ML19212A733

04_14_Fire HRA Training EPRI Examples

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NRC-RES Fire PRA Workshop Module IV August 5-9, 2019 Rockville, MD NRC-RES/EPRI FIRE PRA METHODOLOGY Task 12 - Fire HRA EPRI Approach to Detailed Fire HRA Quantification Examples

Slide 2 EPRI Approach 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 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD EPRI HRA CalculatorTM EPRI software was used, but is not required.

EPRI HRA Calculator TM version 4.1.1 was used for following examples.

Current version of the software is version 5.1

Slide 4 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Assumptions for Examples Example Plant is a 2-loop Westinghouse PWR using Standard Westinghouse EOPs Fire PRA modeling is developed sufficiently

- Detailed scenario descriptions and information available Fire Response Procedures

- Implemented in parallel to the EOPs, and

- Operators enter the fire procedures at the same time as they enter the EOPs Fire and reactor trip modeled to occur at the same time (T=0)

Slide 5 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Crew Composition For Example Problems

Staffing: Minimum staffing of the plant is as follows:

• Dealing with high-level management issues (e.g., communicating with NRC)

• • Can be outside CR. Will be in CR within 10 minutes of reactor trip.

• • • Normally available but not considered to be minimum staffing Shift Manager* (SM)

Shift Supervisor (SS)

Unit 1 Shift Technical Advisor** (STA)

Control Operator (OPER2)

Local Plant Operators Crew #

Auxiliary Operators 3

Turbine Hall Operator 2

Aux bldg/Water Treatment 2

Inside Control Room:

Outside Control Room:

Control Operator***

(OPER3)

Crew composition and titles are plant specific Control Operator (OPER1)

Slide 6 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Crew Member Total Available Before Fire

1. Assisting with fire*

1. Available for EOP actions Shift Manager 1

1 0

Shift Supervisor 1

0 1

STA 1

0 1

Control Room Operators 2

1 1

Plant operators 7

4 3

• This includes members of fire brigade and staff occupied with FPs or otherwise occupied due to the fire Division of Labor During Fire Scenario Following detection of fire, some crew members become members of the fire brigade and are unable to assist in actions directed by the control room. The fire brigades only duty is to extinguish the fire.

The EPRI approach reflects the plant practice that while the fire is ongoing no members of the fire brigade are available to assist with local or control room actions.

Slide 7 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Generic Fire Response Timeline (Plant-specific information may vary)

Time (Minutes)

T=0 Fire causes reactor trip T=0 Control room receives fire alarm and actives fire brigade Control room sends local operator to investigate fire T=5 Control room starts implementing fire procedures in parallel to EOPs T=10 Fire brigade is expected to be assembled and fighting fire within 10 minutes of activations T=15 Emergency Response Facility (ERF) activated and unusual event declared. Typical, plant policy states that if a fire is not under control within 15 minutes must declare unusual event.

T=70 Fire is out 99% of all fires are extinguished per FAQ 50

Slide 8 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Example 1 - Operator fails to manually align 115kV bus (SBO)

Initial Conditions:

Steady state, full power operation.

Minimal staff on shift.

No out-of-service safe shutdown equipment.

Initiating Event: Fire in turbine hall causes SBO

HFE: Operator fails to manually align 115kV (alternate power) power following loss of both buses.

Slide 9 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Accident Sequence & Success Criteria Accident Sequence o

Fire causes reactor trip o

Reactor trip and turbine trip successful.

o AFW failed due to the fire.

o PORV spuriously opens due to the fire.

o The Main Generator breaker opens and the BOP buses are powered through XTF0001 (reverse) and XTF0002.

o EDG A is failed by the fire and fails to start.

o EDG B starts and the Engineered Safety Feature (ESF) Loading Sequencer loads onto bus.

o EDG B trips due to fire damage. The ESF Loading Sequencer is still sending a signal to trip the normal and alternate feeder breakers (for EDG protection) to the bus.

o All diesels failed - SBO o

DC power remains available until batteries deplete. Batteries will last for 4 hrs

Slide 10 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Accident Sequence (continued)

Operators Success Criteria o

Locally trip the alternate feeder breaker by removing power from the ESFLS to remove the trip open signal.

o Energize XSW1DA or 1DB from the alternate power source.

Consequence of failure: Core damage due to stuck open PORV

Slide 11 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Expected Crew Response Time Event Comment T=0min Fire and Reactor Trip T=0min Control Room dispatches fire brigade to fight the fire; immediate memorized actions (steps 1-3 EOP 0) performed Fire brigade comprised of 3 Local Plant Operators T=3min EOP 0, step 3 indicates SBO. Procedure transition brief held by SS to alert all control room staff that they have an SBO and fire. They will be entering ECA 0.0 OPER1 designated to perform ECA 0.0; OPER2 designated to start reviews of fire procedures T=5min OPER1 begins ECA 0.0 T=7min Step 4 ECA 0.0 dispatch local plant operator to investigate failure of AFW Assume this Local Plant Operator will be tied up restoring AFW and not available to assist in additional actions T=10min STA arrives Begins monitoring critical safety functions T=15min OPER1 reaches step 10 ECA 0.0, notifies SS that they need to transition to AOP 304 By this time OPER2 has finished reading through fire procedures T=15min SS briefs control room staff on the AOP coordination with the fire procedures 7 contingent time critical action (need in the first hr) in fire procedure; 2 necessary. Confirmed: fire procedure actions will not interfere with AOP actions; sufficient personnel available to do both in parallel. Late actions (>4hr) are postponed until SBO is recovered.

T=20min OPER1 begins AOP 304; OPER2 begins directing fire procedure actions OPER2 dispatches 1 local plant operator to perform fire procedure actions T=35min OPER1 arrives at step 17 of AOP 304 (locally remove power from ESFLS)

Cue for action

Slide 12 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Expected Procedure Progression o Upon Reactor Trip, enter EOP-0 o Step 3 of EOP-0 verifies that buses are energized. Buses are de-energized; this will take the operator to ECA 0.0 [Station Blackout Procedure]

o Step 10 of ECA 0.0 checks that buses 1DB and 1 DA are energized. Both buses are de-energized; this will take the operator to AOP 304 due to loss of bus with no EDG.

o Step 13 of AOP 304 directs the crew to determine cause of loss of ESF bus o Steps 17 and 18 of AOP 34 provide the execution steps.

Slide 13 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Cognitive Procedure Guidance

Slide 14 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Steps 17 and 18 of AOP 304 are the relevant execution steps for this HFE:

Execution Procedure Guidance

Slide 15 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Cues The cues for this HFE are straight forward however communication between control room and local operators will be impacted by the SBO and the fire.

The control room operators direct local operators to investigate for problems and then report back to the control room.

The travel pathways are not blocked by the fire

Slide 16 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Simulator Observation (SBO non-fire scenario)

Procedure/step Time (Minutes)

Comments : Cue; Feedback; Confusing; Additional information required Initial Conditions 0

G01 out of service EOP-0 0

Unit trip on loss of 1X03 and 1X04. Bus transfer H02 to H01 did not occur, 1a05 dead (G01 OOS, G02 failed to start) and 1A06 powered from G03.

Step 1 & 2 Lost power on 1A06, G03 tripped off - Transition to ECA-0.0 EOP-0 Immediate actions started EOP-0 2

Verify Safeguard buses energized Step 3 Transition to ECA 0.0 RNO There was a short team brief to make the announcement that there was a transition to ECA 0.0 ECA-0.0 5

Verify reactor trip and turbine trip Steps 1&2 ECA-0.0 7

Maintain RCS Inventory Step 3 ECA-0.0 8

Verified 1P29 AFW pump on and feeding both SGs Step 4 CRO makes call for local RO to investigate TDAFW and try and start AFW.

RNO Then briefs STA on status of TDAFW ECA-0.0 9

Attempted start of G02, failed.

Step6 ECA-0.0 9

Attempted start of G03, failed -

Step 7 GO to Step 10 ECA-0.0 10 Check 1DB bus and 1DA are energized Step 10 RNO If 1DA is de-energized Go to AOP-304.01 (LOSS OF BUS 1DA WITH THE DIESEL NOT AVAILABLE)

If 1DB is de-energized Go to AOP-304.02 (LOSS OF BUS 1DB WITH THE DIESEL NOT AVAILABLE)

Slide 17 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Timing o

T = 0 Start of fire and reactor trip o

TSW = 90 minutes Time to core damage based on an IPE thermal hydraulic run for loss of AFW and a station blackout with one primary PORV stuck open.

o Tdelay = 30 minutes from reactor trip unit operators reach step 13

Based on simulator observation for a similar scenario for SBO it took operators 10 minutes to get through ECA 0.0 step 10

Simulation based on non-fire SBO so an additional time has been added to account for fire impacts.

It is estimated that it will take about 10 minutes to reach step 13 of AOP-304

Tdelay=20+10 minutes o

Tcog = 10 minutes based on operator interviews. This is the time operators estimated it would take to locally investigate status of breaker.

This includes time for the SS and STA to confer, coordinate with the fire procedures, approve the action and communicate to control room operators to commence steps 17 and 18.

Slide 18 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Timing (contd) o Texe = 20 minutes o

The action to locally remove power from the Train B ESF Loading Sequencer is trained on using Job Performance Measure (JPM) 12654 - Align ALT Feed Breaker. This JPM has a time requirement to be able to complete the local portion of the actions within 15 minutes, and this has been verified by observations of the JPM. The timing starts once the operator is given the instructions to perform this action and ends once the MCR action had been complete (end of step 18).

o As part of this JPM the operators train on putting on flash gear which is required to locally remove power from the Train B ESF Loading Sequencer. The flash gear is stored in a cabinet at the entrance to the relay room.

o After the operators complete the local action they will need to return to the control room to tell the control room operators they were successful. This additional travel time is expected to take 5 minutes.

o Under ideal conditions the Local Plant Operator could use the phone to call the control room. However, for fire, no cable tracing was performed on the phone lines so the telephones are assumed to unavailable.

o Texe = 15 minutes + 5 minutes = 20 minutes

Slide 19 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Timeline Based on timeline a moderate dependency is considered for recovery

Slide 20 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD CBDTM - Unrecovered

Slide 21 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD CBDTM decision tree:

pc-a Data not available Training on Indication Warning or Alternative in Procedure Indication Accurate Indication Available in CR Yes No (a) neg.

(b) neg.

(c) neg.

(d) 1.5E-03 (e) 5.0E-02 (f) 5.0E-01 (g)

• pc a From the control room the operators can determine that the bus is failed. However the procedure directs the operators to locally verify the status of the bus

Slide 22 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD CBDTM decision tree:

pc-b Data not attended to Alarmed vs.

not alarmed Front vs. back panel Nominal probability Check vs.

monitor Low vs. high workload pcb Yes No (a) neg.

(b) 1.5E-4 (c) 3.0E-3 (d) 1.5E-4 (e) 3.0E-3 (f) 3.0E-4 (g) 6.0E-3 Front Alarmed Back Check Monitor Front Back Alarmed Alarmed Low High Not alarmed Not alarmed Not alarmed Check Front Back Alarmed Alarmed Not alarmed Not alarmed Monitor Front Back Alarmed Alarmed Not alarmed Not alarmed (h) neg.

(j) 7.5E-4 (m) 1.5E-2 (o) 3.0E-2 (i) neg.

(k) 1.5E-2 (l) 7.5E-4 (n) 1.5E-3

Slide 23 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD CBDTM decision tree:

pc-c Data misread or miscommunicated Formal com-munications Good/bad indicator Nominal probability Indicator easy to locate Yes No (a) neg.

(b) 3.0E-3 (c) 1.0E-3 (d) 4.0E-3 (e) 3.0E-3 (f) 6.0E-3 (g) 4.0E-3 (h) 7.0E-3 pcc

Slide 24 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD CBDTM decision tree:

pc-d Information misleading General training Specific training Nominal probability Warning of differences All cues as stated pcd Yes No (a) neg.

(b) 3.0E-3 (c) 1.0E-2 (d) 1.0E-1 (e) 1.0

Slide 25 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD CBDTM decision tree:

pc-e Relevant step in procedure missed Placekeeping aids Graphically distinct Nominal probability Single vs.

multiple Obvious vs.

hidden pce Yes No (a) 1.0E-3 (b) 3.0E-3 (c) 3.0E-3 (d) 1.0E-2 (e) 2.0E-3 (f) 4.0E-3 (g) 6.0E-3 Single Obvious Hidden Multiple (h) 1.3E-2 (i) 1.0E-1

Slide 26 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD CBDTM decision tree:

pc-f Misinterpret instruction Training on step All required information Nominal probability

Standard, unambiguous wording Yes No (a) neg.

(b) 3.0E-3 (c) 3.0E-2 (d) 3.0E-3 (e) 3.0E-2 (f) 6.0E-3 (g) 6.0E-2 pcf

Slide 27 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD CBDTM decision tree:

pc-g Error in interpreting logic Practiced scenario Both and and or Nominal probability And or or statement Not statement pcg Yes No (a) 1.6E-2 (b) 4.9E-2 (c) 6.0E-3 (d) 1.9E-2 (e) 2.0E-3 (f) 6.0E-3 (g) 1.0E-2 (h) 3.1E-2 (j) 1.0E-3 (i) 3.0E-4 (k) neg.

(l) neg.

Slide 28 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD CBDTM decision tree:

pc-h Deliberate violation Policy of verbatim compliance Adverse consequence if comply Nominal probability Reasonable alternative Belief in adequacy of instruction pch Yes No (a) neg.

(b) 5.0E-1 (c) 1.0 (d) neg.

(e) neg.

Slide 29 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD CBDTM Summary Unrecovered

Slide 30 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD No recoveries are applied to Pcc because there are no extra operators available to assist in locally investigating the status of the bus and reporting back to the control room

Slide 31 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Execution PSFs

Environment:

Availability and Accessibility: Given location of fire and layout of plant, the relay room is accessible and there is no degraded environment (e.g., no smoke) in the relay room or en route to the relay room.

Visibility: Given a SBO event, lighting will be significantly reduced (i.e., flashlights and/or emergency lighting).

Communications: Under ideal conditions the local plant operator could use the phone to call the control room. However, for the fire, no cable tracing was performed on the phone lines so the telephones are assumed to unavailable.

Heat/Humidity: Normal - fire effects do not reach this area, however, after some time (>action window) there could be a rise in temperature due to SBO.

Special Requirements:

Operators are required to wear flash gear to locally remove power from the Train A ESF Loading Sequencer.

Operators will need key to access relay rooms due to loss of power all doors will be locked.

Slide 32 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Execution is considered to be complex due to the communication required between control room and local plant operators Portable lighting due to SBO and operators may need to use flashlights Tools are selected because the operators are required to obtain keys from the control room.

The operators are required to wear flash gear to perform the local action

Slide 33 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD EPRI Stress Decision Tree

Slide 34 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Critical Steps (Execution) o LOCALLY Reset ESFLS to clear trip signal

Plant Operator, stationed at or near the MCR, gets ESFLS panel key from the MCR and proceeds to the Relay Room

Dons flash gear

Opens left cabinet (~2ft from floor) and locally removes power from the loading sequencer

Alert control operator that the trip signal is clear and that break can closed from the control room o

Close Breaker in MCR

Ensure BUS 1DA XFER INIT Switch is in OFF

Close BUS 1DA ALT FEED Breaker

Verify BUS 1DA potential lights are energized

Slide 35 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD

Slide 36 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD

Slide 37 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Execution Summary

Slide 38 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Summary Results

Slide 39 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Example 2 Operators fail to perform feed and bleed during a fire For this example, the HFE has been quantified in detail for internal events

Slide 40 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Scenario Description

Initial Conditions:

Steady state, full power operation. Night shift with minimal staff onsite.

No out-of-service unavailability pertinent to this scenario

Initiating Event: Fire in turbine hall causes reactor trip.

IE - TRANS

HFE: Operators fail to perform feed and bleed (fire)

Fire Impacts: The fire fails AFW, MFW and 2/4 SG level indicators in the control room.

Slide 41 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Accident Sequence Operator fails to perform feed and bleed

Slide 42 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Procedure FR-H.1

11. Check For Loss Of Secondary Heat Sink:

WR S/G Level LESS THAN 15% in 2 S/G Return to Step 1

Slide 43 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Procedure FR-H.1

Slide 44 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Procedure FR-H.1

Slide 45 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Fire Procedure

Slide 46 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Timeline T = 0 reactor trip and start of the fire Tsw = 60 minutes -time to SG dryout Tdelay= 20 minutes -time to cue Texe = 5 minutes - time to execute and procedurally verify execution steps. (Based on operator interviews)

For internal events

- Tcog=1 minutes (all cues and indications are accurate)

For fire case with 2/4 SG levels impacted

- Tcog=5 minutes to determine which SG levels indicators are accurate.

Slide 47 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Timeline For fire analysis dependency level assigned is MD For internal events case dependency level assigned is LD

Slide 48 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Cues and Indications Same cue as for internal events except the fire has impacted 2/4 SG level indicators SG level in both SGs less than 15%

Cue is considered to be poor

Slide 49 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD CBDTM decision tree:

pc-a Data not available Training on Indication Warning or Alternative in Procedure Indication Accurate Indication Available in CR Yes No (a) neg.

(b) neg.

(c) neg.

(d) 1.5E-03 (e) 5.0E-02 (f) 5.0E-01 (g)

• pc a Internal events selection Fire selection

Slide 50 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD CBDTM decision tree:

pc-b Data not attended to Alarmed vs.

not alarmed Front vs. back panel Nominal probability Check vs.

monitor Low vs. high workload pcb Yes No (a) neg.

(b) 1.5E-4 (c) 3.0E-3 (d) 1.5E-4 (e) 3.0E-3 (f) 3.0E-4 (g) 6.0E-3 Front Alarmed Back Check Monitor Front Back Alarmed Alarmed Low High Not alarmed Not alarmed Not alarmed Check Front Back Alarmed Alarmed Not alarmed Not alarmed Monitor Front Back Alarmed Alarmed Not alarmed Not alarmed (h) neg.

(j) 7.5E-4 (m) 1.5E-2 (o) 3.0E-2 (i) neg.

(k) 1.5E-2 (l) 7.5E-4 (n) 1.5E-3 Internal events selection Fire selection

Slide 51 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD CBDTM decision tree:

pc-c Data misread or miscommunicated Formal com-munications Good/bad indicator Nominal probability Indicator easy to locate Yes No (a) neg.

(b) 3.0E-3 (c) 1.0E-3 (d) 4.0E-3 (e) 3.0E-3 (f) 6.0E-3 (g) 4.0E-3 (h) 7.0E-3 pcc Internal events selection Fire selection

Slide 52 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD CBDTM decision tree:

pc-d Information misleading General training Specific training Nominal probability Warning of differences All cues as stated pcd Yes No (a) neg.

(b) 3.0E-3 (c) 1.0E-2 (d) 1.0E-1 (e) 1.0 Internal events selection Fire selection

Slide 53 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD CBDTM decision tree:

pc-e Relevant step in procedure missed Placekeeping aids Graphically distinct Nominal probability Single vs.

multiple Obvious vs.

hidden pce Yes No (a) 1.0E-3 (b) 3.0E-3 (c) 3.0E-3 (d) 1.0E-2 (e) 2.0E-3 (f) 4.0E-3 (g) 6.0E-3 Single Obvious Hidden Multiple (h) 1.3E-2 (i) 1.0E-1 Internal events selection Fire selection

Slide 54 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD CBDTM decision tree:

pc-f Misinterpret instruction Training on step All required information Nominal probability

Standard, unambiguous wording Yes No (a) neg.

(b) 3.0E-3 (c) 3.0E-2 (d) 3.0E-3 (e) 3.0E-2 (f) 6.0E-3 (g) 6.0E-2 pcf Internal events selection Fire selection

Slide 55 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD CBDTM decision tree:

pc-g Error in interpreting logic Practiced scenario Both and and or Nominal probability And or or statement Not statement pcg Yes No (a) 1.6E-2 (b) 4.9E-2 (c) 6.0E-3 (d) 1.9E-2 (e) 2.0E-3 (f) 6.0E-3 (g) 1.0E-2 (h) 3.1E-2 (j) 1.0E-3 (i) 3.0E-4 (k) neg.

(l) neg.

Internal events selection Fire selection

Slide 56 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD CBDTM decision tree:

pc-h Deliberate violation Policy of verbatim compliance Adverse consequence if comply Nominal probability Reasonable alternative Belief in adequacy of instruction pch Yes No (a) neg.

(b) 5.0E-1 (c) 1.0 (d) neg.

(e) neg.

Internal events selection Fire selection

Slide 57 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD CBDTM Unrecovered = 1.7E-1 No credit has been given to the usage of the fire procedures

Slide 58 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Calculation of Recovery Factor Using CBDTM an HEP for operators fail to enter fire procedure and diagnose failed indications can be calculated.

Cue - Fire alarm in the control room. The fire alarm will direct the operators to the fire procedure and correct attachment Timeline - This action occurs concurrently with other FR-H.1 actions.

- Tsw= 55 minutes -Longest time in which operators can delay entering FR-H.1 and still successfully perform feed and bleed (60 minutes-5 minutes)

- Tdelay= 5 minutes - Time to enter fire procedures

- Tcog = 5 minutes - Time to determine which indications are correct.

- Texe = 5 minutes - Tm is the time to implement feed and bleed. This time needs to be included to determine the correct time available for recovery.

Slide 59 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Calculation of Recovery Factor Recovery HEP is calculated to be 6E-3 and does not include dependencies.

Based on timing a Moderate dependency is assigned.

Recovery HEP with dependency is (1+ 6 X6E-3) / 7 =1.4E-1 Pcog with recoveries is 2.3E-2 Recovery HEP 1.4E-1 MD Dependency

Slide 60 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Execution Same execution steps as for Internal Events

Slide 61 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Execution Recovery Moderate dependency is assigned for recovery

Slide 62 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD Execution PSFs Fire is outside the control room and has no impact on the control room.

Stress is the same as for internal events Fire selection Internal events selection

Slide 63 EPRI Approach Examples Fire PRA Workshop 2019, Rockville, MD HEP Summary Operator fails to perform feed and bleed during fire with 2/4 SG levels impacted Operator fails to perform feed and bleed (internal events)