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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 343 records · Page 19
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

Advanced Waste Form and Melter Development for Treatment of Troublesome High-level Wastes

A number of waste components in US defense high level radioactive wastes (HLW) have proven challenging for current Joule heated ceramic melter (JHCM) operations and have limited the ability to increase waste loadings beyond already realized levels. Many of these "troublesome" waste species cause crystallization in the glass melt that can negatively impact product quality or have a deleterious effect on melter processing. Recent efforts at US Department of Energy laboratories have focused on understanding crystallization behavior within HLW glass melts and investigating approached to mitigate the impacts of crystallization so that increases in waste loading can be realized. Advanced glass formulations have been developed to highlight the unique benefits of next-generation melter technologies such as the Cold Crucible Induction Melter (CCIM). Crystal-tolerant HLW glasses have been investigated to allow sparingly soluble components such as chromium to crystallize in the melter but pass out of the melter before accumulating.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

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.

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

Solid-liquid Separation Testing for the Remediation of Hanford Waste Treatment Plant Low Activity Waste Melter Off-Gas Condensate

The Low Activity Waste (LAW) vitrification facility at the Hanford Waste Treatment and Immobilization Plant (WTP) will generate an aqueous condensate stream (LAW Off-Gas Condensate) from the off-gas system. The plan for disposition of this stream during Direct Feed LAW operations is to transfer it to the Effluent Management Facility (EMF), where it will be concentrated by evaporation and recycled to the LAW vitrification facility again. The primary reason to recycle this stream is so that the semi-volatile 99Tc isotope eventually becomes incorporated into the glass. However, this stream also contains non-radioactive salt components that are problematic in the melter, so diversion of this stream to another process would eliminate recycling of these salts and would enable simplified operation of the LAW melter and the Pretreatment Facilities. This diversion from recycling this stream within WTP would have the effect of decreasing the quantity of glass waste produced by allowing further increases in waste loading, resulting in a shortened LAW vitrification mission duration. The concept being tested here involves selectively removing the 99 Tc so that the decontaminated aqueous stream, with the problematic salts, can be disposed as a different waste form and avoid reprocessing through vitrification.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2021

Recommended Updates to Solubility Controls for Modeling Leaching of Technetium, Uranium, Neptunium, Plutonium, and Iodine from the Residual Waste Layer of Closed Savannah River Site High Level Waste Tanks

The objective of this report is to relate waste leaching experiments by the Savannah River National Laboratory (SRNL) to performance assessment modeling of release of several radionuclides from residual waste in closed high-level waste tanks. SRNL leached residual waste from Tanks 18F and 12H with solutions simulating the modeled evolution of pore fluids in residual waste layers of closed tanks through various stages of grout degradation. Tc-99, uranium isotopes, Np-237, plutonium isotopes, and I-129 were analyzed in the leachate multiple times over 90 days.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2014

Radioactive Demonstration Of Mineralized Waste Forms Made From Hanford Low Activity Waste (Tank SX-105 And AN-103) By Fluidized Bed Steam Reformation

One of the immobilization technologies under consideration as a Supplemental Treatment for Hanford’s Low Activity Waste (LAW) is Fluidized Bed Steam Reforming (FBSR). The FBSR technology forms a mineral waste form at moderate processing temperatures thus retaining and atomically bonding the halides, sulfates, and technetium in the mineral phases (nepheline, sodalite, nosean, carnegieite). Additions of kaolin clay are used instead of glass formers and the minerals formed by the FBSR technology offers (1) atomic bonding of the radionuclides and constituents of concern (COC) comparable to glass, (2) short and long term durability comparable to glass, (3) disposal volumes comparable to glass, and (4) higher Na2O and SO{sub 4} waste loadings than glass. The higher FBSR Na{sub 2}O and SO{sub 4} waste loadings contribute to the low disposal volumes but also provide for more rapid processing of the LAW. Recent FBSR processing and testing of Hanford radioactive LAW (Tank SX-105 and AN-103) waste is reported and compared to previous radioactive and non-radioactive LAW processing and testing.

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DOE OSTI2017

The Use of Positrons to Survey Alteration Layers on Synthetic Nuclear Waste Glasses

In order to safeguard society and the environment, understanding radioactive waste glass alteration mechanisms in interactions with solutions and near-field materials, such as Fe, is essential to nuclear waste repository performance assessments. Alteration products are formed at the surface of glasses after reaction with solution. In this study, glass altered in the presence of Fe0 in aqueous solution formed two alteration layers: one embedded with Fe closer to the surface and one without Fe found deeper in the sample. Both layers were found to be thinner than the alteration layer found in glass altered in aqueous solution only. For the first time, Doppler Broadening Positron Annihilation Spectroscopy (DB-PAS) is used to non-destructively characterize the pore structures of glass altered in the presence of Fe0. Advantages and disadvantages of DB-PAS compared to other techniques used to analyze pore structures for altered glass samples are discussed. Ultimately, DB-PAS has shown to be an excellent choice for pore structure characterization for glasses with multiple alteration layers. Monte Carlo modeling predicted positron trajectories through the layers, and helped explain DB-PAS data, which showed that the deeper alteration layer without Fe had a similar composition and pore structure to layers on glass altered in water only.

Doppler Broadening Positron Annihilation Spectrosc↗
DOE OSTI2018

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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DOE OSTI2017

A review on technological options of waste to energy for effective management of municipal solid waste

Highlights: • The current status, options and challenges of WTE techniques were analysed. • Incineration is the most widely used WTE technology in the developed countries. • Landfilling is the most common practice of MSWM in developing countries. • Approximately 50 million tonnes of methane is emitted annually from landfills. • WTE will ensure both the energy security and environmental protection. - Abstract: Approximately one-fourth population across the world rely on traditional fuels (kerosene, natural gas, biomass residue, firewood, coal, animal dung, etc.) for domestic use despite significant socioeconomic and technological development. Fossil fuel reserves are being exploited at a very fast rate to meet the increasing energy demands, so there is a need to find alternative sources of energy before all the fossil fuel reserves are depleted. Waste to energy (WTE) can be considered as a potential alternative source of energy, which is economically viable and environmentally sustainable. The present study reviewed the current global scenario of WTE technological options (incineration, pyrolysis, gasification, anaerobic digestion, and landfilling with gas recovery) for effective energy recovery and the challenges faced by developed and developing countries. This review will provide a framework for evaluating WTE technological options based on case studies of developed and developing countries. Unsanitary landfilling is the most commonly practiced waste disposal option in the developing countries. However, developed countries have realised the potential of WTE technologies for effective municipal solid waste management (MSWM). This review will help the policy makers and the implementing authorities involved in MSWM to understand the current status, challenges and barriers for effective management of municipal solid waste. This review concluded WTE as a potential renewable source of energy, which will partly meet the energy demand and ensure effective MSWM.

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DOE OSTI2016

Conversion of Nuclear Waste to Molten Glass: Cold-Cap Reactions in Crucible Tests

The feed-to-glass conversion, which comprises complex chemical reactions and phase transitions, occurs in the cold-cap zone during nuclear waste vitrification. Knowledge of the chemistry and physics of feed-to-glass conversion will help us control the conversion path by changing the melter feed makeup to maximize the glass production rate. To investigate the conversion process, we analyzed heat-treated samples of a simulated high-level waste feed using X-ray diffraction, electron probe microanalysis – wavelength dispersive X-ray spectroscopy, leaching tests, and residual anion analysis. Feed dehydration, gas evolution, and borate phase formation occurred at temperatures below 700 °C before the emerging glass-forming melt was completely connected. Above 800 °C, intermediate aluminosilicate phases and quartz particles were gradually dissolving in the continuous borosilicate melt, which expanded into transient foam. Knowledge of the chemistry and physics of feed-to-glass conversion will help us control the conversion path by changing the melter feed makeup to maximize the glass production rate.

Cold-cap↗
DOE OSTI2017

U.S. Department of Energy Implementation of Chemical Evaluation Requirements for Transuranic Waste Disposal at the Waste Isolation Pilot Plant

This report summarizes new controls designed to ensure that transuranic waste disposed at the Waste Isolation Pilot Plant (WIPP) does not contain incompatible chemicals. These new controls include a Chemical Compatibility Evaluation, an evaluation of oxidizing chemicals, and a waste container assessment to ensure that waste is safe for disposal. These controls are included in the Chapter 18 of the Documented Safety Analysis for WIPP (1).

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DOE OSTI2017

4th Quarter / Annual Transportation Report FY2017: Waste Shipments To and From the Nevada National Security Site (NNSS), Radioactive Waste Management Complex

This report satisfies the U.S. Department of Energy, National Nuclear Security Administration Nevada Field Office commitment to prepare a quarterly summary report of waste shipments to the Nevada National Security Site (NNSS) Radioactive Waste Management Complex at Area 5. This report summarizes the 4th quarter of fiscal year (FY) 2017 low-level radioactive waste (LLW), mixed low-level radioactive waste (MLLW), which includes classified LLW and MLLW, classified non-radioactive and classified non-radioactive hazardous shipments. There were no shipments sent for offsite treatment from an NNSS facility and returned to the NNSS this quarter of FY2017.

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

4 th Quarter / Annual Transportation Report FY16: Waste Shipments To and From the Nevada National Security Site (NNSS), Radioactive Waste Management Complex

This report satisfies the U.S. Department of Energy, National Nuclear Security Administration Nevada Field Office commitment to prepare a quarterly summary report of waste shipments to the Nevada National Security Site (NNSS) Radioactive Waste Management Complex at Area 5. This report summarizes both the 4th quarter and fiscal year (FY) 2016 low-level radioactive waste, mixed low-level radioactive waste, and classified non-radioactive shipments. There were no shipments sent for offsite treatment from a NNSS facility and returned to the NNSS this quarter of FY 2016.

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DOE OSTI2012

Control of the Reduction/Oxidation State of the High Level Waste Form in the Defense Waste Processing Facility at the Savannah River Site - 12451

The Defense Waste Processing Facility at the Savannah River Site treats and immobilizes High Level Waste into a durable borosilicate glass for safe, permanent storage. Among the parameters important to the overall process is the reduction/oxidation state of the glass. Control strategies for the reduction/oxidation state of the glass have been developed and evolved over the last 20 years to provide a current strategy which is both accurate and robust. A description of the methodologies implemented to control, evaluate, and validate the reduction/oxidation state of the glass is discussed along with the impact of future facility changes (made to pursue a more aggressive program to empty High Level Waste tanks at the Savannah River Site) on the reduction/oxidation state of glass. The reduction/oxidation state of the glass is an important parameter to the operation of the Defense Waste Processing Facility. Control, evaluation, and validation of the reduction/oxidation state of the glass is of particular importance for melter operation. Melter feed which is too oxidizing can negatively impact production, while feed which is too reducing can result in catastrophic failure of the melter. Control strategies for the reduction/oxidation state of the glass have been developed and evolved over the last 20 years to provide a current strategy which is both accurate and robust. (authors)

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

Regulatory inspection of the provision of disposability assessment and waste packaging advice in the UK to provide confidence that higher activity waste stored on licensed sites will be suitable for safe handling, transport and disposal - 15088

Radioactive Waste Management Limited (RWM), the developer and future operator of a geological disposal facility (GDF) in the United Kingdom, operates a disposability assessment process to minimise the risk that current conditioning and packaging of higher activity wastes (HAW) will result in packages incompatible with geological disposal in the future. Specialists in nuclear and environmental safety from the Office for Nuclear Regulation (ONR) and the Environment Agency (EA) in 2013/14 completed an inspection of the RWM's process of disposability assessment. The inspection gave the regulators confidence that RWM has in place a systematic process to provide an important means of reducing risks associated with waste packaging in advance of an operational GDF and that the process of disposability assessment is providing the necessary information for licensees to assure future HAW disposal to the GDF. This work forms part of our continuing programme to review RWM's work related to geological disposal of higher activity radioactive waste (HAW). (authors)

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

Tank Side Cesium Removal for Hanford Tank Waste - Actual Waste Demonstrations - 20467

The US DOE and its contractors are evaluating several options for treating Hanford tank supernate streams to provide feed for the Low-Activity Waste Facility at the Hanford Waste Treatment and Immobilization Plant. At this time, the intent is to deploy a Tank-Side Cesium Removal system. The key unit operations for this process are filtration and cesium removal by ion exchange. To assess the anticipated performance of the system, tests with actual waste were performed with samples from Hanford tanks AW-102 and AP-107 to provide basis data regarding the performance of the system in treating these materials. The decanted supernate waste samples from tanks AW-102 and AP-107 were received directly by the Radiochemical Processing Laboratory at Pacific Northwest National Laboratory. These samples were then filtered to provide data on dead-end filtration with a Mott{sup TM} filter media grade 5. Subsequently, the samples were run through 10-milliliter ion exchange columns containing crystalline silicotitanate to assess the dynamic ion exchange performance of these feeds. Test results demonstrated that the planned TSCR operations should meet process performance expectations. (authors)

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NASA NTRS1990

U.S. Space Station Freedom waste fluid disposal system with consideration of hydrazine waste gas injection thrusters

The results are reported of a study of various methods for propulsively disposing of waste gases. The options considered include hydrazine waste gas injection, resistojets, and eutectic salt phase change heat beds. An overview is given of the waste gas disposal system and how hydrozine waste gas injector thruster is implemented within it. Thruster performance for various gases are given and comparisons with currently available thruster models are made. The impact of disposal on station propellant requirements and electrical power usage are addressed. Contamination effects, reliability and maintainability assessments, safety issues, and operational scenarios of the waste gas thruster and disposal system are considered.

Winters, Brian A.↗
DOE OSTI2015

Special Analysis for the Disposal of the Lawrence Livermore National Laboratory Husman Irradiators Waste Stream at the Area 5 Radioactive Waste Management Site, Nevada National Security Site, Nye County, Nevada

This special analysis (SA) evaluates whether the Lawrence Livermore National Laboratories (LLNL) Husman Irradiators waste stream (BCLAHUSMANS00, Revision 0) is suitable for disposal by shallow land burial (SLB) at the Area 5 Radioactive Waste Management Site (RWMS). The LLNL Husman Irradiators waste stream consists of 3 fully self-shielded self-contained cesium-137 (137Cs) irradiators that have exceeded their useful lifetime (LLNL 2015). The LLNL Husman Irradiators waste stream requires an SA because the 137Cs activity concentration exceeds the Nevada National Security Site (NNSS) Waste Acceptance Criteria (WAC) Action Level (U.S. Department of Energy, National Nuclear Security Administration Nevada Field Office [NNSA/NFO] 2013). The results indicate that all performance objectives can be met with disposal of the LLNL Husman Irradiators in a SLB trench. Addition of the LLNL Husman Irradiators inventory had no significant effect on the maximum mean and 95th percentile performance assessment results over the 1,000-year compliance period. The short half-life of 137Cs limits its potential impacts to a few hundred years after disposal. The 3 Husman Irradiators are suitable for disposal by SLB at the Area 5 RWMS.

Lawrence Livermore National Laboratories, LLNL, Hu↗