The Radiation Chemistry of CMPO: Part 2. Alpha Radiolysis

Journal Article · Fri Jan 24 00:00:00 EST 2014 · Solvent Extraction and Ion Exchange

DOI:https://doi.org/10.1080/07366299.2013.850300· OSTI ID:1454602

Mincher, Bruce J. ^[1]; Mezyk, Stephen P. ^[2]; Elias, Gracy ^[3]; Groenewold, Gary S. ^[3]; LaVerne, Jay A. ^[4]; Nilsson, Mikael ^[5]; Pearson, Jeremy ^[5]; Schmitt, Nicholas C. ^[3]; Tillotson, Richard D. ^[1]; Olson, Lonnie G. ^[1]

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1. Idaho National Lab. (INL), Idaho Falls, ID (United States). Aqueous Separations and Radiochemistry Dept.
2. California State Univ. (CalState), Long Beach, CA (United States). Dept. of Chemistry and Biochemistry
3. Idaho National Lab. (INL), Idaho Falls, ID (United States). Chemistry and Radiation Measurements Dept.
4. Univ. of Notre Dame, IN (United States). Dept. of Physics
5. Univ. of California, Irvine, CA (United States). Dept. of Chemical Engineering and Materials Science

Here, Octylphenyl-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) dissolved in dodecane was subjected to α-irradiation using a He-ion beam, ²⁴⁴Cm isotopic α-rays, and He and Li ions created by the n,α reaction of ¹⁰B in a nuclear reactor. Post-irradiation samples were analyzed for the radiolytically-induced decrease in CMPO concentration, the appearance of degradation products, and their Am solvent extraction distribution ratios. The –G _CMPO-value for the radiolytic degradation of CMPO was found to be very low compared to values previously reported for γ-irradiation. Additionally, isotopic irradiation to absorbed α-doses as high as 600 kGy in aerated solution had no effect on Am solvent extraction or stripping. The main CMPO radiolysis products identified in He-ion beam irradiated samples by ESI-MS include amides, an acidic amide, and amines produced by bond rupture on either side of the CMPO carbonyl group. Deaerated samples irradiated using the reactor in the absence of an aqueous phase, or with a dilute nitric acid aqueous phase showed small but measurable decreases in CMPO concentration with increasing absorbed doses. Higher concentrations of nitric acid resulted in lower decomposition rates for the CMPO. The radio-protection by dissolved oxygen and nitric acid previously found for γ-irradiated CMPO also occurs for α-irradiation. This suggests that similar free-radical mechanisms operate in the high-LET system, but with lower degradation yields due to the lower overall radical concentrations produced.

• Research Organization: Idaho National Lab. (INL), Idaho Falls, ID (United States); Univ. of California, Irvine, CA (United States)
• Sponsoring Organization: USDOE Office of Nuclear Energy (NE)
• Grant/Contract Number: NA0000979; AC07-05ID14517
• OSTI ID: 1454602
• Report Number(s): INL/JOU-13-29077; TRN: US1901086
• Journal Information: Solvent Extraction and Ion Exchange, Vol. 32, Issue 2; ISSN 0736-6299
• Publisher: Taylor and Francis
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
CMPO
free radicals
alpha irradiation
solvent extraction