skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: The Changing Adventures of Mixed Low-Level Waste Disposal at the Nevada Test Site

Abstract

After a 15-year hiatus, the United States Department of Energy (DOE) National Nuclear Security Administration Nevada Site Office (NNSA/NSO) began accepting DOE off-site generated mixed low-level radioactive waste (MLLW) for disposal at the Nevada Test Site (NTS) in December 2005. This action was predicated on the acceptance by the Nevada Division of Environmental Protection (NDEP) of a waste analysis plan (WAP). The NNSA/NSO agreed to limit mixed waste disposal to 20,000 cubic meters (approximately 706,000 cubic feet) and close the facility by December 2010 or sooner, if the volume limit is reached. The WAP and implementing procedures were developed based on Hanford’s system of verification to the extent possible so the two regional disposal sites could have similar processes. Since the NNSA/NSO does not have a breaching facility to allow the opening of boxes at the site, verification of the waste occurs by visual inspection at the generator/treatment facility or by Real-Time-Radiography (RTR) at the NTS. This system allows the NTS to effectively, efficiently, and compliantly accept MLLW for disposal. The WAP, NTS Waste Acceptance Criteria, and procedures have been revised based on learning experiences. These changes include: RTR expectations; visual inspection techniques; tamper-indicating device selection; void space requirements; andmore » chemical screening concerns. The NNSA/NSO, NDEP, and the generators have been working together throughout the debugging of the verification processes. Additionally, the NNSA/NSO will continue to refine the MLLW acceptance processes and strive for continual improvement of the program. However, the NNSA/NSO has identified DOE complex-wide issues: (1) the temporary closure of the Hanford facility to off-site generators leaves the NTS as the only Federal facility able to dispose of MLLW. If the Hanford facility is not permitted to accept waste from off-site generators after December 2010, the DOE complex will have no Federal facility to accept higher activity MLLW. It is not known if commercial disposal options for higher activities MLLW will be available by December 2010. (2) MLLW forecasts to the NTS do not fully utilize the 20,000 cubic meter capacity within five years. The DOE has urged generator facilities to re-prioritize projects and has conducted planning meetings to identify actions to increase the use of the NTS disposal capacity. (3) Generators have requested disposal of classified material in the MLLW disposal cell, however closure, safeguard termination, and “irretrievability” issues must be resolved.« less

Authors:
;
Publication Date:
Research Org.:
National Nuclear Security Administration, Nevada Site Office
Sponsoring Org.:
USDOE
OSTI Identifier:
939495
Report Number(s):
DOE/NV-1162
TRN: US0806801
Resource Type:
Conference
Resource Relation:
Conference: Waste Management 2007; February 25 - March 1, 2007; Tucson, AZ
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; CAPACITY; CLOSURES; ENVIRONMENTAL PROTECTION; LEARNING; LOW-LEVEL RADIOACTIVE WASTES; NEVADA TEST SITE; OPENINGS; PLANNING; SAFEGUARDS; SECURITY; VERIFICATION; WASTE DISPOSAL; WASTE MANAGEMENT; WASTES

Citation Formats

Gary Pyles, and Jhon Carilli. The Changing Adventures of Mixed Low-Level Waste Disposal at the Nevada Test Site. United States: N. p., 2007. Web.
Gary Pyles, & Jhon Carilli. The Changing Adventures of Mixed Low-Level Waste Disposal at the Nevada Test Site. United States.
Gary Pyles, and Jhon Carilli. Thu . "The Changing Adventures of Mixed Low-Level Waste Disposal at the Nevada Test Site". United States. doi:. https://www.osti.gov/servlets/purl/939495.
@article{osti_939495,
title = {The Changing Adventures of Mixed Low-Level Waste Disposal at the Nevada Test Site},
author = {Gary Pyles and Jhon Carilli},
abstractNote = {After a 15-year hiatus, the United States Department of Energy (DOE) National Nuclear Security Administration Nevada Site Office (NNSA/NSO) began accepting DOE off-site generated mixed low-level radioactive waste (MLLW) for disposal at the Nevada Test Site (NTS) in December 2005. This action was predicated on the acceptance by the Nevada Division of Environmental Protection (NDEP) of a waste analysis plan (WAP). The NNSA/NSO agreed to limit mixed waste disposal to 20,000 cubic meters (approximately 706,000 cubic feet) and close the facility by December 2010 or sooner, if the volume limit is reached. The WAP and implementing procedures were developed based on Hanford’s system of verification to the extent possible so the two regional disposal sites could have similar processes. Since the NNSA/NSO does not have a breaching facility to allow the opening of boxes at the site, verification of the waste occurs by visual inspection at the generator/treatment facility or by Real-Time-Radiography (RTR) at the NTS. This system allows the NTS to effectively, efficiently, and compliantly accept MLLW for disposal. The WAP, NTS Waste Acceptance Criteria, and procedures have been revised based on learning experiences. These changes include: RTR expectations; visual inspection techniques; tamper-indicating device selection; void space requirements; and chemical screening concerns. The NNSA/NSO, NDEP, and the generators have been working together throughout the debugging of the verification processes. Additionally, the NNSA/NSO will continue to refine the MLLW acceptance processes and strive for continual improvement of the program. However, the NNSA/NSO has identified DOE complex-wide issues: (1) the temporary closure of the Hanford facility to off-site generators leaves the NTS as the only Federal facility able to dispose of MLLW. If the Hanford facility is not permitted to accept waste from off-site generators after December 2010, the DOE complex will have no Federal facility to accept higher activity MLLW. It is not known if commercial disposal options for higher activities MLLW will be available by December 2010. (2) MLLW forecasts to the NTS do not fully utilize the 20,000 cubic meter capacity within five years. The DOE has urged generator facilities to re-prioritize projects and has conducted planning meetings to identify actions to increase the use of the NTS disposal capacity. (3) Generators have requested disposal of classified material in the MLLW disposal cell, however closure, safeguard termination, and “irretrievability” issues must be resolved.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Feb 01 00:00:00 EST 2007},
month = {Thu Feb 01 00:00:00 EST 2007}
}

Conference:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

Save / Share:
  • After a 15-year hiatus, the United States Department of Energy (DOE) National Nuclear Security Administration Nevada Site Office (NNSA/NSO) began accepting DOE off-site generated mixed low-level radioactive waste (MLLW) for disposal at the Nevada Test Site (NTS) in December 2005. This action was predicated on the acceptance by the Nevada Division of Environmental Protection (NDEP) of a waste analysis plan (WAP). The NNSA/NSO agreed to limit mixed waste disposal to 20,000 cubic meters (approximately 706,000 cubic feet) and close the facility by December 2010 or sooner, if the volume limit is reached. The WAP and implementing procedures were developed basedmore » on Hanford’s system of verification to the extent possible so the two regional disposal sites could have similar processes. Since the NNSA/NSO does not have a breaching facility to allow the opening of boxes at the site, verification of the waste occurs by visual inspection at the generator/treatment facility or by Real-Time-Radiography (RTR) at the NTS. This system allows the NTS to effectively, efficiently, and compliantly accept MLLW for disposal. The WAP, NTS Waste Acceptance Criteria, and procedures have been revised based on learning experiences. These changes include: RTR expectations; visual inspection techniques; tamper-indicating device selection; void space requirements; and chemical screening concerns. The NNSA/NSO, NDEP, and the generators have been working together throughout the debugging of the verification processes. Additionally, the NNSA/NSO will continue to refine the MLLW acceptance processes and strive for continual improvement of the program.« less
  • Low-level radioactive waste (LLW) streams which have a clear, defined pathway to disposal are becoming less common as U.S. Department of Energy accelerated cleanup sites enters their closure phase. These commonly disposed LLW waste streams are rapidly being disposed and the LLW inventory awaiting disposal is dwindling. However, more complex waste streams that have no path for disposal are now requiring attention. The U.S. Department of Energy (DOE) National Nuclear Security Administration Nevada Site Office (NSO) Environmental Management Program is charged with the responsibility of carrying out the disposal of onsite and off-site defense-generated and research-related LLW at the Nevada.more » Test Site (NTS). The NSO and its generator community are constantly pursuing new LLW disposal techniques while meeting the core mission of safe and cost-effective disposal that protects the worker, the public and the environment. From trenches to present-day super-cells, the NTS disposal techniques must change to meet the LLW generator's disposal needs. One of the many ways the NTS is addressing complex waste streams is by designing waste specific pits and trenches. This ensures unusual waste streams with high-activity or large packaging have a disposal path. Another option the NTS offers is disposal of classified low-level radioactive-contaminated material. In order to perform this function, the NTS has a safety plan in place as well as a secure facility. By doing this, the NTS can accept DOE generated classified low-level radioactive-contaminated material that would be equivalent to U.S. Nuclear Regulatory Commission Class B, C, and Greater than Class C waste. In fiscal year 2006, the NTS will be the only federal disposal facility that will be able to dispose mixed low-level radioactive waste (MLLW) streams. This is an activity that is highly anticipated by waste generators. In order for the NTS to accept MLLW, generators will have to meet the stringent requirements of the NTS Waste Acceptance Criteria. The disposal operations previously mentioned take place at the NTS in two disposal facilities. The isolation protection and overall performance of the two LLW disposal facilities at the NTS transcend those of any federal radioactive waste disposal site in the United States. The first of the two disposal sites is the Area 5 Radioactive Waste Management Site (RWMS) which is situated on alluvial fan deposits in the Frenchman Flat basin, approximately 770 feet (235 meters) above the water table. The Area 5 RWMS utilizes a combination of engineered shallow land disposal cells and deep augured shafts for the disposal of a variety of waste streams. Fifteen miles (24 kilometers) north of the Area 5 RWMS is the Area 3 RWMS located approximately 1,600 feet (488 meters) above the water table in Yucca Flat. Disposal activities at the Area 3 RWMS center around the placement of bulk LLW in subsidence craters formed from underground testing of nuclear weapons. Native alluvium soil is used to cover waste placed in the disposal cells at both facilities. In addition, information on the technical attributes, facility performance, updates on waste disposal volumes and capabilities, and current and future disposal site requirements will also be described. (authors)« less
  • The Area 5 Radioactive Waste Management Site on the Nevada Test Site has been disposing of low-level, mixed low-level, and transuranic radioactive waste since 1961. In 1988, the U.S. Department of Energy implemented performance objectives for low-level radioactive waste disposal site performance and required all site operators to prepare a performance assessment. Since then, an iterative performance assessment process has been implemented that consists of repeated cycles of site characterization, conceptual model formation/revision, and performance assessment modeling. At the end of each cycle uncertainty and sensitivity analysis are used to determine the need for revision and to identify topics requiringmore » additional research and development. The performance assessment model is implemented in the GoldSim{reg_sign} probabilistic simulation platform. The current site conceptual model, based on site characterization data and process model results, assumes that there is no groundwater pathway under current climatic conditions and that radionuclide releases are predominately upward to the land surface. Radionuclides are released to the land surface by upward liquid advection/diffusion, gas diffusion, biointrusion, and inadvertent human intrusion. The model calculates dose for four members of public exposure scenarios and two intruder scenarios. The highest mean-dose, 0.04 mSv yr{sup -1}, is expected for a low-probability exposure scenario: establishment of a rural community at the site boundary at the end of institutional control. At the end of institutional control, doses are contributed primarily by {sup 3}H in agricultural products produced onsite. After approximately 300 years, the doses are contributed equally by {sup 99}Tc and {sup 210}Pb ingested in vegetables grown at the residence. Technetium is released to the surface by the coupled processes of liquid advection/diffusion occurring deep in the cover and plant uptake/animal burrowing occurring at shallower depths. Lead-210 is deposited in shallow cover soil by the radioactive decay of {sup 222}Rn diffusing in the gas phase. The highest mean dose for the more likely exposure scenario of transient recreational use of the site is 0.002 mSv yr{sup -1}. The transient visitor's dose is contributed predominantly by external irradiation from {sup 214}Pb and {sup 214}Bi, deposited in the cover by diffusion of {sup 222}Rn.« less
  • This paper provides an overview and the impacts of new policies, processes, and opportunities at the Nevada Test Site (NTS). Operational changes have been implemented, such as larger trench sizes and more efficient soil management as have administrative processes to address U.S. Department of Energy and U.S. Code of Federal Regulation analyses. Some adverse conditions have prompted changes in transportation and mixed low-level waste polices, and a new funding mechanism was developed. This year has seen many changes to the NTS disposal family. (authors)
  • A panel of independent scientists was convened by the Department of Energy to assess the performance impacts of disposal of low-level radioactive waste from the Fernald Environmental Management Project. This waste stream was involved in a transportation incident in December 1997. A resulting outgrowth of investigations of the transportation incident was the recognition that the waste was transported and disposed in stress-fractured metal boxes and some of the waste contained excess moisture (high volumetric water contents). The panel was charged with determining whether disposal of this waste in the Area 5 radioactive waste management site on the Nevada Test Sitemore » has impacted the conclusions of the completed performance assessment. Three questions were developed by the panel to assess performance impacts: (1) the performance impacts of reduced container integrity, (2) the impact of reduced container integrity on subsidence of waste in the disposal pits and (3) the performance impacts of excess moisture. No performance or subsidence impacts were noted from disposal of the Fernald waste. The impacts of excess moisture were assessed through simulation modeling of the movement of moisture in the vadose zone assuming high water contents (wet waste) for different percentages of the waste inventory. No performance impacts were noted for either the base-case scenario (ambient conditions) or a scenario involving subsidence and flooding of the waste cells. The absence of performance impacts results form the extreme conservatism used in the Area 5-performance assessment and the robust nature of the disposal site.« less