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Yucca Mountain Project Getter Program Results (Year 1) I-I29 and Other Anions of Concern

Description: Although high level nuclear wastes (HLW) contain a daunting array of radioisotopes, only a restricted number are long-lived enough to be problematic, and of these many are either effectively insoluble or are likely to be scavenged from solution by minerals indigenous to all aquifers. Those few constituents likely to travel significant distances through aquifers either form colloids (and travel as particulates) or anions--which are not sorbed onto the predominantly negatively charged mineral surfaces. Iodine ({sup 129}I) is one such constituent and may travel as either iodide (I{sup -}) or iodate (IO{sub 3}{sup -}) depending on whether conditions are mildly reducing or oxidizing. Conventionally, {sup 99}Tc (traveling as TcO{sub 4}{sup 0}) is regarded as being of greater concern since it is both more abundant and has a shorter half life (e.g., has a higher specific activity). However, it is unclear whether TcO{sub 4}{sup -} will ever actually form in the mildly reducing environments thought likely within degrading HLW canisters. Instead, technetium may remain reduced as highly insoluble Tc(lV), in which case {sup 129}I might become a significant risk driver in performance assessment (PA) calculations. In the 2004-2005 time frame the US Department of Energy (DOE)--Office of Civilian Radioactive Waste Management (OCRUM), Office of Science and Technology International (S&T) funded a program to identify ''getters'' for possible placement in the invert beneath HLW packages in the repository being planned by the Yucca Mountain Project (YMP). This document reports on progress made during the first (and only) year of this activity. The problem is not a new one and the project did not proceed in a complete vacuum of information. Potential leads came from past studies directed at developing anion getters for a near surface low-level waste facility at Hanford, which suggested that both copper-containing compounds and hydrotalcite-group minerals might be promising. Later ...
Date: July 17, 2006
Creator: Krumhansl, J.L.; Pless, J.D.; Chwirka, J.B. & Holt, K.C.
Partner: UNT Libraries Government Documents Department

New {sup 232}U/{sup 228}Th Gamma Source for Tritiated Water Monitor

Description: The {sup 232}U/{sup 228}Th source has been tested for operation with the tritiated water monitor. This source has an effective half-life of 73 years and is an attractive replacement for the reactor activated {sup 24}Na sources, which have half-life of only 15 hours. The tests described in this report appraise the adequacy of this source by comparing its performance to that of {sup 24}Na used in earlier studies. The new source has already been used successfully to assist recovery operations, and it is now apparent that the monitor is ready to be turned over to SRP for routine use.
Date: July 17, 2001
Creator: Winn, W.G.
Partner: UNT Libraries Government Documents Department