Ryan Stewart

Profile Information
Name
Dr. Ryan Stewart
Institution
Idaho National Laboratory
Position
Digital Twin Data Scientist
Affiliation
American Nuclear Society, Institute of Nuclear Material Management
h-Index
ORCID
0000-0003-4867-6555
Expertise
Advanced Reactors, Data Science, Digital Twin, Nuclear Safeguards
Additional Publications:
"Parameter study of the running-in process for the Generic Pebble Bed Reactor (GPBR-200)" Ryan Stewart, Paolo Balestra, Benjamin Lindley, Gerhard Strydom, Ethan Fowler, [2026] Annals of Nuclear Energy · DOI: 10.1016/j.anucene.2025.111719
"Challenges and Opportunities Specific to Microreactors: Compact and Light-Weight Shielding During Operation and Transportation" Abderrafi M. Ougouag, Hikaru Hiruta, Ryan H. Stewart, Samuel E. Bays, [2025] Nuclear Science and Engineering · DOI: 10.1080/00295639.2025.2508585
"Preliminary studies on diversion and misuse for TRISO-fueled heat-pipe-cooled microreactors" Sweet Shanahan, Quinton Williams, Ishita Trivedi, Emerald Ryan, Stefano Terlizzi, Camille Palmer, Ryan Stewart, Nelson Snow, [2025] Annals of Nuclear Energy · DOI: 10.1016/j.anucene.2025.111309
"Selection of Sampling and Surrogate Modeling Methods for State-Point Evaluations of an AGN-201M Reactor" Ryan H. Stewart, Todd S. Palmer, Camille J. Palmer, Chad Pope, Ashley Shields, Christopher Ritter, Quinton J. Williams, [2025] Nuclear Science and Engineering · DOI: 10.1080/00295639.2025.2455908
"Autonomous anomaly detection of proliferation in the AGN-201 nuclear reactor digital twin" Ashley Shields, Ryan Stewart, John Darrington, Jonathan Scott, Chad Pope, Christopher Ritter, Eduardo Treviño, [2025] Annals of Nuclear Energy · DOI: 10.1016/j.anucene.2024.110990
"Capturing the run-in of a pebble-bed reactor by using thermal feedback and high-fidelity neutronics simulations" Jack Cavaluzzi, Paolo Balestra, Gerhard Strydom, Ryan Stewart, [2024] Annals of Nuclear Energy · DOI: 10.1016/j.anucene.2024.110697
"Mass Optimization of a Multilayered Shield for Transportable Microreactors" Samuel E. Bays, Joshua N. Zelina, Robert E. Spears, Adam X. Zabriskie, Efe Kurt, Abderrafi M. Ougouag, Ryan H. Stewart, [2024] Nuclear Science and Engineering · DOI: 10.1080/00295639.2024.2403899
"High-Temperature Gas-Cooled Pebble-Bed Reactors Running In And Transient Modeling Capabilities Demonstration" Ryan Stewart, Paolo Balestra, Zhiee Ooi, Jun Fang, Thanh Hua, Ling Zou, Joshua Hanophy, [2024] · DOI: 10.2172/2474862
"High-Fidelity Neutronics Model of a Realistic Heat Pipe Microreactor Report" Ishita Trivedi, Ryan Stewart, Stefano Terlizzi, [2024] · DOI: 10.2172/2367263
"High-fidelity simulations of the run-in process for a pebble-bed reactor" Paolo Balestra, David Reger, Elia Merzari, Gerhard Strydom, Ryan Stewart, [2024] Annals of Nuclear Energy · DOI: 10.1016/j.anucene.2023.110193
"Utilizing a Virtual Sodium-Cooled Fast Reactor Digital Twin to Aid in Diversion Pathway Analysis for International Safeguards Applications" Ashley Shields, Shaw Wen, Frederick Gleicher, Samuel Bays, Mark Schanfein, Jeren Browning, Katherine Jesse, Christopher Ritter, Ryan Stewart, [2023] Science & Global Security · DOI: 10.1080/08929882.2023.2299560
"Multiphysics Pebble-Bed Reactor Control Rod Withdrawal Study" Paolo Balestra, Javier Ortensi, Joshua Hanophy, Zachary Prince, Ryan Stewart, Gerhard Strydom, Vincent Laboure, [2023] · DOI: 10.2172/2278845
"Discrete element simulation of Pebble Bed Reactors on graphics processing units" Elia Merzari, Paolo Balestra, Ryan Stewart, Gerhard Strydom, David Reger, [2023] Annals of Nuclear Energy · DOI: 10.1016/j.anucene.2023.109896
"Toward an Agent-Based Blackboard System for Reactor Design Optimization" Todd S. Palmer, Samuel Bays, Ryan Stewart, [2022] Nuclear Technology · DOI: 10.1080/00295450.2021.1960783
"An agent-based blackboard system for multi-objective optimization" Todd S Palmer, Samuel Bays, Ryan Stewart, [2022] Journal of Computational Design and Engineering · DOI: 10.1093/jcde/qwac009
Abstract

In the field of multi-objective optimization, there are a multitude of algorithms from which to choose. Each algorithm has strengths and weaknesses associated with the mechanics for finding the Pareto front. Recently, researchers have begun to examine how multi-agent environments can be used to help solve multi-objective optimization problems. In this work, we propose a multi-objective optimization algorithm based on a multi-agent blackboard system (MABS). The MABS framework allows for multiple agents to read and write pertinent optimization problem data to a central blackboard agent. Agents can stochastically search the design space, use previously discovered solutions to explore local optima, or update and prune the Pareto front. A centralized blackboard framework allows the optimization problem to be solved in a cohesive manner and permits stopping, restarting, or updating the optimization problem. The MABS framework is tested against three alternative optimization algorithms across a suite of engineering design problems and typically outperforms the other algorithms in discovering the Pareto front. A parallelizability study is performed where we find that the MABS is able to evaluate a set number of designs, which require an evaluation time ranging from 0 to 300 seconds, quicker than a traditional optimization algorithm: this fact becomes more apparent the longer it takes to evaluate a design. To provide context for the benefits provided by MABS, a real-world nuclear engineering design problem is examined. MABS is used to examine the placement of experiments in a nuclear reactor, where we are able to evaluate hundreds of configurations for experimental placement while maintaining a strict set of safety constraints.

"Demonstrate Capability of NEAMS Tools to Generate Reactor Kinetics Parameters for Pebble-Bed HTGRs Transient Modeling" David Reger, Paolo Balestra, Ryan Stewart, [2021] · DOI: 10.2172/1968285
"A survey of multi-objective optimization methods and their applications for nuclear scientists and engineers" Todd S. Palmer, Bryony DuPont, Ryan H. Stewart, [2021] Progress in Nuclear Energy · DOI: 10.1016/j.pnucene.2021.103830
"FRIDGe: Fast Reactor Input Deck Generator" Ryan Stewart, [2019] Journal of Open Source Software · DOI: 10.21105/joss.01486 · ISSN: 2475-9066
"Design of an in-pile experimental loop for fast test reactor conditions" [2018] Transactions of the American Nuclear Society · EID: 2-s2.0-85060868755
"Metallic fuel design space for sodium fast reactors" [2018] Transactions of the American Nuclear Society · EID: 2-s2.0-85060845133
"EBR-II Reactor Physics Benchmark Evaluation Report" Edward S Lum, Ryan Stewart, Bilguun Byambadorj, Quinton Beaulieu, , Chad L. Pope, , [2017] [] · DOI: 10.2172/1415120
"Fast spectrum reactor fuel assembly sensitivity analysis" Chad Pope, Emerald Ryan, Ryan Stewart, [2017] Annals of Nuclear Energy · DOI: 10.1016/j.anucene.2017.06.058 · EID: 2-s2.0-85027893641
Source: ORCID/CrossRef using DOI