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 NRC U.S. Nuclear Regulatory Commission Safeguards PIF performance-influencing factor (same as CFM cognitive failure mode performance-sharing factor (PSF))
CT critical task PRA probabilistic risk assessment HEP human error probability PZR pressurizer HFE human failure event RHR residual heat removal (system)
HRA human reliability analysis SACADA Scenario Authoring, Characterization, HSI human-system interface and Debriefing Application IDHEAS Integrated Human Event Analysis System SI safety injection IDHEAS-DATA Integrated Human Event Analysis TS Technical Specification System for Human Reliability Data error probability attributed to the CFMs IDHEAS-ECA Integrated Human Event Analysis System of all CTs of an IHA for Event and Condition Assessment error probability attributed to the IDHEAS-G General Methodology of an Integrated uncertainties in and Human Event Analysis System time available IHA important human action time require d I&C instrumentation and control 2
Cognitive basis framework Scientific literature (NUREG-2114)
SACADA and Literature and human other data sources factors practices IDHEAS General Methodology Existing HRA methods (IDHEAS-G) IDHEAS-DATA (NUREG-2198)
Operational experience IDHEAS Internal IDHEAS-ECA Events At-Power (RIL-2020-02)
Application (NUREG-2199, Vol. 1)
HRA applications HRA applications 3
Overview of IDHEAS-G Cognitive Basis Structure Cognition Model PIF Structure Human error data Stage 1 Stage 2 Stage 3 Stage 4 Scenario Modeling of HEP Integrative analysis important human actions quantification analysis 4
Cognitive Basis Structure Human action Task 1 Task 2 Task 3 and cognitive activities and cognitive activities and cognitive activities Under- Decision- Action Interteam Detection coordination standing making execution 5
Cognitive Basis StructureFailure of Human Actions Macrocognitive Cognitive Processors PIFs functions mechanisms
- 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.
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PIF Structure Environment Context and Situation System Personnel Task
- Accessibility/habitability *Staffing *Information availability
- System and I&C of workplace including *Procedures, guidance, and reliability transparency to *Scenario familiarity travel paths and instructions personnel *Multitasking,
- Workplace visibility *Training
- HSI PIF *Noise in workplace and
- Equipment and
- Teamwork and interruptions, and communication organizational factors distractions tools *Task complexity pathways *Work processes
- Cold/heat/humidity *Mental fatigue
- Resistance to physical *Time pressure and movement stress
- Physical demands PIF *Poor lighting in *Tools are difficult to use *Procedure is inadequate workplace *Tools are unfamiliar to personnel *Procedure is difficult to *Sustained high-demand attributes *Glare or reflection on *Tools do not work use cognitive activities Note: The PIF attributes physical structure *Tools or parts are unavailable *Procedure is available, *Long working hours shown are examples *Smoke or fog- *Document nomenclature does not but does not fit the *Sleep deprivation and correspond to the induced low visibility agree with equipment labels situation PIFs highlighted in red.
Links to cognitive See Section 3.4 and Appendix B mechanisms 7
IDHEAS-G HRA Process Stage 1: Scenario analysis Scenarios Scenarios
- Develop operational narrative
- Identify scenario context
- Identify important human actions IHAs IHA 1 IHA 2 IHA 3 Critical Critical task 1 Critical task 2 Critical task 3 Stage 2: Modeling of tasks important human actions
- Identify and analyze critical Macro-tasks
- Identify applicable CFMs cognitive Action Detection Understanding Decisionmaking Teamwork Uncertainty
- Assess PIFs functions execution analysis and CFMs CFMs CFMs CFMs CFMs CFMs CFM1 PIF1 Stage 3 - HEP quantification HEPs due to CFMs
- Estimation of CFM2 PIF2
- Estimation of HEP due to HEP HEP CFM3 PIF3 time uncertainty Stage 4 - Integrative analysis Dependency CFM4 PIF4
- Document uncertainties
- Assess dependencies adjustment 8
HEP QuantificationOverview Time available Time required CFMs PIF attributes HEP of , ,
CFM 1 an IHA Critical task 1 CFM 2 Critical , ,
CFM 3 task 2 Critical , ,
CFM 4 task 3 9
HEP QuantificationPc
- HEP quantification model HEP from Base PIFs PIF weight factors from Recovery factor; set Modification PIFs to 1 unless data suggest otherwise PIF interaction error rate at a given PIF attribute factor; set to 1 with error rate when the PIF linear combination attribute has no or low impact 10
HEP QuantificationPt
- In response to ACRS 0.25 Time Required comments, time Time Available uncertainty model was 0.2 developed probability density 0.15
- Convolution of time available and time 0.1 required distributions 0.05
- Pt is proportional to this 0 10 15 20 25 30 35 40 time (minutes) area 11
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.
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IDHEAS-G Dependency Model: Process
- 1. Identify the dependency context Cut set with
- Consequential dependency multiple HFEs (HFE1, HFE2)
- Resource-sharing dependency
- Cognitive dependency HFE1 and HFE2 are 2. Model the dependency context HFE2lHFE1 independent All no Any Are there changes to HFE2s:
Definition? Time required and time available?
P(HFE1,HFE2)= yes?
Feasibility? CFMs?
P(HFE1)*P(HFE2) Critical tasks? PIF attributes?
Yes
- 3. Calculate P(HFE2lHFE1) based on P(HFE1,HFE2) =
context changes to HFE2 and using P(HFE1)*P(HFE2lHFE1) same method as individual HFEs HFE2lHFE1 means the occurrence of event HFE2 given the occurrence 14 of event HFE1, where HFE1 is the first event and HFE2 is the second event.
IDHEAS-G Dependency Model: Illustration Context HFE1 Success of HFE1 S Failure [P(HFE1)]
Success Context HFE2 S of HFE2 Failure [P(HFE2)] F [P(HFE1)*P(HFE2)]
Context HFE1 Success of HFE1 S Failure [P(HFE1)]
Dependent Success Context of HFE2 S HFE2 Failure [P(HFE2lHFE1)] F [P(HFE1)*P(HFE2lHFE1)]
S = success 15 F = failure