Enriched Uranium Research Articles

Coordination-Induced Magnetism Strategy for Highly Selective and Efficient Uranium Separation.

Highly efficient separation of dispersed uranium is important for the sustainable development of nuclear industry, and adsorption is the most recognized approach. However, there are many coexisting interfering metal ions that compete with uranyl ion for the chelating ligands in the adsorbents and lead to low separation selectivity and efficiency. Herein, a coordination-induced magnetism strategy is presented for the separation of uranium based on the conversion of diamagnetic cyanoferrocene (Fc-CN) nanocrystals to uranium-containing magnetic recoverable ferromagnetic aggregates. Different from previous adsorption strategies, this strategy combines the mechanisms of photocatalytic uranium enrichment and chemical uranium adsorption. Under light irradiation, electron of Fe(II) in Fc-CN is excited and transfers to uranyl ion via the cyano group to form tight coordination bond between N atom in cyano group and uranium. This phenomenon is unique for uranyl ion, and thus, a high uranium removal rate of 97.98% is achieved in simulated nuclear wastewater with the presence of tremendous interfering ions, proving its highly selective and efficient uranium separation performance. The ability to form highly stable magnetic aggregates via photoinduced interaction between Fc-CN and uranium enriches the understanding on the chemical properties of Fc-CN and uranium.

The role of hydrothermal alteration in uranium mineralization at the Xiaoshan uranium deposit, South China

Hydrothermal alteration can be utilized to constrain element migrations during mineralization, as it records the effects of fluid-rock interactions. Previous studies have suggested that uranium in deposits primarily originates from uranium-bearing granites; however, limited knowledge exists regarding the leaching mechamisms of this element and rare earth elements (REEs) from these rocks. In recent years, the Xiaoshan Deposit, a newly discovered medium-sized uranium deposit, has been discovered in the central part of the Lujing uranium ore field, South China. In this study, we examine this deposit to investigate hydrothermal alterations and their impact on elemental mass change. The deposit exhibits seven types of alteration including K-feldspar, albite, illite, sericite, muscovite, quartz and chlorite alteration. These alterations follow a certain sequence, starting from chlorite alteration, followed by widespread K-feldspar alteration, then to albite alteration, accompanied by muscovite alteration, and finally illite, sericite and quartz alteration. The main uranium mineralization stage was coeval with the late acid siliceous hydrothermal fluid, illite and sericite alteration. The pre-ore alkaline alteration (K-feldspar alteration) resulted in the leaching and extraction of uranium, leading to the precipitation of a significant amount of apatite in mineral interstices and initial uranium enrichment (ΔCi (U) = 16.52 ppm). This process facilitated material preparation for subsequent acidic alterations and localized ore enrichment. The original dense rock structure was disrupted, creating fractures/cavities that served as conduits for uranium mineralization. Moreover, under alkaline metasomatism, uranium and REEs was extensively leached out of uranium-bearing accessory minerals such as the apatite. According to apatite compositional variations and alteration geochemistry, these variations reveal the process of uranium dissolution, migration, and precipitation enrichment into ore bodies. Uranium was completely released during alkaline metasomatism, causing a sharp decline in U content from 53.1 ppm to 0.96 ppm. The formation of alkaline alteration fluids facilitates the extraction of uranium from the surrounding rocks (the Indosinian granite).

Electrochemical Drawdown of U3+ and Ce3+ in Molten LiCl-KCl Using a Liquid Cadmium Cathode

Abstract The electrorefining of spent nuclear fuels is a key step to recover uranium and transuranium on separated cathodes. However, the electrolyte salts become contaminated with fission products after batches of electrorefining, and therefore the two unit processes for the drawdown of actinide and lanthanide are suggested before treatment of the contaminated salts. We investigated the electrochemical drawdown of U3+, Ce3+, and U3+ from Ce3+ in molten LiCl-KCl electrolyte using a liquid cadmium cathode (LCC) at 773 K. The drawdown mechanism of U3+ and Ce3+ was determined by cyclic voltammograms and calculating the equilibrium potential. After galvanostatic electrolysis, high recovery yields were obtained for the drawdown of U3+ and Ce3+, but the current efficiency of Ce3+ was at least twice as high as that of U3+ due to the cyclic electrolysis of U3+/U4+. Despite significant underpotential deposition of Ce3+ in the LCC, an exceptional separation factor for Ce relative to U reached 84.67 ± 17.13, which was attributed to the formed pure uranium products hindering the subsequent deposition of Ce3+. Moreover, pure uranium products and Ce-Cd intermetallic compounds were characterized by X-ray diffraction and scanning electron microscope coupled with energy dispersive X-ray spectroscopy.

Assessing Pakistan’s Fissile Material Production

Reports suggest that Pakistan’s indigenous, military nuclear program faces a natural uranium shortage, limiting fissile material production. However, Pakistan has recently built three new plutonium-producing reactors and significantly expanded its reprocessing capabilities. The solution to this apparent contradiction could be an optimized fuel cycle, in which reprocessed uranium is reused to produce more fissile material from the same natural uranium stocks. To estimate Pakistan’s highly enriched uranium (HEU) and plutonium production, this article combines a statistical framework with fuel cycle and reactor simulation codes. It explores different scenarios that Pakistan could use to efficiently allocate its limited uranium resources. The results indicate that Pakistan cannot support simultaneous HEU and plutonium production in a once-through fuel cycle, and that HEU production can only be sustained in alternative cycles. Calculations suggest plutonium stockpiles of 370 to 660 kg and, depending on the scenario, HEU stockpiles of 3,090 to 5,540 kg by the end of 2022.

Evidence of Intraspecific Adaptive Variation in the American Pika (Ochotona princeps) on a Continental Scale Using a Target Enrichment and Mitochondrial Genome Skimming Approach.

Montane landscapes present an array of abiotic challenges that drive adaptive evolution amongst organisms. These adaptations can promote habitat specialisation, which may heighten the risk of extirpation from environmental change. For example, higher metabolic rates in an endothermic species may contribute to heightened cold tolerance, whilst simultaneously limiting heat tolerance. Here, using the climate-sensitive American pika (Ochotona princeps), we test for evidence of intraspecific adaptive variation amongst environmental gradients across the Intermountain West of North America. We leveraged results from previous studies on pika adaptation to generate a custom nuclear target enrichment design to sequence several hundred candidate genes related to cold, hypoxia and dietary detoxification. We also applied a 'genome skimming' approach to sequence mitochondrial DNA. Using genotype-environment association tests, we identified rare genomic variants associated with elevation and temperature variation amongst populations. Amongst mitochondrial genes, we identified intraspecific variation in selective signals and significant changes to the amino acid property equilibrium constant, which may relate to electron transport chain efficiency. These results illustrate a complex dynamic of adaptive variation amongst O. princeps where lineages and populations have adapted to unique regional conditions. Some of the clearest signals of selection were in a genetic lineage that includes pikas of the Great Basin region, which is also where recent localised extirpations have taken place and highlights the risk of losing adaptive alleles during environmental change.

Nuclear energy and international relations: the external strategy of Russia’s Rosatom

AbstractThis article analyses the role of nuclear energy in global politics today through the perspective of three International Relations theories: realism, liberalism and dependency theory. It contends that concepts developed to investigate oil and gas geopolitics do not always apply to the nuclear sector due to its greater complexity. The supply chain for nuclear power involves different, interrelated stages—notably the provision of natural uranium, of enriched uranium, and the construction and servicing of nuclear reactors—which have distinct leading suppliers and relationships of dependence. We illustrate this through a case study of Russia’s state nuclear company Rosatom. Rosatom leads in the provision of enriched uranium and reactor construction. This enables Russia to deepen economic and political relations with Rosatom’s clients. Even after its attack on Ukraine, Russia has not ‘weaponized’ Rosatom’s international business. Its strategy focuses on consolidating its reputation as a trustworthy partner, especially in the Global South and China.

Measuring very low radiation doses in PTFE for nuclear forensic enrichment reconstruction

Every country that has made nuclear weapons has used uranium enrichment to do so. Despite the centrality of this technology to international security, there is still no reliable physical marker of past enrichment in the open literature that can be used to perform forensic verification of historically produced weapons on gas centrifuges. We show that the extremely low radioactivity from uranium alpha emissions during enrichment leaves detectable and irreversible calorimetric signatures in the common enrichment gasket material PTFE, allowing for historical reconstruction of past enrichment activities at a sensitivity better than one weapon's quantity of highly enriched uranium. Fast scanning calorimetry also enables the measurement of recrystallization enthalpies of sequentially microtomed slices, confirming the magnitude and the type of radiation exposure while also providing detection of tampering and a method for analyzing field samples useful for treaty verification. This work opens the door for common items to be turned into precise dosimeters to detect the past presence of radioactivity, nuclear materials, and related activities with high confidence.

Californium-252 production at the High Flux Isotope Reactor − I: Validation study using campaign data

This paper presents a series of 252Cf production validation and code-to-code comparison studies performed based on data from the production campaigns at the High Flux Isotope Reactor (HFIR). These studies support efforts to convert HFIR from using highly enriched uranium (HEU) fuel to low-enriched uranium (LEU) fuel. HFIR must maintain its world-class performance and missions following this conversion, and because 252Cf is a vital neutron-emitting radioisotope used for a variety of high-impact applications (e.g., reactor startup, cancer treatment), the ability to efficiently produce 252Cf must be preserved. In this work, the HFIRCON, Shift, ORIGEN, and TCOMP codes were deployed, and several sets of data libraries were investigated to better understand the calculation codes and the data biases. As-loaded target composition data, as-run irradiation history data, and post-irradiation measurements from recent multi-cycle irradiation campaigns of the HEU core were used to validate and determine methodology biases. The findings demonstrated a good agreement, with results falling within 3 standard deviations of measurements. This paper lays the ground work for the second paper, which evaluates and compares 252Cf production and safety metrics with the HEU core and a proposed LEU core.

Molten Uranium Breeder Reactor (MUBR) and Its Development Steps

Background The Molten Uranium Breeder Reactor (MUBR) is a radical new mixed-energy spectrum breed and burn reactor concept. The MUBR is fueled with molten uranium metal fuel in large fuel tubes instead of thin fuel rods, and is cooled by circulating the molten fuel through a heat exchanger. The purpose of this research is to find MUBR configurations with a SCALE (RSICC request/license 203869) burnup at least 10 times greater than the initial fissile content. Methods A proprietary computer program uses parameters to generate MCNP (RSICC request/license 176034) or SCALE input files and initiate MCNP or SCALE burn simulations and other analysis. This allows relatively fast comparison of different parameters to optimize the configuration. Results MUBR configurations have been found which have SCALE burn simulations through 120 years of fuel life with a burnup of 35% of the initial fuel mass when the initial fuel was Low Enriched Uranium (LEU) (3% U-235). Conclusions These results suggest that if it can be constructed and operated reliably for a long time, the MUBR would be a true breed and burn reactor. Compared to Light Water Reactors (LWR) this would provide many advantages for the nuclear industry and the world such as: reactor operation without shutdowns for refueling or fuel manipulation, no need for special fuel, ten times as much energy per ton of fuel, one tenth as much Used Nuclear Fuel (UNF) per megawatt hour of electricity, no UNF storage required every two years, increased energy security, and reduced nuclear proliferation risk. While development of the MUBR concept from a concept to a prototype reactor will be costly, the advantages suggest that the concept merits further study.

Comprehensive Study on Hydrogeological Conditions and Suitability Evaluation of In Situ Leaching for Sandstone-Hosted Uranium Deposit in Erlian Basin

As a strategic mineral and energy resource, the enrichment and metallogenic mechanism of sandstone-hosted uranium deposits are highly dependent on hydrogeological conditions. However, the relationship between sandstone uranium mineralization and hydrogeological conditions has not received sufficient attention yet. The pumping test, hydrogeological parameters and hydrochemical characteristics were employed to analyze the change characteristics of hydrogeological conditions and evaluate the suitability of in situ leaching (ISL). The results showed that the study area in the Inner Mongolia Autonomous Region could be divided into two groundwater subsystems, namely Quanzha-Engeriyin and Luhai-Zhendai. The latter with relatively high water richness is confined and a main ore-bearing aquifer, which consists of four orebodies. The well discharge (Q) and hydraulic conductivity (K) of Orebody II ranged from 98.40 to 867.36 m3/d and 0.25 to 5.64 m/d, respectively, indicating the aquifer is suitable for the migration, enrichment and mineralization of uranium due to relatively high permeability and fast flow rate. The water storage of Orebodies III-IV gradually deteriorated from east to west in a stepped pattern. And the highest values of Q and K in Orebodies III-IV decreased from 1200 m3/d to 120 m3/d and 1.75 m/d to 0.035 m/d, respectively, suggesting these were conducive to a reduction in and accumulation of uranium under poor hydrodynamic conditions. Additionally, the study area would be defined as three grades, including favorable, relatively favorable and unfavorable areas of ISL according to a comprehensive evaluation. This study provided a scientific basis for evaluating the possibility of in situ leaching for sandstone-hosted uranium deposit.

THERMAL TECHNOLOGICAL CONDITION OF IVG.1M RESEARCH REACTOR CORE UNDER VARIOUS OPERATING MODES

The relevance of the study is related to the determination of the thermal characteristics of the IVG.1M research reactor core with the low enriched uranium fuel under the nominal and design operating modes. The thermal technological condition of the IVG.1M research reactor during the start-up are determined by the readings of the temperature, pressure and coolant flow sensors of the information and measuring system. The indirect methods including the computer simulating ones are used to determine the temperature of the core structural materials and the distribution of the coolant temperature by the height of the fuel assembly. The research has been carried out using the method of the finite element analysis using the ANSYS Fluent software package. The study goal was to verify the adequacy of the calculation methodology and obtain the calculated data on the temperature distribution in the fuel assembly in the reactor power range from the nominal to design one. The article presents a description of the IVG.1M reactor, the research methodology, computer model, simulation results and the comparison of the calculated data with the experimental ones. The study scientific novelty consists in determining the temperature conditions of the fuel rods during the reactor operation at various levels of the design capacity with a conservative approach to the cooling conditions. The significance of the research results lies in the fact that a computer model can be used to determine the characteristics of the IVG.1M reactor core under the reactor various operating modes and to analyze the thermohydraulic processes in the fuel assembly.

Californium-252 production at the High Flux Isotope Reactor - II: Comparison between the highly enriched uranium and a proposed low-enriched uranium core

This is the second paper on a 252Cf production study performed in support of efforts to convert the High Flux Isotope Reactor (HFIR) from highly enriched uranium (HEU) to low-enriched uranium (LEU) fuel. The first paper primarily focuses on validating computational tools and nuclear data. This companion paper evaluates another critical aspect: the 252Cf production capability with a proposed LEU core. HFIR must maintain its world-class performance and missions following conversion and because 252Cf is a vital, multipurpose neutron-emitting radioisotope, the ability to efficiently produce 252Cf must be preserved. In this study, the HFIRCON transport and depletion tool, several nuclear data libraries, and Campaign 78 data were used to compute 252Cf production, sensitivity, and safety metrics. Results indicate the 252Cf production and production rates are slightly higher with a 95MWth LEU core compared with those obtained with the 85MWth HEU core. Additionally, the target peak fission rate densities, discharge cumulative fission densities, and heat deposition rates with the LEU core are within a few percent of those calculated with the HEU core. The findings suggest HFIR’s 252Cf production capability can be effectively maintained with an LEU core without adversely affecting the safety metrics.

ELLA: Modeling Subcellular Spatial Variation of Gene Expression within Cells in High-Resolution Spatial Transcriptomics.

Spatial transcriptomic technologies are becoming increasingly high-resolution, enabling precise measurement of gene expression at the subcellular level. Here, we introduce a computational method called subcellular expression localization analysis (ELLA), for modeling the subcellular localization of mRNAs and detecting genes that display spatial variation within cells in high-resolution spatial transcriptomics. ELLA creates a unified cellular coordinate system to anchor diverse cell shapes and morphologies, utilizes a nonhomogeneous Poisson process to model spatial count data, leverages an expression gradient function to characterize subcellular expression patterns, and produces effective control of type I error and high statistical power. We illustrate the benefits of ELLA through comprehensive simulations and applications to four spatial transcriptomics datasets from distinct technologies, where ELLA not only identifies genes with distinct subcellular localization patterns but also associates these patterns with unique mRNA characteristics. Specifically, ELLA shows that genes enriched in the nucleus exhibit an abundance of long noncoding RNAs or protein-coding mRNAs, often characterized by longer gene lengths. Conversely, genes containing signal recognition peptides, encoding ribosomal proteins, or involved in membrane related activities tend to enrich in the cytoplasm or near the cellular membrane. Furthermore, ELLA reveals dynamic subcellular localization patterns during the cell cycle, with certain genes showing decreased nuclear enrichment in the G1 phase while others maintain their enrichment patterns throughout the cell cycle. Overall, ELLA represents a calibrated, powerful, robust, scalable, and versatile tool for modeling subcellular spatial expression variation across diverse high-resolution spatial transcriptomic platforms.

Nuclear Transmutation of 99Tc Utilizing Proton Spallation and Compact Subcritical Assembly

An innovative design is introduced for neutron transmutation employing a proton accelerator in conjunction with a compact subcritical system. The transmutation converter comprises a spherical target enveloped by a subcritical assembly. The subcritical assembly consists of a moderator and low-enriched uranium in shell plates. The subcritical assembly has an inner radius of 10 cm and a thickness of 40 or 55 cm. The material used for the target is lead, and beryllium or beryllium oxide is used as a moderator. Low-enriched uranium in the subcritical assembly contains 5% 235U. The transmutation half-life is inversely proportional to the integral of epithermal 99Tc capture rates. The MCNP6 simulation demonstrates that the transmutation half-life is less than 1 year when exposed to 1-GeV protons at 5 mA. Additionally, it is notable that this half-life can be further reduced with increased proton energies and currents. Previous studies have reported that the 99Tc transmutation half-life using fast reactors and an accelerator-driven system ranges from tens to hundred years; this design concept represents a substantial advancement to previous research efforts.

Aminomethanesulfonic acid grafted polyamidoxime fibers with hydrophilicity, salt-tolerance and antimicrobial properties for highly efficient uranium extraction from seawater

Uranium extraction from seawater plays a key role in redefining the declining uranium reserves to afford sustainable nuclear power. However, it is an urgent need to develop adsorbents simultaneously possessing enhanced efficiency, collect ability, salt resistance, antibacterial properties and economy to massively extract uranium from seawater. Herein, aminomethanesulfonic acid grafted polyamidoxime fibers (PAO-AMS-A) with hydrophilicity, salt resistance and antibacterial properties were prepared. The resulting fibers display high salt resistance and high uranium uptake capacity, providing the fibers a very high adsorption efficiency of 554.09 mg g−1 in pure uranium solution, 205.43 mg g−1 and 473.44 mg g−1 in 8 ppm and 20 ppm uranium spiked seawater and 10.04 mg g−1 in real seawater, respectively. Furthermore, the material exhibited good salt tolerance, and the uranium adsorption capacity was still as high as 597.97 mg g−1 in high concentrations of NaCl solution. Note that PAO-AMS-A has also good antibacterial activity, the antibacterial rate against bacteriais cultured in seawater is up to 93.49 %. Overall, PAO-AMS-A fibers are promising in industrial uranium extraction from seawater due to their high adsorption efficiency, salt resistance and antimicrobial properties.

Heart Trabeculae‐Inspired Superhydrophilic Electrode for Electric‐Assisted Uranium Extraction from Seawater

AbstractUsing nuclear power to replace electricity generated from fossil fuels is an effective strategy to reduce global carbon dioxide emissions and also spurs the search for new sources of nuclear fuel. Extracting uranium from seawater has a significant reserve advantage, although its ultralow concentration presents substantial challenges. Here, inspired by the fractal structure of cardiac trabeculae on the inner surface of the heart, a uranium enrichment electrode with a superhydrophilic and uranium‐affinitive fractal surface is developed. This innovative design enhances rapid charge/ion transfer, ensures complete surface wetting, and provides numerous adsorption sites. By synergistically integrating the advantages of electric‐assisted processes and bioinspired microstructures predicated on chemical coordination principles, the electrode demonstrates a uranium adsorption capacity of 13.2 mg g−1 following a 7‐d exposure to natural seawater. This research not only demonstrates an effective strategy for the development of advanced uranium enrichment electrodes but also provides more possibilities for innovative approaches in sustainable energy technology.

Applied radiation tags for warhead dismantlement transparency

This study explores the feasibility of applying radiation tags as a Chain of Custody tool to confirm the dismantlement of individual warheads by investigating time dependent emissions from special nuclear material. Precedents of photon and neutron sources that have been used to irradiate warhead components are presented. Measurements of irradiated Highly Enriched Uranium (HEU) are used to benchmark simulations with the CINDER90 depletion code module within MCNP. Delayed gamma emissions are simulated as a function of time since irradiation of moderated HEU and Weapons Grade Plutonium with photon and neutron sources. Models of commercial 9 MV and 15 MV linacs were found to induce ∼109fissions/g and ∼1011fissions/g, respectively, creating 3 to 4 orders of magnitude more delayed gammas than neutron sources, modeled at 1010n/s. However, a DT neutron source was found to induce sufficient fissions, ∼107fissions/g, to create quantifiable signatures relative to intrinsic emissions. Applied radiation tagging is determined to be technically feasible, but its operational context and practical implementation requires significant development.

Resolution of Optimal Mitochondrial and Nuclear DNA Enrichment in Target-Panel Sequencing and Physiological Mitochondrial DNA Copy Number Estimation in Liver Cancer and Non-Liver Cancer Subjects.

Mitochondria generate energy to support cells. They are important organelles that engage in key biological pathways. The dysfunction of mitochondria can be linked to hepatocarcinogenesis, which has been actively explored in recent years. To investigate the mitochondrial dysfunction caused by genetic variations, target-panel sequencing is a flexible and promising strategy. However, the copy number of mitochondria generally exceeds nuclear DNA, which raises a concern that uneven target enrichment of mitochondrial DNA (mtDNA) and nuclear DNA (ncDNA) in target-panel sequencing would lead to an undesirably biased representation of them. To resolve this issue, we evaluated the optimal pooling of mtDNA probes and ncDNA probes by a series of dilutions of mtDNA probes in both genomic DNA (gDNA) and cell-free DNA (cfDNA) samples. The evaluation was based on read count, average sequencing depth and coverage of targeted regions. We determined that an mtDNA:ncDNA probe ratio of around 1:10 would offer a good balance of sequencing performance and cost effectiveness. Moreover, we estimated the median physiological mtDNA:ncDNA copy ratio as 38.1 and 2.9 in cfDNA and gDNA samples of non-liver cancer subjects, respectively, whereas they were 20.0 and 2.1 in the liver cancer patients. Taken together, this study revealed the appropriate pooling strategy of mtDNA probes and ncDNA probes in target-panel sequencing and suggested the normal range of physiological variation of the mtDNA:ncDNA copy ratio in non-liver cancer individuals. This can serve as a useful reference for future target-panel sequencing investigations of the mitochondrial genome in liver cancer.

Uranium mobility and enrichment during hydrocarbon generation and accumulation processes: A review

Black shale serve as a new uranium sources and provide reducing agents for uranium deposits through hydrocarbon generation. However, the systematically interplay between the black shale and the formation of uranium deposits is not obscure. This paper provides a comprehensive summary and critical assessment of the depositional control factors of uranium in black shales, the extent of uranium migration during hydrocarbon generation, the enrichment of uranium in oil/gas reservoirs, and the relationship between crude oil-natural gas leakage and uranium. The study show that U-riched constituents within black shale persist through mechanisms of adsorption, reduction, complexation, and absorption within matrices rich in phosphates, iron, carbonate minerals, and organic matter. The U in black shale originates from continental weathering, volcanic eruptions, and seabed hydrothermal activities. The average U concentration in black shale is determined by the U content in atmosphere, while its relative content is controlled by the degree of anoxia during the geological historical periods.. Black shale prior to the Late Neoproterozoic period exhibits minimal migration with hydrocarbon substances, whereas black shale post the Late Neoproterozoic period demonstrates migration, with a migration rate ranging approximately between 55 and 75 %. However, the migrated uranium does not accumulate in (ancient) reservoirs. The correlation between hydrocarbon substances and sandstone-type uranium deposit is attributed to the oxygen uptake by hydrocarbons or the thermochemical sulfate reduction (TSR). The study has fundamental significance for further understand the interaction mechanisms between uranium and hydrocarbon substances.

The MUSIC Critical Benchmark and Nuclear Data

The Measurement of Uranium Subcritical and Critical (MUSIC) experiment was a series of measurements of critical and subcritical configurations of bare highly enriched uranium. The goal was to compare measurement methods, analysis techniques, and simulation methods across regimes of criticality and to provide high-quality validation of 235U nuclear data. A benchmark evaluation of the two critical configurations of the MUSIC experiments will soon be published in the release of the International Criticality Safety Benchmark Evaluation Project Handbook. The recent execution of the experiment aids in proper quantification of model simplifications and all uncertainties associated with the experiment. Historical benchmark evaluations are heavily relied on for uranium nuclear data validation despite the fact that the same level of documentation and comparable uncertainty analysis may not be present. The MUSIC evaluation is less likely to include “unknown unknowns” that could impede accurately modeling the system. Presented are both highly detailed and very simplified models, which represent the experimental configurations accurately, aiding the users of the benchmark for nuclear data or transport code validation. The sensitivities of k eff to nuclear data and nuclear data–related uncertainties are very similar between this experiment and previous bare uranium sphere experiments. In addition, the nuclear data uncertainties to any nuclides other than 235 U are small. For all these reasons, the recently evaluated MUSIC benchmark critical configurations could prove very useful for 235 U nuclear data validation. Currently, major libraries have good agreement with the experimental results, within 200 pcm for all nuclear data libraries, and within one standard deviation of the experimental result for most. Suggested nuclear data adjustments based on MUSIC and Lady Godiva are also presented, with posterior improvements to both the agreement in k eff and the uncertainty associated with the nuclear data.