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At least 19 records

Exceedance Response Action (ERA) Level 2 Technical Report Update

The Sandia National Laboratories, California (SNL/CA) site comprises approximately 410 acres and is located in the eastern portion of Livermore, Alameda County, California. The property is owned by the United States Department of Energy/National Nuclear Security Administration (DOE/NNSA) and is being managed and operated by National Technology & Engineering Solutions of Sandia, LLC (NTESS). Operations at the SNL/CA facility consist of DOE statutory responsibilities for nuclear weapon research and design, development of energy technologies, and basic scientific research. Specific industrial activities occur in discrete buildings and include electroplating or anodizing, machine shop, permitted hazardous waste treatment, storage and disposal facility (TSDF), and a scrap yard. This report provides an update to the ERA Level 2 Technical Report Update previously submitted in June 2022 (2022 ERA L2 Technical Report Update) for iron, aluminum, and pH. In accordance with the California’s General Permit for Discharges of Storm Water Associated with Industrial Activities (IGP) Section XII.D.3.c, an ERA Level 2 Technical Report update is to be submitted with the annual report when a facility utilizing an Industrial Activity Best Management Practice (BMP) Demonstration (IABMPD) experiences additional exceedances of the numeric action levels.

54 ENVIRONMENTAL SCIENCES↗

Precision studies of observables in $p p \rightarrow W \rightarrow l\nu _l$ and $ pp \rightarrow \gamma ,Z \rightarrow l^+ l^-$ processes at the LHC

This report was prepared in the context of the LPCC "Electroweak Precision Measurements at the LHC WG" and summarizes the activity of a subgroup dedicated to the systematic comparison of public Monte Carlo codes, which describe the Drell-Yan processes at hadron colliders, in particular at the CERN Large Hadron Collider (LHC). This work represents an important step towards the definition of an accurate simulation framework necessary for very high-precision measurements of electroweak (EW) observables such as the $W$ boson mass and the weak mixing angle. All the codes considered in this report share at least next-to-leading-order (NLO) accuracy in the prediction of the total cross sections in an expansion either in the strong or in the EW coupling constant. The NLO fixed-order predictions have been scrutinized at the technical level, using exactly the same inputs, setup and perturbative accuracy, in order to quantify the level of agreement of different implementations of the same calculation. A dedicated comparison, again at the technical level, of three codes that reach next-to-next-to-leading-order (NNLO) accuracy in quantum chromodynamics (QCD) for the total cross section has also been performed. These fixed-order results are a well-defined reference that allows a classification of the impact of higher-order sets of radiative corrections. Several examples of higher-order effects due to the strong or the EW interaction are discussed in this common framework. Also the combination of QCD and EW corrections is discussed, together with the ambiguities that affect the final result, due to the choice of a specific combination recipe.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Integrated CCS for Kansas (ICKan) (Final Technical Report)

The goal of the Phase I activity under CarbonSAFE was to evaluate and develop a plan and strategy to address the challenges and opportunities for commercial-scale Carbon Capture and Storage (CCS) in Kansas, ICKan (Integrated CCS for Kansas). The objectives of this project included identifying and addressing the major technical and nontechnical challenges of implementing CO 2 capture and transport and establishing secure geologic storage for CO 2 in Kansas capable of storing 50Mt. In order to achieve these objectives, it was necessary to establish CCS Coordination Team that consisted of professionals from multiple technical and nontechnical disciplines such as geoscience, policy and law, public relations, engineering and others. The Team conducted an integrated and multi-disciplinary assessment of CCS in Kansas. The assessment included: (1) high-level technical, sub-basinal evaluations of CO 2 storage; (2) high-level technical examination of three of Kansas' largest CO 2 point sources and considered other alternatives; (3) high-level evaluation of transportation systems required, 4) evaluation of energy, environmental, regulatory, business law, and public policy; (5) public outreach and acceptance; and (6) identification of economic, commercial, and financial challenges for deployment of commercial-scale CCS in Kansas.

02 PETROLEUM↗

Exceedance Response Action (ERA) Level 2 (Technical Report)

The Sandia National Laboratories, California (SNL/CA) site comprises approximately 410 acres and is located in the eastern portion of Livermore, Alameda County, California. The property is owned by the United States Department of Energy/National Nuclear Security Administration (DOE/NNSA) and is being managed and operated by National Technology & Engineering Solutions of Sandia, LLC (NTESS). Operations at the SNL/CA facility consist of DOE statutory responsibilities for nuclear weapon research and design, development of energy technologies, and basic scientific research. Specific industrial activities occur in discrete buildings and include electroplating or anodizing, machine shop, permitted hazardous waste treatment, storage and disposal facility (TSDF), and a scrap yard.

54 ENVIRONMENTAL SCIENCES↗

Understanding the Uncertainty in the Technical Performance Level Assessment for Wave Energy

In recent years, the design and development of wave energy converters (WECs) has been explored with intense interest, with highly varying design concepts emerging globally across both research enterprises and industry. The design space for WECs is vast - many concepts ranging in functionality, control systems, power development systems, materials, and scale have been ideated and prototyped, but WEC technology has yet to converge. One critical element of the technology trajectory that governs the speed of adoption is the performance of a WEC concept. In analogous but more-established industries (such as aerospace, and environmentally sustainable electronics design), performance assessment is a quantitative method, based on historical data, that is used as an iterative tool to improve the design of these systems early on in the design process. Though more nascent than these approaches, in wave energy R&D, WEC performance has been assessed using the Technology Performance Level (TPL) assessment, which provides designers with a quantitative score, situating a grid-scale WEC concept on a scale from 1-9 (1 being the lowest performance, and 9 being the highest, trending with the oft-used Technology Readiness Level, or TRL). The TPL assessment is designed to be used during design iteration, when a WEC concept is fully ideated, to enable designers to consider potential means of improving the downstream performance of the concept. One concern that may be slowing the adoption of TPL among WEC developers is the inherent uncertainty in the assessment, and how uncertainty in the individual questions asked as part of the assessment may contribute to perceived inaccuracies in the final score. In this work, we explore the uncertainty present in the assessment and quantify this uncertainty using both traditional mathematical operations and a Monte Carlo simulation. Results imply areas of improvement of the TPL assessment, where reducing uncertainty will be most helpful to end users, enabling both TPL practitioners and users to understand with more accuracy those design elements that can be improved to impact device performance most substantively.

techno-economic analysis↗

Beyond Widgets -- Systems Incentive Programs for Utilities

Utility incentive programs remain one of the most significant means of deploying commercialized, but underutilized building technologies to scale. However, these programs have been largely limited to component-based products (e.g., lamps, RTUs). While some utilities do provide ‘custom’ incentive programs with whole building and system level technical assistance, these programs require deeper levels of analysis, resulting in higher program costs. This results in custom programs being restricted to utilities with greater resources, and are typically applied mainly to large or energy-intensive facilities, leaving much of the market without cost effective access and incentives for these solutions. In addition, with increasingly stringent energy codes, cost effective component-based solutions that achieve significant savings are dwindling. Building systems (e.g., integrated façade, HVAC and/or lighting solutions) can deliver higher savings that translate into large sector-wide savings if deployed at the scale of these programs. However, systems application poses a number of challenges – baseline energy use must be defined and measured; the metrics for energy and performance must be defined and tested against; in addition, system savings must be validated under well understood conditions. This paper presents a sample of findings of a project to develop validated utility incentive program packages for three specific integrated building systems, in collaboration with Xcel Energy (CO, MN), ComEd, and a consortium of California Public Owned Utilities (CA POUs) (Northern California Power Agency(NCPA) and the Southern California Public Power Authority(SCPPA)). Furthermore, these program packages consist of system specifications, system performance, M&V protocols, streamlined assessment methods, market assessment and implementation guidance.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Beyond Widgets: Validated Systems Energy Savings and Utility Custom Incentive Program Systems Trends

Energy efficiency upgrades to buildings to date through avenues such as utility incentive programs have been largely limited to component-based products (e.g., lamps, RTUs). While some utilities do provide ‘custom’ incentive programs with whole building and system level technical assistance, these programs require deeper levels of analysis, resulting in higher program costs. This results in custom programs being restricted to utilities with greater resources, and are typically applied mainly to large or energy-intensive facilities, leaving much of the market without cost effective access and incentives for these solutions. In addition, with increasingly stringent energy codes, cost effective component-based solutions that achieve significant savings are dwindling. Integrated building systems (e.g., integrated façade, HVAC and/or lighting solutions) can deliver higher savings (Regnier et al. 2017) that translate into large sector-wide savings if deployed at the scale of these programs. However, systems application poses a number of challenges – energy savings assessments are inherently more complex and are not easily suited to the deemed measure model, and implementation of systems can be more disruptive. This paper presents the outcomes of a project to develop validated utility incentive program packages for three specific integrated building systems, in collaboration with ComEd, a consortium of California Public Owned Utilities (CA POUs) (Northern California Power Agency(NCPA) and the Southern California Public Power Authority(SCPPA)), and Xcel Energy (CO, MN). Previous work described the potential for energy savings of these systems at the individual and market level, early test findings for the task-ambient lighting system, and described the work products to develop utility incentive programs (Regnier et al. 2016). This paper presents validated end use energy savings of all three systems showing energy savings of ~20% for automated shading combined with daylight dimming (does not include light fixture retrofit savings); 30-46% for task-ambient lighting systems combined with plug load occupancy controls, depending on technology package and office building size (no daylight dimming impacts); and ~94% in the south-façade daylit zone for workstation specific lighting systems with daylight dimming (including lighting retrofit and task tuning). Using a U.S. Department of Energy (DOE) reference building model (DOE 2018), this translates to whole building savings of 2-5% (large-medium commercial), 12-23% (large-small commercial), and 13-15% (medium-large commercial) for these systems respectively. Early findings from the utilities in deploying these systems through their incentive programs indicate that deployment methods such as direct install programs might be best suited for these integrated systems. Further, early findings from a scoping study across custom utility programs and federal retrofit programs indicate that component level retrofits are still prevalent even in these programs, pointing towards an opportunity for deeper energy savings deployment. High performance retrofit case studies demonstrate that deeper energy savings is possible through integrated approaches. Market stakeholder interviews indicate however that there is generally a low level of awareness of the potential for energy savings of these three integrated systems.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

A 2023 Perspective: What Is the Value of Hybridization?

This report takes a wind developer's perspective and provides a summary of the current and future state of hybrid facilities, and ultimately seeks to answer the question: "Are hybrid power plants a pivotal tool for meeting future energy and decarbonization targets?" The intention is not to provide an in-depth system-level technical analysis of hybrid facilities, but to showcase a high-level overview of the hybrid facility ecosystem and its potential future directions. Lastly, the authors acknowledge and recognize that non-renewable generation technologies can be integrated into a hybrid facility, however these technologies are outside the scope of this report.

17 WIND ENERGY↗

Carbon Storage Assurance Facility Enterprise (CarbonSAFE): Integrated CCS Pre-Feasibility CarbonSAFE Illinois East Sub-Basin (Final Report)

Purpose of the project was to conduct a pre-feasibility assessment for commercial-scale CO 2 geological storage complexes in the East Sub-Basin of the Illinois Basin. This work will be used to advance the experience and knowledge about scaling up from demonstration to commercial-scale storage (CCS), and eventually readying sites for more than 50 million tonnes injection from one or more industrial sources. To accomplish this, the project formed a CCS coordination team with varied backgrounds to evaluate aspects of developing an integrated CCS project, including regulatory, legislative, technical, public policy, commercial and financial requirements. We developed a plan and strategy to address the technical and non-technical challenges to enable an economically feasible and publicly acceptable integrated CCS project. A significant output of this high-level technical evaluation of the East Sub-Basin was to identify suitable site(s) within the storage complex(es) that include detailed subsurface characterization and risk identification, along with evaluation of potential industrial CO 2 sources for sequestration.

01 COAL, LIGNITE, AND PEAT↗

International Low Level Waste Management Practices and Technical Bases for Very Low Level Waste Classification - 19415

Different countries around the globe use varying schemes for the classification of radioactive waste. Many countries use adaptations of the International Atomic Energy Agency (IAEA) waste classification scheme. The United States uses the Class A, B, and C waste classification scheme that is loosely based on the IAEA concepts. Classification may be based on concentration limits or dose rate limits or a combination of concentration and dose rate limits. In some countries the existence of very low-level waste categories allows nuclear power plant waste to be disposed of in hazardous waste or shallow land burial sites separate from low and intermediate level waste disposal facilities. In the United States, the very low-level waste (VLLW) classification does not exist. Nuclear power plants use alternative disposal procedures under 10CFR20.2002 and other licensed processes in agreement states in order to dispose of very low activity waste in hazardous waste disposal sites. [1] Disposal of VLLW in hazardous waste or separate VLLW facilities is generally more cost effective than disposing of waste in radioactive waste sites and is protective of the health and safety of the public. This can become an important factor when large volumes of very low activity waste are generated during decommissioning of nuclear power plants. The Electric Power Research Institute (EPRI) Radiation Safety (RS) Program has developed technical bases for the establishment of a very low-level waste category. EPRI studied how VLLW waste is defined, managed, and disposed of in various countries. This included the study of disposal site design, characteristics, and how these sites protect the health and safety of the environment and the public from low levels of radioactivity. EPRI conducted a cost benefit analysis to understand the economic impact of disposing VLLW in hazardous waste disposal sites versus low-level waste disposal sites. Finally, EPRI calculated potential radionuclide limits that may be used to define very low-level waste. The purpose of this work was to provide an example of how one might approach defining limits for VLLW. The same or similar approaches could be applied to derive radionuclide limits for different dose limit objectives. This paper presents the results of research that explored the waste management and disposal practices at six countries around the world with additional focus and details on the implementation of the very low-level waste category. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Topological supercurrents interaction and fluctuations in the multiterminal Josephson effect

We study the Josephson effect in the multiterminal junction of topological superconductors. We use the symmetry-constrained scattering matrix approach to derive band dispersions of emergent subgap Andreev bound states in a multidimensional parameter space of superconducting phase differences. We find distinct topologically protected band crossings that serve as monopoles of finite Berry curvature. Particularly, in a four-terminal junction the admixture of 2π and 4π periodic levels leads to the appearance of finite-energy Majorana-Weyl nodes. This topological regime in the junction can be characterized by a quantized nonlocal conductance that measures the Chern number of the corresponding bands. In addition, we calculate current-phase relations, variance, and cross correlations of topological supercurrents in multiterminal contacts and discuss the universality of these transport characteristics. At the technical level these results are obtained by integrating over the group of a circular ensemble that describes the scattering matrix of the junction. Furthermore, we briefly discuss our results in the context of observed fluctuations of the gate dependence of the critical current in topological planar Josephson junctions and comment on the possibility of parity measurements from the switching current distributions in multiterminal Majorana junctions.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

Technical Assessment of Novel Hydrogen Producing Solid Oxide Fuel Cell Power System

Solid oxide cell-based electrolysis (SOEC) systems are being considered for hydrogen production due to their potential for high efficiencies and for their integrability with base load power generation systems when operated in solid oxide fuel cell (SOFC) mode. However, a cost prohibitive combination of SOFC power systems and SOEC systems may be required to operate the plant flexibly to produce a combination of H 2 and power on-demand. A single (consequently less expensive) reversible SOFC/SOEC system, on the other hand, poses technological challenges related to the on demand switching between power and H 2 production. This report provides a high-level technical assessment of a novel SOFC based H 2 production concept that averts the potential drawbacks of the SOEC systems. The novel concept combines the advantages of steam-reforming of natural gas to produce H 2 with the high efficiency power generation capabilities of a SOFC in a single package.

30 DIRECT ENERGY CONVERSION↗

Comparative analysis of magnetic resonance in the polaron pair recombination and the triplet exciton-polaron quenching models

We present a comparative theoretical study of magnetic resonance within the polaron pair recombination (PPR) and the triplet exciton-polaron quenching (TPQ) models. Both models have been invoked to interpret the photoluminescence detected magnetic resonance (PLDMR) results in π-conjugated materials and devices. We show that resonance line shapes calculated within the two models differ dramatically in several regards. First, in the PPR model, the line shape exhibits unusual behavior upon increasing the microwave power: it evolves from fully positive at weak power to fully negative at strong power. In contrast, in the TPQ model, the PLDMR is completely positive, showing a monotonic saturation. Second, the two models predict different dependencies of the resonance signal on the photoexcitation power, P L . At low P L , the resonance amplitude Δ I/I is ∝ P L within the PPR model, while it is ∝ P 2 L crossing over to P 3 L within the TPQ model. On the physical level, the differences stem from different underlying spin dynamics. Most prominently, a negative resonance within the PPR model has its origin in the microwave-induced spin-Dicke effect, leading to the resonant quenching of photoluminescence. The spin-Dicke effect results from the spin-selective recombination, leading to a highly correlated precession of the on-resonance pair partners under the strong microwave power. This effect is not relevant for TPQ mechanism, where the strong zero-field splitting renders the majority of triplets off resonance. On the technical level, the analytical evaluation of the line shapes for the two models is enabled by the fact that these shapes can be expressed via the eigenvalues of a complex Hamiltonian. This bypasses the necessity of solving the much larger complex linear system of the stochastic Liouville equations. Lastly, our findings pave the way towards a reliable discrimination between the two mechanisms via cw PLDMR.

36 MATERIALS SCIENCE↗

Economic Extraction and Recovery of REEs and Production of Clean Value-Added Products from Low-Rank Coal Fly Ash

The University of North Dakota (UND) Energy & Environmental Research Center (EERC) teamed with Pacific Northwest National Laboratory (PNNL) , the North Dakota Industrial Commission Lignite Research Program, and commercial partners Basin Electric Power Cooperative, Great River Energy, and Southern Company to execute a Cooperative Agreement funded by the U.S. Department of Energy’s (DOE’s) National Energy Technology Laboratory (NETL) focused on identifying unique pathways and pretreatments to extract rare-earth elements (REEs) from low-rank coal (LRC) ash in a more economical and environmentally benign manner than current methods. The EERC drew upon the unique and deep knowledge of the team regarding LRC geochemistry, ash transformation mechanisms during combustion, and fly ash chemistry in the approach to understand the portioning of REEs in LRC ash. A comprehensive characterization effort was undertaken to fully establish the form, associations, and partitioning of the REEs and other elements/minerals of interest in fly ash, as well as the ash chemistry, mineralogy, and morphology. Using this information, the team tested methods of REE extraction to take advantage of the unique and advantageous properties of LRC ash. Multiple complementary approaches were evaluated that combined both novel and proven methods to develop an extractive process for REEs and other high-value metals from LRC ash that provide technological and economic progress on the current state of the art. Methodologies were also evaluated for the potential to synergistically remove toxic metals while extracting other high-value metals from the ash, generating a clean, safe ash material as a value-added product. This would eliminate waste and offer significant additional revenue potential. Based on laboratory-scale testing, an initial high-level technical and economic analysis to estimate operating expenses and product revenues to guide future phases of technology development was implemented. By focusing on minimizing process steps and consumptive use of extraction solutions, a tunable, economically viable process for REE extraction from LRC ash was developed. The tunable process has the ability to be adjusted to adapt to the differing ash chemical and physical properties that are characteristic of LRC ash. This is key to deployment as a commercial process. In demonstrating the process, the EERC was able to illustrate mixed REE concentration greater than the goal of 2 wt%. High-level economic analysis of the process with LRC ash of moderate REE levels demonstrated the potential of the process, but recovery of just the REEs was insufficient to cover operational costs. With the additional extraction of other high-value metals found in LRC ash, the process economics approach would break even, and it is anticipated that with process optimization, the developed process could potentially be economically sound. The same economic analysis performed utilizing LRC ash with high levels of REEs showed the recovery of the REEs alone would make the process economically viable even without further optimization.

01 COAL, LIGNITE, AND PEAT↗

Develop an efficient and cost-effective novel anaerobic digestion system producing high purity of methane from diverse waste biomass

This project focuses on developing an advanced, intensified anaerobic digestion system aimed at transforming the treatment and conversion of organic wastes into valuable products, specifically renewable natural gas. The motivation for this research stems from the limitations of conventional anaerobic digestion technologies, which often face challenges such as long retention times, high operational costs, and incomplete organic material degradation. The new technology called Intensified Versatile Anaerobic Digestion (IVAD), is developed to address these challenges by incorporating innovative reactors and processes that enhance the overall efficiency and output of anaerobic digestion. The significance of this project lies in its potential to revolutionize waste management practices and waste biomass utilization. The IVAD system integrates a hyperthermophilic anaerobic acidification reactor, a hydrothermal treatment (HTT) unit, and both thermophilic and mesophilic methanogenic reactors. This combination enables a higher rate of organic breakdown and energy recovery, resulting in faster processing times, reduced reactor sizes, and lower operational costs compared to traditional systems. Key data include an increase in methane productivity to 1.18 m 3 /m 3 /day, a significant improvement compared to the baseline technology’s 0.64 m 3 /m 3 /day. Additionally, the IVAD system achieves a 45% reduction in levelized cost of energy (LCOE), down to $\$$10.04/MMBTU, and an energy return on investment (EROI) of 3.19, representing an 87% increase over baseline levels. Technical and economic analyses highlight that the IVAD system significantly reduces hydraulic retention time (HRT) and solid retention time (SRT). The HRT for the HTT reactor can be reduced from 1 hour to 0.5 hours, while decoupling SRT from HRT in the anaerobic acidification reactor (AAR) allows for further reductions. These design optimizations lead to smaller reactor volumes, cutting down equipment and construction costs. Despite these advancements, energy consumption remains comparable to conventional methods due to a novel heat recovery strategy, enhancing overall process productivity. The system also achieves in-situ CO 2 removal and ammonia stripping features, resulting in biogas with a methane purity level of 75%, and produces high-quality nitrogen fertilizer as an additional by-product. Public benefits of the IVAD system are substantial, contributing to sustainable waste management and renewable energy production. By providing a scalable solution that can be adopted by dairy farms and similar agricultural operations, the IVAD system helps reduce waste, produce renewable natural gas (RNG) suitable for transportation fuel, and generate fertilizer, supporting a circular economy. This project plays a role in achieving broader environmental objectives by mitigating greenhouse gas emissions and promoting energy independence. Additionally, it offers a pathway for farmers to lower operational costs while adopting practices that are both environmentally sustainable and economically advantageous.

03 NATURAL GAS↗

CarbonSAFE Rocky Mountain Phase I: Ensuring Safe Subsurface Storage of Carbon Dioxide in the Intermountain West

An integrated CCS pre-feasibility study, CarbonSAF E Rocky Mountain Phase I, was conducted by the U niversity of Utah and its partners as part of the US D epartment of Energy’s Carbon Storage Assurance a nd Facility Enterprise (CarbonSAFE) program. The a ssembled project team consisted of academic, indus try and governmental agencies covering the technic al and non- technical challenges of a commercial-sc ale CO 2 storage facility capable of storing 50 million tonnes of anthropogenically-sourced CO 2 . The Rock y Mountain CarbonSAFE team identified the Hunter Power Plant in central Utah as the primary source of CO 2 on which this study would be focused. The nea rby Huntington power plant, also operated by Rocky Mountain Power, was evaluated as a secondary sou rce of CO 2 . The Hunter plant was chosen because o f an interest in CO 2 capture technology by the plant operator, Rocky Mountain Power, and also because i t is a representative example of a typical coal-fired g enerating station in the Rocky Mountain west. Amine -based and cryogenic-based capture assessments w ere performed for approximately 3 million tonnes per year for one of the boiler units at the Hunter plant, yi elding cost of capture estimates of $\$56$/tonne and $\$4 1.50$/tonne. Transportation and intermediate compre ssion would increase the per tonne costs, but will be highly dependent on specific injection locations and available rights-of-way. A high-level technical sub-ba sinal evaluation was performed on the area surround ing the Hunter and Huntington power plants to verify CO 2 storage capacity and integrity. Initial geologic c haracterization efforts focused on sites immediately adjacent to the Hunter plant, including the deep eolia n Permian White Rim Sandstone, which in outcrop a nd core from other locations indicates high permeabi lity and high porosity. However, petrophysical logs fr om wells near Hunter indicate porosity of only 2-4%. As a result, potential injection sites were moved stru cturally down-dip (to the west), into the high permea bility (~200 mD) and high porosity (20%) Navajo san dstone. A comprehensive analysis of the reservoir a nd seals was conducted, providing data to the model , simulation and risk assessment groups on the proje ct. CO 2 capacity estimates for the Navajo Sandston e approximately 18 kilometers from the Hunter plant are well in excess of the 50 million tonnes goal of the project. Area of Review Delineation and Risk Asse ssment on the Navajo, associated seals and shallow groundwater aquifers identified the most significant risks and mitigation options. A non-technical assessment to a commercial-scale CO 2 storage facility in central Utah was conducted. EPA Underground Injection Control Class VI and National Environmental Policy Act permitting present particularly challenging issues related to the development of any saline aquifer for CO 2 storage, including the area around the Hunter plant. While surface and subsurface ownership and ri ghts are not straightforward, especially on any privat e land, many of the stakeholders in central Utah are accustomed and open to oil/gas/mineral-related activities similar to what would be required for CO 2 storage sites.

01 COAL, LIGNITE, AND PEAT↗

Factorization at subleading power and endpoint-divergent convolutions in h → γγ decay

t is by now well known that, at subleading power in scale ratios, factorization theorems for high-energy cross sections and decay amplitudes contain endpoint-divergent convolution integrals. The presence of endpoint divergences hints at a violation of simple scale separation. At the technical level, they indicate an unexpected failure of dimensional regularization and the $\overline{MS}$ subtraction scheme. In this work, we start a detailed discussion of factorization at subleading power within the framework of soft-collinear effective theory. As a concrete example, we factorize the decay amplitude for the radiative Higgs-boson decay h → γγ mediated by a b-quark loop, for which endpoint-divergent convolution integrals require both dimensional and rapidity regulators. We derive a factorization theorem for the decay amplitude in terms of bare Wilson coefficients and operator matrix elements. We show that endpoint divergences caused by rapidity divergences cancel to all orders of perturbation theory, while endpoint divergences that are regularized dimensionally can be removed by rearranging the terms in the factorization theorem. We use our result to resum the leading double-logarithmic corrections of order $α^n_sln^{2n+2}(-M^2_h/m^2_b)$ to the decay amplitude to all orders of perturbation theory.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Six-point functions and collisions in the black hole interior

In the eternal AdS black hole geometry, we consider two signals sent from the boundaries into the black hole interior shared between the two asymptotic regions. We compute three different out-of-time-order six-point functions to quantify various properties of the collision of these signals behind the horizons: (i) We diagnose the strength of the collision by probing the two-signal state on a late time slice with boundary operators. (ii) We quantify two-sided operator growth, which provides a dual description of the signals meeting in the black hole interior, in terms of the quantum butterfly effect and quantum circuits. (iii) We consider an explicit coupling between the left and right CFTs to make the wormhole traversable and extract information about the collision product from behind the horizon. At a technical level, our results rely on the method of eikonal resummation to obtain the relevant gravitational contributions to Lorentzian six-point functions at all orders in the GN-expansion. We observe that such correlation functions display an intriguing factorization property. We corroborate these results with geodesic computations of six-point functions in two- and three-dimensional gravity.

2D Gravity↗