ML22070A147
| ML22070A147 | |
| Person / Time | |
|---|---|
| Issue date: | 03/27/2022 |
| From: | James Chang, Segarra J, Jing Xing NRC/RES/DRA/HFRB |
| To: | |
| Xing, Jing - 301 415 2410 | |
| References | |
| Download: ML22070A147 (17) | |
Text
IDHEAS-ECA - An Integrated Human Event Analysis System for Event and Condition Assessment Jing Xing, Y. James Chang, Jonathan DeJesus Segarra, U.S. Nuclear Regulatory Commission Presented by Jing Xing to EHPG 2022 3-27-2022
Overview of IDHEAS-ECA What is IDHEAS-ECA?
A new method for all NRCs human reliability analysis (HRA) applications Has qualitative guidance for analyzing what can go wrong with operator actions and what may cause human errors Has a quantification model and software for calculating human error probabilities (HEPs)
HEP calculation is supported with many sources of human error data including those from nuclear power plant operator simulator training.
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HRA process Analyze scenario Operational narrative Scenario context Human failure events (HFEs)
Operational narrative Scenario context Human failure events (HFEs)
Human event in a PRA scenario Model human failure event Estimate human error probability (HEP)
Integrate to PRA Critical tasks in the HFE Cognitive failure modes (CFMs)
Performance influencing factors (PIFs)
Critical tasks in the HFE Cognitive failure modes (CFMs)
Performance influencing factors (PIFs)
HEP attributing to time availability HEP attributing to CFMs HEP attributing to time availability HEP attributing to CFMs Dependency between human failure events Uncertainties in the analysis Dependency between human failure events Uncertainties in the analysis 3
How IDHEAS models human failure events Five macrocognitive functions model failure of a human action or task; 20 PIFs model the context that challenges or facilitates human performance of an action.
Human actions /
tasks Event context 5 Macrocognitive functions human event 20 PIFs & Time adequacy PIF attributes 4
How IDHEAS models human failures Detection is noticing cues or gathering information in the work environment.
Understanding is the integration of pieces of information in the work environment with a persons mental model to make sense of the scenario or situation.
Decisionmaking is selecting strategies, planning, adapting plans, and making judgments on qualitative information or quantitative parameters.
Action execution is implementation of the decision or plan to make a change in some physical component or system.
Interteam coordination is various teams interacting and collaborating on tasks.
5 IDHEAS Cognition Model uses five macrocognitive functions to represent how a task is achieved.
Failure of each macrocognitive function is a cognitive failure mode (CFM);
IDHEAS-ECA has five CFMs representing failure of a task.
How IDHEAS models event context - PIF Structure 6
Environment and Situation System Personnel Task
- Accessibility/habitabi lity of workplace and travel paths
- Workplace visibility
- Workplace Noise 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
- Human system interface
- Equipment and tools
- Staffing
- Procedures, guidance, and instructions
- Training
- Team 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 Context
- Indicator is similar to others nearby.
- Indication is not salient
- Labels on controls are ambiguous
- Controls require nonintuitive maneuvering
- Procedure lacks details
- Procedure requires judgment
- Procedure is available, but does not fit the situation
- 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.
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Action Execution E1. Assess action plan and criteria E2. Develop or modify action scripts E3. Prepare or adapt infrastructure for action implementation E4. Initiate and execute action scripts E5. Verify and adjust execution outcomes Action Execution processors Action Execution cognitive mechanisms E.a. Physical movement and motor skills E.b. Mental model of the actions and the systems to be acted on E.c. Working memory E.d. Attention E.e. Vigilance E.f. Sensory feedback of motor movement E.g. Automaticity E.h. Action programming E.i. Executive control E.j. Error monitoring and correction E.k. Initiation of action execution E.l. Spatial precision or accuracy of action execution E.m. Timing precision of action execution E.n. Coordinate motor movement of action execution personnel Cognitive basis for failure of a macrocognitive function (example: action execution)
PIF attributes (e.g., )
Distraction /
disruption
Basis for HEP calculation: Effects of PIF attributes on CFMs 8
PIF Attribute D
U DM E
T MT0 No impact 1
1 1
1 1
MT1 Distraction by other on-going activities that demand attention Weak - 1.2 Moderate - 2 High - 2.8 1.1 1.1 Weak - 1.2 Moderate - 2 High - 2.8 Weak - 1.2 Moderate -
2 High - 2.8 MT2 Interruption taking away from the main task Weak - 1.1 Moderate - 2.8 Frequent or long - 4 Weak - 1.1 Moderate -
1.5 Frequent or long-1.7 Weak - 1.1 Moderate -
1.5 Frequent or long-1.7 Weak - 1.1 Moderate - 2.8 Frequent or long
- 4 Weak - 1.1 Moderate -
2.8 Frequent or long - 4 MT3 Concurrent visual detection and other tasks Low demanding -2 Moderate demanding
- 5 High demanding - 10 NA NA NA NA Demonstration: A portion of Table B-13 PIF Weights for Multitasking, Interruption, and Distraction (From IDHEAS-ECA report Appendix B)
HEP quantification model
Base HEPs 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 9
HEP is calculated through an equation Parameters of the equation were derived from human error data The calculation is performed with IDHEAS-ECA Software
HEP quantification model (cont.)
Base HEPs 10 IDHEAS PIF structure: three base PIFs and 17 modification PIFs Base PIFs:
1)
Information availability and reliability - the uncertainty in the input to brain information processing 2)
Scenario familiarity - The uncertainty in personnels mental representation of the input 3)
Task complexity - The task demands to cognitive resources
An example of IDHEAS-ECA application
- Declaration of Extended Loss of AC Power
Background:
US nuclear power plants implemented diverse and flexible mitigation strategies (FLEX) that would increase defense-in-depth for beyond-design-basis scenarios to address an extended loss of alternating current (ac) power (ELAP) and loss of normal access to the ultimate heat sink.
11 Station-black-out (SBO) event tree ELAP fault tree
An example of IDHEAS-ECA application (cont.)
- Declaration of Extended Loss of AC Power The HRA on Failure of declaring ELAP was performed in 2018 using IDHEAS-ECA.
Declare ELAP Implement FLEX strategies, e.g, use portable generators Station blackout Restore power Implement SBO procedures Yes No Analyze the scenario Operational narrative: A beyond-design-basis seismic event occurs and causes a station blackout. The power cannot be restored quickly. The plant needs to declare ELAP in order to use FLEX equipment.
Event context: Plants emergency operating procedures require restoring ac power. ELAP should be declared timely if ac power is not restored, but it is uncertain whether and when the power can be restored.
12 Task diagram and timeline Time 0 1hrs 4hrs 8hrs
13 Model the human failure event Critical task: Make the decision to declare ELAP Applicable CFMs: CFM3 - Failure of Decisionmaking Applicable PIFs:
Task complexity - Competing or conflict goals / strategies Information availability - Key information is uncertain and not timely Training - FLEX training is not in the Systematic Approach to Training Procedure/Guidance/Instructions - Instruction requires judgment.
Calculate HEP: HEP calculation was made for three cases:
Context HEP estimate Case 1: Definitive Wording Declare ELAP by one hour of SBO if power is not restored.
1.1E-3 to 2.7E-3 Case 2: Wording Requires Judgment Declare ELAP by one hour of SBO if power is not expected to be restored in four hours. Reliable information on diagnosing the diesel generator 1.1E-3 to 3E-2 Case 3: Wording Requires Judgement and Diagnosis is not Obvious Same instruction as Case 2 but diagnosing the diesel generator is uncertain 1.6E-2 to 1E-1 An example of IDHEAS-ECA application (cont.)
- Declaration of Extended Loss of AC Power
Discussion - IDHEAS method applicability IDHEAS method is constructed on a human cognition framework, independent of work domains and technologies The human error data supporting IDHEAS-ECA are generalized from studies of various domains and in various technologies IDHEAS method is applicable, but not limited, to all nuclear risk-informed applications, such as:
Nuclear power plant control room actions and ex-control room actions Nuclear facility operations Normal and emergency operations and severe / beyond-design-basis accidents Current IDHEAS-ECA has limited support of human error data on team and organizational factors 14
Discussion - IDHEAS method adaptability Flexible - Application-specific HRA methods can be developed from IDHEAS methodology Scalable - IDHEAS methodology provides different levels of details of cognitive failure modes (CFMs) and performance influencing factors (PIFs) to model human failure events Adaptable - PIF attributes can be split, merged, and modified to adapt to different work domains; new PIF attributes may be added to model specific features in emergent technologies 15
IDHEAS-ECA Software
- something good and free!
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Request IDHEAS-ECA Software to:
Sean Peters, sean.peters@nrc.gov James Chang, james.chang@nrc.gov 17 IDHEAS methodology documents are publicly available through NRC ADAMS accession numbers. Inquires to Jing Xing, jing.xing@nrc.gov o IDHEAS-G/NUREG-2198: ML21127A272 o IDHEAS-ECA/RIL-2020-02: ML20016A481 o IDHEAS-DEP/RIL-2021-14: ML21316A107 o IDHEAS-DATA (draft report): ML20238B982