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Development of High-Voltage Vertical GaN PN Diodes (invited)

Kaplar, Robert K.; Allerman, A.A.; Crawford, Mary H.; Gunning, Brendan P.; Flicker, Jack D.; Armstrong, Andrew A.; Yates, Luke Y.; Binder, Andrew B.; Dickerson, Jeramy R.; Pickrell, Gregory P.; Sharps, Paul; Anderson, T.; Gallagher, J.; Jacobs, A.; Koehler, A.; Tadjer, M.; Hobart, K.; Ebrish, M.; Porter, M.; Martinez, R.; Zeng, K.; Ji, D.; Chowdhury, S.; Aktas, O.; Cooper, James A.

Abstract not provided.

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TYPE Conference Presenation YEAR 2020
DOIOSTI

SNF Interim Storage Canister Corrosion and Surface Environment Investigations (FY2020 Status Report)

Schaller, Rebecca S.; Knight, Andrew W.; Bryan, Charles R.; Nation, Brendan L.; Montoya, Timothy M.; Katona, Ryan M.

This progress report describes work performed during FY20 at Sandia National Laboratories (SNL) to assess the localized corrosion performance of container/cask materials used in the interim storage of spent nuclear fuel (SNF). Of particular concern is stress corrosion cracking (SCC), by which a through-wall crack could potentially form in a canister outer wall over time intervals that are shorter than possible dry storage times. Work in FY20 further defined our understanding of the potential chemical and physical environment present on canister surfaces, evaluated the relationship between the environment and the resultant corrosion that occurs, and initiated crack growth rate testing under relevant environmental conditions. In FY20, work to define dry storage canister surface environments included several tasks. First, collection of dust deposition specimens from independent spent fuel storage installation (ISFSI) site locations helped to establish a more complete understanding of the potential chemical environment formed on the canister. Second, the predicted evolution of canister surface relative humidity RH) values was estimated using ISFSI site weather data and the horizontal canister thermal model used by the SNL probabilistic SCC model. These calculations determined that for typical ISFSI weather conditions, seasalt deliquescence to produce MgCl2-rich brines could occur in less than 20 years at the coolest locations on the canister surface, and, even after nearly 300 years, conditions for NaCl deliquescence (75% RH) are not reached. This work illustrates the importance of understanding the stability of MgCl2-rich brines on the heated canister surface, and the potential impact of brine composition on corrosion processes, including pitting and stress corrosion cracking. In an additional study, the description of the canister surface environment was refined in order to define more realistic corrosion testing environments including diurnal cycles, soluble salt chemistries, and inert mineral particles. The potential impacts of these phenomena on canister corrosion are being evaluated experimentally. Finally, work over the past few years to evaluate the stability of magnesium chloride brines continued in FY20. MgCl2 degassing experiments were carried out, confirming that MgCl2 brines slowly degas HCl on heated surfaces, converting to less deliquescent magnesium hydroxychloride phases and potentially leading to brine dryout.

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TYPE Other Report YEAR 2020
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Global normal spectral irradiance in Albuquerque: a one-year open dataset for PV research

Driesse, Anton; Stein, Joshua S.

This report describes the creation process and final content of a spectral irradiance dataset for Albuquerque NM. The spectral irradiance measurements were made using a dual-axis tracker; therefore, they represent global normal irradiance. The dataset combines spectroradiometer and weather measurements from a two-year period into a continuous calendar year. The data files are accompanied by extensive metadata as well as example calculations and graphs to demonstrate the potential uses of this database.

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TYPE SAND Report YEAR 2020
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Novel Geometric Operations for Linear Programming

Ebeida, Mohamed S.; Abdelkader, Ahmed; Amenta, Nina; Kouri, Drew P.; Parekh, Ojas D.; Phillips, Cynthia A.; Winovich, Nickolas W.

This report summarizes the work performed under the project "Linear Programming in Strongly Polynomial Time." Linear programming (LP) is a classic combinatorial optimization problem heavily used directly and as an enabling subroutine in integer programming (IP). Specifically IP is the same as LP except that some solution variables must take integer values (e.g. to represent yes/no decisions). Together LP and IP have many applications in resource allocation including general logistics, and infrastructure design and vulnerability analysis. The project was motivated by the PI's recent success developing methods to efficiently sample Voronoi vertices (essentially finding nearest neighbors in high-dimensional point sets) in arbitrary dimension. His method seems applicable to exploring the high-dimensional convex feasible space of an LP problem. Although the project did not provably find a strongly-polynomial algorithm, it explored multiple algorithm classes. The new medial simplex algorithms may still lead to solvers with improved provable complexity. We describe medial simplex algorithms and some relevant structural/complexity results. We also designed a novel parallel LP algorithm based on our geometric insights and implemented it in the Spoke-LP code. A major part of the computational step is many independent vector dot products. Our parallel algorithm distributes the problem constraints across processors. Current commercial and high-quality free LP solvers require all problem details to fit onto a single processor or multicore. Our new algorithm might enable the solution of problems too large for any current LP solvers. We describe our new algorithm, give preliminary proof-of-concept experiments, and describe a new generator for arbitrarily large LP instances.

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TYPE SAND Report YEAR 2020
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Integrating Inter-Node Communication with a Resilient Asynchronous Many-Task Runtime System

Proceedings of ExaMPI 2020: Exascale MPI Workshop, Held in conjunction with SC 2020: The International Conference for High Performance Computing, Networking, Storage and Analysis

Paul, Sri R.; Hayashi, Akihiro; Whitlock, Matthew J.; Bak, Seonmyeong; Teranishi, Keita T.; Mayo, Jackson M.; Grossman, Max; Sarkar, Vivek

Achieving fault tolerance is one of the significant challenges of exascale computing due to projected increases in soft/transient failures. While past work on software-based resilience techniques typically focused on traditional bulk-synchronous parallel programming models, we believe that Asynchronous Many-Task (AMT) programming models are better suited to enabling resiliency since they provide explicit abstractions of data and tasks which contribute to increased asynchrony and latency tolerance. In this paper, we extend our past work on enabling application-level resilience in single node AMT programs by integrating the capability to perform asynchronous MPI communication, thereby enabling resiliency across multiple nodes. We also enable resilience against fail-stop errors where our runtime will manage all re-execution of tasks and communication without user intervention. Our results show that we are able to add communication operations to resilient programs with low overhead, by offloading communication to dedicated communication workers and also recover from fail-stop errors transparently, thereby enhancing productivity.

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TYPE Conference Presenation YEAR 2020
DOIOSTIScopus

Initial conceptual demonstration of control co-design for WEC optimization

Journal of Ocean Engineering and Marine Energy

Coe, Ryan G.; Bacelli, Giorgio B.; Olson, Sterling S.; Neary, Vincent S.; Topper, Mathew B.R.

While some engineering fields have benefited from systematic design optimization studies, wave energy converters have yet to successfully incorporate such analyses into practical engineering workflows. The current iterative approach to wave energy converter design leads to sub-optimal solutions. This short paper presents an open-source MATLAB toolbox for performing design optimization studies on wave energy converters where power take-off behavior and realistic constraints can be easily included. This tool incorporates an adaptable control co-design approach, in that a constrained optimal controller is used to simulate device dynamics and populate an arbitrary objective function of the user’s choosing. A brief explanation of the tool’s structure and underlying theory is presented. To demonstrate the capabilities of the tool, verify its functionality, and begin to explore some basic wave energy converter design relationships, three conceptual case studies are presented. In particular, the importance of considering (and constraining) the magnitudes of device motion and forces in design optimization is shown.

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TYPE Journal Article YEAR 2020
DOIOSTIScopus

High-Level Considerations for Access and Access Controls by Design

Bland, Jesse J.; Evans, Alan S.; Goolsby, Tommy D.; Horowitz, Steven M.; Monthan, Chad W.; Osborn, Douglas M.; Rivers, Joe; Rodgers, Thomas W.; White, Jake; Williams, Adam D.

Nuclear power plants must be, by design and construction, robust structures and difficult to penetrate. Limiting access with difficult-to-penetrate physical barriers is going to be key for staffing reduction. Ideally, for security, the reactors would be sited underground, beneath a massive solid block, too thick to be penetrated by tools or explosives with all communications and power transfer lines also underground and fortified. Having the minimal possible number of access points and methods to completely block access from these points if a threat is detected will greatly help us justify staffing reduction.

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TYPE Other Report YEAR 2020
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Sandia National Laboratories FY20 Progress Report

Aguirre, Brandon A.; Martin, William J.

The Energetic Neutrons campaign led by Sandia National Laboratories (SNL) had a successful year testing electronic devices and printed circuit boards (PCBs) under 14 MeV neutron irradiation at OMEGA. During FY20 the Energetic Neutrons campaign increased the number and complexity of experiments, continued collaborations with external organizations, and generated knowledge that supports SNL’s National Security mission. In FY20 the Energetic Neutrons campaign was executed by an early career team led by a new PI. The SNL team members were trained to take over new responsibilities during the shot day to increase the number and complexity of experiments in the campaigns. Also, in FY20 for the first time the Energetic Neutrons campaign had a graduate student contributing with pre and post-irradiation characterizations at SNL of the semiconductor devices irradiated at OMEGA. In FY20 SNL collaborated with the Air Force Nuclear Weapons Center (AFNWC) and supported experiments related to radiation effects in semiconductor devices. SNL also gave the opportunity to ride along to Los Alamos National Laboratory and multiple scientists from MIT and LLE. SNL continued using the last two generations of the Neutron Effects Diagnostics (NEDs) to field active and passive experiments but also redesigned the latest generation of the NEDs to accommodate larger components and improve the vacuum sealing as shown in figure 1a. The redesigned NEDs allowed SNL to perform active tests of a high voltage (HV) PCB for the first time at OMEGA; where signals before, during and after the irradiation were recorded. The HV PCB installed in one of the SNL NEDs is shown in figure 1b where a 3D-printed nosecone was used to check for mechanical and electrical interference. Passive irradiations of multiple components were followed up with leakage current, gain measurements and radiation-induced defect characterization.

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TYPE Other Report YEAR 2020
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First-Round Testing of the Brine Availability Test in Salt (BATS) at the Waste Isolation Pilot Plant (WIPP)

Kuhlman, Kristopher L.; Mills, Melissa M.; Jayne, Richard S.; Herrick, Courtney G.; Choens, Robert C.; Nemer, Martin N.; Heath, Jason; Matteo, Edward N.; Xiong, Yongliang X.; Otto, Shawn; Dozier, Brian; Weaver, Doug; Stauffer, Phil; Guiltinan, Eric; Boukhalfa, Hakim; Rahn, Thom; Wu, Yuxin; Rutqvist, Jonny; Hu, Mengsu; Crandall, Dustin

Abstract not provided.

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TYPE Conference Poster YEAR 2020
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The performance of a spectral wave model at predicting wave farm impacts

Energies

Cameron Mcnatt, J.; Porter, Aaron; Chartrand, Chris C.; Roberts, Jesse D.

For renewable ocean wave energy to support global energy demands, wave energy converters (WECs) will likely be deployed in large numbers (farms), which will necessarily change the nearshore environment. Wave farm induced changes can be both helpful (e.g., beneficial habitat and coastal protection) and potentially harmful (e.g., degraded habitat, recreational, and commercial use) to existing users of the coastal environment. It is essential to estimate this impact through modeling prior to the development of a farm, and to that end, many researchers have used spectral wave models, such as Simulating WAves Nearshore (SWAN), to assess wave farm impacts. However, the validity of the approaches used within SWAN have not been thoroughly verified or validated. Herein, a version of SWAN, called Sandia National Laboratories (SNL)-SWAN, which has a specialized WEC implementation, is verified by comparing its wave field outputs to those of linear wave interaction theory (LWIT), where LWIT is theoretically more appropriate for modeling wave-body interactions and wave field effects. The focus is on medium-sized arrays of 27 WECs, wave periods, and directional spreading representative of likely conditions, as well as the impact on the nearshore. A quantitative metric, the Mean Squared Skill Score, is used. Results show that the performance of SNL-SWAN as compared to LWIT is “Good” to “Excellent”.

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TYPE Journal Article YEAR 2020
DOIOSTIScopus

High-Level Considerations for Access and Access Controls by Design

Bland, Jesse J.; Evans, Alan S.; Goolsby, Tommy D.; Horowitz, Steven M.; Monthan, Chad W.; Osborn, Douglas M.; Rivers, Joe; Rodgers, Thomas W.; White, Jake; Williams, Adam D.

Nuclear power plants must be, by design and construction, robust structures and difficult to penetrate. Ideally, for security, the reactors would be sited underground, beneath a massive solid block, too thick to be penetrated by tools or explosives with all communications and power transfer lines also underground and fortified. Limiting access with difficult-to-penetrate physical barriers is going to be key for determining response and staffing requirements.

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TYPE Other Report YEAR 2020
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Utilizing temperature and brine inflow measurements to constrain reservoir parameters during a salt heater test

Minerals

Jayne, Richard S.; Kuhlman, Kristopher L.

Brine availability in salt has multiple implications for the safety and design of a nuclear waste storage facility. Brine availability includes both the distribution and transport of brine through a damaged zone around boreholes or drifts excavated into the salt. Coupled thermal, hydrological, mechanical, and chemical processes taking place within heated bedded salt are complex; as part of DECOVALEX 2023 Task E this study takes a parsimonious modeling approach utilizing analytical and numerical one-dimensional simulations to match field measurements of temperature and brine inflow around a heater. The one-dimensional modeling results presented arrive at best-fit thermal conductivity of intact salt, and the permeability and porosity of damaged salt of 5.74 W/m · K, 10−17 m2, and ≈0.02, respectively.

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TYPE Journal Article YEAR 2020
DOIOSTIScopus

An Enhanced Safeguards Approach for Accelerator Driven Systems utilized to Close the Fuel Cycle

Farley, David R.; Uribe, Eva U.; Horowitz, Steven M.; Solodov, Alexander A.

Further to our previous safeguards approach for Accelerator Driven Systems, which focused on estimates of fissile material production using relevant proton accelerator systems and corresponding safeguards needs for fuel storage, the subcritical reactor, and spent fuel storage material balances areas, this report is more expansive and considers utilization of ADS for either burning of transuranics or breeding of fissile materials. We find that the recycled fuels likely intended for ADS will be thermally and radioactively hot to such a degree that it is likely reprocessing and fuel fabrication will have to be co - located with the ADS reactor facility to avoid impractical hot fuel transportation issues. As such, we consider in detail the full ADS system to include material balance areas for spent fuel receiving, reprocessing, storage & cooling, fuel fabrication, subcritical reactor area, and waste storage & handling. Furthermore, aqueous - based separation methods like PUREX cannot tolerate the intense heat of the ADS fuels, so pyroprocessing will likely be required. With these considerations, we developed an Enhanced Safeguards Approach for ADS beyond the work done in our first report, and conclude that significant diagnostic development is needed , a nd provide safeguards recommendations. We have also included an appendix regarding some country programs, in particular the Chinese ADANES burner/breeder program a nd the Indian thorium - based breeder program.

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TYPE SAND Report YEAR 2020
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Helpful Engineering's Universal Citizen Protection Device (UCPD)

Glen, Andrew G.; Mayes, Cathryn M.

The Universal Citizen Protection Device (UCPD) is a UV-based, filterless PPE concept developed by Helpful Engineering that aims to keep viral particles out of eyes, nose and mouth with a 99%+ reliability. The heart of the device is a concealed UV chamber that decontaminates all air going in and out of the PPE. The objective of this project was to provide measurements as evidence of proof of function of a representative prototype. Sandia utilized its aerosol characterization facility to measure the amount of virus that is inactivated by the device at representative flow rates and concentrations, using MS2 bacteriophage as the BSL-1 viral surrogate.

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TYPE Other Report YEAR 2020
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Generic FEPs Catalogue and Salt Knowledge Archive

Freeze, Geoffrey A.; Sevougian, S.D.; Kuhlman, Kristopher L.; Gross, Michael B.; Wolf, Jens; Buhmann, Dieter; Bartol, Jeroen; Leigh, Christi D.; Monig, Jorg

This report describes the development of a comprehensive catalogue of generic features, events, and processes (FEPs) that are potentially important for the post-closure performance of a repository for high-level radioactive waste (HLW) and spent nuclear fuel (SNF) in salt (halite) host rock. The FEPs and other supporting information have been entered into a “SaltFEP” Database. The generic salt repository FEPs include consideration of relevant FEPs from a number of U.S., Dutch, German, and international FEP lists and should be a suitable starting point for any repository program in salt host rock. The salt FEP catalogue and database employ a FEP classification matrix approach that is based on the concept that a FEP is typically a process or event acting upon or within a feature. The FEP matrix provides a two-dimensional structure consisting of a Features/Components axis that defines the “rows” and a Processes/Events axis that defines the “columns” of the matrix. The design of the FEP classification matrix is consistent with repository performance assessment – the Features/Components axis is organized vertically to generally correspond to the direction of potential radionuclide migration (from the waste to the biosphere) and the Processes/Events axis is designed to represent the common two-way couplings between thermal processes and other processes (such as thermal-mechanical or thermal-hydrologic processes). Related FEPs can be easily identified – related FEPs will typically be grouped in a single matrix cell or aligned along a common row (Feature/Component) or column (Process/Event). The online SaltFEP database can be downloaded from www.saltfep.org. It contains the FEP matrix, the FEPs, and the associated processes for each FEP. It provides a starting point to create and document site-specific individual FEPs. Furthermore, the FEP matrix is connected to the Salt Knowledge Archive (SKA), a database of about 20,000 references and documents representing the historical knowledge on radioactive disposal in salt. This work is the result of an ongoing collaboration between researchers in the U.S., the Netherlands, and Germany, and supports the NEA Salt Club Mandate. It builds upon prior work which is documented.

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TYPE SAND Report YEAR 2020
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Results 13201–13400 of 96,771
Results 13201–13400 of 96,771