ML25175A105
| ML25175A105 | |
| Person / Time | |
|---|---|
| Issue date: | 06/23/2025 |
| From: | Niav Hughes, Stephanie Morrow, Jing Xing NRC/RES/DRA, NRC/RES/DRA/HFRB |
| To: | |
| References | |
| Download: ML25175A105 (1) | |
Text
Revisiting Functional Requirements Analysis and Function Allocation to Support Automation Decisions in Advanced Reactor Designs Stephanie Morrow, Jing Xing, & Niav Hughes Green
About Me 2
- Ph.D. in Industrial/Organizational Psychology, University of Connecticut
- 14 years with the U.S. Nuclear Regulatory Commission
- Manage research projects and develop guidance and training on human and organizational factors that impact nuclear safety Human Factors and Reliability Branch Division of Risk Analysis Office of Nuclear Regulatory Research U.S. Nuclear Regulatory Commission stephanie.morrow@nrc.gov https://www.linkedin.com/in/stephaniemorrow Dr. Stephanie Morrow Human Factors Psychologist
- Co-authors Dr. Jing Xing & Dr. Niav Hughes Green
- Contributions and reviews by Jesse Seymour, Dr. Brian Green, Dr. David Desaulniers, Stephen Fleger, and Dr. John OHara Acknowledgements 3
Disclaimer The views expressed in this presentation are those of the presenters and do not necessarily represent an official position of the U.S. Nuclear Regulatory Commission (NRC). This presentation material is declared as a work of the U.S. Government and is not subject to copyright protection in the United States.
Outline 5
- Basis for Functional Requirements Analysis (FRA) and Function Allocation (FA) in nuclear regulation and guidance
- Challenges with applying FRA and FA in practice
- Considerations for modernizing FRA and FA approaches
NUREG-0711, Human Factors Engineering Program Review Model 6
Used by the NRC to review the HFE programs of applicants for construction permits, operating licenses, standard design certifications, combined operating license, and license amendments.
Function Analysis and Allocation Put Simply Decide What Needs to Be Done Functional Requirements Analysis (FRA)
Decide Who is Doing It Function Allocation (FA)
Humans (Personnel)
System (Automation)
§ 53.730 Defining, fulfilling, and maintaining the role of personnel in ensuring safe operations.
(d) Functional requirements analysis and function allocation. A functional requirements analysis and a function allocation must be provided that are sufficient to demonstrate compliance with the following:
(1) The functional requirements analysis must address how safety functions and functional safety criteria are satisfied, and (2) The function allocation must describe how the safety functions will be assigned to human action, automation, active safety features, passive safety features, and/or inherent safety characteristics.
Draft 10 CFR Part 53.730 requires FRA and FA 8
FRA/FA Review Criteria (from NUREG-0711) 9 Scope 1.
Use structured, documented methodology reflecting HFE principles 2.
Perform iteratively and keep current FRA 3.
Describe plants functional hierarchy 4.
Identify requirements for high-level functions
- Purpose of function and conditions indicating it is needed
- Parameters indicating it is available, operating, achieving its purpose
- Parameters indicating that it can or should be terminated FA 5.
Allocate functions and identify basis for allocations 6.
Consider secondary or back-up responsibilities of personnel (e.g., monitoring automation, detect degradations and failures, assume manual control) 7.
Describe the overall role of personnel Verification &
Validation (V&V) 8.
Verify that FRA and FA accomplish objectives:
- All functions needed to achieve safe operation are identified
- Allocations take advantage of human and machine strengths and avoid human and machine limitations
Allocations take advantage of human and machine strengths and avoid human and machine limitations 10 This Photo by Unknown Author is licensed under CC BY
- 1. Allocation decisions are rarely binary
- 2. Advanced technologies increase the integration of human and automatic systems
- 3. Automation can increase cognitive distance between personnel and plant systems
- 4. Allocations can create mismatches between authority and responsibility Challenges with Applying FRA and FA in Practice 11 This Photo by Unknown Author is licensed under CC BY-NC-ND
- 5. Functions may involve passive safety features and inherent safety characteristics
- 6. Important human actions may be outside the control room
- 7. Limited risk information may be available for new designs
- 8. Validation is difficult in early design stages Challenges with Applying FRA and FA in Practice 12
Considerations for Modernizing FRA and FA Approaches 13 Is there a standard methodology and process for iteration and reexamination of functional requirements and allocation decisions that reflects state-of-the-art HFE principles?
Are all functions needed to achieve safety goals identified, including those performed by passive safety features or inherent safety characteristics?
Do allocations consider interactions and interdependencies between humans, automatic systems, passive safety features, and inherent safety characteristics?
Does the validation consider factors that can challenge human and automation performance under a range of scenarios?
Function Analysis and Allocation Put Simply Decide What Needs to Be Done Functional Requirements Analysis (FRA)
Decide Who is Doing It Function Allocation (FA)
Humans (Personnel)
System (Automation) and How it will be done under different conditions Passive Safety Features and Inherent Safety Characteristics to accomplish safety goals
/What
- Modern approaches to FRA and FA are needed to address novel design features, interdependencies between humans and automation, and their collective safety implications.
- A clear understanding of FRA and FA in advanced reactor designs supports NRC reviewers in making appropriate, efficient, and risk-informed regulatory decisions.
- NRC has ongoing research to support guidance on FRA and FA for advanced reactors.
Summary 15 This Photo by Unknown Author is licensed under CC BY-SA-NC
16 This Photo by Unknown Author is licensed under CC BY-NC-ND
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Nuclear Regulatory Commission (NRC), Risk-Informed, Technology-Inclusive Regulatory Framework for Advanced Reactors
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References 17