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At least 523 records · Page 29
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Preliminary Long-term Safety Assessment for the Planned LLW Disposal Facility at Al-Tuwaitha, Iraq - 18142

Before 1991, Iraq had a significant nuclear program which encompassed ten nuclear sites spread out across the country. The largest nuclear site was located at the Al-Tuwaitha site near Baghdad where 18 nuclear facilities were concentrated. During the first Gulf War in 1991, all sites suffered significant damage from bombing and subsequent looting. Currently, the Ministry of Science and Technology is responsible for the ten heavily damaged nuclear sites and for the management of radioactive waste in Iraq in general. The task of decommissioning the damaged nuclear facilities and managing the resulting waste is being supported by the International Atomic Energy Agency (IAEA), the European Commission (EC), and the United States (US). In the framework of its Instrument for Nuclear Safety Cooperation (INSC), the EC has launched a cooperation project to support the planned construction of an engineered repository for short-lived low- and intermediate level waste for the safe disposal of radioactive waste resulting from the decommissioning activities, as well as for waste from the continuing use of radioisotopes in medicine and the oil and gas industry in the country. The main objectives of this project, which was awarded to a Consortium led by NUKEM Technologies Engineering Services GmbH and joined by DBE Technology GmbH of Germany and JAVYS a.s. of Slovakia, are the development of an initial conceptual level basic design and preliminary safety assessment report (PSAR) and the subsequent detailed engineering design and supporting pre-construction safety assessment report (PCSAR). The current paper focuses on the development of the PSAR. Special focus is given to the long-term calculations and difficulties associated with the limited data base in regard to site characterization as well as the expected inventory for the future repository. Because of the ongoing security concerns in Iraq, the Ministry of Science and Technology had already selected the Al-Tuwaitha Site as the best suited location for the planned surface repository at the start of the project. Although some site characterization work had already been carried out prior to the start of the project, certain data for modelling the geology and hydrology of the site are still lacking. Missing data have been compensated by conservative assumptions and the assessment of alternative scenarios. Consequently, for the development of the simplified GoldSim{sup R} computer model used to carry out the long-term calculations supporting the PSAR, existing site information was used and, as appropriate, amended or replaced by conservative assumptions. Due to the nature of the waste, data on the expected inventory are associated with large uncertainties. Although certain estimates related to the future volume of the waste exist, little to no information is available on the expected radionuclide vector and respective activities. Therefore, the long-term calculations were carried out for a generic inventory including a broad range of radionuclides that are to be expected as being important considering the kind of waste to be disposed of in the facility. Based on the results of these calculations, the maximum total capacity of the facility was estimated and converted into activity limits for individual radionuclides that will be integrated into the existing general WAC for the facility. Compliance with these WAC will then guarantee the safety of the repository in regard to potential radionuclide releases via the groundwater pathway. In parallel to the determination of activity limits for the WAC, long-term calculations were carried using different estimates for the expected total activity to determine the general suitability of the proposed technical solution of the repository for receiving the total amount of Iraqi radioactive waste principally acceptable for surface disposal. (authors)

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

Issues Affecting the Assessment of Impacts of Disposal of Radioactive and Hazardous Waste - 18177

BIOPROTA is an international collaborative forum that seeks to address the key uncertainties in long term assessments of radionuclide and other contaminant releases into the environment arising from solid radioactive waste disposal. (see www.bioprota.org). Two workshops have been organized through the BIOPROTA forum to consider the non-radiological post-disposal impacts of radioactive waste disposal. In these workshops, it was noted that, ideally, the assessment of radionuclides and hazardous materials should be such that consistent assumptions and criteria are used in risk evaluation and that in cases where this is not possible, a clear understanding of the reasons why needs to be provided. Accordingly, a detailed review was organized through BIOPROTA to provide information to support development of a consensus on how to address this issue. The study suggests that there is a continuing need for some common measure of hazard that supports identification of risk management priorities for mixed hazardous waste. Without it, effective optimization of management of these mixed hazardous wastes will be restricted. (authors)

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

Reconstruction of Irradiation History of Am-241/Be Startup Sources for Disposal at WIPP - 18644

The National Nuclear Security Administration, Global Material Security (GMS)/ Off-site Source Recovery Program (OSRP) requires an approved final disposition pathway for sealed neutron startup sources with undocumented or questionable irradiation histories. To obtain approval for WIPP disposal, a reliable method is required to determine yields of transmutation, as well as fission and activation products contained within the source at the time of disposal. This paper presents a method to reconstruct the irradiation history of americium beryllium (Am/Be) reactor startup sources using gamma spectroscopy, ORIGEN modeling and the initial composition of the source. Using this method, measured isotopes in the Am/Be startup sources are related to the WIPP disposal requirements. Maximum allowable measurement uncertainties have been quantified and related to uncertainties in the WIPP required isotopes. Characterization calculations and experimental measurements of irradiated Am/Be sources are discussed. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2019

International Government Collaboration in ISD (In Situ Decommissioning/In Situ Disposal) - 19261

In situ decommissioning (ISD) is considered by IAEA as the permanent entombment of a legacy facility in 'a structurally long lived material' (e.g. concrete) and is considered a solution only under 'exceptional circumstances' (e.g. following a severe accident). However, this definition of ISD as 'only' entombment is not universally accepted; the approach has been implemented as a decommissioning approach by the US Dept of Energy in the past decade at the Savannah River Site (P and R reactors)2,3, the Hanford site (U Canyon) and at the Idaho site (CP601, CP640 and CP633). The application of ISD outside of the United States has been much less common for large facilities although its use for underground substructures (e.g. discarded pipelines) is commonplace. Proponents of ISD consider it beneficial since it eliminates the need to remove, package and transport contaminated equipment from a nuclear legacy site to a disposal facility and it maximizes the use of an existing nuclear site footprint by consolidating equipment in one place. ISD is considered to offer major safety benefits to both workers and the public, as well as major cost and schedule benefits to Government. Opponents of the approach cite the fact that, following ISD, the decommissioned facility has effectively become a long-term waste disposal site and that regulations pertaining to long term waste disposal have been circumvented. Given the increasing pressure on environmental cleanup budgets and schedules around the world, countries such as the United Kingdom, Canada and Japan are considering ISD in its various forms as a potential path forward for decommissioning certain facilities in lieu of the more traditional approaches of either deferred decommissioning or immediate decontamination/demolition. To address this emerging area of decommissioning, a Governmental Technical Information Exchange meeting was held in December 2017 at the DOE Savannah River Site in Aiken, SC, to bring together responsible parties from the US Dept of Energy (DOE), Atomic Energy of Canada Ltd (AECL), the UK Nuclear Decommissioning Authority (NDA) and the Japanese Atomic Energy Agency (JAEA) and those countries' respective regulatory agencies to share information about respective 'best practices' and challenges with ISD. Representatives from organizations such as IAEA and US Nuclear Regulatory Commission (US NRC) also participated to discuss their organizations' perspectives and position on ISD. Following the meeting, a series of Working Groups were established which have continued the dialogue in three key areas 5; - ISD-Defined: Identify and share case-specific ISD solutions which allows for the full spectrum of needs and which demonstrate that 'entombment' is not the only definition of 'ISD'. - Regulatory - Share and discuss regulatory concerns and challenges with ISD; - Benchmarking - Share information to support informed and transparent decision-making in ISD. This paper discusses the plans for ISD in some of the countries involved in the December meeting and provides an update on the topics being discussed, and progress being made, by the Working Groups that were formed at the meeting. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2019

Conceptual Design of the Belgian Geological Disposal Facility for Category B and C Wastes - 19341

For more than 40 years, ONDRAF/NIRAS (the federal agency responsible for managing radioactive waste and enriched fissile materials in Belgium) has been studying the concept of a geological disposal facility (GDF), within poorly indurated clays, as an option for the long-term management of both category B waste (low-level and intermediate-level long-lived waste - LILW-LL) and category C waste (high-level waste - HLW and spent fuel). The proposed Belgian reference option for disposal of such waste is a GDF within poorly indurated clays, located at a depth of between 200 m and 600 m. Within the framework of the first Safety and Feasibility Case (SFC-1) undertaken by ONDRAF/NIRAS, the former GDF layout, which dates back from 2003 has been updated. The first part of the paper describes the main drivers behind the evolution of the former 2003 GDF design towards the current reference SFC-1 design. It also details how these drivers, related to operational and constructional constraints, have affected the GDF layout, such as the disposal gallery length, the crossing shapes of the GDF galleries and the layout of access and waste shafts. The second part of the paper focuses on the engineering and construction challenges generated by GDF development within poorly indurated clays. This includes discussion of the impact of the specific mechanical characteristics such poorly indurated clays have on the construction methods used for the shafts, the rock support (concrete lining), the drift connections, the crossings and the global GDF design. These construction methods have been selected based on research conducted at the underground research laboratory HADES in Mol (Belgium). Finally, the main axes for further development of the GDF design within the SFC-1 framework is presented. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2019

Engineering Challenges for the In Situ Disposal (ISD) of the 20 MWe Nuclear Power Demonstration (NPD) Reactor - 19407

The Nuclear Power Demonstration (NPD) reactor is the first CANDU{sup R} type power reactor to be decommissioned. This first of a kind project is to decommission the station using an In-Situ Disposal (ISD) strategy, and presents some engineering challenges to implement. Based on current technology and successful application of industry lessons learned, these challenges are being met. This paper presents a summary of those challenges, to recover from a long period of Storage With Surveillance, solve configuration management, assess the existing structure, determine the performance of the structure following seismic events during the disposal period, adapt the facility design to ISD and select a grout in-fill, and describe the regulatory and public interaction, to demonstrate the integrity of what will be a future disposal site. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

Improving PCM Waste Management Through New Approaches to Screening for LLW Treatment and Disposal - 20145

A major step forward in the management of Plutonium Contaminated Material (PCM) Waste has been taken at the Sellafield site with the introduction of new capabilities to enable wastes previously conservatively designated as PCM Intermediate Level Waste (ILW) to be re-classified for treatment as Low Level Waste (LLW). The Sellafield site, located in the North West of England, within the United Kingdom (UK), has operated plutonium processing plants and waste facilities for almost 70 years. During this time management of the raw PCM waste produced has presented a variety of challenges. The waste is currently processed by high force waste compaction in the Waste Treatment Complex (WTC). The WTC converts 200 litre drums of raw PCM waste into a compacted, grout encapsulated monolith form within stainless steel containment, ready for emplacement within the UK's Geological Disposal Facility (GDF) when it becomes available. To help progress some of the wastes waiting for treatment, recent improvements have been made with the introduction of new waste assay instrumentation which enables the identification of a 'candidate' waste potentially suitable for disposal via the LLW treatment route. Opening a new LLW route for previously designated PCM has been a major advance in PCM waste management policy. It has required a range of technical assessment arrangements to be developed, tested and commissioned and involved the engagement of a wide range of stakeholders. In particular, very detailed technical analysis methods have been developed to ensure that there is a robust and conservative approach to the final sentencing of waste. Following completion of commissioning tests, the first 86 m{sup 3} of previously designated PCM waste was successfully treated through the LLW route and consigned to LLW disposal in June 2019. The direct benefit of sentencing waste to the correct waste route (LLW) is the significant cost savings across the complete range of waste management activities. This work is also strategically important for demonstrating to a range of stakeholders including workforce and regulators, that waste previously designated as PCM can be re-classified in a systematic and justifiable way without increasing risk to personnel or the wider environment. By ensuring that waste is being managed appropriately it will be possible to carry out more remediation work safely, in less time, and at a lower cost. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

Spent Nuclear Fuel Storage and Radioactive Waste Disposal in the United States: A Law and Policy Analysis - 20302

While Congress plays political football, spent nuclear fuel continues to sit in de facto interim nuclear waste storage sites throughout the country. This ad hoc approach - if it can even be called an approach - to nuclear waste management is in no one's best interests, because of financial, safety, environmental, and national security concerns with the status quo. Senate leadership had asserted that an up-or-down vote on the Yucca Mountain Project would take place in September or October 2019, but that did not occur. Rather, a conference bill was agreed to, and it provided that, although the nuclear program should receive some funding, funding was not made available for centralized interim storage ('CIS') or the Yucca Mountain Project. The President's FY2021 Budget Request does not contain any proposed funding for the Yucca Mountain Project ('the Project'). This paper will discuss the implications of that process, both for the Project itself and for the U.S. nuclear waste program more generally. In order to provide context for the current situation, this paper will begin by chronicling the history of U.S. nuclear waste management, from the passage of the Nuclear Waste Policy Act of 1982 and to the present day. It will discuss the roles of the U.S. Department of Energy, the Nuclear Regulatory Commission, federal and state political delegations, and the nuclear energy industry. The paper will then identify key themes that can be expected to affect the future of nuclear waste management in the United States. For example, it will consider whether development of additional CIS facilities is a viable short- to medium-term solution. CIS facilities may relieve immediate pressure at decommissioned or soon-to-be-decommissioned nuclear power plants; but with that pressure partially alleviated, support for building a long-term repository may be reduced. It will also discuss opposition by the State of New Mexico and others to the proposed New Mexico CIS project, based not only on siting concerns but also whether it might become a de facto repository, and whether the State of Texas and others may also be opposed, for similar reasons, to the proposed CIS facility in Texas. Additionally, the paper will examine consent-based siting and its implications for Nevada and other states that are potential hosts for spent nuclear fuel storage and disposal facilities. Further, if the Project is not a politically viable solution, the paper will examine whether it is now time for serious consideration of an alternate location for a permanent repository, as well as consideration of other options entirely, such as deep geologic disposal. The paper will conclude by looking ahead to the 2020 elections. It will describe the positions of candidates (particularly Presidential candidates) on spent nuclear fuel storage and disposal options, without advocating for any particular candidate or political party. Perhaps in 2020, we will at least see a start to a solution to the seemingly intractable problem of nuclear waste management in the United States. (authors)

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

Computational scheme for burnup credit applied to long term waste disposal - 14448

The application of burnup credit (BUC) to criticality safety evaluations (CSE) of geological repositories for long term disposal of spent nuclear fuel (SNF) is under consideration in Switzerland. Therefore, in collaboration with the national waste management organization, PSI is conducting research towards the development of a BUC methodology tailored for Swiss specific applications. As part of this research, a computational sequence from the in-core burnup phase, through the interim storage, until final disposal is being established. The tools selected for this methodology, referred to as BUCSS-R (Burnup Credit System for Swiss reactors and Repositories), are CASMO for the in-core fuel depletion, the decay module of SERPENT for the decay calculations, and MCNP for the criticality calculations. In connection to BUCSS-R, a computational interface to validated reference core models of the Swiss reactors is being developed. The purpose is to apply reconstructed depletion histories based on real core operation conditions with CASMO assembly calculations, to transfer the pin wise nuclide compositions at discharge to the subsequent SERPENT decay calculations, and afterwards to the final MCNP criticality calculations. An objective of this paper is to present the elements of the BUCSS-R methodology, and to show a first application to so-called bounding analyses of a preliminary Swiss disposal canister design loaded with fuel assembly types operated in a Swiss PWR reactor. The rationale for these bounding analyses is that before starting the integration of methodologies for bias and uncertainty quantifications, the span of the k-eff variation between fresh and burnt fuel loadings should first be quantified in a realistic manner. The obtained results are reported in this paper together with studies performed in order to evaluate the effects from burnup levels and nuclides credit at flooded conditions on the k-eff values. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2013

A critical comparison of ten disposable cup LCAs

Disposable cups can be made from conventional petro-plastics, bioplastics, or paperboard (coated with petro-plastics or bioplastics). This study compared ten life cycle assessment (LCA) studies of disposable cups with the aim to evaluate the robustness of their results. The selected studies have only one impact category in common, namely climate change with global warming potential (GWP) as its category indicator. Quantitative GWP results of the studies were closer examined. GWPs within and across each study show none of the cup materials to be consistently better than the others. Comparison of the absolute GWPs (after correction for the cup volume) also shows no consistent better or worse cup material. An evaluation of the methodological choices and the data sets used in the studies revealed their influence on the GWP. The differences in GWP can be attributed to a multitude of factors, i.e., cup material and weight, production processes, waste processes, allocation options, and data used. These factors basically represent different types of uncertainty. Sensitivity and scenario analyses provided only the influence of one factor at once. A systematic and simultaneous use of sensitivity and scenario analyses could, in a next research, result in more robust outcomes. -- Highlights: • Conflicting results from life cycle assessment (LCA) on disposable cups • GWP results of LCAs did not point to a best or worst cup material. • Differences in GWP results are due to methodological choices and data sets used. • Standardized LCA: transparency of LCA studies, but still different in approaches.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

Rock-welding materials development for deep borehole nuclear waste disposal

We report that various versions of deep borehole nuclear waste disposal have been proposed in the past in which effective sealing of a borehole after waste emplacement is generally required. In a high temperature disposal mode, the sealing function will be fulfilled by melting the ambient granitic rock with waste decay heat or an external heating source, creating a melt that will encapsulate waste containers or plug a portion of the borehole above a stack of the containers. However, there are certain drawbacks associated with natural materials, such as high melting temperatures, inefficient consolidation, slow crystallization kinetics, the resulting sealing materials generally being porous with low mechanical strength, insufficient adhesion to waste container surface, and lack of flexibility for engineering controls. In this study, we showed that natural granitic materials can be purposefully engineered through chemical modifications to enhance the sealing capability of the materials for deep borehole disposal. The present work systematically explores the effect of chemical modification and crystallinity (amorphous vs. crystalline) on the melting and crystallization processes of a granitic rock system. The approach can be applied to modify granites excavated from different geological sites. Several engineered granitic materials have been explored which possess significantly lower processing and densification temperatures than natural granites. Finally, those new materials consolidate more efficiently by viscous flow and accelerated recrystallization without compromising their mechanical integrity and properties.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2013

Impact of Construction Waste Disposal Charging Scheme on work practices at construction sites in Hong Kong

Highlights: Black-Right-Pointing-Pointer A significant reduction of construction waste was achieved at the first 3 years of CWDCS implementation. Black-Right-Pointing-Pointer However, the reduction cannot be sustained. Black-Right-Pointing-Pointer Implementation of the CWDCS has generated positive effects in waste reduction by all main trades. - Abstract: Waste management in the building industry in Hong Kong has become an important environmental issue. Particularly, an increasing amount of construction and demolition (C and D) waste is being disposed at landfill sites. In order to reduce waste generation and encourage reuse and recycling, the Hong Kong Government has implemented the Construction Waste Disposal Charging Scheme (CWDCS) to levy charges on C and D waste disposal to landfills. In order to provide information on the changes in reducing waste generation practice among construction participants in various work trades, a study was conducted after 3 years of implementation of the CWDCS via a structured questionnaire survey in the building industry in Hong Kong. The study result has revealed changes with work flows of the major trades as well as differentiating the levels of waste reduced. Three building projects in the public and private sectors were selected as case studies to demonstrate the changes in work flows and the reduction of waste achieved. The research findings reveal that a significant reduction of construction waste was achieved at the first 3 years (2006-2008) of CWDCS implementation. However, the reduction cannot be sustained. The major trades have been influenced to a certain extent by the implementation of the CWDCS. Slight improvement in waste management practices was observed, but reduction of construction waste in the wet-finishing and dry-finishing trades has undergone little improvement. Implementation of the CWDCS has not yet motivated subcontractors to change their methods of construction so as to reduce C and D waste.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2013

Assessment of health-care waste disposal methods using a VIKOR-based fuzzy multi-criteria decision making method

Highlights: • Propose a VIKOR-based fuzzy MCDM technique for evaluating HCW disposal methods. • Linguistic variables are used to assess the ratings and weights for the criteria. • The OWA operator is utilized to aggregate individual opinions of decision makers. • A case study is given to illustrate the procedure of the proposed framework. - Abstract: Nowadays selection of the appropriate treatment method in health-care waste (HCW) management has become a challenge task for the municipal authorities especially in developing countries. Assessment of HCW disposal alternatives can be regarded as a complicated multi-criteria decision making (MCDM) problem which requires consideration of multiple alternative solutions and conflicting tangible and intangible criteria. The objective of this paper is to present a new MCDM technique based on fuzzy set theory and VIKOR method for evaluating HCW disposal methods. Linguistic variables are used by decision makers to assess the ratings and weights for the established criteria. The ordered weighted averaging (OWA) operator is utilized to aggregate individual opinions of decision makers into a group assessment. The computational procedure of the proposed framework is illustrated through a case study in Shanghai, one of the largest cities of China. The HCW treatment alternatives considered in this study include “incineration”, “steam sterilization”, “microwave” and “landfill”. The results obtained using the proposed approach are analyzed in a comparative way.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2025

Predictive Assessment of the Chemical Composition of Coal Ash in Reserve at U.S. Disposal Sites

In the United States, more than 2 Gt of coal combustion residuals (i.e., coal ash) are stored in hundreds of disposal units. Recent federal regulations mandate the closure or retrofitting of most coal ash impoundments, presenting significant challenges for waste management. These regulatory pressures also present opportunities to reuse coal ash. However, the quality and quantity of discarded coal ash across the U.S. are not well known, even though this information is crucial for spurring its reuse for conventional and new material applications. This study describes a predictive model for the major element composition of coal ash in reserve at disposal sites of major U.S. coal-fired power plants. This model was constructed from coal purchase records of 705 power stations from 1973 to 2022 and was trained on coal ash composition data, showing that coal ash elemental composition is strongly associated with the source of feedstock coal. The model showed regional shifts in the major element contents of ash produced by power plants in the last 50 years, particularly for calcium and iron (expressed as %CaO and %Fe2O3), as power stations changed their source of coal over this time frame. Our approach enables an estimation of chemical composition for ash stored in waste impoundments at individual power stations. Such information can help to delineate the regional market resource potential of supplementary cements for concrete and other material innovations that would utilize coal ash harvested from disposal sites across the U.S.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2016

Impact of iron redox chemistry on nuclear waste disposal

For the safe disposal of nuclear waste, the ability to predict the changes in oxidation states of redox active actinide elements and fission products, such as U, Pu, Tc and Np is a key factor in determining their long term mobility. Both in the Geological Disposal Facility (GDF) near-field and in the far-field subsurface environment, the oxidation states of radionuclides are closely tied to changes in the redox condition of other elements in the subsurface such as iron. Iron pervades all aspects of the waste package environment, from the steel in the waste containers, through corrosion products, to the iron minerals present in the host rock. Over the long period required for nuclear waste disposal, the chemical conditions of the subsurface waste package will vary along the entire continuum from oxidizing to reducing conditions. This variability leads to the expectation that redox-active components such as Fe oxides can undergo phase transformations or dissolution; to understand and quantify such a system with respect to potential impacts on waste package integrity and radionuclide fate is clearly a serious challenge. Traditional GDF performance assessment models currently rely upon surface adsorption or single phase solubility experiments and do not deal with the incorporation of radionuclides into specific crystallographic sites within the evolving Fe phases. In this chapter, we focus on the iron-bearing phases that are likely to be present in both the near and far-field of a GDF, examining their potential for redox activity and interaction with radionuclides. To support this, thermodynamic and molecular modelling is particularly important in predicting radionuclide behaviour in the presence of Fe-phases. Examination of radionuclide contamination of the natural environment provides further evidence of the importance of Fe-phases in far-field processes; these can be augmented by experimental and analogue studies.

Environmental Molecular Sciences Laboratory↗
DOE OSTI2021

Wastewater Disposal Has Not Significantly Altered the Regional Stress State in Southern Kansas

Wastewater disposal is primarily responsible for the increased seismicity rate since ~2013 in southern Kansas. Previous work that used shear-wave splitting (SWS) in southern Kansas interpreted an ~90° temporal rotation in the fast polarization direction and attributed it to increased pore pressures resulting from fluid injection. However, this interpreted rotation coincided with a change in the stations used to make the SWS measurements. We investigate the temporal variability of fast azimuths in southern Kansas by making SWS measurements on earthquake families with similar source–receiver paths recorded on a stable local seismic network. We select high-quality SWS measurements by investigating the stability of results across 65 different frequency bands between 0.5 and 15 Hz. We find that the fast polarization direction in southern Kansas is relatively constant with an average east-northeast (~N79°E) orientation between 2014 and 2017. Our fast polarization measurements are primarily a reflection of the maximum principal horizontal stress direction (SHmax). We observe a slight spatial change in SHmax to the northeast (~N55°E) near the Nemaha ridge in Oklahoma. However, we do not observe any significant temporal rotation of SHmax or variation in delay time (i.e., crack density) in southern Kansas, contrary to the earlier study. The previously interpreted ~90° rotation may either be a reflection of a very local stress change or a misinterpretation of SWS results potentially due to the use of inconsistent source–receiver paths. Our SWS measurements cover the period of peak wastewater disposal and seismicity rates and suggest an absence of significant temporal rotations in the local anisotropy and stress orientations associated with wastewater disposal.

Geochemistry & Geophysics↗
DOE OSTI2014

WASTE ISOLATION PILOT PLANT (WIPP): THE NATIONS' SOLUTION TO NUCLEAR WASTE STORAGE AND DISPOSAL ISSUES

In the southeastern portion of my home state of New Mexico lies the Chihuahauan desert, where a transuranic (TRU), underground disposal site known as the Waste Isolation Pilot Plant (WIPP) occupies 16 square miles. Full operation status began in March 1999, the year I graduated from Los Alamos High School, in Los Alamos, NM, the birthplace of the atomic bomb and one of the nation’s main TRU waste generator sites. During the time of its development and until recently, I did not have a full grasp on the role Los Alamos was playing in regards to WIPP. WIPP is used to store and dispose of TRU waste that has been generated since the 1940s because of nuclear weapons research and testing operations that have occurred in Los Alamos, NM and at other sites throughout the United States (U.S.). TRU waste consists of items that are contaminated with artificial, man-made radioactive elements that have atomic numbers greater than uranium, or are trans-uranic, on the periodic table of elements and it has longevity characteristics that may be hazardous to human health and the environment. Therefore, WIPP has underground rooms that have been carved out of 2,000 square foot thick salt formations approximately 2,150 feet underground so that the TRU waste can be isolated and disposed of. WIPP has operated safely and successfully until this year, when two unrelated events occurred in February 2014. With these events, the safety precautions and measures that have been operating at WIPP for the last 15 years are being revised and improved to ensure that other such events do not occur again.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2014

Deep Borehole Disposal Research: Geological Data Evaluation Alternative Waste Forms and Borehole Seals

This report documents deep borehole disposal research during FY2014, as directed by U.S. Department of Energy (DOE) Used Fuel Disposition (UFD) Campaign. These research efforts are principally directed at advancing the deep borehole disposal project to the implementation of a full-scale Research, Development, and Demonstration (RD&D) project. Activities of particular relevance to this goal include evaluation of guidelines for selection of a deep borehole field test site, analyses of deep borehole disposal of alternative waste forms, and technical planning for borehole seals research.

Arnold, Bill W.↗