Source-term analysis for Hanford low-activity tank waste using the reaction-transport code AREST-CT
- Pacific Northwest National Lab., Richland, WA (United States)
A general, integrated performance assessment code, AREST-CT, was used to analyze the influence of various factors on the release rates of radionuclides from a proposed facility for disposal of low-activity tank wastes. The code couples various process models together based on the framework of reaction-transport theory. The disposal facility was modeled as a 1-D column surrounded by soil. A borosilicate waste glass, LD6-5412 was the waste form considered in the analysis. Included in the simulations were 38 aqueous species, 14 minerals, 21 equilibrium reactions, and 16 kinetic reactions. Dissolution rate of the glass and the release rates of Tc, Pu, U, Np, I. Se under different conditions were calculated for 50,000 years. The simulations revealed that (1) open exchange between the atmosphere and pore-water within the vault significantly improves the performance; (2) an ion-exchange reaction between the glass and aqueous phase increases the release rates significantly; and (3) at the hydrogeologic conditions under consideration, variation of the pore-water velocity has little effect on the release rate of radionuclides. These results provide a scientific basis for formulation of waste forms and engineering design of the disposal facility. Reaction-transport modeling can provide information on the long-term performance of disposal systems that are not obtainable from laboratory experiments alone or by conventional decoupled process models.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 572242
- Report Number(s):
- CONF-961202-; TRN: 98:003786
- 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
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