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At least 685 records · Page 38

Data Validation Package: April 2016 Groundwater Sampling at the Falls City, Texas, Disposal Site

Nine groundwater samples were collected at the Falls City, Texas, Disposal Site as specified in the March 2008 Long-Term Surveillance Plan for the US Department of Energy Falls City Uranium Mill Tailings Disposal Site, Falls City, Texas (DOE-LM/1602-2008). Sampling and analyses were conducted as specified in the Sampling and Analysis Plan for US Department of Energy Office of Legacy Management Sites (LMS/PRO/S04351, continually updated). The wells sampled included the cell performance monitoring wells (0709, 0858, 0880, 0906, and 0921) and the groundwater monitoring wells (0862, 0886, 0891, 0924, and 0963). A duplicate sample was collected from location 0891. Water levels were measured at each sampled well. Historically, cell performance monitoring wells 0908 and 0916 have not produced water and were confirmed as dry during this sampling event. These wells are completed above the saturated interval in the formation. Notable observations for time-concentration graphs in this report include: (1) uranium concentrations in well 0891 continue to increase; (2) the uranium concentration in well 0880 is higher than the 2015 value and lower than the 2014 value, and it remains within the range of historical values; and (3) uranium concentrations in the other sampled wells are below 2 mg/L and consistent with previous results.

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Annual Performance Report April 2015 Through March 2016 for the Shiprock, New Mexico, Disposal Site

This annual report evaluates the performance of the groundwater remediation system at the Shiprock, New Mexico, Disposal Site (Shiprock site) for the period April 2015 through March 2016. The Shiprock site, a former uranium-ore processing facility remediated under the Uranium Mill Tailings Radiation Control Act, is managed by the U.S. Department of Energy (DOE) Office of Legacy Management. This annual report is based on an analysis of groundwater quality and groundwater level data obtained from site monitoring wells and the groundwater flow rates associated with the extraction wells, drains, and seeps. Background The Shiprock mill operated from 1954 to 1968 on property leased from the Navajo Nation. Remediation of surface contamination, including stabilization of mill tailings in an engineered disposal cell, was completed in 1986. During mill operation, nitrate, sulfate, uranium, and other milling-related constituents leached into underlying sediments and contaminated groundwater in the area of the mill site. In March 2003, DOE initiated active remediation of groundwater at the site using extraction wells and interceptor drains. At that time, DOE developed a baseline performance report that established specific performance standards for the Shiprock site groundwater remediation system. The Shiprock site is divided into two distinct areas: the floodplain and the terrace. The floodplain remediation system consists of two groundwater extraction wells, a seep collection drain, and two collection trenches (Trench 1 and Trench 2). The terrace remediation system consists of nine groundwater extraction wells, two collection drains (Bob Lee Wash and Many Devils Wash), and a terrace drainage channel diversion structure. All extracted groundwater is pumped into a lined evaporation pond on the terrace. Compliance Strategy and Remediation Goals As documented in the Groundwater Compliance Action Plan, the U.S. Nuclear Regulatory Commission–approved compliance strategy for the floodplain is natural flushing supplemented by active remediation. The contaminants of concern (COCs) at the site are ammonia (total as nitrogen), manganese, nitrate (nitrate + nitrite as nitrogen), selenium, strontium, sulfate, and uranium. The compliance standards for nitrate, selenium, and uranium are listed in Title 40 Code of Federal Regulations Part 192. Regulatory standards are not available for ammonia, manganese, and sulfate; remediation goals for these constituents are either risk-based alternate cleanup standards or background levels. These standards and background levels apply only to the compliance strategy for the floodplain. The compliance strategy for the terrace is to eliminate exposure pathways at the washes and seeps and to apply supplemental standards in the western section.

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Annual Report for Los Alamos National Laboratory Technical Area 54, Area G Disposal Facility - Fiscal Year 2016

As a condition to the disposal authorization statement issued to Los Alamos National Laboratory (LANL or the Laboratory) on March 17, 2010, a comprehensive performance assessment and composite analysis (PA/CA) maintenance program must be implemented for the Technical Area 54, Area G disposal facility. Annual determinations of the adequacy of the PA/CA are to be conducted under the maintenance program to ensure that the conclusions reached by those analyses continue to be valid. This report summarizes the results of the fiscal year (FY) 2016 annual review for Area G.

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Data Validation Package August 2015 Groundwater Sampling at the Grand Junction, Colorado, Disposal Site October 2015

The 1998 Interim Long-Term Surveillance Plan for the Cheney Disposal Site Near Grand Junction, Colorado, requires annual monitoring to assess the performance of the disposal cell. Monitoring wells 0731, 0732 and 0733 were sampled as specified in the plan. Sampling and analyses were conducted in accordance with Sampling and Analysis Plan for the U.S. Department of Energy Office of Legacy Management Sites.

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International Approaches for Nuclear Waste Disposal in Geological Formations: Geological Challenges in Radioactive Waste Isolation—Fifth Worldwide Review

The overall objective of the Fifth Worldwide Review (WWR-5) is to document the current state-of-the-art of major developments in a number of nations throughout the World pursuing geological disposal programs, and to summarize challenging problems and experience that have been obtained in siting, preparing and reviewing cases for the operational and long-term safety of proposed and operating nuclear waste repositories. The scope of the Review is to address current specific technical issues and challenges in safety case development along with the interplay of technical feasibility, siting, engineering design issues, and operational and post-closure safety. In particular, the chapters included in the report present the following types of information: the current status of the deep geological repository programs for high level nuclear waste and low- and intermediate level nuclear waste in each country, concepts of siting and radioactive waste and spent nuclear fuel management in different countries (with the emphasis of nuclear waste disposal under different climatic conditions and different geological formations), progress in repository site selection and site characterization, technology development, buffer/backfill materials studies and testing, support activities, programs, and projects, international cooperation, and future plans, as well as regulatory issues and transboundary problems.

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Solid secondary waste testing for maintenance of the Hanford Integrated Disposal Facility Performance Assessment - FY 2017

The Waste Treatment and Immobilization Plant (WTP) at Hanford is being constructed to treat 56 million gallons of radioactive waste currently stored in underground tanks at the Hanford site. Operation of the WTP will generate several solid secondary waste (SSW) streams including used process equipment, contaminated tools and instruments, decontamination wastes, high-efficiency particulate air filters (HEPA), carbon adsorption beds, silver mordenite iodine sorbent beds, and spent ion exchange resins (IXr) all of which are to be disposed in the Integrated Disposal Facility (IDF). An applied research and development program was developed using a phased approach to incrementally develop the information necessary to support the IDF PA with each phase of the testing building on results from the previous set of tests and considering new information from the IDF PA calculations. This report contains the results from the exploratory phase, Phase 1 and preliminary results from Phase 2. Phase 3 is expected to begin in the fourth quarter of FY17.

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Regional Geologic Evaluations for Disposal of HLW and SNF: The Pierre Shale of the Northern Great Plains

The DOE Spent Fuel and Waste Technology (SWFT) R&D Campaign is supporting research on crystalline rock, shale (argillite) and salt as potential host rocks for disposal of HLW and SNF in a mined geologic repository. The distribution of these three potential repository host rocks is limited to specific regions of the US and to different geologic and hydrologic environments (Perry et al., 2014), many of which may be technically suitable as a site for mined geologic disposal. This report documents a regional geologic evaluation of the Pierre Shale, as an example of evaluating a potentially suitable shale for siting a geologic HLW repository. This report follows a similar report competed in 2016 on a regional evaluation of crystalline rock that focused on the Superior Province of the north-central US (Perry et al., 2016).

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US Sections Prepared for Future NEA Crystalline Club (CRC) Report on Status of R&D in CRC Countries Investigating Deep Geologic Disposal in Crystalline Rock

U.S. knowledge in deep geologic disposal in crystalline rock is advanced and growing. U.S. status and recent advances related to crystalline rock are discussed throughout this report. Brief discussions of the history of U.S. disposal R&D and the accumulating U.S. waste inventory are presented in Sections 3.x.2 and 3.x.3. The U.S. repository concept for crystalline rock is presented in Section 3.x.4. In Chapters 4 and 5, relevant U.S. research related to site characterization and repository safety functions are discussed. U.S. capabilities for modelling fractured crystalline rock and performing probabilistic total system performance assessments are presented in Chapter 6.

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Accelerator-Driven Subcritical System for Disposing of the U.S. Spent Nuclear Fuel Inventory

The current United States inventory of the spent nuclear fuel (SNF) is ~80,000 metric tons of heavy metal (MTHM), including ~131 tons of minor actinides (MAs) and ~669 tons of plutonium. This study describes a conceptual design of an accelerator-driven subcritical (ADS) system for disposing of this SNF inventory by utilizing the 131 tons of MAs inventory and a fraction of the plutonium inventory for energy production, and transmuting some long-lived fission products. An ADS system with a homogeneous subcritical fission blanket was first examined. A spallation neutron source is used to drive the blanket and it is produced from the interaction of a 1-GeV proton beam with a lead-bismuth eutectic (LBE) target. The blanket has a liquid mobile fuel using LBE as the fuel carrier. The fuel materials are dissolved, mixed, or suspended in the liquid fuel carrier. Monte Carlo analyses were performed to determine the overall parameters of the concept. Steady-state Monte Carlo simulations were performed for three similar fission blankets. Except for, the loaded amount of actinide materials in the LBE is either 5, 7, or 10% of the total volume of the blanket, respectively. The neutron multiplication factors of the three blankets are ~0.98 and the initial MAs blanket inventories are ~10 tons. In addition, Monte Carlo burnup simulations using the MCB5 code were performed to analyze the performance of the three conceptual ADS systems. During operation, fresh fuel was fed into the fission blanket to adjust its reactivity and to control the system power. The burnup analysis shows that the three ADS concepts consume about 1.2 tons of actinides per full power year and produce 3 GW thermal power, with a proton beam power of 25 MW. For the blankets with 5, 7, or 10% actinide fuel particles loaded in the LBE, assuming that the ADS systems can be operated for 35 full-power years, the total MA materials consumed in the three ADS systems are about 30.6, 35.3, and 37.2 tons, respectively. Thus, the corresponding numbers of ADS systems to utilize the 131 tons of MA materials of the SNF inventory are 4.3, 3.7, or 3.5, respectively. ADS concepts with tube bundles inserted in the fission blanket were analyzed to overcome the disadvantages of the homogeneous blanket concept. The liquid lead is used as the target material, the mobile fuel carrier, and the primary coolant to avoid the polonium production from bismuth. Reactor physics and thermal-hydraulic analyses were coupled to determine the parameters of the heterogeneous fission blanket. The engineering requirements for a satisfactory operation performance of the HT-9 ferritic steel structure material have been realized. Two heterogeneous concepts of the subcritical fission blanket with the liquid lead mobile fuel inside or outside the tube bundles were considered. The heterogeneous configuration with the mobile fuel inside the tubes showed better performance than the configuration with mobile fuel outside the bundle tubes. The Monte Carlo burnup codes, MCB5 and SERPENT were both used to simulate the fuel burnup in the ADS concepts with the mobile fuels inside the tubes. The burnup analyses were carried out for 35 full power years. The results show that 5 ADS systems can dispose of the total United States inventory of the spent nuclear fuel.

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Annual Status Report (FY2017): Performance Assessment for the Disposal of Low-Level Waste in the 200 West Area Burial Grounds

This annual review provides the projected dose estimates of radionuclide inventories disposed in the active 200 West 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-EP-06451). These estimates are compared with performance objectives defined in U.S. Department of Energy (DOE) requirements (DOE O 435.1 Chg 1 2 and its companion documents DOE M 435.1-1 Chg 1 3 and DOE G 435.1-1 4 ). All performance objectives are currently satisfied, and operational waste acceptance criteria (HNF-EP-0063 5 ) 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, which indicate potential impacts well below performance objectives. Therefore, future compliance with DOE O 435.1 Chg 1 is expected.

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Annual Status Report (FY2017): 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 active 200 East Area Low-Level Waste Burial Grounds (LLBGs) since September 26, 1988. The estimates are calculated using the original dose methodology developed in the performance assessment (PA) analysis (WHC-SD-WM-TI-7301). The estimates are compared with performance objectives defined in U.S. Department of Energy (DOE) requirements (DOE O 435.1 Chg 1, 2 and companion documents DOE M 435.1-1 Chg 1 3 and DOE G 435.1-1 4 ). All performance objectives are currently satisfied, and operational waste acceptance criteria (HNF-EP-00635) 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, which indicate potential impacts well below performance objectives. Therefore, future compliance with DOE O 435.1 Chg 1 is expected.

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Chemical Conversion of Anhydrous Hydrogen Fluoride for Safe Disposal

A procedure for the safe conversion of a small (~ 1 gram) quantity of anhydrous hydrogen fluoride to calcium fluoride is described. The purpose of the conversion is to put the toxic, corrosive, gaseous compound into a chemical form that is a less toxic solid (calcium fluoride) and easier to dispose of. The hydrogen fluoride, which was contained in a 50 cc metal sample cylinder, was drawn by a small mechanical vacuum pump through an all-metal gas manifold and into a metal trap containing alternating layers of calcium oxide powder and Teflon turnings. The anhydrous hydrogen fluoride reacts with the calcium oxide to produce calcium fluoride and water vapor. Because some of the calcium oxide powder was drawn out of the trap and into the vacuum tubing, it was not possible to quantify the amount of anhydrous hydrogen fluoride converted to calcium fluoride. However, it was noted that there was a temperature rise in the trap when the gas was flowing through it, and no HF gas was detected at the vacuum pump exhaust at this time using a colorimetric Dräger tube. The trap was sealed and disposed of as solid chemical waste.

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Geochemical Model of E h and pH Transitions in Pore Fluids during Saltstone and SDU Concrete Aging: Saltstone Disposal Facility PA Revision

The chemical and physical properties of the cementitious materials (dry cement, blast furnace slag, and fly ash) used to construct the Saltstone Disposal Units (SDUs) and saltstone waste form play a key role in the design and long-term performance of the Saltstone Disposal Facility. Chemical degradation of the reducing saltstone and concrete over time will impact radionuclide release and transport due to the changing chemical composition of groundwater (GW) percolating through the porous saltstone waste form. An equilibrium reaction path model was developed using The Geochemist’s Workbench® (GWB) software to estimate the timescales (expressed as number of pore volumes) for chemical degradation of the reducing cementitious materials as indicated by changes in redox potential (E h ) and pH.

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Summary Update on the Feasibility of Direct Disposal of SNF in Existing DPCs

This report is the deliverable M2SF-18SN010305026 FY18 Summary Update on the Feasibility of Direct Disposal of SNF in Existing DPCs. It reports on work done throughout fiscal year (FY) 2018, on work planned at the beginning of that FY, consisting of R&D activities for: 1) injectable fillers that could be used in dual-purpose canisters to prevent postclosure criticality in a geologic repository, and 2) as-loaded DPC data gathering and criticality. The work reported here was performed by Sandia National Laboratories and Oak Ridge National Laboratory. Appropriate attribution to source documents is provided in the text, tables, and figures below. Additional R&D on direct disposal of existing DPCs was planned and funded in mid-FY, and the associated reporting is separate from this milestone. Additional discussion of that new scope and how it implements findings from an independent expert review of the fillers R&D program (Section 10) is provided in the Summary (Section 11).

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A Critical Review of Ion Exchange in Nuclear Waste Glasses to Support the Immobilized Low-Activity Waste Integrated Disposal Facility Rate Model

There are over 50 million gallons of waste in underground tanks at the Hanford site in Washington State which was generated as a byproduct of nuclear materials fabrication for United States strategic defensive purposes. The waste, also known as high-level waste (HLW), is comprised of both radioactive and non-radioactive contaminants. To deal with the tank waste, the United States Department of Energy (DOE) plans to separate out the liquid, or supernatant, and salt-cake portions and treat them as low-activity waste (LAW). The LAW and HLW will be vitrified in separate facilities at the Hanford Tank Waste Treatment and Immobilization Plant (WTP). The LAW will be disposed of at the on-site Integrated Disposal Facility (IDF). The main species of concern in the immobilized low-activity waste (ILAW) include 99 Tc, 129 I, and U and other non-radioactive contaminants. Ultimately, it must be demonstrated that the contaminants released from the waste form pose minimal risk to humans and the environment. To aid in this demonstration, work is currently being done to expand the understanding of long-term glass waste form behavior, especially with regards to exposure to aqueous environments.

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Special Analysis for the Disposal of the Portsmouth Uranium Fluoride Solids Waste Stream at the Area 5 Radioactive Waste Management Site, Nevada National Security Site, Nye County, Nevada

This special analysis (SA) evaluates whether the Portsmouth Gaseous Diffusion Plant (PORT) Uranium (U) Fluoride Solids waste stream is suitable for disposal by shallow land burial at the Area 5 Radioactive Waste Management Site on the Nevada National Security Site (NNSS). The PORT U Fluoride Solids waste stream consists of highly enriched uranium solids. The PORT U Fluoride Solids waste stream requires an SA to resolve whether it is acceptable to dispose of technetium-99 ( 99 Tc), uranium-234 ( 234 U), and thorium-230 ( 230 Th) with activity concentrations exceeding the NNSS Waste Acceptance Criteria Action Levels.

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Special Analysis for the Disposal of U.S. Department of Energy High Activity Cesium Sources Waste Stream at the Area 5 Radioactive Waste Management Site, Nevada National Security Site, Nye County, Nevada

This special analysis evaluates whether the Lawrence Livermore National Laboratory (LLNL) U.S. Department of Energy (DOE) High Activity Cesium (Cs) Sources waste stream is suitable for shallow land burial at the Area 5 Radioactive Waste Management Site on the Nevada National Security Site. Disposal of the LLNL DOE High Activity Cs Sources waste meets all DOE M 435.1-1, “Radioactive Waste Management Manual,” Chapter IV, Section P performance objectives (DOE 1999). The LLNL DOE High Activity Cs Sources waste stream is recommended for acceptance with the conditions that 1) the total waste stream cesium-137 activity be limited to 1.7E16 Bq and 2) the waste be disposed 4.4 m (10 ft) below existing grade.

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Summary of Investigations on Technical Feasibility of Direct Disposal of Dual-Purpose Canisters

This report is a revision of the Fiscal Year (FY)-15 summary report on the investigations on technical feasibility of direct disposal of dual-purpose canisters (DPCs) in a geological repository. Notable progress has been made in the postclosure criticality area supporting direct disposal of DPCs in FY-16 and FY-17. As such, this revision updates the postclosure criticality related studies to capture the advances made over the last two FYs.

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