Stability of mineral matter in aqueous media of the Chernobyl Unit-4 Shelter: Thermodynamic evaluation

Conference · Wed Dec 31 00:00:00 EST 1997

OSTI ID:572295

Sinitsyn, V A ^[1]; Kurepin, V A; Shurpach, N A ^[1]; Kulik, D A ^[2]; Khodorivski, M S; Abramis, A Y; Kolyabina, I L ^[3]

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1. NAS Ukraine, Kyiv (Ukraine). Inst. of Geochemistry, Mineralogy and Ore Formation
2. State Scientific Centre for Environmental Radiogeochemistry, Kyiv (Ukraine)
3. Minchornobyl Ukraine, Chornobyl (Ukraine). R and D Centre META

A special geochemical environment exists within the Shelter (Sarcophagus) erected in 1986 over the destroyed Unit-4 of Chernobyl nuclear power plant (NPP). Based upon the available in situ and compositional data, thermodynamic models of solid-aqueous interactions were developed to clarify the leaching behavior of various materials within the Shelter. The Selektor-A code, based on a convex programming approach to Gibbs free energy minimization, was used for the calculations. A built-in flexible hybrid thermodynamic database for the system Na-K-Ca-Mg-Cl-S-N-H-O-Si-P-Fe-Al-Sr-Cs was extended with the critically selected and matched parameters for aqueous species and solid phases in the U-Zr-Si-O-H subsystem, secondary U-minerals, mineral phases of fully hydrated Portland cements and U-bearing zircons. Modeling results show that the Shelter Waters can selectively leach a significant quantity of U and Si from the fuel-containing masses, while Zr, Fe, Ca, Mg and some other components are rather insoluble. Serpentinite, assemblages of fully-hydrated phases of Portland cements, and oxidation products of steel structural elements are estimated to be sufficiently stable in the aqueous environment of the Shelter. Calculations also define some feasible pathways for secondary mineral formation from evaporation of Shelter water solutions and interactions between these waters with the mineral matter inside the Shelter.

• OSTI ID: 572295
• Report Number(s): CONF-961202-; TRN: 98:003812
• Resource Relation: Conference: 1996 Fall meeting of the Materials Research Society (MRS), Boston, MA (United States), 2-6 Dec 1996; Other Information: PBD: 1997; Related Information: Is Part Of Scientific basis for nuclear waste management XX; Gray, W.J. [ed.] [Pacific Northwest National Lab., Richland, WA (United States)]; Triay, I.R. [ed.] [Los Alamos National Lab., NM (United States)]; PB: 1389 p.; Materials Research Society symposium proceedings, Volume 465
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
22 NUCLEAR REACTOR TECHNOLOGY
21 NUCLEAR POWER REACTORS AND ASSOCIATED PLANTS
CHERNOBYLSK-4 REACTOR
CONTAINMENT SYSTEMS
FLUID-STRUCTURE INTERACTIONS
MINERALOGY
COMPUTERIZED SIMULATION
S CODES
THERMODYNAMICS
PHASE STUDIES
URANIUM MINERALS
INTERMEDIATE-LEVEL RADIOACTIVE WASTES
WASTE WATER