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 Fire PRA Workshop Module IV August 5-9, 2019 Rockville, MD NRC-RES/EPRI FIRE PRA METHODOLOGY Task 12 - Fire HRA Screening Examples
Slide 2 Fire HRA - Screening Analysis Examples Fire PRA Workshop 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
Slide 3 Fire HRA - Screening Analysis Examples Fire PRA Workshop 2019, Rockville, MD Screening examples
Slide 4 Fire HRA - Screening Analysis Examples Fire PRA Workshop 2019, Rockville, MD Quantitative Screening Approach Summary Screening Criteria Short Term Human Actions Long Term Human Actions Definition Value Definition Value Set 1 - like Internal Events HFE, but with some fire effects Required within first hour of trip/fire 10x Internal Events HEP Performed ~one hour after fire/trip (fire effects no longer dynamic, equipment damage understood, fire does not significantly affect ability of operators to perform action) same as Internal Events HEP Set 2 - like Set 1, but with spurious equipment or instrumentation effects in 1 safety-related train/division 0.1, or 10x Internal Events HEP, whichever is greater 0.1, or 10x Internal Events HEP, whichever is smaller Set 3 - new fire HFEs or prior IE HFEs needing to be significantly modified due to fire conditions 1
0.1, or 10x Internal Events HEP, whichever is smaller Set 4 - Alternate Shutdown (including MCR abandonment) 1 for HFE, or 0.1 for single overall probability representing failure to reach safe shutdown
Slide 5 Fire HRA - Screening Analysis Examples 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
Slide 6 Fire HRA - Screening Analysis Examples 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
Slide 7 Fire HRA - Screening Analysis Examples 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.
Slide 8 Fire HRA - Screening Analysis Examples 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
Slide 9 Fire HRA - Screening Analysis Examples Fire PRA Workshop 2019, Rockville, MD Screening Criteria Short Term Human Actions Long Term Human Actions Definition Value Definition Value Set 1 - like Internal Events HFE, but with some fire effects Required within first hour of trip/fire 10x Internal Events HEP Performed ~one hour after fire/trip (fire effects no longer dynamic, equipment damage understood, fire does not significantly affect ability of operators to perform action) same as Internal Events HEP Set 2 - like Set 1, but with spurious equipment or instrumentation effects in 1 safety-related train/division 0.1, or 10x Internal Events HEP, whichever is greater 0.1, or 10x Internal Events HEP, whichever is smaller Set 3 - new fire HFEs or prior IE HFEs needing to be significantly modified due to fire conditions 1
0.1, or 10x Internal Events HEP, whichever is smaller Set 4 - Alternate Shutdown (including MCR abandonment) 1 for HFE, or 0.1 for single overall probability representing failure to reach safe shutdown Example 1: Quantitative Screening Summary 7.7E-2
- 10 =
7.7E-1
Slide 10 Fire HRA - Screening Analysis Examples 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.
Slide 11 Fire HRA - Screening Analysis Examples 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
Slide 12 Fire HRA - Screening Analysis Examples 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
Slide 13 Fire HRA - Screening Analysis Examples Fire PRA Workshop 2019, Rockville, MD Screening Criteria Short Term Human Actions Long Term Human Actions Definition Value Definition Value Set 1 - like Internal Events HFE, but with some fire effects Required within first hour of trip/fire 10x Internal Events HEP Performed ~one hour after fire/trip (fire effects no longer dynamic, equipment damage understood, fire does not significantly affect ability of operators to perform action) same as Internal Events HEP Set 2 - like Set 1, but with spurious equipment or instrumentation effects in 1 safety-related train/division 0.1, or 10x Internal Events HEP, whichever is greater 0.1, or 10x Internal Events HEP, whichever is smaller Set 3 - new fire HFEs or prior IE HFEs needing to be significantly modified due to fire conditions 1
0.1, or 10x Internal Events HEP, whichever is smaller Set 4 - Alternate Shutdown (including MCR abandonment) 1 for HFE, or 0.1 for single overall probability representing failure to reach safe shutdown Example 2: Quantitative Screening Summary
Slide 14 Fire HRA - Screening Analysis Examples 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.
Slide 15 Fire HRA - Screening Analysis Examples 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
Slide 16 Fire HRA - Screening Analysis Examples 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
Slide 17 Fire HRA - Screening Analysis Examples Fire PRA Workshop 2019, Rockville, MD Screening Criteria Short Term Human Actions Long Term Human Actions Definition Value Definition Value Set 1 - like Internal Events HFE, but with some fire effects Required within first hour of trip/fire 10x Internal Events HEP Performed ~one hour after fire/trip (fire effects no longer dynamic, equipment damage understood, fire does not significantly affect ability of operators to perform action) same as Internal Events HEP Set 2 - like Set 1, but with spurious equipment or instrumentation effects in 1 safety-related train/division 0.1, or 10x Internal Events HEP, whichever is greater 0.1, or 10x Internal Events HEP, whichever is smaller Set 3 - new fire HFEs or prior IE HFEs needing to be significantly modified due to fire conditions 1
0.1, or 10x Internal Events HEP, whichever is smaller Set 4 - Alternate Shutdown (including MCR abandonment) 1 for HFE, or 0.1 for single overall probability representing failure to reach safe shutdown Example 3: Quantitative Screening Summary
Slide 18 Fire HRA - Screening Analysis Examples 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
Slide 19 Fire HRA - Screening Analysis Examples 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
Slide 20 Fire HRA - Screening Analysis Examples 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
- 3. New Fire HFE or Existing HFE needs to be significantly altered to reflect fire effects Yes No Simultaneous use of multiple procedures
Slide 21 Fire HRA - Screening Analysis Examples Fire PRA Workshop 2019, Rockville, MD Screening Criteria Short Term Human Actions Long Term Human Actions Definition Value Definition Value Set 1 - like Internal Events HFE, but with some fire effects Required within first hour of trip/fire 10x Internal Events HEP Performed ~one hour after fire/trip (fire effects no longer dynamic, equipment damage understood, fire does not significantly affect ability of operators to perform action) same as Internal Events HEP Set 2 - like Set 1, but with spurious equipment or instrumentation effects in 1 safety-related train/division 0.1, or 10x Internal Events HEP, whichever is greater 0.1, or 10x Internal Events HEP, whichever is smaller Set 3 - new fire HFEs or prior IE HFEs needing to be significantly modified due to fire conditions 1
0.1, or 10x Internal Events HEP, whichever is smaller Set 4 - Alternate Shutdown (including MCR abandonment) 1 for HFE, or 0.1 for single overall probability representing failure to reach safe shutdown Example 4: Quantitative Screening Summary
Slide 22 Fire HRA - Screening Analysis Examples 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
Slide 23 Fire HRA - Screening Analysis Examples Fire PRA Workshop 2019, Rockville, MD Screening Criteria Short Term Human Actions Long Term Human Actions Definition Value Definition Value Set 1 - like Internal Events HFE, but with some fire effects Required within first hour of trip/fire 10x Internal Events HEP Performed ~one hour after fire/trip (fire effects no longer dynamic, equipment damage understood, fire does not significantly affect ability of operators to perform action) same as Internal Events HEP Set 2 - like Set 1, but with spurious equipment or instrumentation effects in 1 safety-related train/division 0.1, or 10x Internal Events HEP, whichever is greater 0.1, or 10x Internal Events HEP, whichever is smaller Set 3 - new fire HFEs or prior IE HFEs needing to be significantly modified due to fire conditions 1
0.1, or 10x Internal Events HEP, whichever is smaller Set 4 - Alternate Shutdown (including MCR abandonment) 1 for HFE, or 0.1 for single overall probability representing failure to reach safe shutdown Example 5: Quantitative Screening Summary
Slide 24 Fire HRA - Screening Analysis Examples Fire PRA Workshop 2019, Rockville, MD Questions
Slide 25 Fire HRA - Screening Analysis Examples Fire PRA Workshop 2019, Rockville, MD Additional Examples Backup Slides
Slide 26 Fire HRA - Screening Analysis Examples 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
Slide 27 Fire HRA - Screening Analysis Examples 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
Slide 28 Fire HRA - Screening Analysis Examples 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
- 3. New Fire HFE or Existing HFE needs to be significantly altered to reflect fire effects Yes No Uncertain what multiple effects might occur
Slide 29 Fire HRA - Screening Analysis Examples Fire PRA Workshop 2019, Rockville, MD Screening Criteria Short Term Human Actions Long Term Human Actions Definition Value Definition Value Set 1 - like Internal Events HFE, but with some fire effects Required within first hour of trip/fire 10x Internal Events HEP Performed ~one hour after fire/trip (fire effects no longer dynamic, equipment damage understood, fire does not significantly affect ability of operators to perform action) same as Internal Events HEP Set 2 - like Set 1, but with spurious equipment or instrumentation effects in 1 safety-related train/division 0.1, or 10x Internal Events HEP, whichever is greater 0.1, or 10x Internal Events HEP, whichever is smaller Set 3 - new fire HFEs or prior IE HFEs needing to be significantly modified due to fire conditions 1
0.1, or 10x Internal Events HEP, whichever is smaller Set 4 - Alternate Shutdown (including MCR abandonment) 1 for HFE, or 0.1 for single overall probability representing failure to reach safe shutdown Example 5: Quantitative Screening Summary 3.6E-03
- 10 = 3.6E-2