Digital Twins

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What is a Digital Twin?

A digital twin (DT), as part of a DT system, is a virtual representation of an entity, process, or system, synchronized at a frequency and fidelity sufficient to maintain state concurrence.  A DT leverages various types of models, data, and frameworks to produce knowledge/insights about the represented entity, process, or system to fulfill an intended purpose.

As a first step in understanding the nuclear DT problem space, the project team engaged extensively with stakeholders and experts in DT-enabling technologies to develop a description of a DT system for nuclear power plant (NPP) applications. An NPP DT system broadly comprises four elements: (1) NPP, (2) DT, (3) data and NPP response flowing from NPP to DT, and (4) actions and recommendations flowing from DT to NPP. As information flows from the NPP, i.e., the physical plant to the DT, that information is processed and analyzed through various methods (e.g., data analytics and data-informed models), and then ultimately returned to the NPP in useful forms such as diagnostics, visualizations, O&M recommendations, and control signals.

This video, which was featured in the NRC's 2022 Regulatory Information Conference, presents an overview of the digital twin concept and introduces the NRC’s future-focused research project on digital twins.

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DT Characteristics and Capabilities

The NRC's DT project team indentified fundamental DT capabilities and characteristics to provide context for understanding DT applications and help inform stakeholders on potential DT use and impact on regulated activities.

A nuclear DT system includes four foundational characteristics:

  • Serves a Nuclear Purpose: must have an purpose related to an NPP lifecycle activity,

  • Exists in Digital Form: must exist in a digital form that can be managed, processed, and executed on a digital device,

  • Maintains State Concurrence: must be capable of updating dynamically to represent the current state of an entity, process or system, and must continuously maintain accurate that state representation, and

  • Ensures State Cognizance: must have the capability to provide novel and integrated insights, information, and outcomes related to the represented entity, process, or system that were not possible, feasible, or efficient prior to implementing the DT.

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Across various industrial applications, DT holds promise for significant enhancement in several capabilities. Recognized for their potential to significantly impact regulated activities, these capabilities are broadly classified as: (1) information, (2) communication, (3) analysis, (4) integration, and (5) control. These capabilities are summarized below.

  • Information: Provides new and improved plant information that is trusted, timely, on-demand, correct, and complete enabled by state concurrence and state cognizance

  • Communication: Propagates information among the various DT-enabling technologies and among nuclear DT stakeholders to facilitate deeper insights and new cognizance of plant states

  • Integration: Establishes a centralized hub and enabler for the integration of a variety of data, information, models, and analytics to address the underlying DT purpose in a reliable and accurate manner

  • Analysis: Leverages advanced analytical products and tools to produce, process, and represent information about a plant’s current, past, and future states, as well as provide insights to support decision making and risk assessments

  • Control: Combines classical and novel framworks that leverage advance technoliges such as ML/AI, state prediction, advanced and virtual sensors multiple real-time input and output systems to enable operations that are adaptive, optimal, robust, and autonomous

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What research is the NRC doing related to Digital Twins?

The NRC recently completed a future-focused research project aimed at assessing the regulatory viability of DTs for NPPs. This project was led by Idaho National Laboratory (INL) in collaboration with Oak Ridge National Laboratory (ORNL). The objectives of this project were to:

Understand the current state of DT technology and potential applications for the nuclear industry

  • Identify and evaluate technical issues that could benefit from regulatory guidance
  • Identify and investigate potential regulatory methodologies, infrastructures, and guidance for DTs in nuclear applications

As part of the future-focused research project, the team of researchers and experts across INL, ORNL, and the NRC conducted the following key activities over the course of 18 months:

  • Organized two virtual workshops on DT applications and enabling technologies for advanced reactors and plant modernization; the two workshops together featured more than 75 presenters and more than 700 attendees from across the globe and provided a forum for nuclear industry and DT stakeholders to discuss the state of knowledge and research activities related to DTs and their applications in the nuclear industry
  • Assessed the spectrum of DT technologies and identified current efforts in the nuclear industry focused on specific DT-enabling technologies
  • Compiled a set of challenges and gaps for implementing DT-enabling technologies in current and advanced reactor applications
  • Hosted an NRC observation public meeting to solicit input from the industry and the public on DT regulatory considerations and opportunities
  • Reviewed NRC-regulated activities that may be impacted by DT-enabling technologies and identified activities meriting special considerations and potential opportunities for the application of DT technology

While the future-focused research project has concluded, the NRC staff is actively pursuing further DT research activities such as the application of advanced sensors for monitoring system performance and integration of safeguards and security. The NRC staff is also considering future research in the assessment of standards and digital communication technologies. Based on nuclear stakeholder interest and activity, the NRC staff will continue to evaluate further industry DT efforts and their regulatory implications, including assessment of potential regulatory frameworks and guidance relevant to DT development and implementation.

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NRC Reports on Digital Twins

Report Type Report Title Report Date

Technical Letter Report

TLR-RES/DE/REB-2021-01 "The State of Technology of Application of Digital Twins"

June 2021

TLR-RES/DE/REB-2021-17 "Technical Challenges and Gaps in Digital-Twin-Enabling Technologies for Nuclear Reactor Application"

December 2021

TLR-RES/DE/REB-2022-06 "Regulatory Considerations for Nuclear Energy Applications of Digital Twin Technologies"

August 2022

TLR-RES/DE/REB-2022-07 "Project Summary of Digital Twin Regulatory Viability in Nuclear Energy Applications"

August 2022

TLR-RES/DE/REB-2023-02 "State of Technology and Technical Challenges in Advanced Sensors, Instrumentation, and Communication to Support Digital Twin for Nuclear Energy Application"

February 2023

   TLR-RES/DE/REB-2023-08 “Digital Twins for Nuclear Safeguards and Security: Assessment of Challenges, Opportunities, and Current State-of-Practice”
    September 2023

Research Information Letter

RIL 2021-02 "Proceedings of the Workshop on Digital Twin Applications for Advanced Nuclear Technologies"

March 2021

RIL 2021-16 "Proceedings of the Workshop on Enabling Technologies for Digital Twin Applications for Advanced Reactors and Plant Modernization"

December 2021

Public Meeting Summary

"Summary of the Observation Public Meeting on Regulatory Considerations and Opportunities for Digital Twins in Nuclear Reactor Applications"

March 2022

Advisory Committee on Reactor Safeguards (ACRS) Briefing

Digital Twins Information Briefing - Official Transcript of Proceedings (pp. 75-220)

May 2022

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