Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Radionuclide”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Comparison of atmospheric radionuclide dispersion models for a risk-informed consequence-driven advanced reactor licensing framework

Current nuclear facility emergency planning zones (EPZs) are based on outdated distance-based criteria, predating comprehensive dose and risk-informed frameworks. Recent advancements in simulation tools have permitted the development of site-specific, dose, and risk-based consequence-driven assessment frameworks. This study investigated the computation of advanced reactor (AR) EPZs using two atmospheric dispersion models: a straight-line Gaussian plume model (GPM) and a semi-Lagrangian Particle in Cell (PIC). Two case studies were conducted: (1) benchmarking the NRC SOARCA study for the Peach Bottom Nuclear Generating Station and (2) analyzing an advanced INL Heat Pipe Design A microreactor's end-of-cycle inventory. The dose criteria for both cases were 10 mSv at mean weather conditions and 50 mSv at 95th percentile weather conditions at 96 h post-release. Results demonstrated that GPM and PIC estimated similar mean peak dose levels for large boiling water reactors in the farfield case, placing EPZ limits beyond current regulations. For ARs with source terms remaining in the nearfield, PIC modeling without specific nearfield considerations could result in excessively high doses and inaccurate EPZ designations. PIC dispersion demonstrated an order of magnitude higher estimate of nearfield inhalation dose contribution when compared to GPM results. Furthermore, both models significantly reduced EPZ sizing within the nearfield. Thus, reductions in the AR source term may eliminate the need for a separate EPZ.

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTAN↗
DOE OSTI2024

Microjet printing of metal salt or oxide targets for nuclear reaction studies on radionuclides

Radioactive targets for direct measurements of neutron-induced reactions are required to improve evaluated cross-section data and, ultimately, the fidelity of neutron reaction network simulations. Electrodeposition and molecular plating are the current state-of-the-art radioactive target production techniques, but not all metals can be electrodeposited or molecular plated with high yields. Alternative techniques can be expensive or may produce targets that are unsatisfactory in terms of thickness, yield, or purity. Microjet printing is a new, rather inexpensive technique that utilizes equipment with a small footprint and has the potential to produce thin, highly radioactive targets with good uniformity and minimal impurities from the target fabrication process. This study involved optimizing the process of producing microjet printed targets to allow for the fabrication of a stable vanadium(V) oxide (V 2 O 5 ) target that was compared with an analogous electrodeposition V 2 O 5 target manufactured via the application of a vanadium chemical conversion coating on aluminum (Al) foil. Finally, the results from these studies suggest microjet printing could be used to produce relatively uniform target layers with adequate film thicknesses (< 15 μm). V 2 O 5 microjet printed targets, when compared with chemical conversion coating V 2 O 5 targets, appeared to be qualitatively less uniform and quantitatively larger in thickness (11.7(27) μm vs. 5.3(18) μm). However, the conversion coating target contained more impurities and the Al backing had a higher background contribution to measurements of neutron-induced reactions as opposed to targets produced via microjet printing. Overall, the results from this study suggest microjet printing has the capability to be an excellent alternative target production technique to the electrodeposition and molecular plating methods.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2021

Assessment of alternative radionuclides for use in a radioisotope thermoelectric generator

238 Pu is the current fuel source for MMRTGs. This is due to favorable properties, such as high decay heat and low gamma emissions. 238 Pu supplies are dwindling rapidly, necessitating the review of potential replacement isotopes for deep space missions. This work considers nine potential replacements, Ac-227, Am-241, Cf-252, Cm-244, Cs-137, Po-210, Sr-90, Th-228, and Th-170. We have assessed performance of alternatives to 238 Pu by modeling the specific decay-heat and gamma spectra of several potential radioisotopes in SCALE-ORIGEN, and comparing these with 238 Pu. An analysis of heat output, heat stability, safety, availability and required mass, baselined against 238 Pu demonstrates that of those radioisotopes studied, 241 Am has properties that make it most conducive for 238 Pu replacement.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2021

Multifunctional two-dimensional metal-organic frameworks for radionuclide sequestration and detection

Two lanthanide containing porous coordination polymers, [Ln2(bpdc)6(phen)2] · nH2O (1) and [Ln2(bpdc)6(terpy)2] · 3H2O (2) (Ln = either Pr, Nd or Sm-Dy); bpdc: 2,2'-bipyridine-5,5'-dicarboxylic acid, phen: 1,10-phenanthroline, and terpy: 2,2':6',2''-terpyridine, have been hydrothermally synthesized and structurally characterized by powder and single crystal X-ray diffraction. The crystallographic analyses reveal compounds 1 and 2 feature Ln3+ containing dimeric nodes that form a porous two-dimensional (2D) and non-porous three-dimensional (3D) framework, respectively. Each material is stable in aqueous media between pH 3-10 and exhibits modest thermal stability to ~400ºC. Notably, a portion of the phen and bpdc ligands in 1 can be removed thermally, without compromising the crystal structure, causing the surface area and pore volume to increase. The optical properties of 1 and 2 with Gd3+, Sm3+, Tb3+, and Eu3+ were explored in the solid-state using absorbance, fluorescence, and lifetime spectroscopies. The analyses reveal a complex blend of metal and ligand emission in the materials containing Sm3+ and Tb3+, while those featuring Eu3+ are dominated by intense metal-based emission. Compound 1 with Eu3+ displayed promise for the capture and detection of the uranyl cation, (UO2)2+, from aqueous media. In short, uranyl capture was observed at pH 4 and the adsorption thereof was detectable via vibrational and fluorescence spectroscopies and colorimetrically as the off-white color of 1 turned yellow with uptake. Finally, both 1 and 2 with Eu3+ produce bright red emission upon irradiation with Cu ka X-ray radiation (8.04 keV) and are candidate materials for applications in solid-state scintillation.

Surbella, Robert G.↗
DOE OSTI2025

Correction to “From Structure to Function: Zn/Mn-Modified Maghemite as an Advanced Nanoplatform for Magnetic Hyperthermia and Radionuclide Therapy”

In the original paper, the acknowledgment contained an error in the attribution of the financial support. The correction is necessary to accurately reflect the source of funding that supported the contributions of the authors from the Institute of Physics Belgrade. The corrected Acknowledgments section is below. Here, this correction pertains solely to the funding acknowledgment and does not affect the scientific content, data, results, or conclusion of the work in any way.

Cancer therapy↗
DOE OSTI2024

Advanced Porous Materials as Designer Platforms for Sequestering Radionuclide Pertechnetate

Technetium-99 ( 99 Tc), predominantly present as pertechnetate ( 99 TcO 4 – ), is a challenging contaminant in nuclear waste from artificial nuclear fission. The selective removal of 99 TcO 4 – from nuclear waste and contaminated groundwater is complex due to (i) the acidic and intricate nature of high-level liquid wastes; (ii) the highly alkaline environment in low-activity level tank wastes, such as those at Hanford, and in high-level wastes at locations like Savannah River; and (iii) the potential for 99 TcO 4 – to leak into groundwater, risking severe water pollution due to its high mobility. This Review focuses on recent developments in advanced porous materials, including metal–organic frameworks (MOFs), covalent organic frameworks (COFs), and their amorphous counterparts, porous organic polymers (POPs). These materials have demonstrated exceptional effectiveness in adsorbing 99 TcO 4 – and similar oxyanions. We comprehensively review the adsorption mechanisms of these anions with the adsorbents, employing macroscopic batch/column experiments, microscopic spectroscopic analyses, and theoretical calculations. In conclusion, we present our perspectives on potential future research directions, aiming to overcome current challenges and explore new opportunities in this area. Our goal is to encourage further research into the development of advanced porous materials for efficient 99 TcO 4 – management.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Modeling Radionuclide Inventories in MSR Off-Gas Systems with Radiochemical Transport Analysis

Molten salt reactors (MSR) contain unique characteristics that may require enhancements to modeling tools to accurately predict phenomena. One characteristic that may be advantageous to leverage during normal operation is on-line processing of the circulating fuel salt, such as an off-gas system (OGS) to remove volatile fission products. Therefore, new modeling tools must be developed to integrate spatial resolution and chemistry effects into fuel depletion tools to be able to account for these non-core sources of radioactivity. Such types of radiochemical transport analysis tools were used to estimate the removal rates for 12 elements within a flow model of the Molten Salt Reactor Experiment (MSRE) by optimizing against legacy experimental data of the gas-borne (GB) percentages of 12 nuclides. The removal rates were used in a depletion model to calculate the FP inventory that enters the MSRE OGS. Calculations are in good agreement with the empirical GB percentages reported for the 12 nuclides, which validates the approach and verifies each tool’s treatment of the radiochemical flow effects. The OGS inventory is discussed in terms of the largest nuclide contributors to activity, dose consequence, decay heat, and elemental composition. Finally, insights from the study allow recommendations to be made for future code development activities.

Shahbazi, Shayan↗
DOE OSTI2021

E- Area Low-Level Waste Facility Multitiered Groundwater and Intruder Radionuclide Screening

Solid Waste Management (SWM) operates the E- Area Low-Level Waste Facility (ELLWF) where low level on-site and off-site solid waste streams are buried. The facility has been in operation since late 1994 and is currently projected to remain in operation until 2065. This facility can accommodate a broad range of waste forms resulting from the six different types of disposal unit (DU) options (i.e., varying degrees of engineered barriers → trenches to concrete vaults). This facility is currently operating under a Performance Assessment (PA)issued back in 2008, along with several subsequent supporting Special Analyses (SA).

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

Project 57 Air Monitoring Report: January 1 through September 30, 2020, with a Review of the Period of Record Radionuclide Analyses

The DOE Environmental Management Nevada Program (EM NV) identified the Project 57 contaminated area as Corrective Action Unit (CAU) 415, Project 57 No. 1 Plutonium Dispersion Site, which consisted of one Corrective Action Site (CAS): NAFR-23- 02, Pu Contaminated Soil (U.S. DOE, 2014). The CAS included several Project 57 operational facilities in addition to the plutonium-contaminated soil. With approval of the State of Nevada Division of Environmental Protection, the DOE closed the Project 57 surface soil contamination site in October 2020. Closure was accomplished by installing a clean soil cap constructed over ground zero and the surrounding areas of the CA that may be entrained with wind-transported soil particles. After completion of the ground zero cap in October 2020, DRI discontinued monitoring of meteorological and associated environmental conditions at the Project 57 site as directed by DOE EM NV. Navarro dismantled air monitoring stations P57-3 and P57-4 and removed the equipment on October 20, 2020. This report presents the meteorological and dust observations and radiological analyses accomplished during the approximately 10 months when the air monitoring data collection equipment was operational during CY2020.

54 ENVIRONMENTAL SCIENCES↗