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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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1,360 records · Page 76
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Robotic Platforms for Remote Access and Sensing Applications for Nuclear Decommissioning - 18325

This paper provides an updated summary of the research being conducted by the University of Manchester Robotics group (UoM Robotics) [1] at the University of Manchester, UK, in the area of remote characterization through the use of robotic systems. The research is in support of the decommissioning plan for the Sellafield nuclear site in west Cumbria, UK and Fukushima Diiachi, Japan. UoM Robotics works in collaboration with a number of companies and research institutes including Sellafield Ltd, the National Nuclear Laboratory, Universities of Lancaster, Birmingham, Bristol Robotics Laboratory, Italian Institute of Technology and the National Maritime Research Institute in Japan. The progress of a number of novel mobile robotic platforms being developed at the University of Manchester is presented in this poster presentation. Also presented is the on-going work on the remote sensing technologies and techniques which will be deployed on the robotic platforms. (authors)

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

Cake Permeability of Waste Simulants found in the Highly Active Storage Tanks at Sellafield - 18676

Caesium Phosphomolybdate (CPM) and Zirconium Molybdate (ZM) are two compounds causing issues within the Highly Active Storage Tanks (HASTs) at Sellafield. CPM has the potential to cause 'hot spots' possibly affecting the integrity of the tanks due to its settling and radioactive properties. ZM is thought to cause mobility issues when it is re-suspended by the jet ballasts in the HASTs. CPM and ZM were synthesised following the method published by Paul. The permeability method followed was published by Loginov. Conclusions: CPM has a higher overall cake resistance; Suggests a more open network for the ZM bed than the CPM bed; Cubes would be expected to pack tighter than spheres, suggesting the orientation of the cubes has some effect on the packing; In future the use of 2 M nitric acid instead of water will be explored as this is the natural conditions found in the HASTs.

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

Panel Session 19: Developments in the Clean-up Mission of Sellafield

This panel focused on the progress towards closure of the legacy ponds and silos on the Sellafield Site. The discussion included progressive learning, technical challenges, safety, and regulatory flexibility required to achieve cleanup. The panel included NDA, regulators and Sellafield Ltd. Presentations proposed include: 1 - Developments in the Cleanup of Sellafield: An Owners Perspective (Adrian Simper, Nuclear Decommissioning Authority UK (United Kingdom)); 2 - Sellafield Ltd (Lee Peck, Sellafield Ltd. (United Kingdom)); 3 - Developments in the Clean-up Mission at Sellafield (Ian Dallas, Office for Nuclear Regulation (United Kingdom)); 4 - Developments in the Clean-up Mission of Sellafield, UK (Steven Thomson, National Nuclear Laboratory (United Kingdom))

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

Investigating Uranium Corrosion in Magnesium-containing Sludge Using X-ray Tomography - 20042

One of the current primary concerns within the British nuclear community is the decommissioning of legacy storage ponds in Sellafield Cumbria, where nuclear fuel cladding material (a Mg-Al alloy) resides along with fuel metallic swarf. Corrosion of the immersed metallic elements, which has been occurring over the storage period, has resulted in the formation of what is commonly known as Corroded Magnox Sludge. The behaviour of uranium metal within this particular environment and, more significantly, the identity of the corrosion products that may have formed is currently unknown. The present study attempts to shed some light on these aspects by investigating simplified surrogate systems, mimicking storage ponds. (authors)

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

Innovative Approaches to the Decommissioning of a Redundant Plutonium Processing Facility - 20147

At Sellafield, in the North West of the United Kingdom (UK), there are a number of redundant plutonium processing facilities. Over the past three decades several decommissioning strategies have been deployed to clean up these redundant facilities. Whilst there have been many successes previously reported, there remain many challenges. As previously presented at WM2017 (Paper Ref 17081) some of these challenges have recently been addressed through a new approach which introduced a number of innovations. The purpose of these innovations is to seek ways to significantly reduce risks to both decommissioning personnel and the environment by minimising the extent of physical 'hands on' decommissioning activities and by simplifying the waste production process. This paper provides an update on the progress of these innovations since 2017. Additionally, the paper also provides details of the new decommissioning technologies which have been introduced over the past 2 years to enable the most challenging aspects of the redundant plutonium processing facility to be decommissioned. These new decommissioning technologies address challenges associated with the preparation of process vessels and pipework to enable their safe in-situ size reduction by remote means: - New decommissioning techniques have been introduced to allow penetrations to be remotely cut into process vessels and pipework to provide a means of accessing and controlling the venting of any potential hydrogen gas present. - Additionally, a new large scale bespoke remote diamond wire cutting machine has been designed and manufactured to enable the process vessels to be size reduced in situ. Both of these new cutting technologies have involved collaborative working with specialist equipment suppliers including extensive development, trialling demonstration and commissioning prior to bringing the equipment into operational service. Several years of work have now culminated in reaching the final stages of decommissioning of the redundant plutonium processing facility with decommissioning of the final process vessels now underway and completion expected by the end of 2019. (authors)

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

Electrochemical Study of BaCl{sub 2} and CsCl on a Liquid Bismuth Cathode in LiCl-KCl Eutectic Salt

Pyro-processing has been proposed and studied for recycling nuclear fuel. In pyro-processing, uranium and other actinides are recovered by electrolytic reduction in molten LiCl-KCl salts within the electro-refiner. However, over time the molten salts experience a buildup of other fission products, mostly alkali/alkaline-earths and rare earths. These products accumulate and degrade the efficiency of the electro-refiner, therefore capture and removal of these products is attractive. However, before a removal system can be designed and studied, fundamental physiochemical and electrochemical knowledge of the behavior of the fission products in the molten salts must be acquired. This project has studied the mass transport and electrochemical properties of BaCl{sub 2} and CsCl within LiCl- KCl eutectic salt on a liquid bismuth electrode. The diffusion coefficient and apparent standard potential of BaCl{sub 2} on the bismuth electrode has been determined from cyclic voltammetry. Charge transfer resistance and exchange current density values have also been obtained from electrochemical impedance spectroscopy (EIS) experiments.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2024

The Electron Thermal Conductivity of Pu and Zr Substituted Gamma-Uranium

Uranium alloys are attractive recycled nuclear fuels because of their high thermal conductivity (k) and fissile density; however, the effects of alloying elements on k remain unclear. Here, the electron thermal conductivity (k_e) of U-Pu-Zr compositions are calculated using density functional theory. The electronic structure is evaluated to understand the effects of plutonium (Pu) and zirconium (Zr) substitution on the k_e of ?-U. Alloys of up to 37.5 at. % Pu and 37.5 at. % Zr are examined. Two methods are applied to calculate k_e; we find that the accuracy of each method depends on the electronic and mass similarities between the solute and solvent atoms. Specifically, when the solute atom is similar in electronic structure and mass, the method that applies the electron relaxation time of ?-U is best, while if the elements are dissimilar, a mixed method that mixes several parameters associated with k_e from each element in the alloy is best. The introduction of all alloying elements decreases k_e; however, in binary compounds, Pu and Zr have different effects. Pu generally flattens the electronic bands but compensates for this deleterious effect by increasing electron density near the Fermi level. Zr flattens the electronic bands more severely without adding electron density near the Fermi level. Therefore, Zr decreases the k_e more than Pu in binary compounds. In ternary compounds, the difference between Pu and Zr is minimal due to the phononic change from the large mass change of Zr substitution, even at 12.5 at. %. Thus, we predict that higher loadings of Pu, and potentially other actinides, can be added to U-Pu-Zr compositions for faster recycling of spent fuel with without sacrificing k. We also note that these k_e calculation methods can be applied to non-fuel alloys that require k_e predictions, such as cladding, heat exchanger, and structural materials.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Sulfur Chloride Radiation Chemistry Activities

Presentation highlight the INL Center for Radiation Chemistry Research's contributions the Material Recovery & Waste Form Development Campaign on sulfur chloride processing technologies.

38 - RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCL↗