ML20267A197
| ML20267A197 | |
| Person / Time | |
|---|---|
| Issue date: | 09/23/2020 |
| From: | Dejesus J Office of Nuclear Regulatory Research |
| To: | |
| Sean Peters, Carmen Franklin | |
| Shared Package | |
| ML20267A193 | List: |
| References | |
| Download: ML20267A197 (15) | |
Text
The General Methodology of an Integrated Human Event Analysis System (IDHEAS-G)
Jonathan DeJesus Presentation to the Advisory Committee on Reactor Safeguards Reliability and PRA Subcommittee September 23, 2020
Acronyms and Terms ACRS Advisory Committee on Reactor Safeguards CFM cognitive failure mode CT critical task HEP human error probability HFE human failure event HRA human reliability analysis HSI human-system interface IDHEAS Integrated Human Event Analysis System IDHEAS-DATA Integrated Human Event Analysis System for Human Reliability Data IDHEAS-ECA Integrated Human Event Analysis System for Event and Condition Assessment IDHEAS-G General Methodology of an Integrated Human Event Analysis System IHA important human action I&C instrumentation and control NRC U.S. Nuclear Regulatory Commission PIF performance-influencing factor (same as performance-sharing factor (PSF))
PRA probabilistic risk assessment PZR pressurizer RHR residual heat removal (system)
SACADA Scenario Authoring, Characterization, and Debriefing Application SI safety injection TS Technical Specification
error probability attributed to the CFMs of all CTs of an IHA
error probability attributed to the uncertainties in and
time available
time required 2
3 IDHEAS General Methodology (IDHEAS-G)
IDHEAS-ECA (RIL-2020-02)
Literature and human factors practices Cognitive basis framework (NUREG-2114)
IDHEAS Internal Events At-Power Application (NUREG-2199, Vol. 1)
HRA applications HRA applications Operational experience Existing HRA methods IDHEAS-DATA Scientific literature HRA applications HRA applications SACADA and other data sources SACADA and other data sources
Overview of IDHEAS-G 4
Stage 2 Modeling of important human actions Stage 3 HEP quantification Stage 1 Scenario analysis Stage 4 Integrative analysis Cognition Model Cognition Model Cognitive Basis Structure PIF Structure Cognitive Basis Structure PIF Structure Human error data
Cognitive Basis Structure 5
Human action Task 1 and cognitive activities Task 2 and cognitive activities Task 3 and cognitive activities Detection Under-standing Decision-making Action execution Interteam coordination
Cognitive Basis StructureFailure of Human Actions
- Failure of any macrocognitive function leads to the failure of the task and the human action.
- Failure of a macrocognitive function results from errors of one or more processors.
- Errors of a processor may occur if one or more associated cognitive mechanisms do not work properly or reliably.
- PIFs affect the capacity limits of the cognitive mechanisms.
6 Macrocognitive functions Processors Cognitive mechanisms PIFs
PIF Structure 7
Environment and Situation System Personnel Task
- Accessibility/habitability of workplace including travel paths
- Workplace visibility
- Noise in workplace and communication pathways
- Cold/heat/humidity
- Resistance to physical movement
- Poor lighting in workplace
- Glare or reflection on physical structure
- Smoke or fog-induced low visibility
- System and I&C transparency to personnel
- HSI
- Equipment and tools
- Staffing
- Procedures, guidance, and instructions
- Training
- Teamwork and organizational factors
- Work processes
- Information availability and reliability
- Scenario familiarity
- Multitasking, interruptions, and distractions
- Task complexity
- Mental fatigue
- Time pressure and stress
- Physical demands PIF PIF attributes Links to cognitive mechanisms Context
- Tools are difficult to use
- Tools are unfamiliar to personnel
- Tools do not work
- Tools or parts are unavailable
- Document nomenclature does not agree with equipment labels
- Procedure is inadequate
- Procedure is difficult to use
- Procedure is available, but does not fit the situation See Section 3.4 and Appendix B
- Sustained high-demand cognitive activities
- Long working hours
- Sleep deprivation Note: The PIF attributes shown are examples and correspond to the PIFs highlighted in red.
IDHEAS-G HRA Process 8
IHAs Critical tasks Scenarios Macro-cognitive functions and CFMs IHA 1 HEP Critical task 2 Critical task 3 HEP Scenarios Stage 1: Scenario analysis
- Develop operational narrative
- Identify scenario context
- Identify important human actions
Stage 3 - HEP quantification
- Estimation of
- Estimation of Stage 4 - Integrative analysis
- Document uncertainties
- Assess dependencies Stage 2: Modeling of important human actions
- Identify and analyze critical tasks
- Identify applicable CFMs
- Assess PIFs CFM1 CFM2 CFM3 CFM4 HEPs due to CFMs HEP due to time uncertainty Dependency adjustment PIF1 PIF2 PIF3 PIF4 Uncertainty analysis IHA 2 IHA 3 Critical task 1 Understanding Detection Decisionmaking Action execution Teamwork CFMs CFMs CFMs CFMs CFMs
HEP QuantificationOverview 9
CFM 1 Critical task 1 CFM 2 CFM 4 PIF attributes PIF attributes Critical task 2 Critical task 3
Time available HEP of an IHA HEP of an IHA
HEP QuantificationPc
- HEP quantification model
10 HEP from Base PIFs PIF weight factors from Modification PIFs PIF interaction factor; set to 1 with linear combination Recovery factor; set to 1 unless data suggest otherwise
error rate at a given PIF attribute error rate when the PIF attribute has no or low impact
HEP QuantificationPt
- In response to ACRS comments, time uncertainty model was developed
- Convolution of time available and time required distributions
- Pt is proportional to this area 11 0
0.05 0.1 0.15 0.2 0.25 10 15 20 25 30 35 40 probability density time (minutes)
Time Required Time Available
IDHEAS-G Changes Since Last Meeting with ACRS Subcommittee
- Addressed ACRS (and public) comments
- Clarified distinction between interteam and intrateam CFMs and PIFs
- Added language so that reader can go to Chapter 4 (HRA Process) without reading Chapters 2 (Cognitive Basis Structure) and 3 (PIF Structure)
- Added PIF attribute in PIFs Staffing and Physical demands to address personnel safety considerations
- Each PIF has its own description table in Chapter 3
- Added list of reviewers in Acknowledgments
- Addressed concern with the use of et al. in References
- Many other editorial changes
- Proposed a dependency model (encouraged by ACRS comments) - Appendix K 12
IDHEAS-G Dependency Context Categories Consequential dependency
- Millstone Unit 3 (ML051860338), spurious alarms triggered an SI signal.
Operator failed to control SI flow that resulted in a water-solid PZR. That, in turn, increased workload and delayed the subsequent operator actions.
Resource-sharing dependency
- Palo Verde (ML042220267), simultaneously perform a boron injection system testing and an atmospheric dump valve test that should be performed in sequence. The prior testing limited the charging flow and the latter testing increased letdown flow that caused high regenerative heat exchanger temperature and a pressurizer level transient above TS limits, and resulted in a loss of letdown event.
Cognitive dependency
- Catawba Unit 1 (1990), forgot to reopen sensing lines of three pressure sensors after maintenance work resulted in RHR over-pressurization.
13
IDHEAS-G Dependency Model: Process 14
- 1. Identify the dependency context Consequential dependency Resource-sharing dependency Cognitive dependency Cut set with multiple HFEs (HFE1, HFE2)
- 2. Model the dependency context HFE2lHFE1 Are there changes to HFE2s:
Definition? Time required and time available?
Feasibility?
CFMs?
Critical tasks? PIF attributes?
HFE1 and HFE2 are independent P(HFE1,HFE2)=
P(HFE1)*P(HFE2)
- 3. Calculate P(HFE2lHFE1) based on context changes to HFE2 and using same method as individual HFEs Any yes?
HFE2lHFE1 means the occurrence of event HFE2 given the occurrence of event HFE1, where HFE1 is the first event and HFE2 is the second event.
All no Yes P(HFE1,HFE2) =
P(HFE1)*P(HFE2lHFE1)
IDHEAS-G Dependency Model: Illustration 15 Context of HFE1 HFE1 S
S Success Failure [P(HFE1)]
HFE2 Success Failure [P(HFE2)]
F [P(HFE1)*P(HFE2)]
Context of HFE2 Context of HFE1 HFE1 S
S Success Failure [P(HFE1)]
HFE2 Success Failure [P(HFE2lHFE1)] F [P(HFE1)*P(HFE2lHFE1)]
Dependent Context of HFE2 S = success F = failure