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Digital Twin Verification for Advanced Reactor Remote Operations
Abstract
Advanced reactors, especially microreactors, must take advantage of remote monitoring and control strategies to reduce the commercial cost of deployment and operations costs to compete with existing electrical generators. A robust and flexible remote concept of operations must be developed to support diverse designs and use cases to ensure safe and reliable operations. This paper presents the unique aspects of remote operations as they contrast existing established operations to highlight issues that must be considered. A key element of the remote operations concept is the ability for a physically separated command and control center to maintain awareness of the reactor’s state and perform supervisory control on the reactor. A digital twin implementation is proposed to serve as a verification system, to provide the remote operations center with verified reactor state information and to provide the remotely situated reactor with verified operation center commands. This approach augments existing communication infrastructure to support operators as they assess the validity of the information they are receiving and confidence that the commands they issue can be executed at the remote reactor.
While there has been a recent growth of interest in the Digital Twin, a variety of definitions employed across industry and academia remain. There is a need to consolidate research such to maintain a common understanding of the topic and ensure future research efforts are to be based on solid foundations. Through a systematic literature review and a thematic analysis of 92 Digital Twin publications from the last ten years, this paper provides a characterisation of the Digital Twin, identification of gaps in knowledge, and required areas of future research. In characterising the Digital Twin, the state of the concept, key terminology, and associated processes are identified, discussed, and consolidated to produce 13 characteristics (Physical Entity/Twin; Virtual Entity/Twin; Physical Environment; Virtual Environment; State; Realisation; Metrology; Twinning; Twinning Rate; Physical-to-Virtual Connection/Twinning; Virtual-to-Physical Connection/Twinning; Physical Processes; and Virtual Processes) and a complete framework of the Digital Twin and its process of operation. Following this characterisation, seven knowledge gaps and topics for future research focus are identified: Perceived Benefits; Digital Twin across the Product Life-Cycle; Use-Cases; Technical Implementations; Levels of Fidelity; Data Ownership; and Integration between Virtual Entities; each of which are required to realise the Digital Twin.
This paper presents results from three experiments in which human operators were teamed with a mixed-initiative robot control system to accomplish various indoor search and exploration tasks. By assessing human workload and error together with overall performance, these experiments provide an objective means to contrast different modes of robot autonomy and to evaluate both the usability of the interface and the effectiveness of autonomous robot behavior. The first experiment compares the performance achieved when the robot takes initiative to support human driving with the opposite case when the human takes initiative to support autonomous robot driving. The utility of robot autonomy is shown through achievement of better performance when the robot is in the driver's seat. The second experiment introduces a virtual three-dimensional (3-D) map representation that supports collaborative understanding of the task and environment. When used in place of video, the 3-D map reduced operator workload and navigational error. By lowering bandwidth requirements, use of the virtual 3-D interface enables long-range, nonline-of-sight communication. Results from the third experiment extend the findings of experiment 1 by showing that collaborative control can increase performance and reduce error even when the complexity of the environment is increased and workload is distributed amongst multiple operators.
From within the umbrella of the Simplified Human Error Experimental Program (SHEEP) framework, this paper analyzes human performance differences between professional and student operators when using a simplified simulator (i.e., Rancor Microworld). This paper represents a crucial step in understanding the fidelity of the simplified simulators and student operators within the SHEEP study. This paper explores a randomized factorial experimental design that features two independent variables: participant type and event class. Six human performance measurements are considered in the experiment. The experiment is conducted using 20 professional reactor operators employed at actual nuclear power plants (NPPs), along with 20 trained students. The experimental data are analyzed via statistical analysis methods. Lastly, this paper examines the differences in human performance between actual operators and students when using Rancor Microworld.
To help address the low-carbon energy challenge, fission batteries could serve a wide variety of markets requiring heat, electricity, or other energy products. Fission batteries would be manufactured in a factory, delivered to the user, and returned to the factory for refurbishment and refueling. Fission battery developers face important tradeoffs between standardization, which is necessary to achieve cost competitiveness through large-scale manufacturing, and customization, which is necessary to meet the various needs of specific markets. Economics-by-design provides a comprehensive and systematic framework for assessing market requirements and adapting fission battery designs for the optimal balance of standardization and customization. The target cost range for fission batteries is $6–15/million BTU. The market review identified existing U.S. markets (primarily petroleum refining, chemicals, paper and pulp, food processing, and biofuels), and the large maritime market to decarbonize global shipping and offshore platforms. Decarbonization of the U.S. economy could increase the FB market by more than an order of magnitude for applications ranging from large-scale biofuels to powering office and industrial parks. High-volume markets have low market entry prices because of competition from other low-carbon alternatives. Remote sites and military applications would allow for higher fission battery costs, but these potential markets are smaller (dozens of units). The market review highlights how no single market is attractive for fission batteries from the standpoint of all metrics considered: market sizing, profitability prospects, operational requirements, and nuclear-specific requirements. As such, fission battery developers following the economics-by-design approach would likely need to rely on a base design satisfying constraints for most markets, then customize a limited set of parameters in order to cater to a larger variety of markets while still leveraging benefits from standardization.
This case study describes the development of technologies that enable digital-engineering and digital-twinning efforts in proliferation detection. The project presents a state-of-the-art approach to supporting IAEA safeguards by incorporating diversion-pathway analysis, facility misuse, and detection of indicators within the reactor core, applying the safeguards-by-design concept, and demonstrates its applicability as a sensitive monitoring system for advanced reactors and power plants. There are two pathways a proliferating state might take using the reactor core. One is “diversion,” where special fissionable nuclear material—i.e., Pu-239, U-233, U enriched in U-233/235—that has been declared to the International Atomic Energy Agency (IAEA) is removed surreptitiously, either by taking small amounts of nuclear material over a long time (known as protracted diversion) or large amounts in a short time (known as abrupt diversion). The second pathway is “misuse,” where undeclared source material—material that can be transmuted into special fissionable nuclear material: depleted uranium, natural uranium, and thorium—is placed in the core, where it uses the neutron flux for transmutation. Digital twinning and digital engineering have demonstrated significant performance improvement and schedule reduction in the aerospace, automotive, and construction industries. This integrated modeling approach has not been fully applied to nuclear safeguards programs in the past. Digital twinning, combined with machine learning technologies, can lead to new innovations in process-monitoring detection, specifically in event classification, real-time notification, and data tampering. It represents a technological leap in evaluation and detection capability to safeguard any nuclear facility.
Global Market Analysis of Microreactors (No. INL/EXT-21-63214-Rev000)
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Rancor: a gamified microworld nuclear power plant simulation for engineering psychology research and process control applications
- T A Ulrich
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- R L Boring
Ulrich, T. A., Lew, R., Werner, S., & Boring, R. L. (2017, September). Rancor: a
gamified microworld nuclear power plant simulation for engineering psychology
research and process control applications. Proceedings of the Human Factors and
Ergonomics Society Annual Meeting, 61, 398-402.
An evaluation of nuclear power plant safety parameter display systems
- D D Woods
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- L F Hanes
Woods, D. D., Wise, J. A., & Hanes, L. F. (1981, October). An evaluation of nuclear
power plant safety parameter display systems. Proceedings of the Human Factors
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