Reduction of Pertechnetate from Off-gas Condensate using Aged Zero-valent Iron as a Reducing Agent

Authors

Abraham T. GebruFollow

Document Type

Thesis

Degree

Master of Science (MS)

Major/Program

Civil Engineering

First Advisor's Name

Dr. Shonali Laha

First Advisor's Committee Title

Committee chair

Second Advisor's Name

Dr. Berrin Tansel

Second Advisor's Committee Title

Committee member

Third Advisor's Name

Dr. Walter Tang

Third Advisor's Committee Title

Committee member

Fourth Advisor's Name

Dr. Yelena Katsenovich

Fourth Advisor's Committee Title

Committee member

Fifth Advisor's Name

Dr. Hilary Emerson

Fifth Advisor's Committee Title

Committee member

Keywords

Civil Engineering

Date of Defense

6-26-2019

Abstract

The Hanford site located in Washington State was one of the major nuclear processing facilities in the U.S. where plutonium was produced between the 1940s and the 1980’s. As a result of this forty yearlong production, approximately 53 million gallons of radioactive waste was generated and currently stored in 177 single and double shelled underground tanks. There were around 60 major and minor leaking incidents in the tanks through the years. These leaking incidents were wakeup calls to a search for an effective long term disposal solution. This paper will concentrate on the low activity waste (LAW), specifically the radioactive element technetium (Tc). Tc-99 is radioactive with a half-life of 211,000 years, formed during nuclear fission of Uranium-235. Tc-99 can be found in different oxidation states. However, Tc(VII), as pertechnetate anion (TcO 4 - ), is the most abundant in Hanford low activity aqueous waste due to its high solubility.

Currently there is no operational treatment plant at the site, but, once the treatment plant starts operation, the planned technique for the LAW is vitrification. Because of the higher volatility of technetium, this method can be challenging to accomplish. Here, we investigate another way of dealing with this highly volatile Tc(VII) via zero valent iron (ZVI). This material could be used to reduce Tc(VII) into a less volatile isotope Tc(IV) followed by possible precipitation.

Identifier

FIDC007811

Recommended Citation

Gebru, Abraham T., "Reduction of Pertechnetate from Off-gas Condensate using Aged Zero-valent Iron as a Reducing Agent" (2019). FIU Electronic Theses and Dissertations. 4223.
https://digitalcommons.fiu.edu/etd/4223