Fabrication of radioactive and non-radioactive titanate and zirconate ceramics for immobilization of
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Reiser, Joelle T.↗
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Studying the impact of radioactive charging on the microphysical evolution and transport of radioactive aerosols with the TOMAS-RC v1 framework
We present that radioactive charging can significantly impact the way radioactive aerosols behave, and as a result their lifetime, but such effects are neglected in predictive model studies of radioactive plumes. The objective of this work is to determine the influence of radioactive charging on the vertical transport of radioactive aerosols in the atmosphere, through its effect on coagulation and deposition, as well as quantifying the impact of this charging on aerosol lifetime. The TwO-Moment Aerosol Sectional (TOMAS) microphysical model was extended to account for radioactive charging effects on coagulation in a computationally efficient way. The expanded model, TOMAS-RC (TOMAS with Radioactive Charging effects), was then used to simulate the microphysical evolution and deposition of radioactive aerosol (containing the isotopes 131 I and 137 Cs) in a number of idealized atmospheric transport experiments. Results indicate that radioactive charging can facilitate or suppress coagulation of radioactive aerosols, thus influencing the deposition patterns and total amount of radioactive aerosol mass available for long-range transport. Sensitivity simulations to uncertain parameters affirm the potential importance of radioactive charging effects. Lastly, an important finding is that charging of neutral, coarse mode aerosol from background radiation can reduce coagulation rates and extend its lifetime in the atmosphere by up to a factor of 2.
54 ENVIRONMENTAL SCIENCES↗
Special Analysis for the Disposal of the Oak Ridge National Laboratory General Radioactive Sources Waste Stream at the Area 5 Radioactive Waste Management Site, Nevada National Security Site, Nye County, Nevada
This special analysis (SA) evaluates whether the Oak Ridge National Laboratory (ORNL) General Radioactive Sources waste stream (ORNLSOURCES01, Revision 3) is suitable for disposal by shallow land burial (SLB) at the Area 5 Radioactive Waste Management Site (RWMS) at the Nevada National Security Site (NNSS). The ORNL General Radioactive Sources waste stream consists of sealed sources and solid radioactive sources that are no longer needed (ORNL 2015). The ORNL General Radioactive Sources waste stream required a special analysis because 26 radionuclides exceeded the NNSS Waste Acceptance Criteria (WAC) Action Levels (U.S. Department of Energy, National Nuclear Security Administration Nevada Field Office [NNSA/NFO] 2015). However, review of the generator’s method to calculate waste concentration indicates that the concentrations are significantly overestimated. Waste concentrations are recalculated in this analysis using a list of individual sources provided by the generator. One radionuclide, radium-226 (226Ra), still exceeds its action level and a Special Analysis (SA) is required. The results indicate that all performance objectives can be met with disposal of the ORNL General Radioactive Sources in a SLB trench. Addition of the ORNL General Radioactive Sources inventory slightly increases the 222Rn flux density. The maximum mean and 95th percentile flux density remain less than the performance objective throughout the compliance period. The ORNL General Radioactive Sources waste stream had no significant effect on the maximum mean and 95th percentile for all other performance assessment results. The ORNL General Radioactive Sources waste stream is suitable for disposal by SLB at the Area 5 RWMS. However, because the activity concentrations on the waste profile sheet are significantly overestimated, approval of the sheet could potentially allow the disposal of high activity radiation sources. To ensure the generator does not include large radiation sources in its waste stream, a control is recommended on the maximum individual source activity from this generator.
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
Incorporating radioactive decay into charging and coagulation of multicomponent radioactive aerosols
Compositional changes by the decay of radionuclides in radioactive aerosols can influence their charging state, coagulation frequency and size distribution throughout their atmospheric lifetime. The importance of such effects is unknown as they have not been considered in microphysical and global radioactivity transport studies to date. Here, we explore the effects of compositional changes on the charging efficiency and coagulation rates of aerosols using a set of kinetic equations that couple all relevant processes (decay, charging and coagulation) and their evolution over time. Compared to a coupled aggregation-tracer model for the prediction of the radioactive composition of particulates undergoing coagulation, our kinetic approach can provide similar results using much less central processing unit time. Altogether with other considerations, our approach is computational efficient enough to allow implementation in 3D atmospheric transport models. The decay of radionuclides and the production of decay products within radioactive aerosols may significantly affect the aerosol charging rates, and either hinder or promote the coagulation of multicomponent radioactive aerosols. Our results suggest that radiological phenomena occurring within radioactive aerosols, as well as subsequent effects on aerosol microphysics, should be considered in regional and global models to more accurately predict radioactivity transport in the atmosphere in case of a nuclear plant accident.
54 ENVIRONMENTAL SCIENCES↗
Laboratory Enrichment of Radioactive Assemblages and Estimation of Thorium and Uranium Radioactivity in Fractions Separated from Placer Sands in Southeast Bangladesh
The present study reports the likely first attempt of separating radioactive minerals for estimation of activity concentration in the beach placer sands of Bangladesh. Several sand samples from heavy mineral deposits located at the south-eastern coastal belt of Bangladesh were processed to physically upgrade their radioactivity concentrations using plant and laboratory equipment. Following some modified flow procedure, individual fractions were separated and investigated using gamma-ray spectrometry and powder-XRD analysis. The radioactivity measurements indicated contributions of the thorium and uranium radioactive series and of {sup 40}K. The maximum values of {sup 232}Th and {sup 238}U, estimated from the radioactivity of {sup 208}Tl and {sup 234}Th in secular equilibrium, were found to be 152,000 and 63,300 Bq/kg, respectively. The fraction of the moderately conductive part in electric separation contained thorium predominantly, while that of the non-conductive part was found to be uranium rich. The present arrangement of the pilot plant cascade and the fine tuning of setting parameters were found to be effective and economic separation process of the radioactive minerals from placer sands in Bangladesh. Probable radiological impacts and extraction potentiality of such radioactive materials are also discussed.
54 ENVIRONMENTAL SCIENCES↗
Proven Technologies for the Solidification of Complex Liquid Radioactive Waste (LRW): Global Case Studies of Applications and Disposal Options - 20424
Legacy radioactive waste streams from the Cold War still exist and newly generated waste streams from nuclear power plants and research institutes go untreated and expose environmental hazards at many nuclear sites. The nature of the waste is diverse, depending upon the source or the process from which it originated. The most problematic waste streams include complex liquids such as organic (tri-butyl-phosphate TBP) solutions contaminated with Pu and U isotopes, mixed sludge types, high acid radioactive waste, H-3 contaminated organic and aqueous streams, etc. Technological, environmental and economic challenges exist for the treatment and disposal of such waste streams. A proven technology that has been applied to LRW on a global basis provides one option as a low-cost solution to legacy streams and small volume, highly complex LRW frequently found during decommissioning at nuclear power plants and weapons sites. The engineered polymer technology from Nochar, USA, is capable of solidifying standard and highly complex LLW and ILW waste streams for interim or final storage, or for incineration. (authors)
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
Containment system for experiments on radioactive and other hazardous materials in a Paris-Edinburgh press
Abstract not provided
Jacobsen, Matthew K.↗
Infrastructure development for radioactive materials at the NSLS-II
The X-ray Powder Diffraction (XPD) Beamline at the National Synchrotron Light Source-II is a multipurpose instrument designed for high-resolution, high-energy X-ray scattering techniques. In this article, the capabilities, opportunities and recent developments in the characterization of radioactive materials at XPD are described. The overarching goal of this work is to provide researchers access to advanced synchrotron techniques suited to the structural characterization of materials for advanced nuclear energy systems. XPD is a new beamline providing high photon flux for X-ray Diffraction, Pair Distribution Function analysis and Small Angle X-ray Scattering. The infrastructure and software described here extend the existing capabilities at XPD to accommodate radioactive materials. Such techniques will contribute crucial information to the characterization and quantification of advanced materials for nuclear energy applications. We describe the automated radioactive sample collection capabilities and recent X-ray Diffraction and Small Angle X-ray Scattering results from neutron irradiated reactor pressure vessel steels and oxide dispersion strengthened steels.
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
UNREVIEWED DISPOSAL QUESTION EVALUATION: Disposal of the Oak Ridge National Laboratory General Radioactive Sources Low-Level Waste at the Area 5 Radioactive Waste Management Site, Nevada National Security Site, Nye County, Nevada
This Unreviewed Disposal Question Evaluation (UDQE) assesses whether the Oak Ridge National Laboratory (ORNL) General Radioactive Sources (ORNLSOURCES01, Revision 5 [ORNL 2017]) is suitable for shallow land burial (SLB) at the Area 5 Radioactive Waste Management Site (RWMS) on the Nevada National Security Site (NNSS). Disposal of the ORNL General Radioactive Sources meets all U.S. Department of Energy (DOE) Manual DOE M 435.1-1, “Radioactive Waste Management Manual,” Chapter IV, Section P performance objectives (DOE 1999).The ORNL General Radioactive Sources waste stream is recommended for acceptance with the following conditions: The total waste stream tritium (3H) inventory shall not exceed 5E10 Bq. The total waste stream strontium-90 (90Sr) inventory shall not exceed 5E9 Bq. The total waste stream cesium-137 (137Cs) inventory shall not exceed 2E11 Bq. The total waste stream radium-226 (226Ra) inventory shall not exceed 2E10 Bq. The total waste stream protactinium-231 (231Pa) inventory shall not exceed 2E9 Bq. The total waste stream uranium-234 (234U) inventory shall not exceed 5E9 Bq.
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
UNREVIEWED DISPOSAL QUESTION EVALUATION: Disposal of the Oak Ridge National Laboratory General Radioactive Sources at the Area 5 Radioactive Waste Management Site, Nevada National Security Site, Nye County, Nevada
This Unreviewed Disposal Question Evaluation (UDQE) assesses whether the Oak Ridge National Laboratory (ORNL) General Radioactive Sources (ORNLSOURCES01, Revision 6 [ORNL 2021]) is suitable for shallow land burial (SLB) at the Area 5 Radioactive Waste Management Site (RWMS) on the Nevada National Security Site (NNSS). Disposal of the ORNL General Radioactive Sources meets all performance objectives of DOE Manual DOE M 435.1-1, Radioactive Waste Management Manual, Chapter IV, Section P (DOE 1999). The ORNL General Radioactive Stream is recommended for acceptance......
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
Salt mass determination by 22 Na-based radioactive tracer dilution of a highly radioactive molten salt system for pyroprocessing spent oxide nuclear fuels
To demonstrate the feasibility of the 22 Na-based radioactive tracer dilution (RTD) for determining the total salt mass in a 60-kg oxide reduction (OR) system at Idaho National Laboratory (INL) for pyroprocessing spent oxide nuclear fuels, a LiCl- 22 NaCl tracer salt was prepared and spiked to the OR vessel, and salt samples were analyzed by gamma spectroscopy. Due to the high radioactivity (around 10 mCi/g) of the OR salt, mainly from 137 Cs, traditional gamma spectroscopy methods, which typically involve diluted salt samples, was not effective for analyzing the RTD samples. Since the 22 Na tracer radioactivity was very low, undiluted samples were necessary to detect the small amount of 22 Na tracer. Here, despite the high gamma radioactivity of the OR salt, increasing the detector-sample distance from 20 cm to 40 cm during gamma spectroscopy allowed the detection of radioactivity as low as 0.12 µCi/g 22 Na. The preparation of the 22 NaCl-LiCl tracer salt suitable for spiking into the OR salt was successful, and the mass determined by RTD was consistent with that estimated by salt level measurement. Therefore, the 22 Na-based RTD technique for total mass determination of the 60-kg molten salt system for OR is feasible, though more development work, particularly in the improving the uncertainty, is needed .
11 - NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Modelling the sulfate capacity of simulated radioactive waste borosilicate glasses
The capacity of simulated high-level radioactive waste borosilicate glasses to incorporate sulfate has been studied as a function of glass composition. Combined Raman, 57 Fe Mössbauer and literature evidence supports the attribution of coordination numbers and oxidation states of constituent cations for the purposes of modelling, and results confirm the validity of correlating sulfate incorporation in multicomponent borosilicate radioactive waste glasses with different models. A strong compositional dependency is observed and this can be described by an inverse linear relationship between incorporated sulfate (mol% SO 4 2- ) and total cation field strength index of the glass, Σ(z/a 2 ), with a high goodness-of-fit (R 2 ≈ 0.950). Similar relationships are also obtained if theoretical optical basicity, Λ th (R 2 ≈ 0.930) or non-bridging oxygen per tetrahedron ratio, NBO/T (R 2 ≈ 0.919), are used. Results support the application of these models, and in particular Σ(z/a 2 ), as predictive tools to aid the development of new glass compositions with enhanced sulfate capacities.
36 MATERIALS SCIENCE↗
Development of Estimation Method for Radioactivity Concentration Distribution of Radioactive Wastes in a Box-shaped Container - 17034
We are developing a new estimation method suitable for determining radioactivity concentration distribution of radioactive wastes stored in a square box-shaped container. This method uses the Maximum A Posteriori (MAP) method which is a way to solve the inverse problem, and it estimates the radioactivity concentration distribution by comparing simulated data with measured data. In the measurement, gamma rays emitted from the radioactive wastes are measured by several gamma ray spectrometers which are set at different positions in relation to each other. On the other hand, the gamma ray spectrum data of each spectrometer are simulated by a Monte Carlo simulation code. The method uses an iterative calculation to solve the concentration distribution with measured spectrum data and simulated spectrum data. We conducted a simulation test to check the algorithm of our estimation method. And we also conducted an experiment using activated objects. We found that the concentration of the wastes in a box-shaped container could be estimated within a 20 % error for the simulation, and within a 40 % error for the experiment and we confirmed that feasibility of our method was favorable. (authors)
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
Product Consistency Test and Vapor Hydration Test Comparisons of a Radioactive Hanford Waste Glass with its Non-Radioactive Simulant Glass
Product Consistency Tests (PCT) and Vapor Hydration Tests (VHT) were performed on a radioactive glass made from Hanford tank AP-107 waste (i.e., R-AP-107) and its non-radioactive equivalent glass made from simulated tank waste (i.e., S-AP-107). The radioactive and non-radioactive experiments were conducted in parallel with identical equipment, protocols, and staff to remove additional experimental uncertainties. PCT and VHT results are reported for all samples and are shown in Table S.1. Average normalized mass loss of B ( NL B ) and Na ( NL Na ) calculated from the three replicate test results for each glass with their respective standard deviations (SD) are presented for PCT results while individual VHT rates ( r VHT ) with their propagated errors ( σ r prop ) from individual thickness measurements on each sample are presented for the VHT results. Some VHT samples experienced more than 50% evaporation loss during the experiments. However, no visible alteration was detected on any VHT samples regardless on the amount of evaporation loss detected as shown in Table S.1.
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
Management of Radioactive Wastes (RWs) and Disused Sealed Radioactive Sources (DSRSs) in Bangladesh: Recent Activities and Challenges Ahead - 16039
The use of radioactive sources in different applications and practices gives rise to various types of RWs that may be detrimental to human health and the environment if not properly managed. Since early sixties of the last century, radioisotopes have found diversified and incremental uses in Bangladesh in the field of medicine, industry, agriculture, food irradiation, research and education and so on. Currently, the country is operating nuclear facilities like 3 MW TRIGA research reactor (TRR), radioisotope production (RIP) facility as well as particle accelerators. Recently, the country has decided to establish nuclear power plants in order to cope with its increasing demand of electric power. The first nuclear power plant is anticipated to come into operation by 2021-2022. Consequently, a notable amount and range of RWs including DSRSs are being expected to be generated from these diversified applications of radioactive materials in near future. Bangladesh has limited facilities and capabilities to manage the RWs which are being currently generated from the conventional activities and practices with radioactive materials. However, the country is also working to improve its necessary capabilities and infrastructures for the management of RWs expected to be generated from both conventional and nuclear activities in future in a comprehensive, integrated and safer manner, ensuring that no undue burden is imposed on present and future generations and on the environment. This paper illustrates the current activities as well as its future plans on the management of RWs and DSRSs in the country. (authors)
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
UNREVIEWED DISPOSAL QUESTION EVALUATION: Disposal of the Idaho National Laboratory Radioactive Waste Management Complex Low-Level Waste at the Area 5 Radioactive Waste Management Site, Nevada National Security Site, Nye County, Nevada
This Unreviewed Disposal Question Evaluation (UDQE) assesses whether the Idaho National Laboratory (INL) Radioactive Waste Management Complex (RWMC) Low-Level Waste (INEL11006367N, Revision 4 [INL 2017]) is suitable for shallow land burial (SLB) at the Area 5 Radioactive Waste Management Site (RWMS) on the Nevada National Security Site (NNSS). Disposal of the INL RWMC Low-Level Waste meets all U.S. Department of Energy (DOE) Manual DOE M 435.1-1, Radioactive Waste Management Manual, Chapter IV, Section P performance objectives (DOE 1999). The INL RWMC Low-Level Waste is recommended for acceptance without conditions.
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
The use of aluminum nitride to improve Aluminum-26 Accelerator Mass Spectrometry measurements and production of Radioactive Ion Beams
We present results and discuss the use of aluminum nitride as a promising source material for Accelerator Mass Spectrometry (AMS) and Radioactive Ion Beams (RIBs) science applications of 26 Al isotopes. The measurement of 26 Al in geological samples by AMS is typically conducted on Al 2 O 3 targets. However, Al 2 O 3 is not an ideal source material because it does not form a prolific beam of Al- required for measuring low-levels of 26 Al. Multiple samples of aluminum oxide (Al 2 O 3 ), aluminum nitride (AlN), mixed Al 2 O 3 –AlN as well as aluminum fluoride (AlF 3 ) were tested and compared using the ion source test facility and the stable ion beam (SIB) injector platform at the 25-MV tandem electrostatic accelerator at Oak Ridge National Laboratory. Negative ion currents of atomic and molecular aluminum were examined for each source material. It was found that pure AlN targets produced substantially higher beam currents than the other materials and that there was some dependence on the exposure of AlN to air. The applicability of using AlN as a source material for geological samples was explored by preparing quartz samples as Al 2 O 3 and converting them to AlN using a carbothermal reduction technique, which involved reducing the Al 2 O 3 with graphite powder at 1600 °C within a nitrogen atmosphere. The quartz material was successfully converted to AlN. Thus far, AlN proves to be a promising source material and could lead towards increasing the sensitivity of low-level 26 Al AMS measurements. The potential of using AlN as a source material for nuclear physics is also very promising by placing 26 AlN directly into a source to produce more intense radioactive beams of 26 Al.
Janzen, Meghan S.↗
Design and construction of a new detector to measure ultra-low radioactive-isotope contamination of argon
Large liquid argon detectors offer one of the best avenues for the detection of galactic weakly interacting massive particles (WIMPs) via their scattering on atomic nuclei. The liquid argon target allows exquisite discrimination between nuclear and electron recoil signals via pulse-shape discrimination of the scintillation signals. Atmospheric argon (AAr), however, has a naturally occurring radioactive isotope, 39Ar, a ß emitter of cosmogenic origin. For large detectors, the atmospheric 39Ar activity poses pile-up concerns. The use of argon extracted from underground wells, deprived of 39Ar, is key to the physics potential of these experiments. The DarkSide-20k dark matter search experiment will operate a dual-phase time projection chamber with 50 tonnes of radio-pure underground argon (UAr), that was shown to be depleted of 39Ar with respect to AAr by a factor larger than 1400. Assessing the 39Ar content of the UAr during extraction is crucial for the success of DarkSide-20k, as well as for future experiments of the Global Argon Dark Matter Collaboration (GADMC). This will be carried out by the DArT in ArDM experiment, a small chamber made with extremely radio-pure materials that will be placed at the centre of the ArDM detector, in the Canfranc Underground Laboratory (LSC) in Spain. The ArDM LAr volume acts as an active veto for background radioactivity, mostly ?-rays from the ArDM detector materials and the surrounding rock. This article describes the DArT in ArDM project, including the chamber design and construction, and reviews the background required to achieve the expected performance of the detector.
Noble liquid detectors, Dark Matter detectors, Cry↗