SYMPOSIA PAPER Published: 01 January 1996
STP14108S

Microbially Influenced Degradation of Cement-Solidified Low-Level Radioactive Waste Forms

Source

Because of its apparent structural integrity, cement has been widely used in the United States as a binder to solidify Class B and C low-level radioactive waste (LLW). However, the resulting cement preparations are susceptible to failure due to the actions of stress and environment. This paper contains information on three groups of microorganisms that are associated with the degradation of cement materials : sulfur-oxidizing bacteria (Thiobacillus), nitrifying bacteria (Nitrosomonas and Nitrobacter), and heterotrophic bacteria, which produce organic acids. Preliminary work using laboratory- and vendor-manufactured, simulated waste forms exposed to thiobacilli has shown that microbiologically influenced degradation has the potential to severely compromise the structural integrity of ion-exchange resin and evaporator-bottoms waste that is solidified with cement. In addition, it was found that a significant percentage of calcium was leached from the treated waste forms. Also, the surface pH of the treated specimens was decreased to below 2. These conditions apparently contributed to the physical deterioration of simulated waste forms after 30 to 60 days of exposure.

Author Information

Rogers, RD
Idaho National Engineering Laboratory, EG&G Idaho, Inc., Idaho Falls, ID
Hamilton, MA
Idaho National Engineering Laboratory, EG&G Idaho, Inc., Idaho Falls, ID
Veeh, RH
Idaho National Engineering Laboratory, EG&G Idaho, Inc., Idaho Falls, ID
McConnell, JW
Idaho National Engineering Laboratory, EG&G Idaho, Inc., Idaho Falls, ID
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Details
Developed by Committee: D34
Pages: 116–132
DOI: 10.1520/STP14108S
ISBN-EB: 978-0-8031-5318-9
ISBN-13: 978-0-8031-1443-2