A performance assessment methodology for high-level radioactive waste disposal in unsaturated, fractured tuff
- Sandia National Labs., Albuquerque, NM (USA)
Sandia National Laboratories, has developed a methodology for performance assessment of deep geologic disposal of high-level nuclear waste. The applicability of this performance assessment methodology has been demonstrated for disposal in bedded salt and basalt; it has since been modified for assessment of repositories in unsaturated, fractured tuff. Changes to the methodology are primarily in the form of new or modified ground water flow and radionuclide transport codes. A new computer code, DCM3D, has been developed to model three-dimensional ground-water flow in unsaturated, fractured rock using a dual-continuum approach. The NEFTRAN 2 code has been developed to efficiently model radionuclide transport in time-dependent velocity fields, has the ability to use externally calculated pore velocities and saturations, and includes the effect of saturation dependent retardation factors. In order to use these codes together in performance-assessment-type analyses, code-coupler programs were developed to translate DCM3D output into NEFTRAN 2 input. Other portions of the performance assessment methodology were evaluated as part of modifying the methodology for tuff. The scenario methodology developed under the bedded salt program has been applied to tuff. An investigation of the applicability of uncertainty and sensitivity analysis techniques to non-linear models indicate that Monte Carlo simulation remains the most robust technique for these analyses. No changes have been recommended for the dose and health effects models, nor the biosphere transport models. 52 refs., 1 fig.
- Research Organization:
- Nuclear Regulatory Commission, Washington, DC (United States). Div. of Engineering; Sandia National Labs., Albuquerque, NM (United States)
- Sponsoring Organization:
- Nuclear Regulatory Commission, Washington, DC (USA)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 138143
- Report Number(s):
- NUREG/CR--5701; SAND--91-0539; ON: TI91015353
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
54 ENVIRONMENTAL SCIENCES
99 GENERAL AND MISCELLANEOUS
BIOSPHERE
D CODES
FLUID FLOW
GROUND WATER
HEALTH HAZARDS
HIGH-LEVEL RADIOACTIVE WASTES
MONTE CARLO METHOD
N CODES
PERFORMANCE TESTING
RADIONUCLIDE MIGRATION
TIME DEPENDENCE
TUFF
UNDERGROUND DISPOSAL
YUCCA MOUNTAIN
Yucca Mountain Project