Evidence of radiolytic oxidation of {sup 241}Am in Na{sup +}/Cl{sup -}HCO{sub 3}{sup -}/CO{sub 3}{sup 2-} media
- CEA, Fontenay aux Roses (France)
This paper examines Americium behavior in Cl{sup -} media at room temperature in connection with environmental and waste disposal programs. Most published values on U, Np, Pu and Am complexation in chloride media have been determined using extraction methods. Spectrophotometric techniques are not sensitive enough to prove actinide complexation by chloride, which is confirmed in this paper for Am(III). Am(OH){sub 3(s)}, AmOHCO{sub 3(s)}, Am{sub 2}(CO{sub 3}){sub 3(s)} or NaAm(CO{sub 3}){sub 2(s)} solid phases can control the Am solubility, depending on the chemical conditions of the aqueous phase (usually P{sub CO{sub 2}}). {sup 241}Am solubility is here found to be higher in NaCl 4M media than in NaCl 0.1 M (up to 3 orders of magnitude). Addition of a reducing agent (metallic iron) lowers the solubility. After a week, solubilities in NaCl 0.1 M and 4 M are similar. These results are consistent with Am(III) radiolytic oxidation to Am(V), due to {alpha} radiations. Little evidence of Cl{sup -} or mixed Cl{sup -}-CO{sub 3}{sup 2-} complexes is found in these conditions. In Na{sup +}-OH{sup -}-Cl{sup -} media, {sup 241}Am(III) oxidation had also been proposed. Slow kinetics of precipitation could induce experimental uncertainties.
- OSTI ID:
- 62262
- Report Number(s):
- CONF-921101-Vol.294; TRN: 95:002922-0079
- Resource Relation:
- Conference: 16. Materials Research Society (MRS) fall meeting, Boston, MA (United States), 30 Nov - 5 Dec 1992; Other Information: PBD: 1993; Related Information: Is Part Of Scientific basis for nuclear waste management XVI; Interrante, C.G. [ed.] [Nuclear Regulatory Commission, Washington, DC (United States)]; Pabalan, R.T. [ed.] [Southwest Research Inst., San Antonio, TX (United States)]; PB: 959 p.
- Country of Publication:
- United States
- Language:
- English
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