source is the presence of Cu as a contaminant in many of the alloy components that comprise the TPBARs and the presence of Zn as a contaminant in the aluminide coating. These two sources are expected to produce metallic transmutation products that could be mobile and be extracted from the metallic components of the TPBARs. Another potential source is the presence of ZnO that is present as part of the crud on the external surfaces of the TPBARs. In addition, it is conceivable to have ZnO within the TPBARs from transmutation products and subsequent oxidation reactions with water. This memo does not attempt to address all of the possible sources, nor does it derive the most likely scenarios as to how Zn or ZnO may be present in the TPBARs it merely posits that it is present as a transmutation product and if present, elementally, it may be mobile under high vacuum conditions at high temperatures as indicated by the pressure temperature curve shown in Fig. 1. Further, this document shows that it is thermodynamically feasible to reduce ZnO to Zn by solid state reactions of the ZnO with other metallic components in the TPBARs. However, for these reactions to occur, the ZnO must be in contact with the more active metal so that the chemical reactions can occur. The proposed reactions are based on equilibrium thermodynamics. For simplicity, they do not take into account the quantities of the various materials, the compositions, the effect of alloying, or other technical issues, they are intended only to provide feasibility for the reduction reactions. A more complete thermodynamic model can be developed, but it will require actual contents and be much more complicated with little value added.
- Research Organization:
- Savannah River Site (SRS), Aiken, SC (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- DE-AC09-96SR18500
- OSTI ID:
- 929470
- Report Number(s):
- SRNL-MST-2008-00078; TRN: US0806620
- Country of Publication:
- United States
- Language:
- English
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