Text

NRC-2019-000253 - Resp 8 - Final, Agency Records Subject to the Request Are Enclosed
	ML20261H314
Person / Time
Site:	Clinton
Issue date:	09/14/2020
From:	; NRC/OCIO
To:	;
Shared Package
ML20261H312	List: ML20261H313; ML20261H314; ML20261H315;
References
	FOIA, NRC-2019-000253
	Download: ML20261H314 (740)
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From: Lara Julio To: Orlikowski Robert Note to requester: The first, second, fourth, and fifth

Subject:

FW: Clinton info discussion next week

Wednesday attachments to this email have been withheld in their Date: Thursday, Janua ry 10 , 2019 8 :28:59 AM entirety under FOIA Ex. 85 (deliberative process Attachments: cu 2018 051 (non-public).docx privilege). The third attachment is publicly available at

...i..._________________, https://www.nrc.gov/docs/ ML1833/ML18333A333.pdf and ERRATA (b )(5)

CPS Div 2 PG Reg cont Presentation '1 l

l 9-l BH01) odt also included following this email document.

BS-18-146 <Attachments 1 and 21 pdf SRO surveys <redacted} pdf From: Kozak, Lau ra Sent: Thursday, Ja nuary 10, 2019 8:11 AM To: Lara, Julio <Ju lio. Lara@nrc.gov>; Riemer, Kenneth <Kennet h.Riemer@nrc.gov>; Stoedter, Karla

<Ka rla.Stoedte r@nrc.gov>; Cameron, Jamnes <Jamnes.Cameron@nrc.gov>; Heck, Jared

<Jared. Heck@nrc.gov>

Subject:

Clinton info discussion next week - Wednesday All (b)(5)

Let me know if you want to discuss in any detail before next week's meeting and I can go through the material with you.

Laura

(b)(5)

Clinton Power Station Regulatory Conference Division 2 Diesel Generator Air Start Isolation Event November 30, 2018 Exelon Generation

Agenda

Introduction . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . Brad Fewel I

Finding Cause and Corrective Actions ............... Brad Kapellas

Key Differences. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gene Kelly/Johnny Weissinger

Initial Conditions for Postulated Event, Recovery and Mitigation Actions ........................... Johnny Weissinger/Gene Kelly

Risk Significance................................ Gene Kelly

Conclusion ..................................... Ted Stoner 1

,,:::- Exelon Generation.,

Clinton Power Station Regulatory Conference Introduction Brad Fewell Senior Vice President, Regulatory Affairs and General Counsel Exelon Generation

Introduction

We agree with the Finding and violation

We recognize our failure to maintain the configuration of an important safety system

We have taken timely, comprehensive, and broad responsive actions

We disagree with the Finding's preliminary significance of White

- Commission Policy and NRC guidance drive risk evaluations to be realistic and based on best available information

- NRC risk evaluation does not reflect the as-built, as-operated plant response

NRC's risk evaluation assumptions do not reflect how CPS would respond to DG recovery, SBO, FLEX, and ELAP by not appropriately crediting:

- Operators' extensive knowledge, training, and experience

- Available time to take recovery actions

- Procedures that control the event and drive successful resolution PRA evaluations should be realistic and based on best available information 3

,,:::- Exelon Generation.,

Introduction (cont.)

We will show that using realistic and best-available information:

- Division 2 DG would have been restored and injection available within one hour

- Expansive time was available to recover AC power and prevent core uncovery

- Procedurally directed alternative power recovery actions would have been pursued in parallel

- Objective data to support different performance shaping factor (PSF) multipliers

We will provide information that the NRC did not previously review and new information that we have recently developed

We had the knowledge, time, and resources to restore AC power and injection Finding should be characterized as Green 4

,,:::- Exelon Generation.,

Clinton Power Station Regulatory Conference Finding Cause and Corrective Actions Brad Kapellas Plant Manager Exelon Generation

Station Event Response

Root Cause

- Contrary to Exelon fleet governance for plant status control, operator logs were utilized as the sole means to track plant configuration

Corrective Action to Prevent Reoccurrence

- Identify and eliminate legacy site-specific administrative procedures/guidance that allow operator logs as a sole method for plant status control

Continuous Procedure Use

- Cause of the event was not an operating procedure execution issue

- Procedure directed operator component manipulation error rate is very low (estimated less than two per million manipulations)

Corrective Actions

- Implemented "I know because I looked" initiative station wide to improve administrative procedure knowledge and compliance

- Reinforced accountability for equipment status control throughout operations

- Revision to safety related operator rounds points

- Three day station wide campaign for change Event taken seriously and being used as burning platform to move culture to sustained levels of high Operational Excellence 6

,,:::- Exelon Generation.,

Clinton Power Station Regulatory Conference Key Differences Gene Kelly Sr. Manager, Risk Management Johnny Weissinger Director, Operations Exelon Generation

Exelon and NRC Risk Results - Differences Exelon change in CDF I NRC change in CDF 3.8E-6/year

Large difference in our results, a factor of almost 400

The difference is not in PRA methods ... both use similar approaches from a PRA standpoint

Key differences:

- Actual site response in SBO conditions

- Available time to recover power and injection

- Operator experience and training applied to recovery actions

- Complexity associated with power recovery actions Risk analysis should reflect manner in which plant is operated 8

,,:::- Exelon Generation.,

Key Choice Letter Disagreements NRC Position Exelon Position Assumption 12

1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months available to recover AC power to Division 1

Air start valves found isolated within 29 minutes; 2 by recovering DG; ELAP declared at 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months and ELAP not declared FLEX power to Division 2 would commence

DG recovery complicated by SBO load shedding 1

Load shed recovery proceduralized and does not that removes all DC control power from DG complicate DG recovery

FLEX electrical lineup impacts DG components 1

ELAP not declared/FLEX staging only Assumption 13

Experience/training considered Low for DG

DG air start valve position easily identified in recovery diagnosis knowledge-based or procedure-based mode

Operators have not trained on, experienced, or

Operators extensively trained on DG malfunctions been exposed to failed DG 9

,,:::- Exelon Generation.,

Key Choice Letter Disagreements {cont.)

NRC Position Exelon Position Assumption 2

Time to TAF does not appear to credit shutdown

Operators will close one shutdown cooling valve cooling isolation per procedure to extend time to TAF from 10.8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months to about 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months Assumptions 14, 23, 24

FLEX implementation success credited as Low

NRC inspections confirm that FLEX strategy meets regulatory requirements

FLEX lineup experience/training considered Low

FLEX trained in accordance with Systematic Approach to Training

FLEX ergonomics considered Poor

FLEX tasks similar to normal EO tasks &

performed in non-adverse conditions Assumption 15

Div 3 to Div 2 AC power cross-tie is Complex

Procedure is straightforward and not complex

Time required to complete cross-tie is 5-6 hours

Time-validated at 1.5 hours5.787037e-5 days 0.00139 hours 8.267196e-6 weeks 1.9025e-6 months 10

,,:::- Exelon Generation.,

Clinton Power Station Regulatory Conference Initial Conditions for Postulated Event, Recovery and Mitigation Actions Johnny Weissinger Director, Operations Gene Kelly Sr. Manager, Risk Management Exelon Generation

Success Criteria lrd~ction Established Before RPV Water Level Reaches the Top of Active Fuel

Division 2 DG is completely recoverable (no equipment malfunction) and operations response would not complicate recovery

- NRC did not model or credit Division 2 DG after one hour

One action to close a shutdown cooling valve (1E12-F008), as directed by procedure, extends the time to TAF to about 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months

- Does not appear to be modeled in NRC's analysis

DC batteries provide ability to control RPV pressure using SRVs permitting use of low or high pressure injection sources

- Does not appear to be modeled in NRC's analysis 12

,,:::- Exelon Generation.,

Exelon Perspective

RPV injection will be restored prior to reactor water level lowering below TAF through multiple, independent, and diverse means

- Rule-based procedural guidance to restore the DG

- Knowledge-based identification of the DG air start valves

- Cross-tie of the Division 3 DG to the Division 2 bus

- Use of FLEX

Identifying the closed air start valves, reopening them, and restarting the DG per procedure terminates the postulated event

- Significant time available before deterioration of plant conditions

- Operators are extremely knowledgeable and experienced with DG operation

- All actions to identify the valves and restart DG are proceduralized

- Air start valves are readily identifiable and accessible

- Reopening a manual ball valve is a simple task

- Emergency battery lighting and portable flashlights available

- Significant resources onsite to support 13

,,:::- Exelon Generation.,

Bus Alignment During Div 1 & 2 DG Unavailability

~ ~

345 kV Switchyard Plant is in Mode 4 - Cold Shutdown RAT-B XFMR RPV Water Level 235" to 250" above TAF Time To Boil -4 hours Divis. 60V Unplanned out-of-

/ oiv1DG service Div 3 DG Div 2 DG System Outage Window Division 1 138 kV Switchyard - -

~ ~ AC Distribution X AC Distribution Diesel Generator X Diesel Generator 0 AC Distribution X Diesel Generator 0

0 ERAT XFMR RHR-A / SOC X RHR-B / SOC 0 HPCS X LPCS X RHR-C 0 DC Batteries 0 DC Batteries o loc Batteries lo 14 Exelon Generation

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Loss of AC Power Procedure 4200.01 r . ""'Ii Station Blackout (SBO) <<cM- 1>>

A total l oss of offsite AC power sources (including main generator) , and failure o f Div 1 & Div 2 DG power sources .

1.5 Extended Loss of AC Power (ELAP)

A total and sustained (>l hour) loss o f both o ffsite and ons ite AC power sources as a result o f a p ostu l ated Be y o nd Design Basis External Event (BDBEE ) which is expected to exceed the 4 hour4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months SBO coping period .

Definitions are in accordance with CPS licensing basis 580 is not a beyond design basis external event 16 Exelon Generation

LOOP Procedure Direction for ELAP Declaration IF Within 1 HOUR o f the Stati o n Blacko ut , there has n o t been acti o n taken that wo uld provide a HIGH ASSURANCE o f rest o rati o n o f Div 1 and/ o r Div 2 p ower within the 4 h o ur SBO c oping peri o d ,

THEN STOP executing Stati o n Blacko ut acti o ns and immediatel y execute CPS 43 0 6 . 01 Extended Lo ss o f AC Po wer/Lo ss o f UHS .

HIGH ASSURANCE that power will be recovered within 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months includes:

Division 2 DG air start valves identified out of position No maintenance performed on Division 2 DG during outage No degraded conditions for the Division 2 DG existed Shift Manager has High Assurance ELAP does not exist 17 Exelon Generation

Entry into ELAP

Operators are exhaustively trained on the DGs and Loss of AC Power due to high risk significance

- Five simulator scenarios, 26 exam questions, biennial training in last two years

- Operator JPMs for DGs include resetting trips/lockouts and manually bypassing the air start system to manually start the engine with 100% pass rates administered a total of 50 times in the last two years

ERO is trained on LOOP/FLEX

- ERO drills include simulated loss of power and/or loss of DG

- TSC personnel experienced in plant restoration

- Restoration of power is high priority

Six CPS Shift Managers were surveyed for four potential ELAP scenarios

- All surveyed Shift Managers stated they would not declare an ELAP during scenarios where action was taken to recover power within the 4-hour SBO coping period

- All Shift Managers stated they would not enter ELAP/FLEX procedures once the DG air start valves are identified out of position

- All Shift Managers surveyed stated they would pre-stage FLEX equipment to improve plant risk

28 SROs from other stations (including non-Exelon) were given CPS procedures and scenarios that recreated the postulated scenario

- All SROs stated that they remain in the LOOP procedure and NOT enter ELAP No ELAP entry conditions 18

,,:::- Exelon Generation.,

Recovery Pathway #1: Division 2 DG Restoration

Time validation for a CPS EO to walkdown and identify the out of position air start valves using only system knowledge was 11 minutes

Time validation for a CPS EO to identify and correct the out of position air start valves per procedure was 29 minutes

- DG full lineup completed within 40 minutes and in service within 50 minutes

JPM performed by non-CPS EOs to identify out of position air start valves

- All six EOs identified closed air start valves using procedure within 32 minutes

- DG full lineup completed within 37 minutes

Multiple operators, engineers, and technicians would respond, improving DG recovery time Division 2 DG will be recovered in < 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months 19

,,:::- Exelon Generation.,

Rule-Based Operator Response to Division 2 DG Failure to Start Knowledge/ Training-Based Response Procedure/ Rule-Based Response I I DG is recovered.

EOs are trained to check the air start A supervisor and additional EOs arrive Air start valves are system after any DG start. The EO is also to support with the procedure in hand. restored by procedure.

cued by the alarm card.

The out of position air start valves are The Div 2 DG starts The out of position air start valves will be identified by procedure. and restores power.

identified during this walkdown.

Multiple means to identify out of position air start valves 20 Exelon Generation

Operator Response to Division 2 DG Failure to Start {Rule-Based)

.., .. ,. - 0 t , . 'y 1

2 3

4 LOSS OF O,CltATlOH 21 Exelon Generation.,

Operator Alarm Response (Rule-Based)

FAILURE TO START TITLE : FAILURE TO START 5285 - 3D I I DEVICE NAME SETPOINT INDI CATION

< 125 rpm LOCKOUT RELAY TRIPPED Overcrank and amber light ON K4 Relay > 10 sec a f ter star t Dedicated EO requests AUTO ACTIONS a copy of t he DG Lockou~ relay trips .

procedures from the Control Room OPERATOR ACTI ONS Verify DG lB is ready ~o start per CPS 3506 . 01 , Diese l Generator And Support Systems (DG) .

")

If the 4160V Bus 1Bl is deenerg ized after DG lB failure to start ,

refer to CPS 3501 . 01 , High Voltage Auxiliary Power System to reenerg i ze the bus .

3. If required, proceed to CPS 4:00 . 01 , Loss Of AC Power .

22 Exelon Generation

Operator Alarm Response (Rule-Based)

Opening of the air start valves is procedurally governed 2.0 Plac ing DG lB in standby CPS 3506 . 01 P002 On Page 6 of DG 2 .2 S tarting Air S ystem operating procedure

6. Open and lock open the f o l lowing Air Starting Sys tem Air Re ceiver Outl et Va l ves :

1) 1DG160, A~r Receive r A Outl et . D

2) 1JG161 , A~r Receive r B Outlet D Restoration of DC control power following load shed is procedurally governed and does not complicate DG recovery

4. 2 .4 Re-Energizing 4160V Bus 1A1 (1B1 ) [lCl] Using DG 1A (1B) [lC]

4. (Loca l } Fo r applicabl e Bus 1A1(1B1) r e - e ne r g iza tion :

Load shed circuits Ve r ify Ckt t l3(1 4 ) [DG 1A (18) control] & Ckt i 32 (RHR are recovered per contro l ) on DC MCC 1A(1B) [1 DC13(1 4 ) EJ are re- energ ized if Loss of AC Power t urned o ff b y CPS 4200 . 01C002 , DC Load Shedding Dur ing A SBO . procedure DG recovered completely by procedures 23 Exelon Generation

Operator Response to Division 2 DG Failure to Start {Knowledge-Based)

I FAILURE TO START I

TITLE : FAILURE TO START 5~85-3D DEVICE NA.'1E SETPOINT INDICATION

< 1:s rpm LOCKOUT RELAY TRIPPED K4 Overcrank and amber light ON Relay > 10 sec after start:

POSSIBLE CAUSE Starting air receiver pressure is

_.._------- 225-250 psig and did not lower as G) Low starting air p ressur e + expected following DG start signal

')

Lockout relay not reset

3. Overspeed trip handle not reset

4. Safety shutdown circuits not re s et

5. Eng ine maintenance switch in LOCKOUT posit ion 24 Exelon Generation

Operator Validates DG Starting Air Parameters Division 2 DG Local Air Start Pressure Division 2 DG Air Receiver Pressure Located on gauge board, as found during the event Tech Spec LCO 3.8.3 Required to log on operator rounds Normal pressure Not on operator rounds prior to event '--------------=-- is 225-250 psig EO identifies closed air start valves based on alarms and local indications 25 Exelon Generation

Operator Response to Division 2 DG Failure to Start This flow path was most recently trained in 2017 Air start path can be easily traced back to the receivers EO JPM to start the DG by overriding the air start system solenoids/lineup; 100% pass rate across 27 Operators in 2017 26

Operator Validates Air Start System Did Not Actuate Through Equipment Checks If the DG received starting air, an oi l spray/mist would be visible below the exhaust of the six air start motors 27 Exelon Generation

Operator Response to Division 2 DG Failure to Start Walking down the air start system is trained and performed with the monthly DG runs CPS 9080 . 02 8 .2 DG 1B Operability (cont ' d) 8 .2.3 Start Diesel Generator lB (cont ' d)

7) Start DG lB with 0G lB control switch .

8 .2.4 Veri:y the following :

6. (Local) Verify that an oil mist was exhausted from OR oil residue exists in the exhaust port of alT""DG air stare motors :

'6"" Can be ind~cated by oil on the engine next to the air start exhaust port.

EOs trained to check air start system response after DG start 28 Exelon Generation

Operator Identifies Out Of Position Air Start Valves Division 2 DG air start valve in the Left over tie wraps from clearance order normal "Locked Open" position tags as found on 5/17/18 "Tags Plus" straps left on air start valves 29 Exelon Generation.,

Operator Response to Division 2 DG Failure to Start Video 30

,,:::- Exelon Generation.,

DG Restoration Summary

Identification of the out of position air start valves will occur in either knowledge or rule-based space

Air start valves are time validated to be identified by knowledge in 11 minutes and procedure in 29 minutes

DG recovery is simple task (open air start valves) using regularly executed DG lineup procedure

Identification of closed air start valves and no visible damage provides Shift Manager High Assurance of Division 2 power recovery

- An ELAP will not be declared

OCC/ERO technical support and large number of resources We had knowledge, time, and resources to restore Division 2 DG 31

,,:::- Exelon Generation.,

Impact of Actual Response: Div 2 DG Recovery Exelon 's DG HEP NRC's DG HEP 0.005 0.2 (99.5% success) (80% success)

Realistic modeling of Division 2 DG recovery, by itself, leads to GREEN significance

- NRC's sensitivity case #3 (using Exelon's HEP) shows Green SPAR-H HEP Impact on PSF I NRC Diagnosis Setting I Exelon Position I Reduction Finding Factor Expansive Available Time Nominal only need 2 hrs, but I -50 (required time <1 hr) 1 hr 24 hrs available Experience/Training I Low I Nominal I -10 Considerable available time, and operator experience and training assure high success 32

,,:::- Exelon Generation.,

Minimum Shift Staffing Control Room Team Shift Manager (SRO) tt t ttt 2 Senior Reactor Operators 3 Reactor Operators tttttt 6 Equipment Operators Dedicated On Duty Security Force Members

+

1 IM/ EM ERO

++ +

2 RP Technicians Chemistry Technician 33 Exelon Generation

Outage Response Staffing

137 - Minimum craft staffing on any shift during the affected window of C1R18 ttttttttt ttt t tt Control Room Team tttttttt ttttttttt tt,* M;~~~er ttt tttttttt ttttttttt 27 Equipment Operators (SRO) 6 Senior Reactor Operators 5 Reactor Operat ors 16 Electricians I 11 tttt tttttttttt ttttttttttt 4 Chemistry Technicians tttt,,,,,, ttttttttttt tttttt tttttttt,,

30 Mechanics ttttttttttt ttttt ttttttttttt 44 Instrument Maintenance 11 Radiation Protection Technicians Technicians 34 Exelon Generation

Event Recovery Timeline Activities in Series Start 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months 10 hours1.157407e-4 days 0.00278 hours 1.653439e-5 weeks 3.805e-6 months 12 hours Restore Div 2 DG to Service (50 min) ~

Complete DC Load Shed (1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months ) =)+

Commence FLEX Pre-Staging (1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months ) Q+

ERO Is Staffed (Alert) (1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months ) Y+

Complete Div 3 to Div 2 X-Tie (1.5 hours5.787037e-5 days 0.00139 hours 8.267196e-6 weeks 1.9025e-6 months ) ~

End of SBO. Commence FLEX (4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months ) ~~ r -'

FLEX is ready for RPV injection (5 hour5.787037e-5 days 0.00139 hours 8.267196e-6 weeks 1.9025e-6 months s*) *.>+

'-.. ~

I RCS Boiling Begins (4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months ) ~~ ~

Shutdown Cooling Isolated within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months ~~

Time to TAF (No Operator Actions) (10.8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months ) I I I I ,.>+

Time to TAF (SOC isolated or RPV pressure '

controlled low with Batteries) (-24 hours) V 5 hours5.787037e-5 days 0.00139 hours 8.267196e-6 weeks 1.9025e-6 months is the worst case for FLEX RPV injection and 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months is the worst case FLEX heat removal and suppression pool makeup. RPV injection commences before TAF in all cases.

1 hour subtracted from FLEX times because they overlap with the first hour of SBO actions.

35 Exelon Generation.,

Recovery Pathway #2:

Cross-Tie Div 3 DG to Div 2 Bus

- Bus cross-tie completion validated to complete in 1.5 hours5.787037e-5 days 0.00139 hours 8.267196e-6 weeks 1.9025e-6 months

- Open one in-plant disconnect

- Open four relay test switches

- Remove one relay control power fuse

- Control Room performs breaker alignments

- Tools pre-staged in operations locked cages and all manipulations in general plant areas

- Switchgear breaker and disconnect training occurs every two years

- Four page procedure with pictures, locations, and diagrams simplify execution At 1AP09EH, 4160V Bus 1B1 DG1B Feed 1DG01KB, remove cover and open the following test switch :

1.2.1 Lock open 1APET4, ET4 Disconnect Switch, CB 737' S.5-129 outside laundry area. (Key #38 - WEC Office) (Figure 1) 1) Test switch 4 (fourth from left, bottom) on relay 227X2-21B1-2 (Figure 4)

Figure1 Control Building737' @

I a I I ET-4 I I I I 11

=Ii Operating handles for ET4 or ET14. Handles are stored in the electri cal equipment locker located In OPS cage on 762' OG (Hl orGMaster Key required for cage access).

36 Exelon Generation

Cross-Tie Div 3 DG to Div 2 Bus During SBO 345kvMchyard ~ ~

RAT-B XFMR Divi" 60V Unplanned Out of Div 1 DG service Div 2 DG System Outage Window Division 1 138 kvMchyard - -

~ ~ AC Distribution Diesel Generator X AC Distribution X Diesel Generator 0 AC Distribution X Diesel Generator 0

0 ERAT XFMR RHR-A / SOC X RHR-B / SOC 0 HPCS X LPCS X RHR-C 0 DC Batteries 0 DC Batteries o loc Batteries lo 37 Exelon Generation

Impact of Actual Response: Div 3 to Div 2 Cross-Tie Exelon's Cross-Tie HEP NRC's Cross-Tie HEP 0.096 0.27 (90.4% success) (73% success)

SPAR-H HEP Impact on PSF I NRC Action Setting I Exelon Position I Reduction Finding Factor I

Available Time Nominal Extra (required time -1.5 hr) (13 hours1.50463e-4 days 0.00361 hours 2.149471e-5 weeks 4.9465e-6 months ) (24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months )

Experience/Training Low Nominal I

-7 I

Ergonomics I Poor I Nominal Complexity I High I Moderate Realistic modeling of Division 3 cross-tie, coupled with higher likelihood of offsite power recovery within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , leads to Green 38

,,:::- Exelon Generation.,

Recovery Pathway #3:

FLEX Implementation and Timeline Extended Loss of AC Power /

Loss of Ultimate Heat Sink ENTRY CONDITION STATION BLACKOUT

ENTER 4200.01 Loss of AC Power, Section, 4.4 G

Station Blackout Do NOT continue in this procedure until directed by 4200.01.

FLEX equipment pre-staged in parallel until implementation required 39 Exelon Generation

FLEX Implementation and Timeline

By 2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months s: Briefs complete, teams ready to dispatch

By 4 hour4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months s: Pre-staging complete, hoses and cables run to location, FLEX generator running in standby; plant realignment occurs when directed by Control Room Supervisor

By 6 hour6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months s: Battery charger in service powering Division 2 batteries, low pressure RPV makeup is available

By 8 hour9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months s: Decay heat removal and suppression pool makeup available

Minimum Personnel: 6 Operators, 6 Security Force Members (for 3 hours3.472222e-5 days 8.333333e-4 hours 4.960317e-6 weeks 1.1415e-6 months ), 2 Radiation Protection Technicians, 1 Chemistry Technician

Outage Personnel: At least 15 Qualified Operators + Supervision, Electrical and Mechanical maintenance dispatched by the ERO to support as necessary 40

,,:::- Exelon Generation.,

FLEX Training and Experience

Task specific procedures are located in field FLEX cabinets

Procedures are designed to be "Grab and go" and have prerequisite steps built into each section to ensure all required manipulations are completed

Most tasks are similar to normal EO tasks

- Racking breakers

- Starting FLEX generator (similar to TSC generator)

- Routing cable or hoses

Trained in accordance with the Systematic Approach to Training

From NRC Inspection Report Tl-191: "licensee has trained their staff to assure personnel proficiency in the mitigation of beyond DB events" EOs trained and proficient with FLEX equipment and procedures 41

,,:::- Exelon Generation.,

Impacts of Actual Response: FLEX Alignment Exelon's FLEX HEP NRC's FLEX HEP 0.002 0.25 (99.8% success) (75% success)

SPAR-H HEP Impact on PSF I NRC Action Setting I Exelon Position I Reduction Finding Factor I

Available Time Nominal Extra (required time -4 hr) (13 hours1.50463e-4 days 0.00361 hours 2.149471e-5 weeks 4.9465e-6 months ) (24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months )

Experience/Training Low Nominal I

-12 I

Ergonomics I Poor I Nominal Complexity I High I Nominal Realistic modeling of FLEX deployment, coupled with higher likelihood of offsite power recovery within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , leads to Green 42

,,:::- Exelon Generation.,

RPV Pressure Control

SRVs are available for pressure control for> 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months

- Division 1 and 2 DC batteries analyzed with > 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months capacity with outage loads

- ADS accumulators and backup air bottles fully charged

Procedure guidance to stabilize pressure in multiple procedures

- Station Blackout, Loss of Shutdown Cooling, EOP-1, FLEX

EOP-1 directs holding RPV pressure< 104 psig until shutdown cooling restored

Time to boil is 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months , SRV usage not needed until at least 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months RPV pressure controlled to allow use of low pressure injection systems 43

,,:::- Exelon Generation.,

Injection

Multiple diverse injection systems available after Division 2 AC power restored using proceduralized actions

- Within 1 minute, start Standby Liquid Control pump "B" from Control Room

43 gpm (4000 gallon tank), injects at any pressure, no field actions required

- Within 1 minute, start RHR-B/C water leg pump from Control Room

50 gpm with RPV depressurized, no field actions required

- Manually start RHR-C for Low Pressure Coolant Injection (LPCI)

- Align RHR-B from shutdown cooling to LPCI mode

Additional injection systems using proceduralized actions

- FLEX pump direct injection from Ultimate Heat Sink

- Suppression Pool Transfer Pump using FLEX generator power

- Fire pump injection (direct to RPV or using hoses)

Any one path restores RPV level 44

,,:::- Exelon Generation.,

Impact of Actual Response - Pressure/Inventory Control Exelon HEP NRC HEP SOC Isolation 0.022 Not modeled (98% success)

Maintain RPV Pressure (Using Division 1 or 2 Batteries) 0.001 Not modeled (99.9% success)

Both actions procedurally directed

Success of EITHER action extends time to TAF to about 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months

- Increases Available Time for Diagnosis and Action to restore onsite equipment

- Increases likelihood of offsite power recovery

Division 1 and 2 batteries available for RPV pressure control (SRVs) for 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months

RPV pressure control enhances ability for low or high pressure injection sources Realistic modeling of loss of shutdown cooling actions and RPV pressure control, coupled with multiple sources of injection, leads to Green 45

,,:::- Exelon Generation.,

Recovery and Mitigation Actions Summary

Identification of out of position air start valves will occur

DG recovery is simple task (open air start valves)

Shift Manager has High Assurance of Division 2 power recovery

Activities to restore power taken in parallel but controlled to minimize conflicts

Other defense-in-depth actions provide additional success paths within the available time AC power and injection recovered quickly and successfully 46

,,:::- Exelon Generation.,

Clinton Power Station Regulatory Conference Risk Significance Gene Kelly Sr. Manager, Risk Management Exelon Generation

Risk Assessment for Safety Significance For White significance, NRC must conclude the SBO condition would not be successfully mitigated because:

- Division 2 DG not recovered within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months and

- ELAP declared at 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months and

- Shutdown cooling valve not isolated and

- RPV pressure not controlled and

- Division 3 to Division 2 AC power cross-tie procedurally complex and

- FLEX strategy inadequate and not sufficiently trained 48

,,:::- Exelon Generation.,

Clinton Power Station Regulatory Conference Conclusion Ted Stoner Site Vice President Exelon Generation

Conclusion

We had the knowledge, time, and resources to restore AC power

NRC policy and guidance dictate risk evaluations to be realistic and based on the best available information

Best available information includes:

- Reflecting a realistic response to the event

- Recognizing extensive operator training and experience

- Appropriately crediting FLEX

Using the best available information as presented today and applying the Commission's guiding policies and principles on risk results in:

50

,,:::- Exelon Generation.,

(b)(5)

(b )(5)

(b)(5)

Note to requester: The first, second, fourth, and fifth attachments to this email have been withheld in their entirety under FOIA Ex. 85 (deliberative process privilege). The third attachment is publicly available at https://www.nrc.gov/docs/ ML 1833/M L 18333A333.pdf and also included following this email document.

From: Heck Jared To: Giessner John

Subject:

FW: Clinton info discussion next week

Wednesday Dat e: Thursday, January 17, 2019 10:19:00 AM Attachments: CU 2018 051 ERRATA (non-oublic).docx (b )(5) I . . . . . . . .... . . ... .... ... . . . . . . . . . . . . . . . . . . . . . I

CPS Qiv 2 DG Reg Conf Presentation. (11-19-18)(01 ).pdt BS-18-146 (Attachments 1 and 2) pdf SRO Surveys (redacted).pd(

Per your request From: Kozak, Lau ra Sent: Thursday, Jan uary 10, 2019 8:11 AM To: Lara, Julio <J ulio. Lara@nrc.gov>; Riemer, Ken neth <Kenneth.Riemer@n rc.gov>; Stoedter, Karla

<Ka rla.Stoedt er@nrc.gov>; Cameron, Jamnes <Jamnes.Cameron@nrc.gov>; Heck, Jared

<Jared.Heck@nrc.gov>

Subject:

Clinton info discussion next week - Wednesday All (b)(S)

Let me know if you want to discuss in any detail before next week's meeting and I can go through the material with you.

Laura

(b)(5)

Clinton Power Station Regulatory Conference Division 2 Diesel Generator Air Start Isolation Event November 30, 2018 Exelon Generation

Agenda

Introduction . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . Brad Fewel I

Finding Cause and Corrective Actions ............... Brad Kapellas

Key Differences. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gene Kelly/Johnny Weissinger

Initial Conditions for Postulated Event, Recovery and Mitigation Actions ........................... Johnny Weissinger/Gene Kelly

Risk Significance................................ Gene Kelly

Conclusion ..................................... Ted Stoner 1

,,:::- Exelon Generation.,

Clinton Power Station Regulatory Conference Introduction Brad Fewell Senior Vice President, Regulatory Affairs and General Counsel Exelon Generation

Introduction

We agree with the Finding and violation

We recognize our failure to maintain the configuration of an important safety system

We have taken timely, comprehensive, and broad responsive actions

We disagree with the Finding's preliminary significance of White

- Commission Policy and NRC guidance drive risk evaluations to be realistic and based on best available information

- NRC risk evaluation does not reflect the as-built, as-operated plant response

NRC's risk evaluation assumptions do not reflect how CPS would respond to DG recovery, SBO, FLEX, and ELAP by not appropriately crediting:

- Operators' extensive knowledge, training, and experience

- Available time to take recovery actions

- Procedures that control the event and drive successful resolution PRA evaluations should be realistic and based on best available information 3

,,:::- Exelon Generation.,

Introduction (cont.)

We will show that using realistic and best-available information:

- Division 2 DG would have been restored and injection available within one hour

- Expansive time was available to recover AC power and prevent core uncovery

- Procedurally directed alternative power recovery actions would have been pursued in parallel

- Objective data to support different performance shaping factor (PSF) multipliers

We will provide information that the NRC did not previously review and new information that we have recently developed

We had the knowledge, time, and resources to restore AC power and injection Finding should be characterized as Green 4

,,:::- Exelon Generation.,

Clinton Power Station Regulatory Conference Finding Cause and Corrective Actions Brad Kapellas Plant Manager Exelon Generation

Station Event Response

Root Cause

- Contrary to Exelon fleet governance for plant status control, operator logs were utilized as the sole means to track plant configuration

Corrective Action to Prevent Reoccurrence

- Identify and eliminate legacy site-specific administrative procedures/guidance that allow operator logs as a sole method for plant status control

Continuous Procedure Use

- Cause of the event was not an operating procedure execution issue

- Procedure directed operator component manipulation error rate is very low (estimated less than two per million manipulations)

Corrective Actions

- Implemented "I know because I looked" initiative station wide to improve administrative procedure knowledge and compliance

- Reinforced accountability for equipment status control throughout operations

- Revision to safety related operator rounds points

- Three day station wide campaign for change Event taken seriously and being used as burning platform to move culture to sustained levels of high Operational Excellence 6

,,:::- Exelon Generation.,

Clinton Power Station Regulatory Conference Key Differences Gene Kelly Sr. Manager, Risk Management Johnny Weissinger Director, Operations Exelon Generation

Exelon and NRC Risk Results - Differences Exelon change in CDF I NRC change in CDF 3.8E-6/year

Large difference in our results, a factor of almost 400

The difference is not in PRA methods ... both use similar approaches from a PRA standpoint

Key differences:

- Actual site response in SBO conditions

- Available time to recover power and injection

- Operator experience and training applied to recovery actions

- Complexity associated with power recovery actions Risk analysis should reflect manner in which plant is operated 8

,,:::- Exelon Generation.,

Key Choice Letter Disagreements NRC Position Exelon Position Assumption 12

1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months available to recover AC power to Division 1

Air start valves found isolated within 29 minutes; 2 by recovering DG; ELAP declared at 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months and ELAP not declared FLEX power to Division 2 would commence

DG recovery complicated by SBO load shedding 1

Load shed recovery proceduralized and does not that removes all DC control power from DG complicate DG recovery

FLEX electrical lineup impacts DG components 1

ELAP not declared/FLEX staging only Assumption 13

Experience/training considered Low for DG

DG air start valve position easily identified in recovery diagnosis knowledge-based or procedure-based mode

Operators have not trained on, experienced, or

Operators extensively trained on DG malfunctions been exposed to failed DG 9

,,:::- Exelon Generation.,

Key Choice Letter Disagreements {cont.)

NRC Position Exelon Position Assumption 2

Time to TAF does not appear to credit shutdown

Operators will close one shutdown cooling valve cooling isolation per procedure to extend time to TAF from 10.8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months to about 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months Assumptions 14, 23, 24

FLEX implementation success credited as Low

NRC inspections confirm that FLEX strategy meets regulatory requirements

FLEX lineup experience/training considered Low

FLEX trained in accordance with Systematic Approach to Training

FLEX ergonomics considered Poor

FLEX tasks similar to normal EO tasks &

performed in non-adverse conditions Assumption 15

Div 3 to Div 2 AC power cross-tie is Complex

Procedure is straightforward and not complex

Time required to complete cross-tie is 5-6 hours

Time-validated at 1.5 hours5.787037e-5 days 0.00139 hours 8.267196e-6 weeks 1.9025e-6 months 10

,,:::- Exelon Generation.,

Clinton Power Station Regulatory Conference Initial Conditions for Postulated Event, Recovery and Mitigation Actions Johnny Weissinger Director, Operations Gene Kelly Sr. Manager, Risk Management Exelon Generation

Success Criteria lrd~ction Established Before RPV Water Level Reaches the Top of Active Fuel

Division 2 DG is completely recoverable (no equipment malfunction) and operations response would not complicate recovery

- NRC did not model or credit Division 2 DG after one hour

One action to close a shutdown cooling valve (1E12-F008), as directed by procedure, extends the time to TAF to about 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months

- Does not appear to be modeled in NRC's analysis

DC batteries provide ability to control RPV pressure using SRVs permitting use of low or high pressure injection sources

- Does not appear to be modeled in NRC's analysis 12

,,:::- Exelon Generation.,

Exelon Perspective

RPV injection will be restored prior to reactor water level lowering below TAF through multiple, independent, and diverse means

- Rule-based procedural guidance to restore the DG

- Knowledge-based identification of the DG air start valves

- Cross-tie of the Division 3 DG to the Division 2 bus

- Use of FLEX

Identifying the closed air start valves, reopening them, and restarting the DG per procedure terminates the postulated event

- Significant time available before deterioration of plant conditions

- Operators are extremely knowledgeable and experienced with DG operation

- All actions to identify the valves and restart DG are proceduralized

- Air start valves are readily identifiable and accessible

- Reopening a manual ball valve is a simple task

- Emergency battery lighting and portable flashlights available

- Significant resources onsite to support 13

,,:::- Exelon Generation.,

Bus Alignment During Div 1 & 2 DG Unavailability

~ ~

345 kV Switchyard Plant is in Mode 4 - Cold Shutdown RAT-B XFMR RPV Water Level 235" to 250" above TAF Time To Boil -4 hours Divis. 60V Unplanned out-of-

/ oiv1DG service Div 3 DG Div 2 DG System Outage Window Division 1 138 kV Switchyard - -

~ ~ AC Distribution X AC Distribution Diesel Generator X Diesel Generator 0 AC Distribution X Diesel Generator 0

0 ERAT XFMR RHR-A / SOC X RHR-B / SOC 0 HPCS X LPCS X RHR-C 0 DC Batteries 0 DC Batteries o loc Batteries lo 14 Exelon Generation

C

.o 0

m tn ca

....0 Q) tn C

0 Q.

tn Q) 0::

C 0

-....ca tn 11-0

~

Q)

Q) 0

Loss of AC Power Procedure 4200.01 r . ""'Ii Station Blackout (SBO) <<cM- 1>>

A total l oss of offsite AC power sources (including main generator) , and failure o f Div 1 & Div 2 DG power sources .

1.5 Extended Loss of AC Power (ELAP)

A total and sustained (>l hour) loss o f both o ffsite and ons ite AC power sources as a result o f a p ostu l ated Be y o nd Design Basis External Event (BDBEE ) which is expected to exceed the 4 hour4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months SBO coping period .

Definitions are in accordance with CPS licensing basis 580 is not a beyond design basis external event 16 Exelon Generation

LOOP Procedure Direction for ELAP Declaration IF Within 1 HOUR o f the Stati o n Blacko ut , there has n o t been acti o n taken that wo uld provide a HIGH ASSURANCE o f rest o rati o n o f Div 1 and/ o r Div 2 p ower within the 4 h o ur SBO c oping peri o d ,

THEN STOP executing Stati o n Blacko ut acti o ns and immediatel y execute CPS 43 0 6 . 01 Extended Lo ss o f AC Po wer/Lo ss o f UHS .

HIGH ASSURANCE that power will be recovered within 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months includes:

Division 2 DG air start valves identified out of position No maintenance performed on Division 2 DG during outage No degraded conditions for the Division 2 DG existed Shift Manager has High Assurance ELAP does not exist 17 Exelon Generation

Entry into ELAP

Operators are exhaustively trained on the DGs and Loss of AC Power due to high risk significance

- Five simulator scenarios, 26 exam questions, biennial training in last two years

- Operator JPMs for DGs include resetting trips/lockouts and manually bypassing the air start system to manually start the engine with 100% pass rates administered a total of 50 times in the last two years

ERO is trained on LOOP/FLEX

- ERO drills include simulated loss of power and/or loss of DG

- TSC personnel experienced in plant restoration

- Restoration of power is high priority

Six CPS Shift Managers were surveyed for four potential ELAP scenarios

- All surveyed Shift Managers stated they would not declare an ELAP during scenarios where action was taken to recover power within the 4-hour SBO coping period

- All Shift Managers stated they would not enter ELAP/FLEX procedures once the DG air start valves are identified out of position

- All Shift Managers surveyed stated they would pre-stage FLEX equipment to improve plant risk

28 SROs from other stations (including non-Exelon) were given CPS procedures and scenarios that recreated the postulated scenario

- All SROs stated that they remain in the LOOP procedure and NOT enter ELAP No ELAP entry conditions 18

,,:::- Exelon Generation.,

Recovery Pathway #1: Division 2 DG Restoration

Time validation for a CPS EO to walkdown and identify the out of position air start valves using only system knowledge was 11 minutes

Time validation for a CPS EO to identify and correct the out of position air start valves per procedure was 29 minutes

- DG full lineup completed within 40 minutes and in service within 50 minutes

JPM performed by non-CPS EOs to identify out of position air start valves

- All six EOs identified closed air start valves using procedure within 32 minutes

- DG full lineup completed within 37 minutes

Multiple operators, engineers, and technicians would respond, improving DG recovery time Division 2 DG will be recovered in < 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months 19

,,:::- Exelon Generation.,

Rule-Based Operator Response to Division 2 DG Failure to Start Knowledge/ Training-Based Response Procedure/ Rule-Based Response I I DG is recovered.

EOs are trained to check the air start A supervisor and additional EOs arrive Air start valves are system after any DG start. The EO is also to support with the procedure in hand. restored by procedure.

cued by the alarm card.

The out of position air start valves are The Div 2 DG starts The out of position air start valves will be identified by procedure. and restores power.

identified during this walkdown.

Multiple means to identify out of position air start valves 20 Exelon Generation

Operator Response to Division 2 DG Failure to Start {Rule-Based)

.., .. ,. - 0 t , . 'y 1

2 3

4 LOSS OF O,CltATlOH 21 Exelon Generation.,

Operator Alarm Response (Rule-Based)

FAILURE TO START TITLE : FAILURE TO START 5285 - 3D I I DEVICE NAME SETPOINT INDI CATION

< 125 rpm LOCKOUT RELAY TRIPPED Overcrank and amber light ON K4 Relay > 10 sec a f ter star t Dedicated EO requests AUTO ACTIONS a copy of t he DG Lockou~ relay trips .

procedures from the Control Room OPERATOR ACTI ONS Verify DG lB is ready ~o start per CPS 3506 . 01 , Diese l Generator And Support Systems (DG) .

")

If the 4160V Bus 1Bl is deenerg ized after DG lB failure to start ,

refer to CPS 3501 . 01 , High Voltage Auxiliary Power System to reenerg i ze the bus .

3. If required, proceed to CPS 4:00 . 01 , Loss Of AC Power .

22 Exelon Generation

Operator Alarm Response (Rule-Based)

Opening of the air start valves is procedurally governed 2.0 Plac ing DG lB in standby CPS 3506 . 01 P002 On Page 6 of DG 2 .2 S tarting Air S ystem operating procedure

6. Open and lock open the f o l lowing Air Starting Sys tem Air Re ceiver Outl et Va l ves :

1) 1DG160, A~r Receive r A Outl et . D

2) 1JG161 , A~r Receive r B Outlet D Restoration of DC control power following load shed is procedurally governed and does not complicate DG recovery

4. 2 .4 Re-Energizing 4160V Bus 1A1 (1B1 ) [lCl] Using DG 1A (1B) [lC]

4. (Loca l } Fo r applicabl e Bus 1A1(1B1) r e - e ne r g iza tion :

Load shed circuits Ve r ify Ckt t l3(1 4 ) [DG 1A (18) control] & Ckt i 32 (RHR are recovered per contro l ) on DC MCC 1A(1B) [1 DC13(1 4 ) EJ are re- energ ized if Loss of AC Power t urned o ff b y CPS 4200 . 01C002 , DC Load Shedding Dur ing A SBO . procedure DG recovered completely by procedures 23 Exelon Generation

Operator Response to Division 2 DG Failure to Start {Knowledge-Based)

I FAILURE TO START I

TITLE : FAILURE TO START 5~85-3D DEVICE NA.'1E SETPOINT INDICATION

< 1:s rpm LOCKOUT RELAY TRIPPED K4 Overcrank and amber light ON Relay > 10 sec after start:

POSSIBLE CAUSE Starting air receiver pressure is

_.._------- 225-250 psig and did not lower as G) Low starting air p ressur e + expected following DG start signal

')

Lockout relay not reset

3. Overspeed trip handle not reset

4. Safety shutdown circuits not re s et

5. Eng ine maintenance switch in LOCKOUT posit ion 24 Exelon Generation

Operator Validates DG Starting Air Parameters Division 2 DG Local Air Start Pressure Division 2 DG Air Receiver Pressure Located on gauge board, as found during the event Tech Spec LCO 3.8.3 Required to log on operator rounds Normal pressure Not on operator rounds prior to event '--------------=-- is 225-250 psig EO identifies closed air start valves based on alarms and local indications 25 Exelon Generation

Operator Response to Division 2 DG Failure to Start This flow path was most recently trained in 2017 Air start path can be easily traced back to the receivers EO JPM to start the DG by overriding the air start system solenoids/lineup; 100% pass rate across 27 Operators in 2017 26

Operator Validates Air Start System Did Not Actuate Through Equipment Checks If the DG received starting air, an oi l spray/mist would be visible below the exhaust of the six air start motors 27 Exelon Generation

Operator Response to Division 2 DG Failure to Start Walking down the air start system is trained and performed with the monthly DG runs CPS 9080 . 02 8 .2 DG 1B Operability (cont ' d) 8 .2.3 Start Diesel Generator lB (cont ' d)

7) Start DG lB with 0G lB control switch .

8 .2.4 Veri:y the following :

6. (Local) Verify that an oil mist was exhausted from OR oil residue exists in the exhaust port of alT""DG air stare motors :

'6"" Can be ind~cated by oil on the engine next to the air start exhaust port.

EOs trained to check air start system response after DG start 28 Exelon Generation

Operator Identifies Out Of Position Air Start Valves Division 2 DG air start valve in the Left over tie wraps from clearance order normal "Locked Open" position tags as found on 5/17/18 "Tags Plus" straps left on air start valves 29 Exelon Generation.,

Operator Response to Division 2 DG Failure to Start Video 30

,,:::- Exelon Generation.,

DG Restoration Summary

Identification of the out of position air start valves will occur in either knowledge or rule-based space

Air start valves are time validated to be identified by knowledge in 11 minutes and procedure in 29 minutes

DG recovery is simple task (open air start valves) using regularly executed DG lineup procedure

Identification of closed air start valves and no visible damage provides Shift Manager High Assurance of Division 2 power recovery

- An ELAP will not be declared

OCC/ERO technical support and large number of resources We had knowledge, time, and resources to restore Division 2 DG 31

,,:::- Exelon Generation.,

Impact of Actual Response: Div 2 DG Recovery Exelon 's DG HEP NRC's DG HEP 0.005 0.2 (99.5% success) (80% success)

Realistic modeling of Division 2 DG recovery, by itself, leads to GREEN significance

- NRC's sensitivity case #3 (using Exelon's HEP) shows Green SPAR-H HEP Impact on PSF I NRC Diagnosis Setting I Exelon Position I Reduction Finding Factor Expansive Available Time Nominal only need 2 hrs, but I -50 (required time <1 hr) 1 hr 24 hrs available Experience/Training I Low I Nominal I -10 Considerable available time, and operator experience and training assure high success 32

,,:::- Exelon Generation.,

Minimum Shift Staffing Control Room Team Shift Manager (SRO) tt t ttt 2 Senior Reactor Operators 3 Reactor Operators tttttt 6 Equipment Operators Dedicated On Duty Security Force Members

+

1 IM/ EM ERO

++ +

2 RP Technicians Chemistry Technician 33 Exelon Generation

Outage Response Staffing

137 - Minimum craft staffing on any shift during the affected window of C1R18 ttttttttt ttt t tt Control Room Team tttttttt ttttttttt tt,* M;~~~er ttt tttttttt ttttttttt 27 Equipment Operators (SRO) 6 Senior Reactor Operators 5 Reactor Operat ors 16 Electricians I 11 tttt tttttttttt ttttttttttt 4 Chemistry Technicians tttt,,,,,, ttttttttttt tttttt tttttttt,,