A benchmark study on the thermal conductivity of nanofluids

Buongiorno, Jacopo,Venerus, David C.,Prabhat, Naveen,McKrell, Thomas,Townsend, Jessica,Christianson, Rebecca,Tolmachev, Yuriy V.,Keblinski, Pawel,Hu, Lin-wen,Alvarado, Jorge L.,Bang, In Cheol,Bishnoi, American Institute of Physics 2009 JOURNAL OF APPLIED PHYSICS - Vol.106 No.9

Physics informed neural networks for surrogate modeling of accidental scenarios in nuclear power plants

Antonello Federico,Buongiorno Jacopo,Zio Enrico 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.9

Licensing the next-generation of nuclear reactor designs requires extensive use of Modeling and Simulation (M&S) to investigate system response to many operational conditions, identify possible accidental scenarios and predict their evolution to undesirable consequences that are to be prevented or mitigated via the deployment of adequate safety barriers. Deep Learning (DL) and Artificial Intelligence (AI) can support M&S computationally by providing surrogates of the complex multi-physics high-fidelity models used for design. However, DL and AI are, generally, low-fidelity ‘black-box’ models that do not assure any structure based on physical laws and constraints, and may, thus, lack interpretability and accuracy of the results. This poses limitations on their credibility and doubts about their adoption for the safety assessment and licensing of novel reactor designs. In this regard, Physics Informed Neural Networks (PINNs) are receiving growing attention for their ability to integrate fundamental physics laws and domain knowledge in the neural networks, thus assuring credible generalization capabilities and credible predictions. This paper presents the use of PINNs as surrogate models for accidental scenarios simulation in Nuclear Power Plants (NPPs). A case study of a Loss of Heat Sink (LOHS) accidental scenario in a Nuclear Battery (NB), a unique class of transportable, plug-and-play microreactors, is considered. A PINN is developed and compared with a Deep Neural Network (DNN). The results show the advantages of PINNs in providing accurate solutions, avoiding overfitting, underfitting and intrinsically ensuring physics-consistent results

A central facility concept for nuclear microreactor maintenance and fuel cycle management

Fakhry Faris,Buongiorno Jacopo,Rhyne Steve,Cross Benjamin,Roege Paul,Landrey Bruce 한국원자력학회 2024 Nuclear Engineering and Technology Vol.56 No.3

Commercial deployment of nuclear microreactors presents an opportunity for the industry to rethink its approach to manufacturing, siting, operation and maintenance, and fuel cycle management as certain principles used in grid-scale nuclear projects are not applicable to a decentralized microreactor economy. The success of this nascent industry is dependent on its ability to reduce infrastructure, logistical, regulatory and lifecycle costs. A utility-like ‘Central Facility’ that consolidates the services required and responsibilities borne by vendors into one or a few centralized locations will be necessary to support the deployment of a fleet of microreactors. This paper discusses the requirements for a Central Facility, its implications on the cost structures of owners and suppliers of microreactors, and the impact of the facility for the broader microreactor industry. In addition, this paper discusses the pre-requisites for eligibility as well as the opportunities for a Central Facility host site. While there are many suitable locations for such a capability across the U.S., this paper considers a facility co-located with the Vogtle Nuclear Power Plant and Savannah River Sites to illustrate how a Central Facility can leverage the existing infrastructure and stimulate a local ecosystem.

The 2019 materials by design roadmap

Alberi, Kirstin,Nardelli, Marco Buongiorno,Zakutayev, Andriy,Mitas, Lubos,Curtarolo, Stefano,Jain, Anubhav,Fornari, Marco,Marzari, Nicola,Takeuchi, Ichiro,Green, Martin L,Kanatzidis, Mercouri,Toney, M IOP 2019 Journal of Physics. D, Applied Physics Vol.52 No.1

<P>Advances in renewable and sustainable energy technologies critically depend on our ability to design and realize materials with optimal properties. Materials discovery and design efforts ideally involve close coupling between materials prediction, synthesis and characterization. The increased use of computational tools, the generation of materials databases, and advances in experimental methods have substantially accelerated these activities. It is therefore an opportune time to consider future prospects for materials by design approaches. The purpose of this Roadmap is to present an overview of the current state of computational materials prediction, synthesis and characterization approaches, materials design needs for various technologies, and future challenges and opportunities that must be addressed. The various perspectives cover topics on computational techniques, validation, materials databases, materials informatics, high-throughput combinatorial methods, advanced characterization approaches, and materials design issues in thermoelectrics, photovoltaics, solid state lighting, catalysts, batteries, metal alloys, complex oxides and transparent conducting materials. It is our hope that this Roadmap will guide researchers and funding agencies in identifying new prospects for materials design.</P>

Measurement of wetted area fraction in subcooled pool boiling of water using infrared thermography

Kim, H.,Park, Y.,Buongiorno, J. North-Holland Pub. Co 2013 Nuclear engineering and design Vol.264 No.-

The wetted area fraction in subcooled pool boiling of water at atmospheric pressure is measured using the DEPIcT (DEtection of Phase by Infrared Thermography) technique. DEPIcT exploits the contrast in infrared (IR) light emissions between wet and dry areas on the surface of an IR-transparent heater to visualize the instantaneous distribution of the liquid and gas phases in contact with the heater surface. In this paper time-averaged wetted area fraction data in nucleate boiling are reported as functions of heat flux (from 30% up to 100% of the Critical Heat Flux) and subcooling (ΔT<SUB>sub</SUB>=0, 5, 10, 30 and 50<SUP>o</SUP>C). The results show that the wetted area fraction monotonically decreases with increasing heat flux and increases with increasing subcooling: both trends are expected. The range of time-averaged wetted area fractions is from 90%, at low heat flux and high subcooling, to 50% at high heat flux (right before CHF) and low subcooling. It is also shown that the dry areas are periodically rewetted by liquid sloshing on the surface at any subcooling and heat flux; however, the dry areas expand irreversibly at CHF.

Consequence-based security for microreactors

Gateau Emile,Todreas Neil,Buongiorno Jacopo 한국원자력학회 2024 Nuclear Engineering and Technology Vol.56 No.3

Assuring physical security for Micro Modular Reactors (MMRs) will be key to their licensing. Economic constraints however require changes in how the security objectives are achieved for MMRs. A promising new approach is the so-called performance based (PB) approach wherein the regulator formally sets general security objectives and leaves it to the licensee to set their own specific acceptance criteria to meet those objectives. To implement the PB approach for MMRs, one performs a consequence-based analysis (CBA) whose objective is to study hypothetical malicious attacks on the facility, assuming that intruders take control of the facility and perform any technically possible action within a limited time before an offsite security force can respond. The scenario leading to the most severe radiological consequences is selected and studied to estimate the limiting impact on public health. The CBA estimates the total amount of radionuclides that would be released to the atmosphere in this hypothetical scenario to determine the total radiation dose to which the public would be exposed. The predicted radiation exposure dose is then compared to the regulatory dose limit for the site. This paper describes application of the CBA to four different MMRs technologies.

EXPERIMENTAL STUDY OF CRITICAL HEAT FLUX WITH ALUMINA-WATER NANOFLUIDS IN DOWNWARD-FACING CHANNELS FOR IN-VESSEL RETENTION APPLICATIONS

Dewitt, G.,Mckrell, T.,Buongiorno, J.,Hu, L.W.,Park, R.J. Korean Nuclear Society 2013 Nuclear Engineering and Technology Vol.45 No.3

The Critical Heat Flux (CHF) of water with dispersed alumina nanoparticles was measured for the geometry and flow conditions relevant to the In-Vessel Retention (IVR) situation which can occur during core melting sequences in certain advanced Light Water Reactors (LWRs). CHF measurements were conducted in a flow boiling loop featuring a test section designed to be thermal-hydraulically similar to the vessel/insulation gap in the Westinghouse AP1000 plant. The effects of orientation angle, pressure, mass flux, fluid type, boiling time, surface material, and surface state were investigated. Results for water-based nanofluids with alumina nanoparticles (0.001% by volume) on stainless steel surface indicate an average 70% CHF enhancement with a range of 17% to 108% depending on the specific flow conditions expected for IVR. Experiments also indicate that only about thirty minutes of boiling time (which drives nanoparticle deposition) are needed to obtain substantial CHF enhancement with nanofluids.

Experimental Study of Critical Heat Flux with Alumina-Water Nanofluids in Downward-Facing Channels for In- Vessel Retention Applications

G. DEWITT,T. Mckrell,J. Buongiorno,L.W. Hu,R.J. Park 한국원자력학회 2013 Nuclear Engineering and Technology Vol.45 No.3

The Critical Heat Flux (CHF) of water with dispersed alumina nanoparticles was measured for the geometry and flow conditions relevant to the In-Vessel Retention (IVR) situation which can occur during core melting sequences in certain advanced Light Water Reactors (LWRs). CHF measurements were conducted in a flow boiling loop featuring a test section designed to be thermal-hydraulically similar to the vessel/insulation gap in the Westinghouse AP1000 plant. The effects of orientation angle, pressure, mass flux, fluid type, boiling time, surface material, and surface state were investigated. Results for water-based nanofluids with alumina nanoparticles (0.001% by volume) on stainless steel surface indicate an average 70%CHF enhancement with a range of 17% to 108% depending on the specific flow conditions expected for IVR. Experiments also indicate that only about thirty minutes of boiling time (which drives nanoparticle deposition) are needed to obtain substantial CHF enhancement with nanofluids.

Technology Selection for Offshore Underwater Small Modular Reactors

Koroush Shirvan,Ronald Ballinger,Jacopo Buongiorno,Charles Forsberg,Mujid Kazimi,Neil Todreas 한국원자력학회 2016 Nuclear Engineering and Technology Vol.48 No.6

This work examines the most viable nuclear technology options for future underwaterdesigns that would meet high safety standards as well as good economic potential, forconstruction in the 2030-2040 timeframe. The top five concepts selected from a survey of 13 nuclear technologies were compared to a small modular pressurized water reactor(PWR) designed with a conventional layout. In order of smallest to largest primary systemsize where the reactor and all safety systems are contained, the top five designs were: (1) aleadebismuth fast reactor based on the Russian SVBR-100; (2) a novel organic cooledreactor; (3) an innovative superheated water reactor; (4) a boiling water reactor based onToshiba's LSBWR; and (5) an integral PWR featuring compact steam generators. A similarstudy on potential attractive power cycles was also performed. A condensing and recompressionsupercritical CO2 cycle and a compact steam Rankine cycle were designed. It wasfound that the hull size required by the reactor, safety systems and power cycle can besignificantly reduced (50-80%) with the top five designs compared to the conventionalPWR. Based on the qualitative economic consideration, the organic cooled reactor andboiling water reactor designs are expected to be the most cost effective options.

Systematic Band Gap Tuning of BaSnO₃ via Chemical Substitutions: The Role of Clustering in Mixed-Valence Perovskites

Lee, Seunghun,Wang, Haihang,Gopal, Priya,Shin, Jongmoon,Jaim, H. M. Iftekhar,Zhang, Xiaohang,Jeong, Se-Young,Usanmaz, Demet,Curtarolo, Stefano,Fornari, Marco,Buongiorno Nardelli, Marco,Takeuchi, Ichir American Chemical Society 2017 Chemistry of materials Vol.29 No.21

<P>By combining high-throughput experiments and first-principles calculations based on the DFT-ACBN0 approach, we have investigated the energy band gap of Sr-, Pb-, and Bi-substituted BaSnO<SUB>3</SUB> over wide concentration ranges. We show that the band gap energy can be tuned from 3 to 4 eV by chemical substitution. Our work indicates the importance of considering the mixed-valence nature and clustering effects upon substitution of BaSnO<SUB>3</SUB> with Pb and Bi. Starting from the band gap of ∼3.4 eV for pure BaSnO<SUB>3</SUB>, we find that Pb substitution changes the gap in a nonmonotonic fashion, reducing it by as much as 0.3 eV. Bi substitution provides a monotonic reduction but introduces electronic states into the energy gap due to Bi clustering. Our findings provide new insight into the ubiquitous phenomena of chemical substitutions in perovskite semiconductors with mixed-valence cations that underpin their physical properties.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cmatex/2017/cmatex.2017.29.issue-21/acs.chemmater.7b03381/production/images/medium/cm-2017-03381d_0005.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/cm7b03381'>ACS Electronic Supporting Info</A></P>