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Title: Contaminant Boundary at the Faultless Underground Nuclear Test

Abstract

The U.S. Department of Energy (DOE) and the Nevada Division of Environmental Protection (NDEP) have reached agreement on a corrective action strategy applicable to address the extent and potential impact of radionuclide contamination of groundwater at underground nuclear test locations. This strategy is described in detail in the Federal Facility Agreement and Consent Order (FFACO, 2000). As part of the corrective action strategy, the nuclear detonations that occurred underground were identified as geographically distinct corrective action units (CAUs). The strategic objective for each CAU is to estimate over a 1,000-yr time period, with uncertainty quantified, the three-dimensional extent of groundwater contamination that would be considered unsafe for domestic and municipal use. Two types of boundaries (contaminant and compliance) are discussed in the FFACO that will map the three-dimensional extent of radionuclide contamination. The contaminant boundary will identify the region wi th 95 percent certainty that contaminants do not exist above a threshold value. It will be prepared by the DOE and presented to NDEP. The compliance boundary will be produced as a result of negotiation between the DOE and NDEP, and can be coincident with, or differ from, the contaminant boundary. Two different thresholds are considered for the contaminant boundary.more » One is based on the enforceable National Primary Drinking Water Regulations for radionuclides, which were developed as a requirement of the Safe Drinking Water Act. The other is a risk-based threshold considering applicable lifetime excess cancer-risk-based criteria The contaminant boundary for the Faultless underground nuclear test at the Central Nevada Test Area (CNTA) is calculated using a newly developed groundwater flow and radionuclide transport model that incorporates aspects of both the original three-dimensional model (Pohlmann et al., 1999) and the two-dimensional model developed for the Faultless data decision analysis (DDA) (Pohll and Mihevc, 2000). This new model includes the uncertainty in the three-dimensional spatial distribution of lithology and hydraulic conductivity from the 1999 model as well as the uncertainty in the other flow and transport parameters from the 2000 DDA model. Additionally, the new model focuses on a much smaller region than was included in the earlier models, that is, the subsurface within the UC-1 land withdrawal area where the 1999 model predicted radionuclide transport will occur over the next 1,000 years. The purpose of this unclassified document is to present the modifications to the CNTA groundwater flow and transport model, to present the methodology used to calculate contaminant boundaries, and to present the Safe Drinking Water Act and risk-derived contaminant boundaries for the Faultless underground nuclear test CAU.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Desert Research Institute, University and Community College System of Nevada (US)
Sponsoring Org.:
USDOE Office of Environmental Management (EM) (US)
OSTI Identifier:
812176
Report Number(s):
DOE/NV/13609-24; DRI Pub. No. 45196
TRN: US0303278
DOE Contract Number:  
AC08-00NV13609
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 1 Apr 2003
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE; CONTAMINATION; UNDERGROUND EXPLOSIONS; HYDRAULIC CONDUCTIVITY; LITHOLOGY; RADIOISOTOPES; SPATIAL DISTRIBUTION; RADIONUCLIDE MIGRATION; NUCLEAR EXPLOSIONS; BOUNDARY CONDITIONS; GROUND WATER

Citation Formats

Pohll, Greg, Pohlmann, Karl, Daniels, Jeff, Hassan, Ahmed, and Chapman, Jenny. Contaminant Boundary at the Faultless Underground Nuclear Test. United States: N. p., 2003. Web. doi:10.2172/812176.
Pohll, Greg, Pohlmann, Karl, Daniels, Jeff, Hassan, Ahmed, & Chapman, Jenny. Contaminant Boundary at the Faultless Underground Nuclear Test. United States. https://doi.org/10.2172/812176
Pohll, Greg, Pohlmann, Karl, Daniels, Jeff, Hassan, Ahmed, and Chapman, Jenny. Tue . "Contaminant Boundary at the Faultless Underground Nuclear Test". United States. https://doi.org/10.2172/812176. https://www.osti.gov/servlets/purl/812176.
@article{osti_812176,
title = {Contaminant Boundary at the Faultless Underground Nuclear Test},
author = {Pohll, Greg and Pohlmann, Karl and Daniels, Jeff and Hassan, Ahmed and Chapman, Jenny},
abstractNote = {The U.S. Department of Energy (DOE) and the Nevada Division of Environmental Protection (NDEP) have reached agreement on a corrective action strategy applicable to address the extent and potential impact of radionuclide contamination of groundwater at underground nuclear test locations. This strategy is described in detail in the Federal Facility Agreement and Consent Order (FFACO, 2000). As part of the corrective action strategy, the nuclear detonations that occurred underground were identified as geographically distinct corrective action units (CAUs). The strategic objective for each CAU is to estimate over a 1,000-yr time period, with uncertainty quantified, the three-dimensional extent of groundwater contamination that would be considered unsafe for domestic and municipal use. Two types of boundaries (contaminant and compliance) are discussed in the FFACO that will map the three-dimensional extent of radionuclide contamination. The contaminant boundary will identify the region wi th 95 percent certainty that contaminants do not exist above a threshold value. It will be prepared by the DOE and presented to NDEP. The compliance boundary will be produced as a result of negotiation between the DOE and NDEP, and can be coincident with, or differ from, the contaminant boundary. Two different thresholds are considered for the contaminant boundary. One is based on the enforceable National Primary Drinking Water Regulations for radionuclides, which were developed as a requirement of the Safe Drinking Water Act. The other is a risk-based threshold considering applicable lifetime excess cancer-risk-based criteria The contaminant boundary for the Faultless underground nuclear test at the Central Nevada Test Area (CNTA) is calculated using a newly developed groundwater flow and radionuclide transport model that incorporates aspects of both the original three-dimensional model (Pohlmann et al., 1999) and the two-dimensional model developed for the Faultless data decision analysis (DDA) (Pohll and Mihevc, 2000). This new model includes the uncertainty in the three-dimensional spatial distribution of lithology and hydraulic conductivity from the 1999 model as well as the uncertainty in the other flow and transport parameters from the 2000 DDA model. Additionally, the new model focuses on a much smaller region than was included in the earlier models, that is, the subsurface within the UC-1 land withdrawal area where the 1999 model predicted radionuclide transport will occur over the next 1,000 years. The purpose of this unclassified document is to present the modifications to the CNTA groundwater flow and transport model, to present the methodology used to calculate contaminant boundaries, and to present the Safe Drinking Water Act and risk-derived contaminant boundaries for the Faultless underground nuclear test CAU.},
doi = {10.2172/812176},
url = {https://www.osti.gov/biblio/812176}, journal = {},
number = ,
volume = ,
place = {United States},
year = {2003},
month = {4}
}