Rhenium Uptake, as Analogue for Tc-99, by Steel Corrosion Products
Static batch experiments were used to examine the sorption of dissolved perrhenate [Re(VII)], as a surrogate for pertechnetate [Tc(VII)], on corrosion products of A-516 carbon steel coupons contacted with synthetic groundwater or dilute water. After 109 days of contact time, the concentration of dissolved Re(VII) in the synthetic groundwater matrix decreased by approximately 26%; the dilute water matrix experienced a 99% decrease in dissolved Re(VII) over the same time period. Bulk XRD results for the corroded steel coupons showed that the corrosion products consisted primarily of maghemite, lepidocrocite, and goethite. Analyses of the coupons by SEM/EDS indicated that Re was present with the morphologically complex assemblages of Fe oxide/hydroxide corrosion products for samples spiked with the highest dissolved Re(VII) concentration (1.0 mmol/L) used for these experiments. Analyses of corroded steel coupons contacted with solutions containing 1.0 mmol/L Re(VII) by synchrotron-based methods confirmed the presence of Re sorbed with the corrosion product on the steel coupons. Analyses showed that the Re sorbed on these corroded coupons was in the +7 oxidation state, suggesting that the Re(VII) uptake mechanism did not involve reduction of Re to a lower oxidation state, such as +4. The results of our studies using Re(VII) as an analogue for Tc(VII)-99 suggest that Tc(VII)-99 would also be sorbed with steel corrosion products and that the inventory of Tc(VII)-99 released from breached waste packages would be lower than what is now conservatively estimated.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 895172
- Report Number(s):
- PNNL-SA-48149; DF0961000; TRN: US0700788
- Resource Relation:
- Conference: Proceedings of the 11th International High-Level Radioactive Waste Management Conference (IHLRWM), April 30 - May 4, 2006, Las Vegas, Nevada, 905-912
- Country of Publication:
- United States
- Language:
- English
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Rhenium Uptake as Analogue for 99Tc by Steel Corrosion Products
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Related Subjects
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
CARBON STEELS
CORROSION PRODUCTS
GOETHITE
HIGH-LEVEL RADIOACTIVE WASTES
MANAGEMENT
PERRHENATES
PERTECHNETATES
RHENIUM
SORPTION
STEELS
VALENCE
WASTES
WATER
X-RAY DIFFRACTION
Yucca Mountain
technetium
rhenium
corrosion
iron oxide
sorption
adsorption
precipitation