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At least 19 records

RCRA Part A Permit Application for Waste Management Activities at the Nevada National Security Site Hazardous Waste Storage Unit (HWSU), Explosive Ordnance Disposal Unit (EODU), Mixed Waste Storage Unit (MWSU), and Mixed Waste Disposal Unit (MWDU)

This document is the first volume in a Resource Conservation Recovery Act (RCRA) Permit Application to the Nevada Division of Environmental Protection for continued operation of certain facilities on the Nevada National Security Site (NNSS), owned by the U.S. Department of Energy, National Nuclear Security Administration Nevada Field Office (NNSA/NFO). This RCRA permit application pertains to the Hazardous Waste Storage Unit (HWSU), the Explosive Ordnance Disposal Unit (EODU), the Mixed Waste Storage Unit (MWSU), and the Mixed Waste Disposal Unit (MWDU). This volume lists the relevant permits for each of these facilities and provides maps and drawings of many aspects of them. The companion volumes, which provide descriptive text and discussion and additional graphics, are jointly considered Part B of the permit application. Those volumes are identified by the following document numbers: DOE/NV/25946--2442, DOE/NV/25946--2448, DOE/NV/25946--2425, and DOE/NV/25946--2429.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Host-guest prospects of neodymium and gadolinium ultraphosphate frameworks for nuclear waste storage: Multi-temperature topological analysis of nanoporous cages in RP{sub 5}O{sub 14}

Highlights: • The temperature-dependent cage topologies of RP{sub 5}O{sub 14} (R = Nd or Gd) were examined. • A topological analysis revealed similar cage structure for RP{sub 5}O{sub 14} (R = Nd or Gd). • One exception: the 8/4 cage topology of NdP{sub 5}O{sub 14} lacks structural cross-linking. • Volume (UO{sub 2} or PuO{sub 2}) ≫ 8/4 topology in RP{sub 5}O{sub 14} (R = Nd or Gd). • RP{sub 5}O{sub 14} (R = Nd or Gd) are good prospective host media for nuclear waste storage. - Abstract: Rare-earth ultraphosphate (RP{sub 5}O{sub 14}) framework materials are potential host media for nuclear waste storage, since cages within their nanoporous structures have volumes that match well those of prospective guests such as uranium or plutonium ions. Good volume matches of host cages and guest compounds are nonetheless not the only structural requirement for ensuring viable nuclear waste storage. Host structures also need to be stable enough to withstand the typical environmental conditions of long-term storage of spent nuclear fuel. To this end, the nanoporous cage topologies of neodymium and gadolinium ultraphosphate, NdP{sub 5}O{sub 14} and GdP{sub 5}O{sub 14}, are investigated as a function of temperature. Topological analysis shows that, while both compounds are essentially isostructural, thus displaying the same type of cage structures, the cage volumes of NdP{sub 5}O{sub 14} are significantly larger than those of GdP{sub 5}O{sub 14}, with one stark exception. This exception concerns the cage of NdP{sub 5}O{sub 14} whose 8/4 topology lacks structural cross-linking that would otherwise give it much more strength. This 'squashed' cage appears to owe its origins to the specific nature of crystallographic twinning in NdP{sub 5}O{sub 14}, which causes strain that needs alleviating; squashing the 8/4 cage in NdP{sub 5}O{sub 14} would be the most susceptible option towards this end, since its cage manifests the weakest structural construct. GdP{sub 5}O{sub 14} succumbs to a gradual contraction of its 8/4 cage only with increasing temperature above 300 K; this is well below its second-order monoclinic-to-orthorhombic phase transition at 420–430 K; which is 420 K for NdP{sub 5}O{sub 14}. Fortunately, the volumes of heavy metal ions that arise from spent nuclear fuels do not match the size requirements of cages with 8/4 topology in RP{sub 5}O{sub 14} hosts needed for encapsulation; otherwise, radiation leakage of such containment would present a risk. Both NdP{sub 5}O{sub 14} and GdP{sub 5}O{sub 14} would therefore seem to offer good prospects as host media for nuclear waste storage.

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Hydrogen Recombiner Catalyst Evaluations for Waste Storage

Radiolysis of water in nuclear waste storage generates hydrogen gas that can accumulate within sludge style waste and be rapidly released during agitation events, creating a significant flammability hazard. Engineering controls are therefore required to limit hydrogen concentrations during both quiescent storage and transient disturbances. Catalytic recombination of hydrogen in waste storage offgas is a proven mitigation strategy, maintaining hydrogen levels below flammability limits and managing sudden concentration spikes. Conventional recombiners rely on platinum and/or palladium catalysts, with development efforts focused on extending service life, increasing active surface area, and ensuring safe deployment in radioactive environments. Savannah River National Laboratory (SRNL) is evaluating a newly developed hydrogen recombiner catalyst from Canadian Nuclear Laboratories as a cost-effective and durable alternative for nuclear waste applications. Testing was conducted in SRNL’s Shielded Cells facility, which enables reduced-scale experimental modeling under radiation fields and near-use-case conditions relevant to radioactive waste storage. Catalyst performance was evaluated using a custom offgas characterization system designed for near-zero flow conditions. The experimental apparatus consisted of a gas-tight 2.7 L PTFE vessel equipped with temperature monitoring, gas flow controls, and a variable-speed mixer to simulate sludge agitation. Offgas composition was monitored using a dedicated gas chromatograph with argon carrier gas and a krypton internal standard. Measurements were obtained for an empty vessel, the vessel containing a well characterized radioactive tank waste sample, and the same configuration with the candidate catalyst installed. Results demonstrate that the new catalyst effectively reduced hydrogen concentrations in the offgas within the constraints of the experimental design. In addition to confirming catalytic activity, the testing provided valuable insights into experimental optimization and considerations for future performance evaluations. These findings support the potential scalability of the technology and highlight its applicability to broader nuclear waste management operations, offering improved safety and reduced operational costs through enhanced catalyst durability and lower replacement frequency.

Tener, Zachary P. [Savannah River National Laborat↗

Decommissioning of a Historic Waste Storage Facility in Austria - 19059

Nuclear Engineering Seibersdorf Ltd. (NES) performed decommissioning of an old waste storage facility, the so called 'bunker', which was commissioned in 1968 and used until 1978 for the storage of radioactive waste from medical, industrial and research activities, as well as from the operation of the Austrian research reactor ASTRA. Due to the layout of the bunker the initial decommissioning plan was to decontaminate the inner walls of the caverns and afterwards perform clearance measurements on the standing structure. However, throughout the first phase of decommissioning it turned out, that contaminations penetrated deeper into the concrete structure as initially anticipated, which made an adoption of the decommissioning strategy necessary. By changing the workflow and to remove non-contaminated parts of the structure first, also the strategy for the clearance measurements had to be adapted. The selective decommissioning strategy and the demand that measurements shall be performed by an accredited body, required to set up an adequate communication structure to keep the workflow going. Moreover, a fast communication between NES, the competent authority and the authority's (external) experts was necessary to receive clearance licenses on time, and to prevent backlog of dismantled material. The paper reports on the initial and the adapted decommissioning strategy and the challenges within the changed approach. Applied decontamination and decommissioning methods and the implemented radiation protection measures will be discussed. Furthermore, information on the methodologies for clearance measurements, the collaboration of the accredited body with the decommissioning team, as well as on the communication between NES and the competent authority will be given. Finally, a balance of radioactive waste vs. conventionally disposed waste will be shown. (authors)

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RCRA Part B Permit Application Nevada National Security Site (NNSS) for Waste Management Activities at the NNSS Mixed Waste Storage Unit (MWSU)

This volume of the Resource Conservation and Recovery Act (RCRA) permit application to the Nevada Division of Environmental Protection focuses on continued operation of the Mixed Waste Storage Unit at the Nevada National Security Site (NNSS), under the auspices of DOE’s National Nuclear Security Administration Nevada Field Office (NNSA/NFO). Low-level mixed waste (LLMW) accepted at the NNSS contains both radioactive and hazardous material components as defined by various laws and regulations. The Mixed Waste Storage Unit (MWSU) is located at the Area 5 Radioactive Waste Management Complex (RWMC). Existing facilities at the RWMC are used to store LLMW generated at or shipped to the NNSS prior to disposal at the Mixed Waste Disposal Unit (MWDU). The document describes the MWSU, its general design, its operation, the materials it stores, and relevant health and safety regulations with which NNSS complies. The currently permitted MWSU has been operated since December 2010. Each of the four designated storage areas is RCRA-compliant for the storage of hazardous waste. This application represents a renewal request by DOE for the permitted MWSU. For security reasons, some of the contents of the full application are not available for public viewing. This version of the application contains most but not all of the contents as submitted to the regulatory agencies.

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Long-Term Performance of Reference Electrodes in Alkaline Radioactive Waste Storage Environments

Accurate measurements of corrosion potential are important for assessing the likelihood of internal localized corrosion and stress corrosion cracking of carbon steel tanks used for storing radioactive wastes. Reference electrodes in underground radioactive waste storage tanks are challenging to deploy, and more difficult to extract and replace frequently due to radiological exposure and disposal constraints. Hence, electrodes that exhibit stable performance over long periods of immersion in these waste environments are desirable. The present study evaluates the stability of reference electrodes used in radioactive waste storage tanks over a much longer period than previously studied. Long-term tests on Ag/AgCl and Hg/HgO reference electrodes were performed in nonradioactive simulants formulated from wastes stored at the Hanford site. Electrode degradation, which was studied by various in situ and ex situ evaluation techniques, was correlated to changes in electrode fill chemistry from waste intrusion via the porous frit junction. An intentional contamination study was performed to better understand and predict contamination effects on electrode potential drift.

Materials Science↗

RCRA Part B Permit Application Nevada National Security Site (NNSS) for Waste Management Activities at the NNSS Hazardous Waste Storage Unit (HWSU)

This volume of the permit application by the DOE’s National Nuclear Security Administration Nevada Field Office (NNSA/NFO) to the Nevada Division of Environmental Protection (NDEP) focuses on the Area 5 Hazardous Waste Storage Unit (HWSU). The HWSU was established to support testing, research, and remediation activities at the Nevada National Security Site (NNSS), a large-quantity generator of hazardous waste. The HWSU, located adjacent to the Area 5 Radioactive Waste Management Complex (RWMC), is a prefabricated, rigid steel-framed, roofed shelter used to store hazardous nonradioactive waste generated on the NNSS. No offsite-generated wastes are managed at the HWSU. Waste managed at the HWSU includes the following: Flammables/Combustibles, Acid Corrosives, Alkali Corrosives, Oxidizers/Reactives, Toxics/Poisons, and Other Regulated Materials (ORMs). A list of regulated waste codes accepted for storage at the HWSU is provided in this volume. Hazardous wastes are stored at the HWSU in containers that are compliant with U.S. Department of Transportation (DOT) regulations and compatible with the stored waste. Waste packages (e.g., drums) without inner closed containers of waste remain closed except during inspection or sampling. Transfer of uncontainerized waste between waste packages at the HWSU is prohibited. Closed inner containers may be transferred or consolidated into larger waste packages, and small closed containers may be placed into larger containers. Containers are stored on secondary containment pallets, and the unit is inspected monthly. For safety and security reasons, some of the contents of the full application are not available for public viewing. This public version of the application contains most, but not all, of the contents as submitted to the regulatory agencies.

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Review of Mercury in the SRS Tank Waste Storage and Treatment Processes for Applicability to Hanford Waste Processing

The Savannah River Site (SRS) and Hanford produced large quantities of plutonium and other radioisotopes. The separations processes recovered plutonium and produced large quantities of High- Level Waste (HLW) that accumulated at each site in large, underground storage tanks. SRS has been retrieving the stored HLW, pretreating the waste for immobilization, and immobilizing the waste in glass or grout waste forms since the mid-1990s. Treatment of the waste at Hanford is expected to start in the early 2020s. Mercury is present in both the SRS and Hanford tank waste. SRS has recently completed an evaluation of mercury speciation throughout the tank waste treatment and immobilization flowsheet. This study was reviewed to determine what information from the study can be applied to the Hanford tank waste treatment program.

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Default Radioactive and Hazardous Waste Management (RHWM) Dose Conversion Factors (DCFs) and Weighting Factors and plutonium-239 equivalent Curie (PE-Ci) methodology for acceptance into the Waste Storage Facilities

DOE-STD-5506-2007 (Ref. 1) is the standard that provides the methodology for preparing hazard analysis and accident analysis for transuranic (TRU) waste facilities. The Waste Storage Facilities hazard and accident analysis for the DSA is developed in accordance with DOE-STD- 5506-2007. Two related issues need to be addressed when implementing DOE-STD-5506-2007 regarding the calculation of consequences from TRU waste releases in accident analysis: Consequences determined in accident analysis must be modeled using inhalation Dose Conversion Factors (DCFs) that are consistent with those from the International Commission on Radiological Protection Publication 72 (ICRP-72, Ref. 2).; The use of a statistical Material at Risk (MAR) representing the distribution of radiological loading of TRU waste containers based on the use of a plutonium-239 equivalent Curie (PE-Ci) methodology. The PE-Ci methodology simplifies accident analysis by allowing one to model releases based on the Curie value of one standard nuclide (e.g., Pu-239) instead of needing to model releases for every potential nuclide of interest. This is accomplished by normalizing the Curie value of all nuclides to a single Curie value of a standard nuclide by using a Weighting Factor that is a ratio of the DCFs associated with the nuclides and that of the standard nuclide. By using the ICRP-72 DCFs to calculate PE-Ci values used in the statistical MAR, the accident analysis that uses that statistical MAR will be consistent with the consequence methodology identified in DOE-STD- 5506-2007.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Application of QMU to the design of a nuclear waste storage tank

Defining the reliability of complex physical systems is crucial for system certification and guaranteeing safety, but is often complicated by the presence of many uncertainties and system sub-components. One such example is the certification of the Hanford Waste Treatment Plant, where radioactive and toxic chemical waste that spontaneously generates flammable gases is stored in large tanks. We introduce the QMU methodology to quantify the system safety of waste storage tanks in the event of a loss of tank ventilation, which poses a safety risk to workers. We also show how QMU can be used as a design tool to find operating regimes that maintain a desired confidence level. A simplified physical model is used to analyze the build-up of hydrogen gas in storage tanks and conduct an uncertainty propagation study to quantify the operating margin with respect to the flammability conditions. A demonstration problem is shown in which the radiation loading in a waste tank is iteratively modified until a desired confidence ratio is achieved. The results show that the resulting designs are sensitive to the use of interval or full QMU to achieve a confidence ratio, and it is not always possible to realize a design at a particular confidence ratio.

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Use of Automation in Low Level Waste Storage and Management - 19227

The Australian Nuclear Science and Technology Organisation (ANSTO) generates Low Level Waste (LLW) and Intermediate Level Waste (ILW) from various site operations such as the operation of a research Reactor and the manufacture of Molybdenum 99. The Low Level Solid Waste (LLSW) generated is stored at ANSTO before and after conditioning. The current process flow involves the storage of LLSW waste before conditioning on racks, handled using forklifts. When the unconditioned waste is ready for conditioning, it is transferred to another facility, where volume reduction and packaging is carried out. Once conditioned, the waste is placed in further storage, pending dispatch to the proposed Australian National Radioactive Waste Management Facility (NRWMF). A new purpose built facility has been constructed, adjacent to the LLSW processing facility, for the storage and management of LLSW in both unconditioned and conditioned forms. This new facility will streamline the waste management process and significantly enhance the safety and efficiency of the process. In line with international best practises, the new facility utilises automation solutions to minimise the build footprint, and minimise the use of forklifts and other mobile plant. Most importantly, it applies the principle of ALARA (As Low as Reasonably Achievable) to minimise operator activities in areas where radioactive material is stored and eliminates double handling of the waste. The automation for unconditioned waste utilises an Automated Storage and Retrieval System (ASRS), a vertical stacker crane within high density racking, to provide easy storage and retrieval for processing and/or routine inspections. This system allows operators to control it from outside of the storage area whilst utilising integrated software that allows for the required tracking of the unconditioned waste. From the ASRS storage area, unconditioned waste will have a smooth transition to the processing facility which is located adjacent to the ASRS system. Once conditioned, the waste is catalogued and returned to a designated storage area within the new facility using an automated building gantry crane with a target delivery system to eliminate the need for operators in the main storage bay. The waste will be held here in preparation for dispatch to the future repository. The utilisation of the ASRS for the purpose of storing LLSW is an innovative use of automation that will eliminate operators from active areas, reduce dose rates received and integrate with the waste tracking software. Furthermore, the system has significant advantages with operational efficiencies increased, reduced double handling of nuclear waste and maximum use of building footprint. (authors)

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Testing of Novel Application of GOTHIC{sup TM} to Modelling of Hydrogen Distribution in Intermediate Level Waste Storage Facilities - 16499

One of the strategies for treatment of intermediate level waste in the United Kingdom is to retrieve the waste from the legacy storage area, condition in a suitable storage container and then hold on-site in an intermediate level waste store until permanent storage in a geological disposal facility becomes available. During storage, hydrogen may be generated inside the containers at a slow rate by a number of mechanisms. The containers can be equipped with vents that release hydrogen and other gasses into the intermediate level waste store, a building which would be constructed to high standards to minimise ingress of moisture. With the low number of air changes associated with the building design there is the potential for gas to accumulate over time. There is, therefore, a requirement to be able to predict future gas concentrations inside the building over a range of operating conditions to ensure that a safe operating envelope is maintained. The usual approach to this problem is to model the evolution of the hydrogen distribution by use of computational fluid dynamics tools. In a situation where weeks of real time need to be simulated in order to understand the slow build-up of a very small volumetric concentration of hydrogen, the use of computational fluid dynamics is not practicable within the time scales demanded by industry. This paper investigates a new approach to tackling this problem using the thermal hydraulic code GOTHIC{sup TM} (GOTHIC{sup TM} incorporates technology developed for the electric power industry under the sponsorship of EPRI, the Electric Power Research Institute). (authors)

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A Versatile Remediation Module for Remote Repair of Spent Nuclear Fuel and High-Level Waste Storage Containers

Oak Ridge National Laboratory (ORNL) successfully demonstrated the Versatile Remediation Module (VRM), a prototype module designed and built by ORNL for on-site remote repair of welded stainless steel storage containers for spent nuclear fuel and high-level radioactive waste. This paper describes the VRM prototype and its design features and components to support continued long-term storage or off-site transportation of spent nuclear fuel and high-level radioactive waste currently stored in storage containers. A remote (100 ft away from the simulated radiative environment) demonstration of the VRM was successfully performed on a full-scale mock-up welded stainless steel canister. The VRM is designed with features to accommodate remediation techniques beyond those currently selected and described in this paper. Therefore, many of the VRM’s features may benefit other remote nuclear or nonnuclear applications. The VRM is envisioned to serve as a development center to facilitate and enhance further development of new remediation technologies.

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Calcined Waste Storage at the Idaho Nuclear Technology and Engineering Center

This comprehensive report provides definitive information regarding the volume, mass, and composition (chemical and radioactivity) of the calcined waste stored at the Idaho Nuclear Technology and Engineering Center on the Idaho National Laboratory Site. The calcine composition data are required for current regulatory compliance and safe operation of the INTEC’s six Calcined Solids Storage Facilities (CSSFs), as well as future retrieval, treatment, and shipping the calcine to an off-Site facility (such as a geologic repository). This report also contains a description of the calcine storage bins that compose each of the CSSFs, emphasizing the features that may be of concern to future calcine retrieval. The CSSFs were designed by different architectural engineering firms and built at different times. Each CSSF has a unique design, reflecting varying design criteria and lessons learned from historical CSSF operation. The varying CSSF designs will affect future calcine retrieval processes and equipment. This revision (5) of the report presents refinements of the databases used to calculate the volume, mass, chemical content, and radioactivity of calcined waste produced and stored within the CSSFs. This revision corrects minor errors and inconsistencies noted in an extensive validation and verification effort of the prior version of the Microsoft Excel workbooks upon which the calcine composition described in this report is based. Historical calcine samples are insufficient in number and scope of analysis to fully characterize the entire inventory of calcine in the CSSFs. Sample data exist for all of the liquid wastes that were calcined. This report provides calcine composition data based on liquid waste sample analyses, the volume of liquid waste calcined, calciner operating data, and CSSF operating data using several large Microsoft Excel (Microsoft 2010) databases and spreadsheets. The Excel spreadsheets are collectively called the Historical Processing Model (HPM). The calcine composition determined by this method compares favorably with historical calcine sample data.

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Cold Spray of C22Gd Coatings for Nuclear Waste Storage

C22-Gd films were deposited onto 316 stainless steel up to 2.4mm thick using three different cold spray conditions. No differences in visible coating adhesion was observed between grit-blasted and as-received 316 stainless steel substrates. All of the coatings produced had a density greater than 95% of bulk. EDS and backscattered imaging suggest that no secondary phases precipitated during coating fabrication, but potential micro-segregation of phases were likely present in the as-received material. The phase segregation was still observable in the as-deposited coatings. EDS could not resolve the differences in composition of the two phases.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗