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DOE OSTI2022

EVSE Cybersecurity and Resilience

Consequence-driven Cybersecurity Analysis for Extreme Fast Charging Electric Vehicle Infrastructure Electric vehicle (EV) development and associated charging infrastructure are expected to advance rapidly. Thirty percent of all global vehicle sales may be EVs and hybrid EVs by 2025, and they will rely on increasingly sophisticated strategies for grid integration. Next-generation EV charging infrastructure is expected to include interconnected renewable resources, such as photovoltaic (PV) arrays and battery storage systems, along with grid-edge devices. Although distributed energy resources (DERs) are useful in several ways, such as peak shaving at high demand times and backup supply for added resilience, the integration of vehicle charging and DERs could create more avenues for cyberattack. Physical and/or remote access to EV charging station components, including charge ports, power electronics, controllers, and local generation (e.g., PV and energy storage) could be paths to cause power fluctuations, leading to altered operations at the charging station, escalated privileges to administrative systems, exfiltration of financial information (including personally identifiable information), and reduced grid stability. One compromised EV supply equipment component can open the door to a variety of exploitable vulnerabilities. Cloud computing and mobile application control have the potential to expand the threat surface to non-repudiation and firmware integrity challenges. Vendor clouds have access to hundreds of chargers, and if compromised, can scale the attack surface exponentially. The high power and voltage levels of xFC infrastructure (e.g., 400 kW at 1000- V DC) increase the hazards and ability to impact the grid and vehicles more than lower-power charging systems. Legacy communications systems and protocols could also put EV infrastructure at risk of cyberattacks requiring a robust patch management process. Communications networks link EVs and chargers to several stakeholders - including charging station operators, grid operators, vendors/manufacturers, and aggregators - who have both physical and network access to share information for control, monitoring, and analytics. Information in these networks that is vulnerable to compromise includes the state of charge, charging duration, payment information, electricity price, and load control. Analyzing and prioritizing these interconnections risks could help address cybersecurity related to data leakage and manipulation.

charging↗

DOE OSTI2022

CyTRICS: Vulnerability Analysis Tailored for Critical Infrastructure

Society and modern life are dependent on critical infrastructure that is composed of expensive, special purpose devices that have long life cycles and may be in use for decades before being replaced. There are an abundance of organizations and individuals doing vulnerability analysis on a variety of systems, but what makes the Cyber Testing for Resilient Industrial Control Systems (CyTRICS) program unique and valuable is its strategic focus on high-priority critical infrastructure, close partnership with vendors, and ability to leverage bills of materials (BOMs) to identify and relate vulnerabilities to affected systems. Creating a bill of materials is a formal way of understanding and documenting the components of a system, including everything from integrated circuits to operating systems to third-party libraries. This is beneficial for connecting known vulnerabilities to affected devices, since vulnerabilities in a specific component are often not mapped to all systems that use that vulnerable component. Additionally, CyTRICS finds novel vulnerabilities through its vulnerability testing process and works closely with vendor partners to provide vulnerability reports so that affected systems can be patched in a timely manner. This presentation will describe the interrelated technical processes CyTRICS uses to create bills of materials and conduct vulnerability analysis.

99 GENERAL AND MISCELLANEOUS↗

DOE OSTI2023

Cyber-Resilient Distributed Autonomous Energy Grid

The DARPA Assured Micropatching (AMP) program focuses on creating the capability for rapid patching of legacy binaries in mission critical systems leveraging the field of formal methods. NREL's Cyber Resilient TLDRD effort, focuses on leveraging the field of formal methods to develop tools and methods for formally verifiable implementations of security architectures such as Zero Trust Architecture. The presentation at the DARPA AMP PI meeting is primarily inspired by common interests and ongoing work on leveraging Formal Methods for OT cybersecurity.

cybersecurity↗

DOE OSTI2023

Are System Baselines within OT Environments Feasible?

Critical infrastructure stakeholders need to baseline their systems to understand expected protocol communications.Baseline behaviors may vary based on operational context.Expected operations during a maintenance window, for example, may be different from normal operations.Furthermore, constructing system baselines for Industrial Control Systems (ICS) is difficult and time-consuming.ICS processes generate artifacts expressed across heterogeneous data sources such as network and device logs. There needs to be a corpus of data in order to develop and compare methods that evaluate the feasibility, performance, and generality of approaches to construct baselines for ICS events. Standalone repositories of network packet captures are insufficient to develop methods to classify or recognize operational events expressed across multiple data sources. Moreover, static data corpora do not enable researchers to compare the impact of changing the underlying system for which a baseline is being constructed and this limits the ability to evaluate the performance of system baselines given system changes (e.g. patches, configuration, maintenance events). In order to address these limitations within the community, this talk intends to promote discussion about the state of the practice of constructing baselines. In this manner, we can continue to understand requirements within industry that are not being met by current approaches to baseline construction. This talk builds on two previous talks on the topic of system baselines for OT environments. First, Weaver co-presented at the RSA Conference ICS Sandbox with Dan Gunter. The talk confirmed the need within industry to construct baselines across multiple types of data sources relative to the semantics of specific business processes. Second, Weaver presented at IEEE Security and Privacy Workshop on Language-Theoretic Security.

02 PETROLEUM↗

DOE OSTI2023

Flow control valve

Disclosed is a flow device including an inlet, an outlet, and a plurality of fluid flow paths hydraulically connected in parallel to the inlet and the outlet, wherein the plurality of fluid flow paths forms a first ring of fluid flow paths circumferentially arranged at a first radial distance from a centerline of the fluid flow device a second ring of fluid flow patch circumferentially arranged at a second radial distance from the centerline of the fluid flow device, each of the plurality of fluid flow paths has a first hydraulic resistance in a forward flow direction and a second hydraulic resistance in a reverse flow direction, and the second hydraulic resistance is greater than the first hydraulic resistance.

Siebert, Brett W.↗

DOE OSTI2015

Magnetic fields and galactic star formation rates

The regulation of galactic-scale star formation rates (SFRs) is a basic problem for theories of galaxy formation and evolution: which processes are responsible for making observed star formation rates so inefficient compared to maximal rates of gas content divided by dynamical timescale? Here we study the effect of magnetic fields of different strengths on the evolution of giant molecular clouds (GMCs) within a kiloparsec patch of a disk galaxy and resolving scales down to ≃0.5 pc. Including an empirically motivated prescription for star formation from dense gas (n{sub H}>10{sup 5} cm{sup −3}) at an efficiency of 2% per local free-fall time, we derive the amount of suppression of star formation by magnetic fields compared to the nonmagnetized case. We find GMC fragmentation, dense clump formation, and SFR can be significantly affected by the inclusion of magnetic fields, especially in our strongest investigated B-field case of 80 μG. However, our chosen kiloparsec-scale region, extracted from a global galaxy simulation, happens to contain a starbursting cloud complex that is only modestly affected by these magnetic fields and likely requires internal star formation feedback to regulate its SFR.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2015

An approach to evaluating and monitoring ecological resources for sustainability on DOE remediation sites: Hanford as a case study - 15524

Protecting ecological and environmental resources is a worthy aspect of the Department of Energy's site missions, for each of its sites, during and after remediation. Ecological resources are important to a range of stakeholders, including regulatory agencies, resource agencies, natural resource trustees, Tribal governments, and the public, and may be an essential component of Native American cultural resources. Because the nature and value of ecological resources can change over time as a result of remediation, succession, and global climate change, it is imperative for DOE to have instituted an acceptable method of evaluating resources before initiation of active remediation, over the ensuing century when institutional and engineering controls are considered to be in effect. Having such a methodology in place also would be key to resource sustainability. Department of Energy sites generally have environmental programs, so instituting specific unified practices for evaluating resources should not be difficult to implement. Instituting these practices would assure the public that ecological resources, as well as human and cultural resources, are being protected now, and can be protected into the future. Key ecological species and/or unique habitats have been preserved at Department of Energy sites since the mid-20. century because of federal government stewardship. Such preservation is particularly true for the sites with larger land areas, including the Hanford Reservation, the Idaho National Laboratory and the Savannah River Site. Individual sites typically have extensive studies of site biodiversity, but site resources are not routinely examined within a regional or national context (Eco-region). The evaluation of the on-site resources with those resources in the appropriate Eco-region provides a context for 'valuing' on- site resources. On-site resources should also be evaluated in terms of federal and state legislation where species may have legal protection and require legal consideration during remediation if present or adjacent to the remediation site. A method is needed in this study for evaluating ecological resources prior to remediation and during remediation, and a paradigm is proposed that will ensure sustainability. Finally, in a period of climate change and instability, developing methods of evaluating ecological resources is essential to successful protection, enhancement, and sustainability. The ecological methodology is part of a Hanford site-wide Risk Review Project, conducted by the Consortium for Risk Evaluation with Stakeholder Participation (CRESP). Our method adapts an existing methodology that includes using established levels for evaluating ecological resources by expanding the existing methodology to include field work for validating previous resource level designations, to assess the occurrence of invasive/exotic species, and to identify landscape scale features (patch size, connectivity). Evaluations should be conducted in the remediation unit itself, and in a buffer zone surrounding the remediation site. The methodology described has been applied to several remediation areas at Hanford, and issues that emerged during its application are discussed. The methodology can be applied at the major sites. Application of the Eco-region analysis will provide regulators and the public with an understanding of the value of the ecological resources in relation to the region, as well as an appreciation for the stewardship role the Department of Energy has played in protecting these resources since the beginning of the Cold War Era and can continue to do so sustainably. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2016

Application of Field Evaluations of Ecological Resources at Hanford and Other DOE Sites for Consistency of Resource Protection and Sustainability - 16404

Remediation and management of contaminated facilities, soil, sediment and biota is an essential element of the DOE-EM mission for site completion, contaminant footprint reduction, and protection of human health and the environment. Protecting ecological resources is an integral part of protecting human health because people are part of the ecosystem and rely on ecological resources for food, fiber, clean air and water, recreational, aesthetic, and cultural values. Evaluation and management require understanding the past and current conditions, as well as protecting, preserving, and enhancing ecological resources. Understanding past and current resources includes evaluation of individual and population health within a local and regional context. The objective of this research is to describe a field method of evaluating ecological resources, based on work at the Hanford Site, which can be applied to sustainability of ecological resources as another mandate of DOE. This requires objective methods to characterize and evaluate resources spatially, within a context of local and regional importance. The DOE complex is large, diverse, and multi-state. The habitats and ecological resources are diverse, and the relative importance of ecological resources to the local ecosystem, region, and human communities varies. Large and diverse sites such as Hanford, Idaho National Laboratory, Los Alamos, hold resources of substantial importance to local and regional ecosystems, as well as to the ecology and cultural values of Tribes and other residents. However, other smaller sites (e.g. Oak Ridge, Brookhaven) also hold key ecological resources to local and regional ecosystems, cultures, and economics. Understanding the relative importance of ecological resources on each remediation site at different spatial scales, within and among DOE-EM sites is critical to management, stewardship, and ensuring sustainability for generations to come. Without a standardized methodology it is difficult to develop sound remediation and management plans to protect human health and the environment. The Ecological Evaluation of Resources described in this paper is part of the Consortium for Risk Evaluation with Stakeholder Participation's (CRESP) Risk Review Project on the Hanford Site. It is an independent assessment based of on-site field evaluations that encompasses evaluations of site resources in comparison to the Columbia Basin Ecosystem prior evaluations made by DOE, the States of Washington and Oregon, Nature Conservancy and Tribes. The on-site field evaluations are the focus of the current paper. The on-site field evaluation methodology was developed to update existing information on habitat values in light of changing landscape features (edge, patch size and shape, connectivity) and the current presence of invasive species. Both aspects change with time, especially given that remediation of remediation units changes the landscape. That is, every time there is a remediation and restoration of an operable unit (remediation site) on a DOE site, it changes the adjacent landscape (and ecological resources). The changes are greater where new roads were built to access a remediation site, staging areas constructed, and as a function of the size and time-frame for the remediation. Since ecological resources form a continuum across the landscape, and activities from remediation on a given site can affect those on adjacent areas, we evaluated resources both on the remediation site itself, and on a buffer equal to the largest diameter of the remediation site. The field evaluation methodology developed at Hanford Site makes use of existing resource level maps (DOE/RL-96-32 2013) and field surveys and measurements of current vegetation and habitat conditions to evaluate potential ecological impacts associated with cleanup activities at the evaluation unit. Additional information used in the ecological resource evaluations include current Endangered and Threatened Species distribution data (both state and federal), aerial imagery, locations of waste sites and infrastructure, and species and habitats of special concern. We suggest that the field methodology developed for the Hanford Site could be used across the DOE complex to evaluate ecological resources. This would provide DOE-EM with a common data base to make long-term decisions about the protection and sustainability of resources on the DOE complex, and would provide Tribes and the public with information on ecological resources on DOE sites. Such information could be provided in a web-based format which DOE, regulators, Tribes, and the public could easily access. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2016

TRACE Code Validation of BWR SVEA Fuel Assembly Spray Cooling

Emergency spray cooling injection is a safety feature implemented in many boiling water reactor designs to reflood a reactor during an accident. Significant experimental work has qualified the efficacy of spray cooling, and ongoing computational modeling efforts strive to more accurately portray the phenomena involved. This work examines the physical phenomena pertaining to emergency spray cooling injection over SVEA-type fuel assemblies. BWR emergency core cooling system (ECCS) designs commonly incorporate a Low-Pressure Core Spray (LPCS) system that introduces coolant through spray nozzles directed to the top of the core, and are located in the upper plenum region. This design is effective for LOCA response, particularly during the initial refill and reflood stages of accident response where the goal is limiting the peak cladding temperature rise in the core. The U.S. NRC thermal-hydraulics code TRACE version 5.0 Patch 4 has been chosen to simulate the separate-effect tests performed by ASEA-ATOM. The computational model was evaluated by performing forward uncertainty quantification using Dakota as the analysis tool and code driver on 31 identified parameters from the input model and TRACE physical constitutive models. This paper discusses the sensitivity of the investigated parameters with respect to spray cooling simulation. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

DOE OSTI2019

Factors Affecting the Service-life of HDPE Geomembranes in an LLW Disposal Facility - 19320

The assessment of a suitable maximum allowable strain (MAS) for high density polyethylene (HDPE) geomembranes (GMBs) considered suitable for a proposed low level radioactive waste engineered containment mound with a 550-year design-life is described in the context of the available literature and data in 2018. Consideration is given to both the material properties and the factors contributing to the development of sustained tensile strain in the GMB. The assessment is based on the service-life of the GMB eventually being reached due to stress cracking after depletion of the protective antioxidants to a residual value. With respect to the selection of a GMB with a suitable stress crack resistance (SCR), it is noted that morphological changes can result in a substantial reduction in SCR with time, from the initial just manufactured value (SCRo) to a more representative value (SCRm), as the material tends to a thermodynamically more stable post-manufactured state. Thus, SCRm should be considered more representative of the true SCR of the material than the value obtained from the off-roll material just after manufacture. SCRm of can be estimated by aging the candidate GMBs in liquid at 55 deg. C for 270 days. Considering the potential implications of failure of the textured GMB to be used at this facility, and the potential for repair and replacement if it does fail, it is recommended that a maximum allowable strain (MAS), from all sources, of 3%, 4% and 5% be adopted on the base, side slopes, and cover GMBs, respectively. These maximum allowable strain values were selected considering the nature of the waste to be contained and the design-life that is required; they may be too conservative for some other applications with a much shorter design-life or lower consequence of premature failure. It is also indicated that the most critical locations on the GMB are often the welded seams where GMB panels are joined or repaired. Welds act a stress-raisers (increasing the stress and strain the GMB compared to that on either side of the weld). To minimize the need for patching areas damaged by the removal of samples for destructive tests, it is recommended that destructive tests on welds should generally be restricted to the minimum possible. It is also recommended that the German limits on welded GMB thickness be adopted in construction. Since strains can be significantly increased by failure to construct in accordance with the design drawings and specifications, it is recommended that there be Construction Quality Assurance (CQA) by very experienced personnel with a good knowledge of compacted clay liners, Geosynthetic Clay Liners (GCLs), and GMBs and the facility design, and that there be an experienced individual watching the construction work at all times prior to completion of the liner system. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2016

Single-Bubble Flow Boiling Phenomena - Interface Tracking Simulation

Boiling, as one of the most efficient heat transfer mechanisms, is widely used in various engineering systems. Better understanding and modeling of this process remains a major challenge in multiphase flow research. The distribution of vapor in boiling system affects the heat transfer rate and may cause unfavorable conditions, such as heater burn-out. A number of flow regimes have been observed experimentally. In general, there are three regimes under boiling conditions: nucleate boiling, transition boiling, and film boiling. The nucleate boiling regime is categorized into partial boiling regime and fully developed nucleate boiling, according to behavior of bubble dynamics and heat transfer characteristics. In the first region, as the wall temperature increases, the fraction of the wall surface subject to nucleate boiling increases until bubble formation occupies the entire heated surface. Heat transfer in this region is a complex mixture of single-phase forced convection and nucleate boiling. As bubble density increases, bubbles turn to coalesce and form insulating vapor patches, which impedes liquid flow back to the surface. The heat transfer rate under this condition reduces dramatically. This point is called Critical Heat Flux (CHF), which leads to boiling crisis. The behavior of boiling crisis is dependent on local fluid conditions due to bubble growth and departure. Experiments are the ultimate tool for boiling model development and verification, but they still lack some capabilities needed for better understanding of the local mechanism of this phenomena. It's difficult to capture many important details at the pressure/temperature conditions of interest using experimental techniques, such as full three dimensional measurements of velocity and temperature distribution and estimates of heat flux partitioning during the boiling process. The interface tracking simulation (ITS) is one of the promising approaches to describe heat transfer of boiling phenomena and their underlying mechanisms. The advances of high performance computing (HPC) in recent years made it possible to apply DNS to a wide variety of adiabatic flows. Some work has been done to implement evaporation / condensation models as well. Lee and Nydahl performed a numerical simulation of bubble growth and departure assuming that the bubble has the shape of a truncated sphere and a micro-layer exists during bubble growth. A 2-D cylindrical bubbles simulation has been done by Son with a simplified model to predict the heat flux in a thin liquid micro-layer. A direct simulation of 2D film boiling is conducted by Juric and Tryggvason. The film boiling, below critical pressure with a modified Level Set Method, is studied by Son and Dhir. Ose and Kunugi have developed a boiling and condensation model on subcooled boiling phenomena. Fuchs performed numerical simulations of bubble growth and departure considering wall conduction effects. Fully transient heat and fluid flow is modeled with a free surface of a rising bubble and a periodic calculation of the whole cycling of a growing, detaching, and rising bubble. Mukherjee and Kandikar have done a numerical simulation of an evaporating meniscus on a moving heated surface with level set method. The heat transfer associated with the advancing and receding contact angle has been studied. To develop the capability of physics-based boiling process, in the presented work the energy and momentum equations are coupled to simulate single-bubble growth scenarios. For a single bubble simulation in infinite liquid, the analytical solution exists and can be compared with the numerical results for verification purposes. The presented capabilities will be utilized in the large scale DNS of boiling flows in the future. The finite-element based code, PHASTA is used for the simulation. It is a parallel, hierarchic, higher-order accurate, adaptive, stabilized, transient analysis flow solver, which has been shown to be an effective tool for a wide range of single and two-phase flow problems. It has been shown to be highly scalable on top supercomputers ({approx}85% scaling on up to 3 million mesh partitions using a 92 billion element mesh . PHASTA has been shown to reliably predict the details of adiabatic bubbly flows as well as single-phase flows with heat transfer. To develop the capability of physics-based boiling process, in the presented work the energy and momentum equations are coupled to simulate a single-bubble growth scenario. For a single bubble growth in superheated water, the analytical solution exists and can be compared with the numerical results for verification purposes. The second-order accurate spatial and time discretization is used for the flow solver in the presented work. (authors)

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

DOE OSTI2024

Developing a Supply Chain Security Program

Amid growing concerns over foreign manufacturing for components and devices deployed in critical energy infrastructure, this research from the national labs will highlight best practices for developing and maintaining a supply chain security program. Tools for asset inventory, tips for developing and maintaining software- and hardware-bills-of-materials (SBOMs and HBOMs), recommended contractual language for vendor agreements, and identification of responsibilities will be shared. We discuss the one-time requirements to enable a successful supply chain security program and the best ways to operationalize this program for maximum impact, including development of robust practices for vulnerability tracking, patch management, and workarounds, with understanding of the reliability and uptime requirements for utilities. The recommendations shared are based on a cyber-informed engineering approach to identification of high-consequence impacts and the engineering controls related to supply chain management that can best mitigate these impacts. This approach allows for prioritization of resources. Additionally, we highlight relative up-front and ongoing costs associated with recommended controls. Viewers will leave with an understanding what a supply chain security program is, and what steps, prioritized for resource-constrained organizations, can build a robust program.

14 SOLAR ENERGY↗

DOE OSTI2024

Multiphysics Degradation Modeling of Energy Storage Materials via RKPM with a Neural Network-Enhancement

In energy storage materials, strong electrochemical-mechanical coupling and highly anisotropic material properties contribute to the formation and propagation of micro-cracking during charge/discharge cycling, resulting in reduced performance and service life. A coupled electro-chemo-mechanical reproducing kernel particle method (RKPM) formulation is developed, and a patch-test is formulated to certify optimal convergence of the proposed RKPM method for the coupled physics system. With microstructural images supplied by the National Renewable Energy Laboratory (NREL), pixel-based model construction by RKPM is then used to represent the complex material microstructures for modeling the coupled physics of these systems. Further, a neural network-enhanced reproducing kernel particle method (NN-RKPM) [1, 2] is introduced to effectively model damage and crack propagation in the material microstructures; the location, orientation, and solution transition near a localization are automatically captured by superimposed block-level NN optimizations. This NN enrichment approach allows for effective modeling of localizations via a fixed background discretization, relieving tedious efforts for adaptive refinement in traditional mesh-based methods. Applications to the heterogeneous microstructures of Li-ion battery cathodes will be presented to demonstrate the effectiveness of the proposed methods. Reference: [1] Baek, J., Chen, J. S., Susuki, K., "Neural Network enhanced Reproducing Kernel Particle Method for Modeling Localizations," International Journal for Numerical Methods in Engineering, Vol. 123, pp 4422-4454, https://doi.org/10.1002/nme.7040, 2022. [2] Baek, J., Chen, J. S., "A Neural Network-Based Enrichment of Reproducing Kernel Approximation for Modeling Brittle Fracture", Computer Methods in Applied Mechanics and Engineering Vol. 410, 116590, 2024.

electro-chemo-mechanical coupling↗

DOE OSTI2024

Shared aperture antenna array

A shared aperture antenna array including an array of antennas is disclosed. Elements of neighboring antennas are shared to create additional antennas. The shared elements include radiating patches and apertures. Each antenna shares an aperture with neighboring antennas. The array of antennas may be linear or two-dimensional. A phase shifting network with single-pole-single-throw reflective switches may be coupled to the antennas.

Tedeschi, Jonathan R.↗

DOE OSTI2025

Measurement of Parity-Violating Modes of the Dark Energy Spectroscopic Instrument (DESI) Year 1 Luminous Red Galaxies' 4-Point Correlation Function

Here we report the first measurement of the parity-violating (PV) 4-Point Correlation Function (4PCF) of the Dark Energy Spectroscopic Instrument's Year 1 Luminous Red Galaxy (DESI Y1 LRG) sample, motivated by the potential detection of the PV 4PCF in the Sloan Digital Sky Survey Baryon Oscillation Spectroscopic Survey (SDSS BOSS) galaxies. In our auto-correlation ("auto") analysis, we find a statistically significant excess of the PV signal compared to mocks without any PV, at 4-10$σ$ depending on details of the analysis. This could arise either from genuine PV or from an underestimation of the variance in the mocks; it is unlikely to arise, at the signal level, from a systematic. We then cross-correlate ("cross") the putative PV signal between different, independent patches of sky, and there find no detection of parity violation. The two measurements are in significant tension: while the cross has somewhat larger error bars than the auto, this is not sufficient to explain the discrepancy. We thus present the current work as an intriguing addition to the PV work on BOSS and as motivation for exploring further the relationship between the auto and cross PV 4PCF analyses.

Slepian, Zachary [Florida U.]↗

DOE OSTI2025

The Automatic Reactor Control System (ARCS) Upgrade, version 2.0 for TREAT

The Transient REActor Test Facility (TREAT) recently underwent an upgraded to the Automatic Reactor Control System (ARCS). The purpose of the upgrade was to institute a new software architecture that is better suited for the programming environment, patched software bugs and applied two new segments for reactor control. This paper will focus on the new segments for reactor control. The two new control segments added to ARCS are called Generic Power and Generic Rods. The original version of ARCS provided only two power related functions, namely periods and ramps, that had to be spliced together to generate any power shape. The Generic Power segment allows the user to input data points to define the function and then the algorithm does its best to create the desired shape. The original ARCS program utilized two direct rod commands (i.e. open loop control), these were a rod stop and clip. A Generic Rod segment extends the ability of the computer to directly command any rod position. The functionality of these new segments was proven during the TREAT outage in 2024.

46 - INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AN↗

DOE OSTI2026

Primordial Neutron Stars

We propose a novel cosmological scenario in which baryonic neutron stars could plausibly form in the early universe. If baryogenesis initially produces an excessively-large baryon asymmetry, $Y_B \gg 10^{-10},$ the baryonic mass inside the horizon can exceed the minimum neutron star mass before big bang nucleosynthesis (BBN). While this large asymmetry is present, non-relativistic baryons can dominate the universe and enhanced density perturbations on small scales can gravitationally collapse Hubble patches shortly after horizon re-entry. For some initial perturbations, just below the threshold for black hole formation, this collapse will be arrested only by nuclear pressure, possibly resulting in neutron star formation. Afterwards, there must be a large entropy injection to restore the observed baryon asymmetry, $Y_B \sim 10^{-10}$, and preserve the successful predictions of standard BBN. Unlike neutron stars that form from stellar collapse, primordial neutron stars can, in principle, be as light as $\sim 0.1 M_\odot$, limited only by the nuclear equation of state.

Krnjaic, Gordan [Fermilab; Chicago U., Astron. Ast↗

DOE OSTI2026

The South Pole Telescope AGN Monitoring Campaign: First Release of SPTpol Bright AGN Light Curves

The South Pole Telescope (SPT) collaboration has recently embarked upon a campaign to monitor the brightness of a sample of active galactic nuclei (AGN), both in real time and in archival SPT data. The original design of the SPT was optimized for observations of the cosmic microwave background (CMB) at arc-minute and larger angular scales, and it has been used for this purpose for nearly twenty years, using three generations of CMB cameras. Recently it has been recognized that data from CMB experiments have the potential to be used for AGN monitoring. In this paper, we present the first public release of data from a full sample of SPT-monitored AGN, comprising 158 AGN light curves and associated data from the SPTpol camera, which was operational from 2012-2016. These light curves were created using observations from the SPTpol 500 deg$^{2}$ survey, in which the instrument was used to scan a 500 deg$^2$ patch of the sky several times per day with detectors sensitive to radiation in bands centered at 90 and 150 GHz. We provide a comprehensive description of the observations, the data processing methods, and the resulting light curve catalog. As an example of analyses that these data enable, we searched for a correlation between variability and spectral index, and we looked for ``bluer-when-brighter'' trends in the sample. Our analysis finds $> 10 σ$ correlation between fractional intrinsic variance and mean spectral index in the sample, but no significant evidence for bluer-when-brighter trends. The datasets from this study can be accessed through the SPT Treasury Record of AGN With Historical Activity and Time-Series or STRAWHAT catalog. This initial data release includes SPTpol light curves at 90 and 150 GHz, focusing on total intensity. In later updates, SPTpol polarization data and new observations from the SPT-3G instrument at 90, 150, and 220 GHz will be included.