Long-Term Performance of Transuranic Waste Inadvertently Disposed in a Shallow Land Burial Trench at the Nevada Test Site
In 1986, 21 m3 of transuranic (TRU) waste was inadvertently disposed in a shallow land burial trench at the Area 5 Radioactive Waste Management Site on the Nevada Test Site. U.S. Department of Energy (DOE) TRU waste must be disposed in accordance with Title 40, Code of Federal Regulations (CFR), Part 191, Environmental Radiation Protection Standard for Management and Disposal of Spent Nuclear Fuel, High-Level, and Transuranic Radioactive Wastes. The Waste Isolation Pilot Plant is the only facility meeting these requirements. The National Research Council, however, has found that exhumation of buried TRU waste for disposal in a deep geologic repository may not be warranted when the effort, exposures, and expense of retrieval are not commensurate with the risk reduction achieved. The long-term risks of leaving the TRU waste in-place are evaluated in two probabilistic performance assessments. A composite analysis, assessing the dose from all disposed waste and interacting sources of residual contamination, estimates an annual total effective dose equivalent (TEDE) of 0.01 mSv, or 3 percent of the dose constraint. A 40 CFR 191 performance assessment also indicates there is reasonable assurance of meeting all requirements. The 40 CFR 191.15 annual mean TEDE for a member of the public is estimated to reach a maximum of 0.055 mSv at 10,000 years, or approximately 37 percent of the 0.15 mSv individual protection requirement. In both assessments greater than 99 percent of the dose is from co-disposed low-level waste. The simulated probability of the 40 CFR 191.13 cumulative release exceeding 1 and 10 times the release limit is estimated to be 0.0093 and less than 0.0001, respectively. Site characterization data and hydrologic process modeling support a conclusion of no groundwater pathway within 10,000 years. Monte Carlo uncertainty analysis indicates that there is reasonable assurance of meeting all regulatory requirements. Sensitivity analysis indicates that the results are insensitive to TRU waste-related parameters. Limited quantities of TRU waste in a shallow land burial trench can meet DOE performance objectives for disposal of TRU waste and contribute negligibly to disposal site risk. Leaving limited quantities of buried TRU waste in-place may be preferred over retrieval for disposal in a deep geologic repository.
- Research Organization:
- National Security Technologies, LLC (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NA)
- DOE Contract Number:
- DE-AC52-06NA25946
- OSTI ID:
- 961545
- Report Number(s):
- DOE/NV/25946-734; TRN: US0903149
- Resource Relation:
- Conference: 54th Annual Meeting of the Health Physics Society; Minneapolis, MN; July 12-16, 2009
- Country of Publication:
- United States
- Language:
- English
Similar Records
A Title 40 Code of Federal Regulations Part 191 Evaluation of Buried Transuranic Waste at the Nevada Test Site
Special Analysis of Transuranic Waste in Trench T04C at the Area 5 Radioactive Waste Management Site, Nevada Test Site, Nye County, Nevada, Revision 1
Related Subjects
ALPHA-BEARING WASTES
CONTAMINATION
DOSE EQUIVALENTS
GROUND DISPOSAL
NEVADA TEST SITE
NUCLEAR FUELS
PROBABILITY
RADIATION PROTECTION
RADIOACTIVE WASTE MANAGEMENT
RADIOACTIVE WASTES
REGULATIONS
RELEASE LIMITS
SENSITIVITY ANALYSIS
SITE CHARACTERIZATION
WASTES
WIPP
SPENT FUELS
transuranic
Nevada Test Site