ML25071A221
| ML25071A221 | |
| Person / Time | |
|---|---|
| Issue date: | 03/14/2025 |
| From: | Robert Kuntz NRC/NRR/DORL/LPL3 |
| To: | |
| References | |
| Download: ML25071A221 (1) | |
Text
1 March 13-14, 2025 NRC Headquarters Rockville, MD Digital I&C Workshop on Lessons Learned from the Implementation of DI&C-ISG-06
Overview
- Human Factors Engineering (HFE) Reviews
- DI&C-ISG- 06
- Regulatory Basis and Guidance Documents
- Pre-application Activities
- HFE Technical Review: Challenges & Positive Observations
- Submittal Contents
- Scheduling
- Audit Activities
- Validation Testing 2
HFE Reviews
- Topics for Review:
- Impact of the proposed changes on the control room design including any changes to layout
- Impact of proposed changes to manual operator actions significant to safety
- Incorporation of HFE principles into:
- the development of updated Human System Interfaces (HSI) and
- the planned implementation of the proposed changes 3
HFE Reviews
- HFE review activities consists of:
- Evaluating the incorporation of HFE principles by reviewing elements of the licensees analyses including but not limited to -
- operating experience
- tasks analysis
- functional requirements analysis & function allocation
- verification & validation of HSI design
- Observing the proposed changes to the control room design and relevant manual operator actions in a testbed* to evaluate validation testing 4
- A testbed is the HSI representation used to perform validation evaluations. This can be accomplished with a compliant simulator per ANS guidance or a high-fidelity version of the facility simulator (e.g., a glass-top simulator)
DI&C-ISG-06 5
- 1. Tier 1, 2,and 3 Review Process (Use of topical reports)
- 2. The Alternate Review Process (ARP)
- Topical Reports for a DI&C platforms may or may not include HFE Considerations
- The ARP was originally developed for projects without human factors engineering impacts.
DI&C-ISG-06 6
- Page 4 of ISG-06, Section B.1.4 Review Areas Outside the Scope of this Interim Staff Guidance states the following:
A proposed modification described in an LAR will necessitate the review of all information to make a safety determination using the review criteria found in the Standard Review Plan (SRP) for all relevant review areas.
For example, some DI&C equipment modifications may involve human factors engineering (HFE) considerations (e.g., HFE analyses and design processes). In these cases, an HFE safety evaluation should be performed in accordance with appropriate guidance.
Regulatory Basis and Guidance 7
- Regulations for Evaluating HFE Considerations
- 10 CFR Part 50 Appendix A, General Design Criteria for Nuclear Power Plants, Criterion 19, Control room (GDC 19)
- Post-TMI Requirements (as described in NUREG-0737 and subsequent clarifications including GL 82-33)
Regulatory Basis and Guidance 8
- Obligations dependent upon when the initial licenses, construction permits, or early site permits were issued
- Plants licensed before the TMI accident received post-TMI orders
- Plants licensed after the TMI accident must comply with 10 CFR 50.34(f)(2)(iii)
- Applicable Guidance
- SRP Chapter 18, Human Factors Engineering
- NUREG-0711, Human Factors Engineering Program Review Model with applicable linkages to NUREG 0700 Human-System Interface Design Review Guidelines
- NUREG-1764, Guidance for the Review of Changes to Human Actions,
Regulatory Basis and Guidance 9
- Submittals should be written and organized such that there is a clear demonstration of the processes and methods used to comply with the requirements regarding control room design Licenses issued prior to TMI orders were bound by legacy guidance revisions and initial responses to the orders regarding control room design review. However, to address digital modifications, licensees can choose to use modern revisions of NRC guidance documents which are better suited than legacy guidance developed in the 1980s In assessing compliance of the proposed changes, a comparison of current technologies and practices that span multiple decades may be necessary, which increases the complexity of an HFE review Describing changes to the control room design at a comparable scope and level of detail as described in the original operating license application helps mitigate the complexity
Pre-application activities 10
- Licensee presentations Familiarize NRC staff with the proposed changes by providing a general overview of the changes that require an HFE technical review Introduce validation approaches and the associated placement within the schedule Communicate regarding compliance path for topical reports and select safety related systems Provide preview of proposed schedule and status of HFE activities before submitting LAR
- Initial meetings Facilitate an opportunity for staff to provide initial observations and clarifying questions for licensees to consider when determining the contents of the submittal
HFE Technical Review:
Challenges & Positive Observations 11
- Due to the comprehensive nature of modernization project,
it is difficult to identify every possible challenge early in the review, thus an extended audit period is helpful
- The HFE review for extensive digital I&C upgrades requires review of control room design elements and changes to operator actions important to safety
HFE Technical Review:
Challenges & Positive Observations 12
- Organization of submittal contents has a substantial effect on the efficiency of the review
- An approach that balances providing comprehensive information in the submittal with organizing the information in a way that is easily navigated supports an efficient review process
- If referencing multiple layered documents in the initial submittal is necessary, clarify how they demonstrate compliance by providing additional detail as necessary
- The incorporation of non-docketed information into submittals to demonstrate regulatory compliance decreases the efficiency of the review
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- Scheduling
- Licensees providing a realistic timeline as early as possible assists NRC staff in accurately developing the review timeframe
- Periodic updates the status of HFE design development is of great value
- NRC staff can identify possible scheduling challenges regarding the review of integrated system validation (ISV) testing and proposed timelines when provided a timeline early
- If ISV scheduling challenges arise there are potential alternatives to having completed ISV test results available prior to issuance of a licensing amendment:
Early-stage results from a multi-stage validation (MSV) test program Alternative testbeds for the completion of ISV testing HFE Technical Review:
Challenges & Positive Observations
HFE Technical Review:
Challenges & Positive Observations 14
- Audit Activities
-Exchange of clarifying information easily facilitated via portal
-Referenced documents provided
-Validation testing approaches demonstrated
-Virtual showings & in person visits to observe glass-top simulator
- Visual comparison available for proposed vs existing HSI for familiarization however the virtual option limits what staff can observe and evaluate
- Provide opportunity to ensure that the glass-top simulator is fit for HFE validation testing and will not negatively impact the quality of testing
HFE Technical Review:
Challenges & Positive Observations 15 While there is value in the virtual observation for visualizing the before and after effect of the proposed changes, the staff determined there is more value in an in-person interaction with the current control room design before observing proposed changes via testbed.
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- Alternatives to full-scope, high-fidelity simulators as validation testbeds may be acceptable, depending on:
- the stage of validation being credited
- nature of the control room modification
- capabilities of the simulator
- If the credited validation testing will not be performed on a traditional full-scope, high-fidelity plant-referenced simulator, justification should be provided as to why the alternative testbed being used is adequate.
The NRC staff identified one solution to the challenge presented with the scheduling issue which may arise under the ARP: Multi-Stage Validation (MSV)
This HFE technical review approach that relies on an applicants early-stage testing results from a MSV program (in addition to other design activities and supporting analyses) as a basis for making the safety determination and approving proposed design changes.
To be considered as providing sufficient basis for the NRCs safety determination, early-stage MSV testing should provide reasonable assurance that the eventual ISV testing will be successful. Testing, Validation and verification activities should not be postponed in the process HFE Technical Review:
Challenges & Positive Observations 17
The NRC staff identified one solution to the challenge presented with the scheduling issue which may arise under the ARP: Multi-Stage Validation (MSV)
This HFE technical review approach that relies on an applicants early-stage testing results from a MSV program (in addition to other design activities and supporting analyses) as a basis for making the safety determination and approving proposed design changes.
To be considered as providing sufficient basis for the NRCs safety determination, early-stage MSV testing should provide reasonable assurance that the eventual ISV testing will be successful. Testing, Validation and verification activities should not be postponed in the process HFE Technical Review:
Challenges & Positive Observations 18
HFE Technical Review:
Challenges & Positive Observations 19
- In -person audits activities allows staff to:
- examine the validation approach in the design phase as described in the submittal
- gain up close understanding of the limits and functionality of the testbed used to complete the preliminary validation process
- observe a demonstration of scenarios used for the preliminary validation while being provided detailed guides for each scenario
- identify any information that may require docketing to support staffs regulatory finding
HFE Technical Review:
Challenges & Positive Observations 20 Preliminary Validation Workshop - Limerick Generating Station Instrumental in HFE technical review
- NRC staff engaged in discussions regarding the proposed changes and the iterative process used to develop the HSI design changes to the control room
- NRC staff observed the limitations of the testbed during the workshop including which systems were/were not fully functioning, what isnt included in the proposed design changes, and what was planned to be operational during the performance of the ISV
HFE Technical Review:
Challenges & Positive Observations 21 Preliminary Validation Workshop - Limerick Generating Station Via testbed
- NRC staff observed the proposed control room changes including functioning modifications to the annunciators alongside heads-up display screens which mimic the current (unchanging) annunciators
- NRC staff observed the spatial elements of control room changes
- NRC staff observe validation techniques during the workshop which are consistent with the submitted HFE Program Plan
Closing Thoughts 22
- Challenges
- Scheduling of validation activities
- Comprehensive nature of major digital I&C upgrades presents a challenge in finding issues early in the process due to the volume of information
- Navigating through a high volume of information that lacked clear organization
- Observations
- In-person activities are important to an efficient review process for both familiarization of current design and proposed changes and observation of validation activities
- Free flowing exchange of information during audit period supports an efficient review
- HFE not considered in ISG-06
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