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DOE OSTI2019

Initial Assessment of Cover Degradation Features at the Mexican Hat, Utah, UMTRCA Disposal Site - 19556

The Mexican Hat, Utah, Uranium Mill Tailings Radiation Control Act (UMTRCA) Title I Disposal Site is located on the Navajo Reservation in southeast Utah. The US Nuclear Regulatory Commission licensed the site to the US Department of Energy Office of Legacy Management (LM) for custody and long-term care. LM manages long-term surveillance and maintenance activities at the site with the principal goal of protecting human health and the environment. The disposal cell was designed to encapsulate low-level radioactive mill tailings and other residual radioactive materials (RRM) in a way that minimizes the need for active maintenance and limits radon gas emanation and precipitation infiltration. The disposal cell has a multicomponent cover, consisting of a 60 cm thick (24 inch), low-permeability, bentonite-amended radon barrier, overlain by a 15 cm thick (6 inch) sandy gravel bedding/filter layer and a 30 cm thick (12 inch) riprap erosion-protection layer. Under UMTRCA, designs intended to control and contain RRM shall be effective for up to 1000 years, to the extent reasonably achievable and, in any case, for at least 200 years. In 2016, multiple subtle depressions were identified on the rock cover along the toe and lower portions of the northeast side slope of the disposal cell. Due to concerns regarding potential impacts to disposal cell performance and erosion resistance, evaluations of the depressions and cell cover design and construction were initiated. The evaluations included reviews of the disposal cell as-built drawings and supporting design calculations for the rock cover components. Also, in 2017, a weather monitoring station was installed at the site to collect continuous site-specific meteorological data, and repeatable ground-based light imaging, detection, and ranging (lidar) topographical and aerial photogrammetry surveys were implemented to monitor for potential changes in the surface depression features. The evaluations also included visual inspections of the depressions, and in 2018, small-area manual excavations of the rock cover components (test pits) were performed to observe the conditions of the cover components, scan for radioactivity, and observe evidence of erosion on the surface of the radon barrier material. Voids and incisions were discovered within the radon barrier on the north and northeast side slopes of the disposal cell. Visual observations at test pits indicate that the bedding/filter material is highly segregated and may not be in conformance with the disposal cell engineering and construction design specifications. Post-construction development of a weak to strongly cemented material has also been observed immediately below the base of the bedding layer in test pits with observed radon barrier degradation. A series of radiological surveys have been performed at the site, and radiological readings have not exceeded natural background conditions in the vicinity of the site. Thus, the site remains protective of human health and the environment. Implementation of continuous radiological monitoring at the site will be initiated in fall 2018 through the deployment of radon cups and thermoluminescent dosimeters to obtain data that provides supporting evidence that the disposal cell remains protective of human health and the environment. Evaluations to determine the cause(s) of the depression features and associated radon barrier erosion are ongoing. Possible mechanisms of cover degradation identified thus far include segregated bedding material that would allow for higher precipitation runoff velocities, resulting in erosion of the radon barrier; post-construction cementation of radon barrier or aeolian material that could negatively affect the performance of the radon barrier; cation exchange leading to the development of cementation; and aeolian deposition affecting precipitation runoff. Moreover, geotechnical sampling and testing is planned to verify spatial cover conditions relative to design specifications. The resulting information will be used to identify possible causes for the surface depressions and associated radon barrier degradation, gain insight on potential long-term performance implications along the side slopes of the disposal cell, and identify potential corrective actions. (authors)

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DOE OSTI2020

On Temperature Limits for the Outer Surface of a Container in a Disposal Facility - 20313

The temperature in a disposal facility for high-level radioactive waste (HLRW) is an issue for safety. When the recommencement of the search for and selection of a site for a disposal facility for HLRW in Germany was stipulated by the Site Selection Act (StandAG 2017) in 2017, a precautionary temperature limit of 100 deg. C on the outer surface of the containers with high-level radioactive waste in the disposal facility section was set. This precautionary temperature limit shall be applied in preliminary safety analyses provided that the 'maximum physically possible temperatures' in the respective host rocks have not yet been determined due to pending research. Therefore, this issue is addressed and discussed in this paper, contributing to 'pending research' by a review of the literature. This paper briefly discusses a few examples of thermohydraulic, mechanical, chemical and biological processes in a disposal facility, because temperature limits are derived based on safety impacts regarding THMCB-processes. The temperature-dependent processes have been extracted from databases for features, events and processes (FEP-databases). Furthermore, it is discussed if the feasibility to retrieve and recover HLRW is hampered at high temperatures. A design temperature concerning single components of a disposal facility for the preservation of their features can be derived when a safety concept is established. However, the interactions of all relevant processes in a disposal concept must be considered to determine a specific temperature limit for the outer surface of the containers. Therefore, applicable temperature limits may vary for particular safety and disposal concepts in the following host rocks: rock salt, clay stone and crystalline rock. Technical solutions for retrieval and design options for recovery seem to be viable up to temperatures of 200 deg. C with different, sometimes severe, downsides according to expert judgement. Temperature limits regarding the outer surface of the containers can be derived specifically for each safety concept and design of the disposal facility in a host rock. General temperature limits without reference to specific safety concepts or the particular design of the disposal facility may narrow down the possibilities for optimisation of the disposal facility and could adversely affect the site selection process in finding the best suitable site. (authors)

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DOE OSTI2016

Advances in Geologic Disposal System Modeling and Application to Crystalline Rock

The Used Fuel Disposition Campaign (UFDC) of the U.S. Department of Energy (DOE) Office of Nuclear Energy (NE), Office of Fuel Cycle Technology (OFCT) is conducting research and development (R&D) on geologic disposal of used nuclear fuel (UNF) and high-level nuclear waste (HLW). Two of the high priorities for UFDC disposal R&D are design concept development and disposal system modeling (DOE 2011). These priorities are directly addressed in the UFDC Generic Disposal Systems Analysis (GDSA) work package, which is charged with developing a disposal system modeling and analysis capability for evaluating disposal system performance for nuclear waste in geologic media (e.g., salt, granite, clay, and deep borehole disposal). This report describes specific GDSA activities in fiscal year 2016 (FY 2016) toward the development of the enhanced disposal system modeling and analysis capability for geologic disposal of nuclear waste. The GDSA framework employs the PFLOTRAN thermal-hydrologic-chemical multi-physics code and the Dakota uncertainty sampling and propagation code. Each code is designed for massively-parallel processing in a high-performance computing (HPC) environment. Multi-physics representations in PFLOTRAN are used to simulate various coupled processes including heat flow, fluid flow, waste dissolution, radionuclide release, radionuclide decay and ingrowth, precipitation and dissolution of secondary phases, and radionuclide transport through engineered barriers and natural geologic barriers to the biosphere. Dakota is used to generate sets of representative realizations and to analyze parameter sensitivity.

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DOE OSTI2026

Annual Summary Report for the Remote-Handled Low-Level Waste Disposal Facility—FY 2025

The U.S. Department of Energy (DOE) requires the performance assessment (PA) (Department of Energy Idaho Operations Office [DOE-ID] 2018a), composite analysis (CA) (DOE-ID 2012), and CA addendum (DOE-ID 2018b) for the Remote-Handled Low-Level Waste (RHLLW) Disposal Facility at the Idaho National Laboratory (INL) Site shall be maintained to evaluate changes that could affect the performance, design, and operating basis for the facility (DOE Manual 435.1-1 Change 3, “Radioactive Waste Management Manual,” Section IV.P. [4]). The RHLLW Disposal Facility became operational in September 2018 after the completion of operational readiness activities required by DOE Order 425.1D, “Verification of Readiness to Start Up or Restart Nuclear Facilities,” and the issuance of the startup authorization by the Startup Approval Authority (Boston 2018). The first waste disposals at the RHLLW Disposal Facility began in Fiscal Year (FY) 2019. In Fiscal Year (FY) 2025, no significant operational changes or other activities occurred that would cause deviation from the assumptions in the PA and CA pertaining to disposal geometry, verification of waste characteristics, tracking disposal inventories against total limits, facility closure design, or institutional controls. This FY 2025 annual summary report (ASR) documents the continued adequacy of the PA, CA, operating disposal authorization statement (ODAS) (ODAS 2018), ODAS technical-basis documents, and the radioactive waste management basis (RWMB) (INL 2024a) to meet DOE Order 435.1, “Radioactive Waste Management,” performance objectives for the RHLLW Disposal Facility. Annual review of the adequacy of the PA and CA at the RHLLW Disposal Facility ensures that conclusions of the analyses remain valid in accordance with requirements of DOE Order 435.1.

12 - MGMT OF RADIOACTIVE AND NON-RADIOACTIVE WASTE↗
DOE OSTI2013

Operating Experience and Lessons Learned in the Use of Soft-Sided Packaging for Transportation and Disposal of Low Activity Radioactive Waste

This paper describes the operating experience and lessons learned at U.S. Department of Energy (DOE) sites as a result of an evaluation of potential trailer contamination and soft-sided packaging integrity issues related to the disposal of low-level and mixed low-level (LLW/MLLW) radioactive waste shipments. Nearly 4.3 million cubic meters of LLW/MLLW will have been generated and disposed of during fiscal year (FY) 2010 to FY 2015—either at commercial disposal sites or disposal sites owned by DOE. The LLW/MLLW is packaged in several different types of regulatory compliant packaging and transported via highway or rail to disposal sites safely and efficiently in accordance with federal, state, and local regulations and DOE orders. In 1999, DOE supported the development of LLW containers that are more volumetrically efficient, more cost effective, and easier to use as compared to metal or wooden containers that existed at that time. The DOE Idaho National Engineering and Environmental Laboratory (INEEL), working in conjunction with the plastic industry, tested several types of soft-sided waste packaging systems that meet U.S. Department of Transportation requirements for transport of low specific activity and surface contaminated objects. Since then, soft-sided packaging of various capacities have been used successfully by the decontamination and decommissioning (D&D) projects to package, transport, and dispose D&D wastes throughout the DOE complex. The joint team of experts assembled by the Energy Facility Contractors Group from DOE waste generating sites, DOE and commercial waste disposal facilities, and soft-sided packaging suppliers conducted the review of soft-sided packaging operations and transportation of these packages to the disposal sites. As a result of this evaluation, the team developed several recommendations and best practices to prevent or minimize the recurrences of equipment contamination issues and proper use of soft-sided packaging for transport and disposal of waste.

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DOE OSTI2017

Optimization of Low Level Waste Disposal Policy, Strategies and Techniques - 17201

The mission of low level radioactive waste disposal facilities is to accept and dispose of waste in compliance with all applicable laws, regulations, license requirements, and social expectations. These facilities need to provide a cost effective disposal service to the waste generators, so that the cost savings could be passed down to business, industry, and ultimately, to the general public. To fulfil this mission, waste disposal facilities need to establish and maintain review and optimization mechanisms to respond to changing circumstances that may impact the long-term safe, cost effective operation of their facilities. Maintaining existing disposal resources available as long as possible, managing increased demand for disposal space as a consequence of growing number of nuclear facilities to be decommissioned, and developing capacity for future needs and uncertainties are some of the key challenges that drive optimization of disposal facilities. While the concept of optimization of low level waste disposal facilities is not new, the framework for holistic optimization of waste disposal facilities, enabling them to provide cost effective, sustainable services to the nuclear industry, as well as maintaining optimized safety and radiation protection systems is a notable gap in the current radioactive waste management body of knowledge. A comprehensive optimization framework is required to support the implementation of safe, effective, and sustainable integrated waste management strategies. (authors)

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DOE OSTI2019

Deep Isolation - Innovation for the Storage and Disposal of High-level Waste and Spent Nuclear Fuel - 19367

Deep Isolation, Inc. is a private, Berkeley based company that has brought innovation to nuclear waste disposal. Deep Isolation has developed a disposal technique that adapts mature drilling technology and customizes it for the purpose of providing a safe and secure solution. Though the stalled nuclear waste program in the US has created unwanted burdens and costs, it has also provided object lessons which Deep Isolation has learned from and designed a novel approach. The solution proposed by Deep Isolation combines the best of the geosciences and social sciences to present the US and other countries with an optimized and tailored approach to disposing of a variety of nuclear waste. This system can complement existing potential storage and disposal sites, or in the case of countries with smaller amounts of waste--the national solution. Deep Isolation innovates where others have stalled and offers a means of deep geological disposal that costs less, takes less time to implement, and cuts down and in some cases eliminates the need for transportation of the waste. The technical solution optimized by Deep Isolation uses established directional drilling technology from the oil and gas industry to drill a vertical drill hole thousands of meters deep and then transition to a horizontal drill hole that is thousands of meters in length. The target media is in or below shale formations, which are present at various depths throughout much of the United States and throughout the world. The availability of suitable geology allows for permanent disposal at multiple locations - including existing nuclear sites, without a need to transport the waste to a central repository. This innovative solution not only offers options for commercial used nuclear fuel and defense spent nuclear fuel and high-level waste, but also other nuclear wastes such as those considered by DoE's past deep bore-hole program, i.e. cesium and strontium capsules. Greater-Than-Class-C (GTCC) waste is also an opportunity for Deep Isolation. DoE's preferred alternative for GTCC includes 'land disposal at generic commercial facilities.' Deep Isolation could provide safe, secure, and permanent disposal at a commercial facility. Deep Isolation complements the technical innovation with best practices from the social sciences. In acknowledgement that the past challenges to implement nuclear waste disposal facilities have been primarily due to socio-political failings, we have designed a means to deeply engage with public and stakeholders. Our approach is committed to partnering with communities, local jurisdictions, states, and Tribes to determine a path forward that benefits all involved, that is fully transparent, collaborative and accountable. (authors)

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DOE OSTI2020

Issue Resolution During the Development of the Performance Assessment for the Savannah River Site Saltstone Disposal Facility - 20125

In 2019, Savannah River Remediation developed a revision to the performance assessment (PA) on behalf of the U.S. Department of Energy (DOE) Savannah River Operations Office (SR) for the near-surface disposal of low-level waste at the Savannah River Site (SRS) Saltstone Disposal Facility (SDF). Soluble waste from SRS Tank Farms undergoes salt processing to remove cesium and other high-activity constituents. The low-activity decontaminated salt solution (DSS) is then immobilized by mixing it into a cementitious waste form known as saltstone. After mixing, the saltstone is poured into leak-tight concrete vaults, known as saltstone disposal units (SDUs), where the waste form cures. By the time of facility closure, the SDF is expected to consist of 15 SDUs with a combined capacity of 1.06 E+09 L (280 Mgal) of cured saltstone. The facility operates under a Disposal Authorization Statement from DOE and a permit from the South Carolina Department of Health and Environmental Control (SCDHEC). Since the start of operations in 1990, the SDF has received almost 6.7 E+07 L (18 Mgal) of DSS, resulting in the safe disposal of 2.7 E+16 Bq (7.3 E+05 Ci) of activity. Due to the radioactive decay of short-lived contaminants, the total remaining activity in the disposed waste is estimated to be approximately 1.4 E+16 Bq (3.9 E+05 Ci), as of September 2018. The Disposal Authorization Statement requires a demonstration that the system of engineered and natural features of the disposal facility will limit releases from the facility and be protective of human health and the environment for at least the next 1,000 years. The long-term performance of the facility was evaluated under the requirements of the DoE's Radioactive Waste Management Manual (US DOE Manual 435.1-1). Simulations were performed to demonstrate that the disposal facility would meet performance objectives specified in the manual. The evaluation was based on numerical models that simulate the releases of contaminants from the saltstone waste form. Contaminants were transported through groundwater and air pathways to points of assessment to evaluate compliance (i.e., 100 m from the SDUs). In addition, the potential consequences of an inadvertent human intrusion (IHI) were also evaluated. A number of issues were overcome during the development of these simulations. These issues were identified as part of internal technical reviews. Simulations are developed by people and people make mistakes, so the internal technical review process is a vital step in PA development. Specific examples of resolved issues include a unit-conversion error, an inappropriate definition for a model boundary condition, a model time-stepping issue, and an error in the calculation for the buildup of contaminants in soil. Actions taken to address these issues resulted in an improved product with a better supported technical basis and more defensible results. The identification and correction of these issues are discussed. By understanding these issues, model developers and technical reviewers working on PAs in the future may avoid repeating these types of mistakes. Transparency with respect to these mistakes builds trust between waste management sites, regulators, and stakeholders. (authors)

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DOE OSTI2019

Annual Status Report (FY 2018): Performance Assessment for the Environmental Restoration Disposal Facility

DOE O 435.1 and DOE M 435.1-1 require that a determination of continued adequacy of the performance assessment (PA), composite analysis, and disposal authorization statement be made on an annual basis, and it must consider the results of data collection and analysis from research, field studies, and monitoring. Beginning in 1996, the Environmental Restoration Disposal Facility (ERDF) started accepting low-level radioactive, hazardous, and mixed wastes that were generated during cleanup activities at the Hanford Site. ERDF is composed of a series of cells or disposal areas and can accommodate future design expansions as needed. Currently, there are 10 cells. During this reporting period (fiscal year 2018, which extends from October 1, 2017, through September 30, 2018), approximately 193,358 U.S. tons of waste was disposed at ERDF. From ERDF inception through September 30, 2018, approximately 18.3 million U.S. tons of waste had been disposed at ERDF, which equates to consumption of approximately 87% of the disposal volume. As a condition of the Disoposal Authorization Statement, disposal operations within ERDF must be in accordance with the waste acceptance criteria (WAC) that provides specific radionuclide disposal limits, waste form restrictions, and descriptions of acceptable waste packages in compliance with the requirements of DOE 435-1.1. The ERDF WAC stipulates that waste destined for disposal at ERDF be controlled based on source, physical form, and contaminant concentration and activity levels. Concentration limits included in the ERDF WAC were extracted from the ERDF PA. A sum of fraction analysis of of the ERDF inventory against the threshold concentration limits from inception through fiscal year 2018 produces a result <1. This result provides confirmation of compliance with PA imposed radionuclide limits.

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DOE OSTI2021

Annual Status Report (FY 2020): Performance Assessment for the Disposal of Low Level Waste in the 200 East Area Burial Grounds

This annual review provides the projected dose estimates of radionuclide inventories disposed in the 200 East Area Low-Level Waste Burial Grounds (LLBGs) since September 26, 1988. These estimates are calculated using the original dose methodology developed in the performance assessment (PA) analysis (WHC-SD-WM-TI-730). The estimates are compared with requirements of DOE O 435.1 Chg 1 and performance objectives defined in companion documents DOE M 435.1-1 Chg 1and DOE-STD-5002-2017). All performance objectives are currently satisfied, and operational waste acceptance criteria (HNF-EP-0063) and waste acceptance practices continue to be sufficient to maintain compliance with performance objectives. Inventory estimates and associated dose estimates from future waste disposal actions are unchanged from previous years’ evaluations that indicate potential impacts well below performance objectives; therefore, future compliance with DOE O 435.1 Chg 1 is expected. A new PA study was initiated in fiscal year (FY) 2019 for evaluation of active disposal sites within the 200 East and 200 West Areas (Trench 94 in 200 East; Trenches 31 and 34 in 200 West) due to extended time elapsing between the current annual status report and the original PA for the active disposal sites. The new PA for the active disposal sites is expected to be completed in FY 2021. Within the active burial grounds in the 200 East Area, low-level waste and mixed low-level waste will continue to be disposed of in the dedicated U.S. Navy reactor compartment trench at the 218-E-12B Burial Ground (Trench 94). During this reporting period (FY 2020, from October 1, 2019, through September 30, 2020), two reactor compartments were disposed in Trench 94. Results from sorption experiments are summarized for this reporting period to quantify the efficacy of concrete waste forms in retaining key radionuclides (e.g., technetium-99 and iodine-129). The test durations ranged from 1 to 3 months. Continued groundwater monitoring of the 200 East Area LLBGs indicates no groundwater contamination due to LLBG waste. Current assumptions about future land use at the Hanford Site are consistent with PA analysis1 assumptions of a post-closure facility that will not be degraded by human activity. The LLBGs are located in an area identified for waste management and containment of residual contamination. This area will remain after final environmental remediation and the proposed shrinkage of Hanford Site boundaries to small sections within the 200 East and 200 West Areas in the Central Plateau (DOE/EIS-0391). The current closure plan for the LLBGs (DOE/RL-2000-707) estimates that the 200 East LLBGs will be closed in the 2050 timeframe. The Disposal Authorization Statement, other technical basis documents, and the radioactive waste management basis are of continued adequacy to meet the performance objectives of DOE O 435.1 Chg 1. Overall, there are no substantive changes to primary PA assumptions nor the PA analysis conclusion; therefore, compliance with DOE O 435.1 Chg 1 and the Disposal Authorization Statement is maintained.

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DOE OSTI2023

The role of international collaboration in the United States geologic disposal research program

Abstract. More than a decade ago, the United States disposal program discontinued all research activities focused on the unsaturated fractured tuff formation at Yucca Mountain as the geologic disposal site for spent fuel and high-level radioactive waste. A new research and development (R&D) program was initiated to provide a sound technical basis for alternative disposal options across clay, crystalline, and salt rocks. The goals of this broad program were (and still are) to (1) increase confidence in the robustness of generic disposal concepts, (2) develop the science and engineering tools needed to support disposal concept implementation, and (3) conduct R&D on the direct disposal of existing dual-purpose (storage and transportation) canisters. Recognizing the benefits of international collaboration toward the common goal of safely and efficiently managing the back end of the nuclear fuel cycle, the program emphasized international cooperation as an effective strategy for sharing information and knowledge. In a multi-laboratory effort coordinated by Lawrence Berkeley National Laboratory, the United States Department of Energy (DOE) program established formal and informal cooperation partnerships with several international initiatives and institutions and developed a number of collaborative R&D activities in important research areas, such as engineered barrier integrity, near-field perturbations, radionuclide transport, performance assessment, and methods for characterization and monitoring of engineered and natural barriers. This presentation gives an overview of these R&D activities, with a specific focus on activities that improve our current understanding of the coupled thermal–hydrological–mechanical–chemical (THMC) processes occurring in engineered and natural barriers. We start with a brief review of selected international collaboration initiatives and then describe a few specific collaboration projects. We focus specifically on such studies that use experimental data sets provided by international research cooperation for joint modeling work to increase confidence in performance-relevant predictions of coupled processes. Overall, the focus on international collaboration has allowed deep engagement of US researchers with the international waste management R&D community in terms of best practices, new scientific advances, state-of-the-art simulation tools, new monitoring and performance confirmation approaches, and lessons learned. The joint R&D with international researchers, worldwide sharing of knowledge and experience, and access to relevant data and experiments from a variety of host rocks have helped our researchers to significantly improve their understanding of the current technical basis for disposal in a range of potential host rock environments. International collaboration also provides ample opportunity for training and educating junior staff that are well suited to move the United States disposal research program forward into the next decades, a promising avenue for developing a next-generation workforce of disposal scientists.

Birkholzer, Jens T.↗
DOE OSTI2023

Addendum 2 to the Closure Report for CAU 577 Area 5 Chromium Containing Waste Disposal Cells, NNSS, Nevada

Corrective Action Unit (CAU) 577, “Area 5 Chromium Containing Waste Disposal Cells,” includes five low-level waste cells at the Nevada National Security Site Area 5 Radioactive Waste Management Site where buried waste received from Nuclear Fuel Services, Inc., was subsequently determined to contain chromium that exceeded the toxicity characteristic leaching procedure regulatory limit, which would require the waste to carry hazardous waste code D007. CAU 577 was created to satisfy the requirements of the Settlement Agreement (SA) executed between the Nevada Division of Environmental Protection (NDEP) and the U.S. Department of Energy, National Nuclear Security Administration Nevada Field Office (NNSA/NFO) on April 25, 2019 (NDEP 2019). The SA required that the chromium-containing waste received from NFS would be addressed following the closure process laid out in the Federal Facility Agreement and Consent Order (FFACO). The FFACO process ensures proper closure of the chromium-containing waste and documentation of that closure through FFACO-type documents. The following three Corrective Action Sites (CASs) were closed, and their closure was documented in the Closure Report for Corrective Action Unit 577: Area 5 Chromium Containing Waste Disposal Cells, Nevada National Security Site, Nevada, DOE/EMNV--0030, dated September 2021 (U.S. Department of Energy [DOE] Environmental Management [EM] Nevada Program 2021a): • CAS 05-21-02, Waste Disposal Cell 12 • CAS 05-21-03, Waste Disposal Cell 15 • CAS 05-21-04, Waste Disposal Cell 17 Closure of the following CAS was previously documented in the Addendum to the Closure Report for Corrective Action Unit 577: Area 5 Chromium Containing Waste Disposal Cells, Nevada National Security Site, Nevada, DOE/EMNV--0030-ADD, dated September 2022 (DOE EM Nevada Program 2022): • CAS 05-21-05, Waste Disposal Cell 20 This second addendum to the Closure Report documents the closure activities that have occurred for CAS 05-21-06, Waste Disposal Cell 21. This is the last CAS in CAU 577. The final waste shipment was placed in the waste disposal cell on November 21, 2022. Following this, closure activities began on November 28, 2022, and were conducted according to the Corrective Action Decision Document/Corrective Action Plan (CADD/CAP) for CAU 577 (DOE EM Nevada Program 2021b). The following closure activities were performed: • Constructing an engineered evapotranspiration cover • Installing two subsidence monuments and vadose zone monitoring equipment • Seeding the cover with a mixture of native plant species • Installing four concrete monuments on the corners of the cover and placing two use restriction (UR) warning signs on each monument These activities fulfill applicable federal and state regulations for closure of CAS 05-21-06 and minimize potential future exposure pathways to buried waste. Completed closure activities are also consistent with closure of the nine historical Resource Conservation and Recovery Act (RCRA) units included in Section 10.2.2 of the RCRA Permit that governs hazardous waste management activities at the Nevada National Security Site (Permit NEV HW0101) (NDEP 2023). UR documentation for this CAS is included in Appendix B of this report. The post-closure plan is presented in detail in the CADD/CAP for CAU 577 (DOE EM Nevada Program 2021b), and the requirements are summarized in Section 5.2 of this document. In accordance with paragraph 5D of the SA, a request to incorporate the requirements for post-closure monitoring of CAU 577 was included with the permit application for RCRA Permit NEV HW0101 that was submitted in January 2022 (NNSA/NFO 2022). The request included the post-closure requirements for the three CASs that had been closed at the time of submittal of the application as well as requirements that would be implemented upon future approval of closure of the remaining two CASs. All CAU 577 post-closure monitoring requirements have been captured in the April 4, 2023, Revision 7 of the RCRA Permit (NDEP 2023). As the RCRA Permit NEV HW0101 has been revised since the submittal of the original CAU 577 Closure Report (DOE EM Nevada Program 2021a) and Addendum 1 (DOE EM Nevada Program 2022), the post-closure requirements in this Addendum 2 report do not align with the previous documents. Specific changes resulting from the issuance of Revision 7 of the RCRA Permit are discussed in Section 5.2 of this report. The requirements in this report are consistent with the current permit (NDEP 2023) and supersede all requirements listed in the CAU 577 Closure Report and Addendum 1. All CAU 577 post-closure requirements should be conducted in accordance with the version of the RCRA Permit that is current at the time of the activities being performed. The DOE EM Nevada Program is requesting a Notice of Completion from NDEP for closure of CAU 577. Although CAU 577 is not a legacy site, the FFACO process is being followed to ensure proper closure of the chromium-containing waste. Therefore, transfer of CAU 577 from Appendix III of the FFACO to Appendix IV, Closed Corrective Action Units, is requested, as all closure activities have been completed.

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DOE OSTI2013

Operational Strategies for Low-Level Radioactive Waste Disposal Site in Egypt - 13513

The ultimate aims of treatment and conditioning is to prepare waste for disposal by ensuring that the waste will meet the waste acceptance criteria of a disposal facility. Hence the purpose of low-level waste disposal is to isolate the waste from both people and the environment. The radioactive particles in low-level waste emit the same types of radiation that everyone receives from nature. Most low-level waste fades away to natural background levels of radioactivity in months or years. Virtually all of it diminishes to natural levels in less than 300 years. In Egypt, The Hot Laboratories and Waste Management Center has been established since 1983, as a waste management facility for LLW and ILW and the disposal site licensed for preoperational in 2005. The site accepts the low level waste generated on site and off site and unwanted radioactive sealed sources with half-life less than 30 years for disposal and all types of sources for interim storage prior to the final disposal. Operational requirements at the low-level (LLRW) disposal site are listed in the National Center for Nuclear Safety and Radiation Control NCNSRC guidelines. Additional procedures are listed in the Low-Level Radioactive Waste Disposal Facility Standards Manual. The following describes the current operations at the LLRW disposal site. (authors)

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DOE OSTI2012

EC MoDeRn Project: In-situ Demonstration of Innovative Monitoring Technologies for Geological Disposal - 12053

Monitoring to provide information on the evolution of geological disposal presents several challenges. The 4-year, euros M 5, EC MoDeRn Project (http://www.modern-fp7.eu/), which commenced in 2009, addresses monitoring processes, state-of-the-art technology and innovative research and development of monitoring techniques. This paper discusses some of the key drivers for the development of innovative monitoring techniques and provides outlines of the demonstration programmes being conducted within MoDeRn. The aim is to develop these innovative monitoring techniques and to demonstrate them under realistic conditions present in underground laboratories. These demonstration projects, applying a range of different monitoring techniques, are being carried out at underground research facilities in different geological environments at HADES URL in Belgium (plastic clay), Bure in France (indurated clay) and at Grimsel Test Site (granite) in Switzerland. These are either built upon existing infrastructure (EC ESDRED Low pH shotcrete and TEM experiments at Grimsel; and PRACLAY experiment and underground galleries in HADES) or will be attached to infrastructure that is being developed and financed by resources outside of this project (mock-up disposal cell in Bure). At Grimsel Test Site, cross-hole and hole-to-tunnel seismic methods are being employed as a means to monitor induced changes in an artificially saturated bentonite wall confined behind a shotcrete plug. Recognising the limitations for travel-time tomography for monitoring a disposal cell, full waveform inversion techniques are being employed to enhance the capacity to monitor remote from the excavation. At the same Grimsel location, an investigation will be conducted of the potential for using a high frequency wireless (HFW) sensor network embedded within the barrier system; this will include the possibility of providing energy remotely to isolated sensors. At the HADES URL, the monitoring programme will utilise the PRACLAY gallery equipped to simulate a disposal gallery for heat-generating high-level waste evaluating fibre-optic based sensing techniques, including distributed sensing for thermal distribution and long-term reliability in harsh conditions. It also includes the potential to improve the treatment of signals from micro-seismic monitoring to enable enhanced understanding of the evolution around the gallery following its excavation due to ventilation, saturation and heating, and to image a water-bearing concretion layer. HADES URL will also be used to test wireless techniques to transmit monitoring data from the underground to the surface. The main focus of this contribution is to evaluate magneto-inductive data transmission; and to optimise energy usage. At the Bure underground facility in France, monitoring systems have been developed and will be embedded into the steel liner for the mock-up high-level waste disposal tunnel. The aim of this programme is to establish the capacity to conduct integrated monitoring activities inside the disposal cell, on the cell liner and in the near-field and to assess the capability of the monitoring to withstand construction and liner emplacement procedures. These projects, which are supported by focused development and testing of the monitoring systems, will allow the testing of both the effectiveness of these techniques applied to disposal situations and to understand the limits of these monitoring technologies. This approach should also enhance the confidence of key stakeholders in the ability to understand/confirm the changes occurring within a disposal cell. In addition, remote or 'non-intrusive' monitoring technologies are evaluated to provide a means of enhancing understanding of what is occurring in an isolated disposal cell. The projects also test solutions for embedded monitoring systems in challenging (risk of damage) situations. The outputs from this work will lead to improved understanding of these state-of-the-art techniques and allow focused development of those techniques beneficial to future monitoring programmes. It is also planned, as part of the MoDeRn programme of stakeholder engagement to show some of these monitoring demonstrations to lay stakeholders in order to receive their feed-back on the approach taken and their views on the value of this work. This feedback will help improve our understanding of how this work and future work on monitoring can be more effectively communicated. (authors)

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DOE OSTI2014

Risk management for outsourcing biomedical waste disposal – Using the failure mode and effects analysis

Highlights: • This study is based on a real case in hospital in Taiwan. • We use Failure Mode and Effects Analysis (FMEA) as the evaluation method. • We successfully identify the evaluation factors of bio-medical waste disposal risk. - Abstract: Using the failure mode and effects analysis, this study examined biomedical waste companies through risk assessment. Moreover, it evaluated the supervisors of biomedical waste units in hospitals, and factors relating to the outsourcing risk assessment of biomedical waste in hospitals by referring to waste disposal acts. An expert questionnaire survey was conducted on the personnel involved in waste disposal units in hospitals, in order to identify important factors relating to the outsourcing risk of biomedical waste in hospitals. This study calculated the risk priority number (RPN) and selected items with an RPN value higher than 80 for improvement. These items included “availability of freezing devices”, “availability of containers for sharp items”, “disposal frequency”, “disposal volume”, “disposal method”, “vehicles meeting the regulations”, and “declaration of three lists”. This study also aimed to identify important selection factors of biomedical waste disposal companies by hospitals in terms of risk. These findings can serve as references for hospitals in the selection of outsourcing companies for biomedical waste disposal.

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DOE OSTI2012

Preliminary Safety Design Report for Remote Handled Low-Level Waste Disposal Facility

A new onsite, remote-handled low-level waste disposal facility has been identified as the highest ranked alternative for providing continued, uninterrupted remote-handled low-level waste disposal for remote-handled low-level waste from the Idaho National Laboratory and for nuclear fuel processing activities at the Naval Reactors Facility. Historically, this type of waste has been disposed of at the Radioactive Waste Management Complex. Disposal of remote-handled low-level waste in concrete disposal vaults at the Radioactive Waste Management Complex will continue until the facility is full or until it must be closed in preparation for final remediation of the Subsurface Disposal Area (approximately at the end of Fiscal Year 2017). This preliminary safety design report supports the design of a proposed onsite remote-handled low-level waste disposal facility by providing an initial nuclear facility hazard categorization, by discussing site characteristics that impact accident analysis, by providing the facility and process information necessary to support the hazard analysis, by identifying and evaluating potential hazards for processes associated with onsite handling and disposal of remote-handled low-level waste, and by discussing the need for safety features that will become part of the facility design.

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DOE OSTI2012

Disposal Process for High Activity Sources by a University through the U.S. Dept. of Energy's Off-Site Source Recovery Project - 12076

Sealed radioactive sources are used in a wide variety of applications by a large number of license holders in the Unites States. Applications range from low-activity calibration sources to high-activity irradiators for engineering, research, or medical purposes. This paper describes and evaluates the safety and security measures in place for disused sealed sources, in particular of high activity sealed sources at the end of their operational life-time. The technical, radiation protection, and financial challenges for licensees and the Competent Authorities are reviewed from the point of view of the license holder. As an example, the waste management processes and the chain of custody for disused research irradiator sources are followed from extraction from the irradiator facility to the source disposal or recycling contractor. Possible safety and security concern in the waste disposal process are investigated in order to identify improvement potential for radiation protection or source security. Two shipments of disused sealed sources from Colorado State University (CSU) have been conducted through the CSU Radiation Control Office (RCO) in the last two years, with a third shipment expected to be completed by the end of November 2011. Two of the sources shipped are considered 'high' activity and exceed the U.S. NRC limits requiring increased controls for security purposes. Three sources were shipped in 2009 and ten more are expected in 2011. A total activity of 117.3 GBq was shipped in 2009. Nine sources were recently shipped in October 2011 through a third party waste broker where the total activity was 96.34 GBq. The last source is scheduled for shipment no later than 30 November 2011 and contains an activity of 399.96 GBq. Radiation waste disposal of high activity sources in large shields with unknown manufacturers, serial numbers, or model numbers is an arduous process requiring multiple contacts with various state and federal agencies. DOE's OSRP has made it possible for CSU to dispose of older unused sources in an economically viable way. Disposal of multiple sources all at once was not an option prior to the establishment of the SCATR program. While CSU was able to dispose of sealed sources when funds were available, the cost to the University would have been prohibitive for this type of mass removal and disposal of radiation sources initiated within this initiative. Where we estimate a cost of about $130 k to ship these sources otherwise, CSU's contribution of $21 k realized a significant savings in what would have been an impossible disposal cost. Removing unused radiation sources from CSU has realized a cost savings while removing a potential security threat. (authors)

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DOE OSTI2017

Recent Developments in the United Kingdom Geological Disposal Facility Programme - 17558

The United Kingdom Government remains committed to the policy of geological disposal. All major nuclear nations are actively pursuing geological disposal. It is internationally recognised that geological disposal represents the safest and most sustainable option as the end point of the management of high level waste and spent fuel considered as waste. Other countries that have also decided on a policy of geological disposal include Canada, Finland, France, Switzerland, Sweden and the United States of America. The United Kingdom Government continues to favour an approach to siting a Geological Disposal Facility that is based on the willingness of local communities to participate in the siting process. Construction and operation of a Geological Disposal Facility will be a multi-billion pound project that will provide skilled employment for hundreds of people over many decades. It will contribute greatly to the local economy and wider socio-economic framework. There are also likely to be spin-off industry benefits, infrastructure investments, benefits to local education or academic resources, and positive impacts on local service industries that support the facility and its workforce. It is also likely to involve major investments in local transport facilities and other infrastructure, which would remain after the facility had been closed. The United Kingdom Government published a renewed process for siting a Geological Disposal Facility in 2014 - the Implementing Geological Disposal White Paper. This paper discusses the status of activities in the 2014 White Paper that have been accomplished or are underway through to 2016. (authors)

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