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Validation study of sodium pool fire modeling efforts in MELCOR and SPHINCS codes

Nuclear Engineering and Design

Foulk, James W.; Aoyagi, Mitsuhiro; Uchibori, Akihiro; Takata, Takashi; Luxat, David L.

Discharge of sodium coolant into containment from a sodium-cooled fast reactor vessel can occur in the event of a pipe leak or break. In this situation, some of the liquid sodium droplets discharged from the coolant system will react with oxygen in the air before reaching the containment. This phase of the event is normally termed the sodium spray fire phase. Unreacted sodium droplets pool on the containment floor where continued reaction with containment atmospheric oxygen occurs. This phase of the event is normally termed the sodium pool fire phase. Both phases of these sodium-oxygen reactions (or fires) are important to model because of the heat addition and aerosol generation that occur. Any fission products trapped in the sodium coolant may also be released during this progression of events, which if released from containment could pose a health risk to workers and the public. The paper describes progress of an international collaborative research in the area of the sodium fire modeling in the sodium-cooled fast reactors between the United States and Japan under the framework of the Civil Nuclear Energy Research and Development Working Group. In this collaboration between Sandia National Laboratories and Japan Atomic Energy Agency, the validation basis for and modeling capabilities of sodium spray and pool fires in MELCOR of Sandia National Laboratories and SPHINCS of Japan Atomic Energy Agency are being enhanced. This study documents MELCOR and SPHINCS sodium pool fire model validation exercises against the JAEA's sodium pool fire experiments, F7-1 and F7-2. The proposed enhancement of the sodium pool fire models in MELCOR through addition of thermal hydraulic and sodium spreading models that enable a better representation of experimental results is also described.

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TYPE Conference Paper YEAR 2023
DOIOSTIScopus

Semiannual Categorical Process Report - January Through June 2023

Manger, Trevor J.

The Sandia National Laboratories, in California (SNL/CA) is a research and development facility, owned by the U.S. Department of Energy’s National Nuclear Security Administration agency (DOE/NNSA). The laboratory is located in the City of Livermore (the City) and is comprised of approximately 410 acres. The SNL/CA facility is operated by National Technology and Engineering Solutions of Sandia, LLC (NTESS) under a contract with the DOE/NNSA. The DOE/ NNSA’s Sandia Field Office (SFO) oversees the operations of the site. North of the SNL/CA facility is the Lawrence Livermore National Laboratory (LLNL), in which SNL/CA’s sewer system combines with before discharging to the City’s Publicly Owned Treatment Works (POTW) for final treatment and processing. The City’s POTW authorizes the wastewater discharge from SNL/CA via the assigned Wastewater Discharge Permit #1251 (the Permit), which is issued to the DOE/NNSA’s main office for Sandia National Laboratories, located in New Mexico (SNL/NM). The Monitoring and Reporting Condition 2.B of the Permit requires compliance with the semiannual reporting requirements contained in federal categorical pretreatment standards regulations (40 CFR 403.12). These regulations set numerical limits on the concentration of pollutants allowed to discharge from certain categories of industrial processes. This report is submitted to the City to satisfy this reporting requirement.

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TYPE Other Report YEAR 2023
DOIOSTI

Parallel Matrix Multiplication Using Voltage-Controlled Magnetic Anisotropy Domain Wall Logic

IEEE Journal on Exploratory Solid-State Computational Devices and Circuits

Zogbi, Nicholas; Liu, Samuel; Bennett, Christopher; Agarwal, Sapan; Marinella, Matthew J.; Incorvia, Jean A.C.; Xiao, Tianyao P.

The domain wall-magnetic tunnel junction (DW-MTJ) is a versatile device that can simultaneously store data and perform computations. These three-terminal devices are promising for digital logic due to their nonvolatility, low-energy operation, and radiation hardness. Here, we augment the DW-MTJ logic gate with voltage-controlled magnetic anisotropy (VCMA) to improve the reliability of logical concatenation in the presence of realistic process variations. VCMA creates potential wells that allow for reliable and repeatable localization of domain walls (DWs). The DW-MTJ logic gate supports different fanouts, allowing for multiple inputs and outputs for a single device without affecting the area. We simulate a systolic array of DW-MTJ multiply-accumulate (MAC) units with 4-bit and 8-bit precision, which uses the nonvolatility of DW-MTJ logic gates to enable fine-grained pipelining and high parallelism. The DW-MTJ systolic array provides comparable throughput and efficiency to state-of-the-art CMOS systolic arrays while being radiation-hard. These results improve the feasibility of using DW-based processors, especially for extreme-environment applications such as space.

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TYPE Journal Article YEAR 2023
DOIOSTIScopusDOIOSTIScopus
Results 2751–2800 of 99,299
Results 2751–2800 of 99,299