Second performance assessment iteration of the Greater Confinement Disposal facility at the Nevada Test Site
- GRAM, Inc., Albuquerque, NM (United States)
- Science Applications International Corp., Albuquerque, NM (United States)
- Sandia National Labs., Albuquerque, NM (United States)
The Greater Confinement Disposal (GCD) facility was established in Area 5 at the Nevada Test Site for containment of waste inappropriate for shallow land burial. Some transuranic (TRU) waste has been disposed of at the GCD facility, and compliance of this disposal system with EPA regulation 40 CFR 191 must be evaluated. We have adopted an iterative approach in which performance assessment results guide site data collection, which in turn influences the parameters and models used in performance assessment. The first iteration was based upon readily available data, and indicated that the GCD facility would likely comply with 40 CFR 191 and that the downward flux of water through the vadose zone (recharge) had a major influence on the results. Very large recharge rates, such as might occur under a cooler, wetter climate, could result in noncompliance. A project was initiated to study recharge in Area 5 by use of three environmental tracers. The recharge rate is so small that the nearest groundwater aquifer will not be contaminated in less than 10,000 years. Thus upward liquid diffusion of radionuclides remained as the sole release pathway. This second assessment iteration refined the upward pathway models and updated the parameter distributions based upon new site information. A new plant uptake model was introduced to the upward diffusion pathway; adsorption and erosion were also incorporated into the model. Several modifications were also made to the gas phase radon transport model. Plutonium solubility and sorption coefficient distributions were changed based upon new information, and on-site measurements were used to update the moisture content distributions. The results of the assessment using these models indicate that the GCD facility is likely to comply with all sections of 40 CFR 191 under undisturbed conditions.
- Research Organization:
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 10170999
- Report Number(s):
- SAND-93-0089; ON: DE94016147; BR: GB0103012; TRN: 94:015499
- Resource Relation:
- Other Information: PBD: Apr 1994
- Country of Publication:
- United States
- Language:
- English
Similar Records
Results from the second performance assessment iteration for the Greater Confinement Disposal facility
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Related Subjects
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
GROUND WATER
RADIONUCLIDE MIGRATION
SOILS
ALPHA-BEARING WASTES
UNDERGROUND DISPOSAL
RECHARGE
UPTAKE
NEVADA TEST SITE
AQUIFERS
TRACER TECHNIQUES
540230
052002
RADIOACTIVE MATERIALS MONITORING AND TRANSPORT
WASTE DISPOSAL AND STORAGE