Geochemical Testing and Model Development - Residual Tank Waste (PNNL Scope # 45073)
EMSL Project ID
11694
Abstract
Mössbauer Analysis of C-204 Sludge Previous selective extraction work conducted on tank sludge samples from several Hanford tanks indicate that significant fractions of several typically highly mobile contaminants of concern have been effectively immobilized in a number of these sludge samples. The selective extractions indicate that immobile fractions of 99Tc and Cr are associated with iron containing phases. XRD has not been successful at identifying any crystalline iron phase. As a result of these findings, we would like to apply Mössbauer spectroscopy to investigate the identity of the iron containing phase or phases responsible for sequestering 99Tc and Cr in these tank sludges. Understanding the nature of these immobile forms of contaminants of concern will be valuable for developing mechanistically based release models for risk assessments. In addition, fundamental knowledge of how these normally mobile contaminants have been so effectively sequestered could be applied in other applications for environmental benefit. C-204 sludge has been selected for this investigation because of its relatively high iron content and low radioactivity. Previous analyses indicate an iron content of approximately 13%. Because of the radioactive nature of these samples, they will be prepared in epoxy to eliminate the possibility of sample dispersion.
Project Details
Project type
Exploratory Research
Start Date
2004-11-01
End Date
2005-11-06
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members