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At least 541 records · Page 30
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Anthropogenic influences on groundwater in the vicinity of a long-lived radioactive waste repository: Anthropogenic influences on groundwater

The groundwater flow system in the Culebra Dolomite Member (Culebra) of the Permian Rustler Formation is a potential radionuclide release pathway from the Waste Isolation Pilot Plant (WIPP), the only deep geological repository for transuranic waste in the United States. We did not expect that early conceptual models of the Culebra, groundwater levels would fluctuate markedly, except in response to long-term climatic changes, with response times on the order of hundreds to thousands of years. Recent groundwater pressures measured in monitoring wells record more than 25 m of drawdown. The fluctuations are attributed to pumping activities at a privately-owned well that may be associated with the demand of the Permian Basin hydrocarbon industry for water. Furthermore, the unprecedented magnitude of drawdown provides an opportunity to quantitatively assess the influence of unplanned anthropogenic forcings near the WIPP. Spatially variable realizations of Culebra saturated hydraulic conductivity and storativity were used to develop groundwater flow models to estimate a pumping rate for the private well and investigate its effect on advective transport. Simulated drawdown shows reasonable agreement with observations (average Model Efficiency coefficient = 0.7). Steepened hydraulic gradients associated with the pumping reduce estimates of conservative particle travel times across the domain by one-half and shift the intersection of the average particle track with the compliance boundary by more than two kilometers. Finally, the value of the transient simulations conducted for this study lie in their ability to (i) improve understanding of the Culebra groundwater flow system and (ii) challenge the notion of time-invariant land use in the vicinity of the WIPP.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

Public Preferences Related to Radioactive Waste Management Nuclear Energy and Environment: Methodology and Response Reference Report for the 2014 Energy and Environment Survey

The results described in this report are from nationwide surveys between 2006 and 2014 on preferences of US residents concerning the environment and energy sources. The most recent 2014 survey was undertaken to determine how consent, in the context of nuclear facility siting, is understood and evaluated by a cross-section of the American public. Continuing attention to the events at the Fukushima nuclear facility, coupled with its negative implications for public support for nuclear energy, has changed the balance of risk and benefit perceptions, and thus the context in which nuclear facility siting efforts will occur. In addition, the portion of the public most concerned about climate change have typically been those most concerned about the environment in general, and in turn, are those that have traditionally been hostile to nuclear energy. The overall survey results show that the broader public is not well informed about the nuclear fuel cycle including energy production from nuclear reactors and current policies for the management of used nuclear fuel. In addition, the surveys find that respondents are reluctant to continue to rely on temporary on-site storage of used nuclear fuel, and that there is moderate support for developing one or more interim storage facilities. The survey responses also suggest that the level of trust accorded a new nuclear waste authority by the public will be sensitive to how it is institutionally defined. For a hypothetical community, which had volunteered to host an interim storage facility within 50 miles of their homes, the majority of respondents indicated that veto authority in the siting process should be limited to (a) majorities of local and statewide voters, (b) state and federal environmental regulatory authorities, and (c) governors. The respondents also indicated that the state and local host community should be permitted to withdraw consent up to the point at which a license to build the facility is submitted, but not after the license is received and facility construction initiated. The 2013 and 2014 surveys posed a set of questions concerning respondents' expectations about engaging in the process for siting an interim storage facility. Roughly half of the respondents said they would likely attend informational meetings, and nearly half said they would likely communicate with elected officials or would likely express their views on the topic via social media. Relatively few -- about one in five -- said they would be likely to actively participate in support for or opposition of an ISF. Finally, the 2014 results suggest that while respondents are more likely to support a citizen-led deliberative panel process than one led by experts, this preference does not seem to influence their opinion about the expected outcome of the siting process.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2018

Public Views on Nuclear Facility Siting and Radioactive Waste Management in the United States: Methodology and Response Reference Report for the 2017 Energy and Environment Survey

This report presents the questions and responses to a nationwide survey of U.S. residents taken May 2017. The focus of the 2017 survey is public perceptions on (1) nuclear energy and new nuclear technology, such as small modular reactors; (2) the risks and benefits of nuclear energy; (3) different options for managing spent nuclear fuel (SNF); and (4) the role of individuals, organizations and elected officials in locating SNF facilities. Highlights of survey results related to nuclear energy found the U.S. public (1) wants nuclear energy to continue to contribute 20% of total electrical power produced for the next 20 years; (2) is more supportive of adding new reactors at existing sites than at new sites; and (3) is more supportive of small modular reactors than traditional reactors. Highlights related to risks and benefits of nuclear energy include (1) the public believes that terrorist attacks are the greatest threat and that energy independence is the greatest benefit; (2) 56% of the public believes that nuclear power has both high benefit and high risk; (3) the 2011 accident at the Fukushima nuclear facility continues to negatively influence the perceived benefits and risks of nuclear energy except for those who perceive nuclear power as low risk and high benefit; (4) building new reactors is supported by those who perceive nuclear power as low risk and high benefit, and opposed by those who perceive it as high risk and low benefit. Highlights related to SNF management options include (1) support remains higher for permanent disposal than either consolidated interim storage or continued on-site storage; (2) support for private initiatives for interim storage in New Mexico and Texas are higher than generic storage and disposal options; (3) the general public is more likely to increase support if a majority of the local and state residents support an SNF facility. Highlights related to the role of individuals, organizations, and elected officials include (1) 54% of the public agrees that if an SNF facility is deemed safe by regulators, political considerations should not derail the location; (2) 47% of the US public agrees that non-governmental organizations should be able to provide input to locating an SNF facility; (3) 36% of the public believes that the federal government should lead siting of an SNF facility while 25% believes private companies should lead; (4) 81% of the public believes local residents and farmers/ranchers should have a say in the final decision on locating a SNF facility and 56% believe that they should have veto power; and (5) only 27% of the public believes the state governor should have a say and veto power.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2013

Public involvement on closure of Asse II radioactive waste repository in Germany

From 1967 to 1978, about 125,800 barrels of low- and intermediate level waste were disposed of - nominally for research purposes - in the former 'Asse' salt mine which had before been used for the production of potash for many years. Since 1988 an inflow of brine is being observed which will cause dangers of flooding and of a collapse due to salt weakening and dissolution if it should increase. Since several years the closure of the Asse repository is planned with the objective to prevent the flooding and collapse of the mine and the release of radioactive substances to the biosphere. The first concept that was presented by the former operator, however, seemed completely unacceptable to regional representatives from politics and NGOs. Their activities against these plans made the project a top issue on the political agenda from the federal to the local level. The paper traces the main reasons which lead to the severe safety problems in the past as well as relevant changes in the governance system today. A focus is put on the process for public involvement in which the Citizens' Advisory Group 'A2B' forms the core measure. Its structure and framework, experience and results, expectations from inside and outside perspectives are presented. Furthermore the question is tackled how far this process can serve as an example for a participatory approach in a siting process for a geological repository for high active waste which can be expected to be highly contested in the affected regions. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2023

Radioactive waste repository when contacted by water provides borates that absorb neutrons

A container holds radioactive material. A sub-criticality controller protects the radioactive material from reaching a criticality from contact with the water. The sub-criticality controller includes a metallic composition having at least one metal component and at least one borate component bonded to the at least one metal component. The metallic composition forms borates when the metallic composition contacts the water.

Xiong, Yongliang↗
DOE OSTI2015

Special Analysis for the Disposal of the Oak Ridge National Laboratory General Radioactive Sources Waste Stream at the Area 5 Radioactive Waste Management Site, Nevada National Security Site, Nye County, Nevada

This special analysis (SA) evaluates whether the Oak Ridge National Laboratory (ORNL) General Radioactive Sources waste stream (ORNLSOURCES01, Revision 3) is suitable for disposal by shallow land burial (SLB) at the Area 5 Radioactive Waste Management Site (RWMS) at the Nevada National Security Site (NNSS). The ORNL General Radioactive Sources waste stream consists of sealed sources and solid radioactive sources that are no longer needed (ORNL 2015). The ORNL General Radioactive Sources waste stream required a special analysis because 26 radionuclides exceeded the NNSS Waste Acceptance Criteria (WAC) Action Levels (U.S. Department of Energy, National Nuclear Security Administration Nevada Field Office [NNSA/NFO] 2015). However, review of the generator’s method to calculate waste concentration indicates that the concentrations are significantly overestimated. Waste concentrations are recalculated in this analysis using a list of individual sources provided by the generator. One radionuclide, radium-226 (226Ra), still exceeds its action level and a Special Analysis (SA) is required. The results indicate that all performance objectives can be met with disposal of the ORNL General Radioactive Sources in a SLB trench. Addition of the ORNL General Radioactive Sources inventory slightly increases the 222Rn flux density. The maximum mean and 95th percentile flux density remain less than the performance objective throughout the compliance period. The ORNL General Radioactive Sources waste stream had no significant effect on the maximum mean and 95th percentile for all other performance assessment results. The ORNL General Radioactive Sources waste stream is suitable for disposal by SLB at the Area 5 RWMS. However, because the activity concentrations on the waste profile sheet are significantly overestimated, approval of the sheet could potentially allow the disposal of high activity radiation sources. To ensure the generator does not include large radiation sources in its waste stream, a control is recommended on the maximum individual source activity from this generator.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

A record of uranium-series transport at Nopal I, Sierra Pena Blanca, Mexico: Implications for natural uranium deposits and radioactive waste repositories

Studies of uranium-series (U-series) disequilibria within and around ore deposits provide valuable information on the extent and timing of actinide mobility, via mineral-fluid interaction, over a range of spatial and temporal scales. Such information is useful in studies of analogs of high-level nuclear-waste repositories, as well as for mining and mineral extraction sites, locations of previous nuclear weapons testing, and legacy nuclear waste contamination. In this study we present isotope dilution mass spectrometry U-series measurements for fracture-fill materials (hematite, goethite, kaolinite, calcite, dolomite and quartz) from one such analog; the Nopal I uranium ore deposit situated at Peña Blanca in the Chihuahua region of northern Mexico. The ore deposit is located in fractured, unsaturated volcanic tuff and fracture-fill materials from surface fractures as well as fractures in a vertical drill core have been analyzed. High uranium concentrations in the fracture-fill materials (between 12 and 7700 ppm) indicate uranium mobility and transport from the deposit. Furthermore, uranium concentrations generally decrease with horizontal distance away from the deposit but in this deposit there is no trend with depth below the surface.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

Mechanical environmental transport of actinides and ¹³⁷Cs from an arid radioactive waste disposal site

Particulate transport represents an important mechanism for actinides and fission products at the Earth's surface; soil samples taken in the early 1970's near the Subsurface Disposal Area (SDA) at Idaho National Laboratory (INL) provide a case study for examining the mechanisms and characteristics of actinide transport under arid conditions. Transuranic waste was disposed via shallow land burial at the SDA until shortly after a flooding event that occurred in 1969. In this study we analyze soils collected in the early 1970's for ¹³⁷Cs, ²⁴¹Am, and Pu using a combination of radiometric and mass spectrometric techniques. Two distinct ²⁴⁰Pu/²³⁹Pu isotopic ratios are observed for contamination from the SDA, with values ranging from at least 0.059 to 0.069. ²⁴¹Am concentrations are observed to increase only slightly in 0-4 cm soils over the ~40 year period since soil sampling, contrary to Markham's previous hypothesis that ²⁴¹Pu is principally associated with the 0-4 cm soil fractions (Markham 1978). The lack of statistical difference in ²⁴¹Am/²³⁹⁺²⁴⁰Pu ratios with depth suggests mechanical transport and mixing discrete contaminated particles under arid conditions. Occasional samples beyond the northeastern corner are observed to contain anomalously high Pu concentrations with corresponding low ²⁴⁰Pu/²³⁹Pu atoms ratios, suggesting the occurrence of "hot particles;" application of a background Pu subtraction results in calculated Pu atom ratios for the "hot particles" which are statistically similar to those observed in the northeastern corner. Taken together, our data suggests that flooding resulted in mechanical transport of contaminated particles into the area between the SDA and the flood containment dike in the northeastern corner, following which subsequent contamination spreading resulted from wind transport of discrete particles.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2015

Approach for Configuring a Standardized Vessel for Processing Radioactive Waste Slurries

A standardized vessel design is being considered at the Waste Treatment and Immobilization Plant (WTP) that is under construction at Hanford, Washington. The standardized vessel design will be used for storing, blending, and chemical processing of slurries that exhibit a variable process feed including Newtonian to non-Newtonian rheologies over a range of solids loadings. Developing a standardized vessel is advantageous and reduces the testing required to evaluate the performance of the design. The objectives of this paper are to: 1) present a design strategy for developing a standard vessel mixing system design for the pretreatment portion of the waste treatment plant that must process rheologically and physically challenging process streams, 2) identify performance criteria that the design for the standard vessel must satisfy, 3) present parameters that are to be used for assessing the performance criteria, and 4) describe operation of the selected technology. Vessel design performance will be assessed for both Newtonian and non-Newtonian simulants which represent a range of waste types expected during operation. Desired conditions for the vessel operations are the ability to shear the slurry so that flammable gas does not accumulate within the vessel, that settled solids will be mobilized, that contents can be blended, and that contents can be transferred from the vessel. A strategy is presented for adjusting the vessel configuration to ensure that all these conditions are met.

pulse jet mixing↗