Potential microbial impact on transuranic wastes under conditions expected in the Waste Isolation Pilot Plant (WIPP). Annual report, October 1, 1978-September 30, 1979
Description: Previous results were confirmed showing elevated frequencies of radiation-resistant bacteria in microorganisms isolated from shallow transuranic (TRU) burial soil that exhibits nanocurie levels of beta and gamma radioactivity. Research to determine whether plutonium could be methylated by the microbially produced methyl donor, methylcobalamine, was terminated when literature and consulting radiochemists confirmed that other alkylated transuranic elements are extremely short-lived in the presence of oxygen. Emphasis was placed on investigation of the dissolution of plutonium dioxide by complex formation between plutonium and a polyhydroxamate chelate similar to that produced by microorganisms. New chromatographic and spectrophotometric evidence supports previous results showing enhanced dissolution of alpha radioactivity when /sup 239/Pu dioxide was mixed with the chelate Desferol. Microbial degradation studies of citrate, ethylenediamine tetraacetate (EDTA), and nitrilo triacetate (NTA) chelates of europium are in progress. Current results are summarized. All of the chelates were found to degrade. The average half-life for citrate, NTA, and EDTA was 3.2, 8.0, and 28 years, respectively. Microbial CO/sub 2/ generation is also in progress in 72 tests on several waste matrices under potential WIPP isolation conditions. The mean rate of gas generation was 5.97 ..mu..g CO/sub 2//g waste/day. Increasing temperature increased rates of microbial gas generation across treatments of brine, varying water content, nutrient additions, and anaerobic conditions. No microbial growth was detected in experiments to enumerate and identify the microorganisms in rocksalt cores from the proposed WIPP site. This report contains the year's research results and recommendations derived for the design of safe storage of TRU wastes under geologic repository conditions.
Date: July 1, 1980
Creator: Barnhart, B.J.; Campbell, E.W.; Martinez, E.; Caldwell, D.E. & Hallett, R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department