The role of a detailed aqueous phase source release model in the LANL Area G performance assessment
- Los Alamos National Lab., NM (United States)
- Rogers Engineering Associates, Salt Lake City, UT (United States)
The Performance Assessment for the LANL Low-Level Radioactive Waste (LLRW) Disposal Facility, Area G, is on-going. A detailed review of the inventory data base records and the existing models for source release led to the development of a new modeling capability to describe the liquid phase aqueous transport from the waste package volumes. Inventory is sorted into four release form categories and screened in a comparison of leachate concentrations to the drinking water limit. Percolation through the disposal unit is prescribed in an independent surface water balance model incorporating site rainfall statistics. Waste package types and the disposal unit matrix have independently specified solubility limits and solid-liquid phase partition coefficients, or Kd values. Analytic solutions for inventory limited release of each nuclide in each of the four different waste package release forms are computed. Isotopic contributions are summed over elements to limit the waste package liquid phase concentrations to the elemental solubility limits. Time dependent releases from the waste packages for each nuclide which may be inventory or solubility limited are specified as model output which is provided as the source term to the unsaturated transport model. The waste package efflux is distributed over the 2-D unsaturated zone model grid points corresponding to the cross-sections for 5 representative disposal units within the mesa top. Results show the Area G release is dominated by the inventory in the rapid release waste form (Kd = 0), which percolates from the waste packages over 5--100 years and from the disposal unit over 50--1,000 years. Nuclides in waste package categories with larger Kd values are released proportionately slower. U and Th are the main nuclides of concern released as solubility limited nuclides from the historical inventory at Area G.
- Research Organization:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 212462
- Report Number(s):
- LA-UR-96-368; CONF-960212-69; ON: DE96008122; TRN: 96:010543
- Resource Relation:
- Conference: Waste management `96: HLW, LLW, mixed wastes and environmental restoration - working towards a cleaner environment, Tucson, AZ (United States), 25-29 Feb 1996; Other Information: PBD: [1996]
- Country of Publication:
- United States
- Language:
- English
Similar Records
Phase two of the source release modeling for the Los Alamos Area G Disposal Facility Performance Assessment
The role of a detailed aqueous phase source release model in the LANL area G performance assessment