ML19212A731
| ML19212A731 | |
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| Issue date: | 07/31/2019 |
| From: | Office of Nuclear Regulatory Research |
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| D. Stroup 415-1649 | |
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NRC-RES/EPRI FIRE PRA METHODOLOGY Task 12 - Fire HRA Scoping 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 - Scoping Analysis Examples Slide 2 Fire PRA Workshop 2019, Rockville, MD
Scoping Example Fire HRA - Scoping Analysis Examples Slide 3 Fire PRA Workshop 2019, Rockville, MD
General assumptions for examples Actions have applicable plant emergency procedures and fire procedures Fire does not impact control room environment There is a full area burn out Adequate inventory in fire protection system (FPS)
The fire is not in the same location as the execution Note: Similar examples are being used to illustrate screening, scoping and detailed approaches, but scenario specifics may not be identical Fire HRA - Scoping Analysis Examples Slide 4 Fire PRA Workshop 2019, Rockville, MD
Example 1A:
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 - Scoping Analysis Examples Slide 5 Fire PRA Workshop 2019, Rockville, MD
Example 1A:
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 - Scoping Analysis Examples Slide 6 Fire PRA Workshop 2019, Rockville, MD
Example 1A:
Minimum Criteria
- 1. Procedures
- Plant procedures covering each operator action being modeled
- Support both diagnosis & execution of the action
- 2. Training - on the procedures and the actions
- 3. Availability and accessibility of equipment Fire HRA - Scoping Analysis Examples Slide 7 Fire PRA Workshop 2019, Rockville, MD
Example 1A:
Feasibility Timing analysis:
- Time available (60 mins) > Time required (12 mins)
Cues available to aid diagnosis
- Cable tracing was done on CST alarms Fire activity would not prevent the execution of the actions Enough crew members available to complete the action Fire HRA - Scoping Analysis Examples Slide 8 Fire PRA Workshop 2019, Rockville, MD
Example 1A:
Time Margin Tavail (Tcog + Texe ) 60 ( 2 + 10)
Time Margin =
- 100% =
- 100% = 400%
(Tcog + Texe ) ( 2 + 10)
Tsw Tavail Tdelay Tcog Texe To Cue Crew Action received diagnosis complete Action no Start complete longer beneficial Fire HRA - Scoping Analysis Examples Slide 9 Fire PRA Workshop 2019, Rockville, MD
Example 1A:
Assessing Key Conditions & PSFs Condition Status Do the procedures match the scenario? Yes Is the execution complexity high? No Is the fire suppressed when the cue is Yes received?
Whats the time window (Tavail)? 60 min Is there any smoke or other hazardous No elements in the action areas?
Is the action area accessible? Yes Fire HRA - Scoping Analysis Examples Slide 10 Fire PRA Workshop 2019, Rockville, MD
Example 1A:
Search Scheme Fire HRA - Scoping Analysis Examples Slide 11 Fire PRA Workshop 2019, Rockville, MD
Example 1A:
EXCR Fire HRA - Scoping Analysis Examples Slide 12 Fire PRA Workshop 2019, Rockville, MD
Example 1A:
EXCR Lookup Table HEP Lookup Time Margin HEP HEP Label Table
> 100% 0.002 EXCR12 R 50 - 99% 0.01 EXCR13
< 50% 1.0 EXCR14 Fire HRA - Scoping Analysis Examples Slide 13 Fire PRA Workshop 2019, Rockville, MD
Example 1B:
Operator fails to align FPS water to AFW pumps with failed alarm Same basic scenario as Example 1A
- 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. Assumed that the action would not occur (error of omission) and the spurious indication flowchart must be used!
- The fire procedure does direct the crew to locally check tank level to make sure there is enough inventory.
Fire HRA - Scoping Analysis Examples Slide 14 Fire PRA Workshop 2019, Rockville, MD
Example 1B:
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 - Scoping Analysis Examples Slide 15 Fire PRA Workshop 2019, Rockville, MD
Example 1B:
Minimum Criteria
- 1. Procedures
- Fire procedures covering each operator action being modeled
- Support both diagnosis & execution of the action
- 2. Training - on the procedures and the actions
- 3. Availability and accessibility of equipment Fire HRA - Scoping Analysis Examples Slide 16 Fire PRA Workshop 2019, Rockville, MD
Example 1B:
Feasibility Timing Analysis:
- Time available (60 mins) > Time required (25 mins)
Cues available to aid recovery Fire activity would not prevent the execution of the actions Enough crew members available to complete the action Fire HRA - Scoping Analysis Examples Slide 17 Fire PRA Workshop 2019, Rockville, MD
Example 1B:
Time Margin Tavail (Tcog + Texe ) 60 (15 + 10)
Time Margin =
- 100% =
- 100% = 140%
(Tcog + Texe ) (15 + 10)
Tsw Tavail Tdelay Tcog Texe To Cue Crew Action received diagnosis complete Action no Start complete longer beneficial Fire HRA - Scoping Analysis Examples Slide 18 Fire PRA Workshop 2019, Rockville, MD
Example 1B:
Assessing Key Conditions & PSFs Condition Status Do the procedures match the scenario? Yes Is the execution complexity high? No Is the fire suppressed when the cue is Yes received?
Whats the time window (Tavail)? 60 min Is there any smoke or other hazardous No elements in the action areas?
Is the action area accessible? Yes Fire HRA - Scoping Analysis Examples Slide 19 Fire PRA Workshop 2019, Rockville, MD
Example 1B:
Search Scheme Fire HRA - Scoping Analysis Examples Slide 20 Fire PRA Workshop 2019, Rockville, MD
Example 1B:
SPI Fire HRA - Scoping Analysis Examples Slide 21 Fire PRA Workshop 2019, Rockville, MD
Example 1B:
SPI Fire HRA - Scoping Analysis Examples Slide 22 Fire PRA Workshop 2019, Rockville, MD
Example 1B:
SPI Lookup Table HEP Lookup Time Margin HEP HEP Label Table
> 100% 0.1 SPI27 AT 50 - 99% 0.5 SPI28
< 50% 1.0 SPI29 Fire HRA - Scoping Analysis Examples Slide 23 Fire PRA Workshop 2019, Rockville, MD
Example 2A:
Operator fails to initiate bleed & feed The action to initiate bleed and feed will be done when the 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 all indications of level are accurate With the main feedwater and auxiliary feedwater systems unavailable at the beginning of the initiating event, the SG goes to dry out in 45 minutes Fire HRA - Scoping Analysis Examples Slide 24 Fire PRA Workshop 2019, Rockville, MD
Example 2A:
Operator fails to initiate bleed & feed MCR action Timing information
-TSW = 45 minutes
-Tdelay = 20 minutes
-Tcog = 3 minutes
-Texe = 8 minutes Fire HRA - Scoping Analysis Examples Slide 25 Fire PRA Workshop 2019, Rockville, MD
Example 2A:
Minimum Criteria
- 1. Procedures
- Plant procedures covering each operator action being modeled
- Support both diagnosis & execution of the action
- 2. Training - on the procedures and the actions
- 3. Availability and Accessibility of Equipment Fire HRA - Scoping Analysis Examples Slide 26 Fire PRA Workshop 2019, Rockville, MD
Example 2A:
Feasibility Timing Analysis:
- Time available (25 mins) > Time required (11 mins)
Cues available to aid diagnosis
- All indications of SG level are accurate Fire activity would not prevent the execution of the actions Enough crew members available to complete the action Fire HRA - Scoping Analysis Examples Slide 27 Fire PRA Workshop 2019, Rockville, MD
Example 2A:
Time Margin Tavail (Tcog + Texe ) 25 (3 + 8)
Time Margin = *100% = *100% = 127%
(Tcog + Texe ) (3 + 8)
Tsw Tavail Tdelay Tcog Texe to Cue Crew Action received diagnosis complete Action no Start complete longer beneficial Fire HRA - Scoping Analysis Examples Slide 28 Fire PRA Workshop 2019, Rockville, MD
Example 2A:
Assessing Key Conditions & PSFs Condition Status Do the procedures match the scenario? Yes Is the execution complexity high? No Is the fire suppressed when the cue is No received?
Whats the time window (Tavail)? 25 min Is there any smoke or other hazardous No elements in the action areas?
Is the action area accessible? Yes Fire HRA - Scoping Analysis Examples Slide 29 Fire PRA Workshop 2019, Rockville, MD
Example 2A:
Search Scheme Fire HRA - Scoping Analysis Examples Slide 30 Fire PRA Workshop 2019, Rockville, MD
Example 2A:
INCR (part 1)
Fire HRA - Scoping Analysis Examples Slide 31 Fire PRA Workshop 2019, Rockville, MD
Example 2A:
INCR (part 2)
Fire HRA - Scoping Analysis Examples Slide 32 Fire PRA Workshop 2019, Rockville, MD
Example 2A:
INCR Lookup Table HEP Lookup Time Margin HEP HEP Label Table
> 100% 0.05 INCR14 E 50 - 99% 0.25 INCR15
< 50% 1.0 INCR16 Fire HRA - Scoping Analysis Examples Slide 33 Fire PRA Workshop 2019, Rockville, MD
Example 2B:
Operator fails to initiate bleed & feed and use of fire procedures The action to initiate bleed and feed will be done when the 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 and auxiliary feedwater systems unavailable at the beginning of the initiating event, the SG goes to dry out in 45 minutes Fire HRA - Scoping Analysis Examples Slide 34 Fire PRA Workshop 2019, Rockville, MD
Example 2B:
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 - Scoping Analysis Examples Slide 35 Fire PRA Workshop 2019, Rockville, MD
Example 2B:
Minimum Criteria
- 1. Procedures
- Fire procedures covering each operator action being modeled
- Support both diagnosis & execution of the action
- 2. Training - on the procedures and the actions
- 3. Availability and accessibility of equipment Fire HRA - Scoping Analysis Examples Slide 36 Fire PRA Workshop 2019, Rockville, MD
Example 2B:
Feasibility Timing Analysis:
- Time available (25 mins) > Time required (16 mins)
Cues available to aid diagnosis
- Some indications of SG level are accurate
- Fire procedures used to determine which indicators to trust Fire activity would not prevent the execution of the actions Enough crew members available to complete the action Fire HRA - Scoping Analysis Examples Slide 37 Fire PRA Workshop 2019, Rockville, MD
Example 2B:
Time Margin Tavail (Tcog + Texe ) 25 (8 + 8)
Time Margin =
- 100% =
- 100% = 56%
(Tcog + Texe ) (8 + 8)
TSW Tavail Tdelay Tcog Texe To Cue Crew Action received diagnosis complete Action no Start complete longer beneficial Fire HRA - Scoping Analysis Examples Slide 38 Fire PRA Workshop 2019, Rockville, MD
Example 2B:
Assessing Key Conditions & PSFs Condition Status Do the procedures match the scenario? Yes Is the execution complexity high? No Is the fire suppressed when the cue is No received?
Whats the time window (Tavail)? 25 min Is there any smoke or other hazardous No elements in the action areas?
Is the action area accessible? Yes Fire HRA - Scoping Analysis Examples Slide 39 Fire PRA Workshop 2019, Rockville, MD
Example 2B:
Search Scheme Fire HRA - Scoping Analysis Examples Slide 40 Fire PRA Workshop 2019, Rockville, MD
Example 2B:
INCR (part 1)
Fire HRA - Scoping Analysis Examples Slide 41 Fire PRA Workshop 2019, Rockville, MD
Example 2B:
INCR (part 2)
Fire HRA - Scoping Analysis Examples Slide 42 Fire PRA Workshop 2019, Rockville, MD
Example 2B:
INCR Lookup Table HEP Lookup Time Margin HEP HEP Label Table
> 100% 0.05 INCR14 E 50 - 99% 0.25 INCR15
< 50% 1.0 INCR16 Fire HRA - Scoping Analysis Examples Slide 43 Fire PRA Workshop 2019, Rockville, MD
Questions?
Fire HRA - Scoping Analysis Examples Slide 44 Fire PRA Workshop 2019, Rockville, MD