ML19212A729
| ML19212A729 | |
| Person / Time | |
|---|---|
| Issue date: | 07/31/2019 |
| From: | Office of Nuclear Regulatory Research |
| To: | |
| D. Stroup 415-1649 | |
| Shared Package | |
| ML19212A718 | List: |
| References | |
| Download: ML19212A729 (29) | |
Text
NRC-RES/EPRI FIRE PRA METHODOLOGY Task 12 - Fire HRA Screening Examples NRC-RES Fire PRA Workshop Module IV August 5-9, 2019 Rockville, MD
Outline of the Presentation
- 1. Introduction to HRA
- 2. Overview of the EPRI/NRC Fire HRA Guidelines
- 3. Identification and definition of fire human failure events
- 4. Qualitative analysis
- 5. Fire HRA Application Experience
- 6. Quantitative analysis a) Screening b) Scoping c) Detailed EPRI approach & ATHEANA (detailed)
- 7. Recovery analysis
- 8. Dependency analysis
- 9. Uncertainty analysis Fire HRA - Screening Analysis Examples Slide 2 Fire PRA Workshop 2019, Rockville, MD
Screening examples Fire HRA - Screening Analysis Examples Slide 3 Fire PRA Workshop 2019, Rockville, MD
Quantitative Screening Approach Summary Short Term Human Actions Long Term Human Actions Screening Criteria Definition Value Definition Value Set 1 - like Internal Events HFE, but with 10x Internal Events same as Internal some fire effects HEP Events HEP Performed ~one hour after fire/trip Set 2 - like Set 1, but with spurious equipment or (fire effects no longer instrumentation effects in Required within 0.1, or 10x Internal dynamic, equipment 0.1, or 10x Internal 1 safety-related first hour of Events HEP, whichever Events HEP, damage understood, train/division trip/fire is greater whichever is smaller fire does not significantly affect ability of operators to Set 3 - new fire HFEs or perform action) prior IE HFEs needing to 0.1, or 10x Internal be significantly modified 1 Events HEP, due to fire conditions whichever is smaller Set 4 - Alternate 1 for HFE, or 0.1 for single overall probability Shutdown (including representing failure to reach safe shutdown MCR abandonment)
Fire HRA - Screening Analysis Examples Slide 4 Fire PRA Workshop 2019, Rockville, MD
General Assumptions for Screening Examples Actions have applicable plant emergency procedures and fire procedures Limited information is available on fire locations and equipment impacts since fire modeling and circuit analysis are usually still in early stages Fire PRA model needs preliminary fire HEPs to test model logic and ensure that HFEs are not lost in the noise Fire effects minimized after one hour Note: Similar examples are being used to illustrate screening, scoping & detailed approaches, but scenario specifics may not be identical Fire HRA - Screening Analysis Examples Slide 5 Fire PRA Workshop 2019, Rockville, MD
Example 1:
Operator fails to switch turbine building SW header Fire cause a valve in the Service Water (SW) header line to spurious close and a low SW pressure condition develops. At the same time fire causes a reactor trip (RT).
Annunciators activate and Service Water pressure indicates less than 72 psig Operator fails to respond per appropriate Alarm Response Procedure (ARP) and swap the turbine building SW header selector switch to the opposite header Fire HRA - Screening Analysis Examples Slide 6 Fire PRA Workshop 2019, Rockville, MD
Example 1:
Operator fails to switch turbine building SW header Summary of internal events analysis
- MCR action
- Timing information:
TSW = 14 minutes Tcog = 4 minutes Texe = 1 minute Tdelay = 4 minutes
- Internal events HEP using HCR/ORE/THERP in EPRI HRA Calculator
= 7.7 E-02 Summary of fire context
- The fire does not impact the instrumentation required for diagnosis.
(I.E No spurious)
- The MCR response to the fire does not impact the MCR response to this action.
Fire HRA - Screening Analysis Examples Slide 7 Fire PRA Workshop 2019, Rockville, MD
Example 1:
Screening Selection Criteria
- 1. Operator Action timeframe
- Short (<1 hour)
- Long (> 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />)
- 2. Spurious Instrumentation/Equipment effects in one safety-related train
- Yes
- No
- Yes
- No Fire HRA - Screening Analysis Examples Slide 8 Fire PRA Workshop 2019, Rockville, MD
Example 1: Quantitative Screening Summary Short Term Human Actions Long Term Human Actions Screening Criteria Definition Value Definition Value Set 1 - like Internal 10x Internal Events Events HFE, but with HEP Performed ~one same as Internal some fire effects 7.7E-2
- 10 = hour after Events HEP 7.7E-1 Set 2 - like Set 1, but fire/trip Required 0.1, or 10x 0.1, or 10x with spurious equipment or instrumentation within first Internal Events (fire effects no longer Internal Events effects in 1 safety-related hour of HEP, whichever is dynamic, equipment HEP, whichever train/division damage understood, trip/fire greater is smaller fire does not Set 3 - new fire HFEs or significantly affect 0.1, or 10x prior IE HFEs needing to ability of operators to Internal Events be significantly modified 1 perform action) due to fire conditions HEP, whichever is smaller Set 4 - Alternate 1 for HFE, or 0.1 for single overall probability Shutdown (including MCR abandonment) representing failure to reach safe shutdown Fire HRA - Screening Analysis Examples Slide 9 Fire PRA Workshop 2019, Rockville, MD
Example 2:
Operator fails to align FPS water to AFW pumps The auxiliary feedwater (AFW) pumps take water from the condensate store tank (CST).
With low low level in the tank, the operator would align the Fire Protection System (FPS ) to the pumps.
Consider the tank low low level (10%) would be reached in 10 hrs after the start of the fire.
This is a local action and the operator must manually open two valves.
Internal events HEP = 5E-3 Fire HRA - Screening Analysis Examples Slide 10 Fire PRA Workshop 2019, Rockville, MD
Example 2:
Operator fails to align FPS water to AFW pumps Cable tracing for CST level transmitters has been performed and the cues are not impacted by fire Timing information
-Tsw = 11 hours1.273148e-4 days <br />0.00306 hours <br />1.818783e-5 weeks <br />4.1855e-6 months <br /> - 10 hrs to low low level then 1 additional hr until tank is empty and pumps cavitate
-Tdelay = 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> - Time to reach low low level
-Tcog = 2 minutes
-Texe = 10 minutes Fire HRA - Screening Analysis Examples Slide 11 Fire PRA Workshop 2019, Rockville, MD
Example 2:
Screening Selection Criteria
- 1. Operator Action timeframe
- Short (<1 hour)
- Long (> 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />)
- 2. Spurious Instrumentation/Equipment effects in one safety-related train
- Yes
- No
- Yes
- No Fire HRA - Screening Analysis Examples Slide 12 Fire PRA Workshop 2019, Rockville, MD
Example 2: Quantitative Screening Summary Short Term Human Actions Long Term Human Actions Screening Criteria Definition Value Definition Value Set 1 - like Internal Events HFE, but with 10x Internal Performed ~one same as Internal some fire effects Events HEP hour after Events HEP Set 2 - like Set 1, but fire/trip Required 0.1, or 10x 0.1, or 10x with spurious equipment or instrumentation within first Internal Events (fire effects no longer Internal Events effects in 1 safety-related hour of HEP, whichever is dynamic, equipment HEP, whichever train/division damage understood, trip/fire greater is smaller fire does not Set 3 - new fire HFEs or significantly affect 0.1, or 10x prior IE HFEs needing to ability of operators to Internal Events be significantly modified 1 perform action) due to fire conditions HEP, whichever is smaller Set 4 - Alternate 1 for HFE, or 0.1 for single overall probability Shutdown (including MCR abandonment) representing failure to reach safe shutdown Fire HRA - Screening Analysis Examples Slide 13 Fire PRA Workshop 2019, Rockville, MD
Example 3:
Operator fails to align FPS water to AFW pumps with failed alarm Same basic scenario as Example 2
- The auxiliary feedwater (AFW) pumps take water from the condensate store tank (CST).
- When low low level in the tank is reached, the operator needs to align the FPS (fire protection system) to the pumps.
Cable tracing has not been done therefore assume that fire fails the CST alarm at the 10% level
- The cue is no longer an alarm in MCR
- The fire procedure does direct the crew to locally check tank level to make sure there is enough inventory.
Fire HRA - Screening Analysis Examples Slide 14 Fire PRA Workshop 2019, Rockville, MD
Example 3:
Operator fails to align FPS water to AFW pumps with failed alarm Local action Timing information
-Tsw = 11 hrs - 10 hrs to low low level then 1 additional hr until tank is empty and pumps cavitate.
-Tdelay = 2 hrs - Estimated time before the crew sends local operator to verify CST level. This action is low priority.
-Tcog = 15 minutes - Time to determine CST level
-Texe = 10 minutes Fire HRA - Screening Analysis Examples Slide 15 Fire PRA Workshop 2019, Rockville, MD
Example 3:
Screening Selection Criteria
- 1. Operator Action timeframe
- Short (<1 hour)
- Long (> 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />)
- 2. Spurious Instrumentation/Equipment effects in one safety-related train
- Yes
- No
- Yes
- No Fire HRA - Screening Analysis Examples Slide 16 Fire PRA Workshop 2019, Rockville, MD
Example 3: Quantitative Screening Summary Screening Criteria Short Term Human Actions Long Term Human Actions Definition Value Definition Value Set 1 - like Internal Events HFE, but with 10x Internal Performed ~one same as Internal some fire effects Events HEP hour after Events HEP Set 2 - like Set 1, but fire/trip Required 0.1, or 10x 0.1, or 10x with spurious equipment or instrumentation within first Internal Events (fire effects no longer Internal Events effects in 1 safety-related hour of HEP, whichever is dynamic, equipment HEP, whichever train/division damage understood, trip/fire greater is smaller fire does not Set 3 - new fire HFEs or significantly affect 0.1, or 10x prior IE HFEs needing to ability of operators to Internal Events be significantly modified 1 perform action) due to fire conditions HEP, whichever is smaller Set 4 - Alternate 1 for HFE, or 0.1 for single overall probability Shutdown (including MCR abandonment) representing failure to reach safe shutdown Fire HRA - Screening Analysis Examples Slide 17 Fire PRA Workshop 2019, Rockville, MD
Example 4:
Operator fails to initiate bleed & feed and use of fire procedures The action to initiate bleed and feed will be done when the Steam Generators (SGs) are almost in dry out Cue to initiate bleed and feed is when 2 SGs are at less than 15% WR level In this case half of the indicators of SG level are failed and fire procedures must be used to identify which indicators are accurate With the main feedwater (MFW) and AFW unavailable at the beginning of the initiating event, the SG goes to dry out in 45 minutes Fire HRA - Screening Analysis Examples Slide 18 Fire PRA Workshop 2019, Rockville, MD
Example 4:
Operator fails to initiate bleed & feed and use of fire procedures MCR action Timing information
-TSW = 45 minutes
-Tdelay = 20 minutes
-Tcog = 8 minutes - additional time than standard bleed & feed due to using multiple procedures.
-Texe = 8 minutes Fire HRA - Screening Analysis Examples Slide 19 Fire PRA Workshop 2019, Rockville, MD
Example 4:
Screening Selection Criteria
- 1. Operator Action timeframe
- Short (<1 hour)
- Long (> 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />)
- 2. Spurious Instrumentation/Equipment effects in one safety-related train
- Yes 1/2 the level indications are given an incorrect reading
- No
- Yes Simultaneous use of multiple procedures
- No Fire HRA - Screening Analysis Examples Slide 20 Fire PRA Workshop 2019, Rockville, MD
Example 4: Quantitative Screening Summary Short Term Human Actions Long Term Human Actions Screening Criteria Definition Value Definition Value Set 1 - like Internal Events HFE, but with 10x Internal Performed ~one same as Internal some fire effects Events HEP hour after Events HEP Set 2 - like Set 1, but fire/trip Required 0.1, or 10x 0.1, or 10x with spurious equipment or instrumentation within first Internal Events (fire effects no longer Internal Events effects in 1 safety-related hour of HEP, whichever is dynamic, equipment HEP, whichever train/division damage understood, trip/fire greater is smaller fire does not Set 3 - new fire HFEs or significantly affect 0.1, or 10x prior IE HFEs needing to ability of operators to Internal Events be significantly modified 1 perform action) due to fire conditions HEP, whichever is smaller Set 4 - Alternate 1 for HFE, or 0.1 for single overall probability Shutdown (including MCR abandonment) representing failure to reach safe shutdown Fire HRA - Screening Analysis Examples Slide 21 Fire PRA Workshop 2019, Rockville, MD
Example 5:
Operator fails to maintain control from alternate shutdown location Multiple MCR and local actions Procedures exist but actions require significant coordination and communication among operators In such cases, presume detailed analysis will be required if risk-significant in fire PRA model Fire HRA - Screening Analysis Examples Slide 22 Fire PRA Workshop 2019, Rockville, MD
Example 5: Quantitative Screening Summary Short Term Human Actions Long Term Human Actions Screening Criteria Definition Value Definition Value Set 1 - like Internal Events HFE, but with 10x Internal Performed ~one same as Internal some fire effects Events HEP hour after Events HEP Set 2 - like Set 1, but fire/trip Required 0.1, or 10x 0.1, or 10x with spurious equipment or instrumentation within first Internal Events (fire effects no longer Internal Events effects in 1 safety-related hour of HEP, whichever is dynamic, equipment HEP, whichever train/division damage understood, trip/fire greater is smaller fire does not Set 3 - new fire HFEs or significantly affect 0.1, or 10x prior IE HFEs needing to ability of operators to Internal Events be significantly modified 1 perform action) due to fire conditions HEP, whichever is smaller Set 4 - Alternate 1 for HFE, or 0.1 for single overall probability Shutdown (including MCR abandonment) representing failure to reach safe shutdown Fire HRA - Screening Analysis Examples Slide 23 Fire PRA Workshop 2019, Rockville, MD
Questions Fire HRA - Screening Analysis Examples Slide 24 Fire PRA Workshop 2019, Rockville, MD
Additional Examples Backup Slides Fire HRA - Screening Analysis Examples Slide 25 Fire PRA Workshop 2019, Rockville, MD
Example 5:
Operator fails to establish containment spray sump recirculation when RWST depleted Operator action to align containment spray (CS) to sump recirc when the RWST is depleted The operators cue on RWST level <37%, per the foldout page in Procedure E-1 Transition to ES-1.3, Transfer to Containment Sump Recirculation.
The following assumptions are made:
-All equipment operates as designed
-Conditions requiring CS exist Fire HRA - Screening Analysis Examples Slide 26 Fire PRA Workshop 2019, Rockville, MD
Example 5:
Operator fails to establish containment spray sump recirculation when RWST depleted MCR action Since CS is needed, fire is presumed to be severe in its consequences RWST level indicators have cable tracing and the cues are not impacted by fire Total system time window = for the 37% RWST level to have been reached, more than 60 min are assumed to have passed since the reactor trip Internal Events HEP using CBDTM/THERP in EPRI HRA Calculator = 3.6E-03 Fire HRA - Screening Analysis Examples Slide 27 Fire PRA Workshop 2019, Rockville, MD
Example 5:
Screening Selection Criteria
- 1. Operator Action timeframe
- Short (<1 hour)
- Long (> 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />)
- 2. Spurious Instrumentation/Equipment effects in one safety-related train
- Yes
- No Uncertain what multiple effects might occur
- Yes
- No Fire HRA - Screening Analysis Examples Slide 28 Fire PRA Workshop 2019, Rockville, MD
Example 5: Quantitative Screening Summary Short Term Human Actions Long Term Human Actions Screening Criteria Definition Value Definition Value Set 1 - like Internal Events HFE, but with 10x Internal Performed ~one same as Internal some fire effects Events HEP hour after Events HEP Set 2 - like Set 1, but fire/trip Required 0.1, or 10x 0.1, or 10x with spurious equipment or instrumentation within first Internal Events (fire effects no longer Internal Events effects in 1 safety-related hour of HEP, whichever is dynamic, equipment HEP, whichever train/division damage understood, trip/fire greater is smaller fire does not Set 3 - new fire HFEs or significantly affect 0.1, or 10x prior IE HFEs needing to ability of operators to Internal Events be significantly modified 1 perform action) due to fire conditions HEP, whichever is smaller Set 4 - Alternate 1 for HFE, or 0.1 for single overall probability 3.6E-03