Text

License Amendment Request: Inverter Allowed Outage Time (AOT) Extension
	ML18103A218
Person / Time
Site:	Hope Creek
Issue date:	04/13/2018
From:	Carr E; Public Service Enterprise Group
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	LAR H18-02, LR-N18-0032
	Download: ML18103A218 (104)
	v • d • e

PSEG Nuclear LLC P.O. Box 236, Hancocks Bridge, New Jersey 08038-0236 0PSEG Nuclear LLC 10 CFR 50.90 LR-N18-0032 LAR H18-02 APR 13 2018 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001 Hope Creek Generating Station Renewed Facility Operating License No. NPF-57 NRC Docket No. 50-354

Subject:

License Amendment Request: Inverter Allowed Outage Time (AOT)

Extension In accordance with 10 CFR 50.90, PSEG Nuclear LLC (PSEG) hereby requests an amendment to Renewed Facility Operating License No. NPF-57 for Hope Creek Generating Station.

This license amendment request proposes changes to Technical Specification (TS) 3.8.3.1, "Distribution - Operating." The proposed change would increase the Alternating Current (AC)

Inverters allowed outage time (AOD from 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months to 7 days. The proposed extended AOT is based on application of the Hope Creek Generating Station (HCGS) Probabilistic Risk Assessment (PRA), and on additional considerations and compensatory actions. The risk evaluation and deterministic engineering analysis supporting the proposed change have been developed in accordance with the guidelines established in NRC Regulatory Guide 1.177, "An Approach for Plant-Specific Risk-Informed Decisionmaking: Technical Specifications," and NRC Regulatory Guide 1.174, "An Approach for Using Probabilistic Risk Assessment in Risk Informed Decisions on Plant-Specific Changes to the Licensing Basis."

The proposed change will allow increased flexibility in the scheduling and performance of corrective maintenance, allow better control and allocation of resources, and avert unnecessary plant shutdowns.

95-2168 REV. 7/99

APR 13 2rniB 10 CFR 50.90 Page 2 LR-N18-0032 PSEG's technical and regulatory evaluation of this LAR and the TS change are provided in an enclosure to this letter which includes the supporting risk-informed evaluation of the proposed change.

The proposed change has been evaluated in accordance with 10 CFR 50.91 (a)(1), using the criteria in 10 CFR 50.92(c), and it has been determined that this request involves no significant hazards considerations.

There are no regulatory commitments contained in this letter.

PSEG requests NRC approval of the proposed License Amendment within one year of submittal acceptance, to be implemented within 60 days of issuance.

In accordance with 10 CFR 50.91(b)(1), a copy of this request for amendment has been sent to the State of New Jersey.

If you have any questions or require additional information, please contact Mr. Lee Marabella at (856) 339-1208.

I declare under penalty of perjury that the foregoing is true and correct.

Executed on __ Cf-;_

...!L..- r....J"--.::; /;--__-!./ ?

(Date)

Eric Carr Site Vice President Hope Creek Generating Station

Enclosure:

Evaluation of the Proposed Change C. Administrator, Region I, NRC Project Manager, NRC NRC Senior Resident Inspector, Hope Creek Mr. P. Mulligan, Chief, NJBNE Mr. L. Marabella, Corporate Commitment Tracking Coordinator Mr. T. MacEwen, Hope Creek Commitment Tracking Coordinator

APR 1.3 2018 10 CFR 50.90 Page 3 LR-N18-0032 (The bee list should not be submitted as part of the EIE submittal. The bee shall be on a new page.)

bee: PresidenUChief Nuclear Officer Senior Director, Regulatory Operations and Nuclear Oversight Director, Site Regulatory Compliance Hope Creek Plant Manager Manager, Licensing Records Management

LR-N 1 8-0032 LAR H 1 8-02 Enclosure Evaluation of the Proposed Change

LR-N 1 8-0032 LAR H 1 8-02 Enclosure H O P E CRE E K N U CLEAR G E N E RATI N G STATION RE N EWED FAC I LITY OPERAT I N G LICENSE N O . N P F-57 DOCKET NO. 50-354 L icense Amend ment Request: Inverter Allowed Outage Time (AOT) Extension Table of Contents 1 .0 S U M MARY DESCRI PT I O N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.0 D ETAI LED DESCRI PTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2. 1 SYSTEM D ES I G N A N D OPERATI O N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.2 CU RRENT TECH N I CAL S P EC I F I CATI O N REQ U I RE M E NTS . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 2.3 REASON F O R T H E PROPOS E D CHANG E . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2.4 DESCRI PTI O N O F T H E PROPOS E D C HANG E . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 5 3.0 TEC H N I CAL EVALUAT I O N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 5

3. 1 DETERM I N I STIC ASS ESSMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 5

3. 1 . 1 Defense- I n-Depth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 6

3. 1 . 2 Safety M a rg i n . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 3.2 R I S K ASS ESS M E N T . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

. . . . . . . . 19 3.2. 1 PRA Q u a lity and Tech nical Adequacy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . . . . 22 3.2.2 Probabilistic R i s k Assessment Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 3.2.3 External Event Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 3.2.4 U n certainty Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 3.2.5 Tier 2 - Avoidance o f Risk-Sign ificant Plant Config u rations . . . . . . . . . . . . . . 57 3.2.6 Tier 3 - Risk-I nformed Configuration Management . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 8 3.2.7 Risk S u m m ary and Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 0 4.0 REG U LATORY EVALUATI O N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1

4. 1 APPLICABLE REG U LATO RY REQ U I REM E NTS AN D C RITERIA . . . . . . . . . . . . . . . . . . . . 6 1 4.2 PRECE D E NT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 4.2. 1 License Amendments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 4.2.2 N otice o f E nforcement Discretion ( N O E D) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 4.3 N O S IG N I FI CANT HAZARDS CONS I D E RATI O N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 4.4 CONCLU S I O N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 5.0 E NVI RON M ENTAL CONS I DE RATI O N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

6.0 REFERENCES

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 1

LR-N 1 8-0032 LAR H 1 8-02 Enclosure ATTAC H M E NTS :

1 . Tech n ical Specification Page Marku ps

2. Tech n ical Adeq uacy of the PRA Models 3 . Parametric U n certainty Methodology

4. S i ng l e Line Drawing of Typical I nverter 2

LR-N 1 8-0032 LAR H 1 8-02 Enclosure 1.0

SUMMARY

DESCRIPTION This l icense amendment req uest proposes a change wh ich would revise H ope Creek Tech nical S pecification (TS) ACT I O N 3 . 8 . 3 . 1 . d concern ing inoperable Alternating C urrent (AC) I nverters .

The proposed change would i ncrease the AC I nverters allowed outage time (AOT) for one or both i nverters inoperable i n one channel from 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months to 7 days . The proposed change is based on appl ication of the H ope Creek Generating Station ( HCGS) Probabilistic Risk Assessment (PRA) i n support of a risk-i nformed extensio n , and o n additional considerations and com pensatory actions.

2.0 DETAIL ED DESCRIPTION

2. 1 System Design and Operatio n T h e Class 1 E A C power system is desig ned t o provide a reliable source o f power t o all Class 1 E l oads i n the plant. The system is d ivided i nto 4 channels (A, B , C , and D). These loads are essential for safe and orderly shutdown of the plant, maintai n i ng the plant in a safe conditio n ,

a n d m itigati ng t h e conseq uences of an accident. T h e loads are d ivided i nto 4 g ro u ps such that any com b i n ation of 3 out of the 4 g ro u ps has the abil ity to su pply the m i n i m u m req u i red safety loads to perform the above fu nctions. The channels do not have l oad sharing ability. Each of these channels has two associated Class 1 E 1 20V AC u n i nterru ptable power su pply (U PS) u n its . U PS panels supply loads such as diesel generator control panels, 4 . 1 6 KV switchgear, Emergency Core Cooling Syste m (ECCS) and Reactor Core I solation Cooling (RCIC) system i n strumentation and contro l , and the remote sh utdown pane l .

Each U PS is com prised o f a static rectifier, a static i nverter, a static switch assembly, and a reg ulated power s u pply. The static rectifier provides reg ulated D i rect Cu rrent (DC) power to the i nverter. The norm a l AC su pply from a Class 1 E 480V AC m otor control center (MCC) is rectified and auctioneered with the alternate DC supply. The static i nverter converts the DC i n put from the static rectifier to 1 20V AC for appl icati on to system loads via the static switch assem bly. The output of the static inverter is a single phase, 60 Hz, 1 20V AC The static switch m o nitors the output of the static inverter, and shifts to the backup AC power supply (Class 1 E 480V AC MCC powered from a n MCC d ifferent than the one powering the U PS static rectifier) , if a loss of inverter output is indicated . A single line d rawi ng of a typical i nverter is provided i n .

Loss of Power Effects for 1 20 Volt AC Distri butio n panels With the [A-D]48 1 U PS inverter inoperable, the associated 1 20 VAC distribution panel is energ ized from the associated backup Class 1 E 480 VAC MCC via the voltage reg ulator. In the event of a loss of offsite power (LOP) the affected distri butio n panel wi l l experience a momentary loss of power u ntil the associated emergency d iesel generator (E DG) re-energ izes the backup 480 VAC MCC. With the [A-D]482 U PS inverter inope rable, the associated 1 20VAC d istri bution panel is energ ized from the associated backup Class 1 E 480 VAC MCC via the voltage reg u l ator. In the event of a LO P the affected d istri butio n panel wi l l experience a l oss of power. The associated EDG would not automatical ly re-energ ize the backu p 480 VAC MCC.

The abnormal operating procedure for station blackout, LO P , and E DG malfu nctions provides operational direction to start the E DG from the remote panel or the local cont rol panel if needed .

A detai led descri ption of the plant response to the loss of power to each 1 20V AC d istribution panel is provided below. Abnormal operating procedure H C . O P -AB.ZZ-0 1 36(0) , Loss of 1 20 3

LR-N 1 8-0032 LAR H 1 8-02 E n clos u re VAC I nverter, is the primary govern i ng procedure for addressing this abnormal condition.

Add itional abnormal operati ng proced u res provide o perato r g u idance for actions req uired to support stable plant operatio n , reset isolations and restore system fu nctions. These actions focus on m itigating the transient effects , enteri ng the appl icable Tech n ical S pecification Action Statements and subseq uently coord i n ating with Mai ntenance on the restoration of the i nverte r.

Depending on which inverter was l ost as described below, operator actions would be req u i red to ensure that:

Turbine Auxiliary Cool ing System (TACS) transfer is com pleted i n accordance with H C . OP-AB. ZZ-000 1 , Transient Plant Conditions

Reactor Water Clea n u p (RWCU) system operation is restored i n accord ance with H C . OP-AB . CONT-0002, Pri m a ry Containment

Fuel Pool Cooling and C lea n u p ( FPCC) system operation is restored i n accordance with H C . OP-AB . COO L-0004, Fuel Pool Cooling

Primary Containment I nstru ment Gas (PC I G) system operatio n is restored i n accordance with H C . O P-AB . CO M P-0002 , P rimary Conta i nment I n stru m e nt Gas

Reactor Building ventil ation d ifferential press u re is restored i n accordance with H C . O P-AB . CONT-0003, Reactor Building The principal loss of power i m pacts for each distri bution panel are listed i n the following tables.

Panel Eq uipment/Fu n ction Affected by Loss of [A-D]J48 1 A B c D TACS transfer (cond itional) X X X X RWCU isolation and pump trip X X FPCC pump tri p X X Loss of Reactor Building venti lation X X Control Area Ventilation tra i n trip/auto start X X Associated Primary Conta i n ment Isolation System (PCIS) X X X X i n itiation/actuatio n Associated loss-of-coolant accident/loss o f offsite power X X X X

( LOCA/LOP) seq uencer Associated Core Spray auto m atic i n itiations/actuations X X X X Associated low pressu re coolant i njection (LPC I ) automatic X X X X i n itiations/actuations Associated high pressure coolant i njection (HPCI) X X automatic i n itiations/actuations Associated reactor core isolation cooling ( RC I C) automatic X X i n itiations/actuations Associated automatic depressu rization system (ADS) X X automatic operation Associated Safety/Rel ief Valve l ow-low set function X X H PC I manual and a uto flow co ntroller X RC I C manual and auto flow co ntroller X Associated Fi ltratio n , Reci rcul ation . and Ventilation X X X X System (FRVS) recircu lation fans Associated F RVS venti lation fans X X 4

LR-N 1 8-0032 LAR H 1 8-02 Enclosure Panel E q u i pment/Function Affected by Loss of [A-D]J482 A B c D TAGS transfer (conditional) X X X X RWC U isolation and pump trip X X X F PCC filter/demineralizer (F/D) isolati o n , FPCC pump trip X X Loss of Reactor B u i lding venti lation X Associated EDG LOCA, LOP and control room manual start X X X X Attachm ents 1 thro ug h 8 of H C . O P-AB .ZZ-0 1 36(0) provide a description of the effects of inverter fai l u res on plant controls and indication and are s u m marized below:

1 AJ481 DISTRIBUTION PANEL Automatic Plant Response 1 . TAGS Loop A i n board supply valve EG-HV-2522A fails closed . If TAGS is being s u p plied by the "A" Loop, it wil l automatically swap to " B" Loop.

2 . RWCU p u m p suction i n board containment isolation valve BG-HV-F00 1 closes due t o a false Standby Liq uid Control (S LC) P u m p O perating Signal. This causes RWCU system isolation and RWCU pump tri p .

3 . T h e ru n n i ng F PCC pumps trip due t o low flow due t o closure of fuel pool cle anup filter/demineralizer valves.

4. "A" Channel Primary Conta i n ment I solati on System (PC I S) i n itiation/actuation sig nals as a res u lt of loss of power to Refueling Floor Exhaust (RFE) and Reactor Building Exhaust (RBE) radiation monitors.

5 . H i g h Pressu re Coolant I njection ( H P C I ) suctio n swaps from t h e condensate storage tank (CST) to the Torus due to l oss of power to the CST Low Level Tri p U n its .

Control and Indication Failures General 1 . Channel "A" LOCAILOP Seq uencer is i n operative .

2 . Loss of Division I (Channels "A" and "E") Emergency Core Cooling System (ECCS) Auto Trip U n its and Start Relays - in genera l , process signal transm itter fai l u res affecti n g i n itiation sig nals, pump m i n i m u m flow valves and pressure perm issives .

3. "A" and "E" Filtratio n , Fi ltration Reci rcu lation and Ventilation System (FRVS) reci rcu latio n fans and "A" F RVS venti latio n fa n_ receive trip sig nals due to false Deluge Activation signals.

4 . Loss of Chan nel "A" RBE and RFE Radiation Monitors .

5 . Loss of Channel "A" Remote Sh utdown P a n e l (RSP) contro l s .

6 . Loss of power t o "A" Primary Contain ment Hydrogen/Oxygen Analyzer Panel .

7. Loss of 1 AJ48 1 1 20V AC power to 1 0C60 1 Redundant Reactivity Contro l System (RRCS) Panel affects indications and Self-Test Circuits only.

8. Loss of voltage and am pere transducers for 1 AD4 1 3 and 1 AD4 1 4 Battery Chargers .

EDG A 1 . Loss of power to "A" E DG Remote Engine Panel .

2 . Diesel control a n d indicatio n transmitters failed .

3 . E lectronic G overnor is powered b y 1 25 V D C and not affected . Mechan ical G overnor n ot affected .

4 . T h e "A" EDG wil l start a n d breaker wi ll close d u ring a LOP .

5

LR-N 1 8-0032 LAR H 1 8-02 Enclosure Core Spray 1 . Channei "A" wi l l not automatically i nitiate on High Drywel l P ressure or Low Reactor Pressure Vesse l (RPV) Leve l .

2 . Outboard a n d i nboard i njection valves HV-F004A a n d F005A wi ll not automatically o pen whe n RPV pressure d rops below the perm issive setpoint with a LOCA Level 1 sig nal present.

3. "A" su bsystem m i n i m u m flow valve will not automatically close .

4. P C I S Channei "A" LOCA Level 2 fu nctions do not occu r.

RHR 1 . Channel "A" wi l l not automati cally i n itiate on High Drywel l Pressu re or Low RPV Leve l .

2 . Low Pressure Coolant I njecti on (LPC I) system i njection valve F0 1 7A wi l l n ot auto m atically open whe n RPV pressu re drops below the perm issive setpoint with a LOCA Level 1 signal present.

3. F0 1 7A can n ot be opened manually below the low pressu re perm issive setpoint.

4. "A" p u m p minimum flow valve does not automatically close .

HPCI 1 . H P C I wi l l not automatically i n itiate on High Drywel l Pressure or Low RPV Level from Channei "A" or "E".

2. Fai l u re of HPCI Manual and Auto Flow Controllers . Loss of setpoint and flow indications.

3. Pump m i n i m u m flow valve wi l l not automatically operate.

4. H P C I wil l not a utomatically tri p on the following trip co nditions:

a . RPV Level 8 from chan nels "A" or "E".

b. Low pump suction pressure .

c . H i g h Turbine exhaust pressure .

d . Division 1 I solation Signals.

5. Division 3 Outboard Steam Line Isolation Valve F003 and P u m p Torus Suction Valve F042 do not close on the followi ng sig n als:

a. Low Steam Line pressure .

b. H i g h Turbine Exhaust Diaphragm pressu re .

c. H i g h Steam Line flow.

6 . Vacuum Breaker I solation Valve F075 wi l l n o t isolate with H i g h Drywel l Pressu re and Low Steam Line Pressure .

7. Loss of power to trip u n its which control HPCI suction swap from the CST to the Suppression Pool .

1 BJ481 DISTRIBUTION PANEL Automatic Plant Response 1 . TAGS Loop 8 i nboard supply valve EG-HV-25228 fails closed. If TAGS is being supplied by the "8" Loop, it will automatically swap to "A" Loop.

2 . T h e ru nning F P C C pumps tri p due t o low flow due t o closure of fue l pool cleanup filter/demineralizer valves.

3. "8" Channel P C I S i n itiation/actu ation signals as a resu lt of loss of power to RFE and RBE radiation m o n itors .

4. RC I C suction swaps from the CST to the Torus due to loss of power to level switches.

6

L R-N 1 8-0032 LAR H 1 8-02 E nclos u re Control and Ind ication Failures General 1 . Channei "B" LOCA/LO P Seq uencer is i noperative .

2 . Loss of Division I I (Chan nels " B " a n d "F") ECCS Auto Tri p U n its a n d Start Relays - i n genera l , process signal transm itter fai l u res affecting i n itiati on signals, p u m p m i n i m u m flow valves a n d pressu re perm issives.

3. "B" and "F" F RVS reci rculation fans and "B" F RVS venti lation fan receive trip signals due to false Deluge Activation signals.

4. Loss of Channel "B" RSP controls.

5 . Loss of Channei " B" R B E and R F E Radiation Monitors .

6. Loss of power to "B" Pri m a ry Conta i n ment Hydrogen/Oxygen Analyzer Pane l .

7 . Loss of 1 BJ48 1 1 20V A C power t o 1 OC602 R RCS Panel affects indications and S elf Test Circu its only.

8 . Loss o f voltage and am pe re transducers for 1 BD4 1 3 a n d 1 B D4 1 4 Battery Chargers .

EDG 8 1 . Loss of power to "B" EDG Remote Engine Panel .

2 . Diesel control a n d indicati on transm itters failed .

3 . Electronic Governor is powered b y 1 25 V D C a n d not affected . Mechanical G overnor not affected .

4. The "B" E DG wil l start and breaker wil l close d u ring a LO P .

CORE SPRAY 1 . Channei "B" wil l not automati cal ly i nitiate on High Drywel l Pressure or Low RPV Leve l .

2 . O utboard and in board injection valves HV-F004B and HV-F005B wi l l n o t a utomatically open whe n RPV pressure decreases below the perm issive setpoint with a LOCA Level 1 signal present.

3. "B" su bsystem m i n i m u m flow valve F03 1 B wil l not automatically close.

4. P C I S Channei "B" LOCA Level 2 isolations d o not occur.

RHR 1 . Channei "B" wi l l not automatical ly in itiate on High Drywel l Pressu re or Low RPV Leve l .

2 . L P C I system i njectio n valve F0 1 7B wil l n o t automatically open when RPV p ress u re d rops below the perm issive setpoint with a LOCA Level 1 signal present.

3. F0 1 7 B cannot be opened m a n u ally below the low pressu re perm issive setpoint.

4. "B" pump m i n i m u m flow valve wi l l not automatically close.

ADS

1. Channel "B" Automatic Depressu rization System (ADS) automatic operation wil l be inoperable.

2. Safety/Relief Valve (S RV) "H" wil l n ot perform LO-LO Set Functio n .

RCIC 1 . RC I C wi l l not automatically i n itiate on low RPV level from channels "B" or "F" 2 . Auto a n d m a n u a l control o f t h e R C I C Flow Controller wil l b e failed t o t h e l ow flow position, along with setpoi nt and flow ind ications.

3. P u m p minimum flow valve F0 1 9 wil l not autom atically open or close .

4. RC I C wil l not autom atically tri p o n the following tri p conditions:

a. RPV Level 8 from Channei "B" or " F" Tri p U n its .

b . Low p u m p suction press u re .

7

LR-N 1 8-0032 LAR H 1 8-02 Enclosure

c. H i g h Turbine exhaust pressu re .

d . Division 2 Isolation Signals.

5 . RC I C steam line Outboard Isolation Valve F008 wi l l not close o n the followi ng sig nals:

a . Low Steam Line pressu re .

b . H i g h Turbine Exhaust Diaphrag m p ressu re .

c . H i g h Steam L i n e flow.

6 . Vacu u m Breaker I solation Valve F062 wi l l not isolate with H i g h Drywel l Pressu re and Low Steam Line Pressu re .

7 . Loss o f power t o level switches wh ich control RC I C suction swap from t h e CST to t h e S u ppression Poo l .

1 CJ481 DISTRIBUTION PANEL Automatic Plant Response 1 . TACS Loop A outboard supply valve EG-HV-2522C fails closed . I F TACS is on the "A" Loop, it wil l automatically swap to " B" Loop.

2. Control Area Circulati ng Water Pump AP400 trips, if ru n n i n g , ca using a trip of Contro l Area Chiller AK400 and Control Room Venti l atio n Tra i n "A" . Control Room Venti l ation Tra i n "B" automatically starts .

3 . Loss o f Reactor Building Ventilation due t o closure o f Supply a n d Exhaust Dampe rs .

4 . "C" C h a n n e l PC I S i n itiation/actuation s i g n a l s as a res u lt o f loss o f power t o RFE/RB E rad iation mon itors .

Control and Ind ication Failures General 1 . Channei "C" LOP/LOCA Seq uencer is i n operative. Automatic PC I S I solations wil l n ot occur.

2 . Loss of Division I l l (Channels "C" and "G") ECCS Auto Tri p U n its and Start Relays . - i n genera l , process signal transm itter fai l u res affecting i n itiati on signals, m i n i m u m flow valves , and pressu re perm issives .

3 . " C " F RVS Reci rculation F a n receives a tri p s i g n a l due t o false Deluge Activation i nput.

4 . RS P Channei "C" controls become inoperative .

5 . Loss of voltage a n d ampere transducers for 1 C D4 1 3 a n d 1 C D4 1 4 Battery Chargers .

EDGC 1 . Loss of power to "C" E DG Rem ote Eng ine Pane l .

2 . Diesel control and indication transmitters failed .

3 . Electronic Governor wil l not operate. Mechanical Governor not affected .

4 . T h e "C" E D G wil l sta rt a n d breaker wi l l close d u ring a LO P .

Core Spray 1 . Channel "C" wi ll not automatically i nitiate o n H i g h Drywell Pressure or Low RPV Leve l .

2 . PC I S Channei "C" LOCA Level 2 isolati ons do n ot occur.

RHR 1 . Channei "C" wi ll not automatically i nitiate on H i g h Drywel l Pressure or Low RPV Leve l .

2 . L P C I system i njection valve F0 1 7C wi l l not automatically open when RPV pressure d rops below the perm issive setpoi nt with a LOCA Level 1 signal.

3. F0 1 7C cannot be opened manually below the perm issive setpoint.

4. "C" pump m i n i m um flow valve wi l l not automatically close.

8

LR-N 1 8-0032 LAR H 1 8-02 E n closure HPCI 1 . H P C I wil l not autom atically i n itiate from High Drywell Pressu re or Low RPV Level from Chan nels "C" or "G".

2. HPCI wi l l not autom atically trip on the following trip co nd itions:

a. RPV Level 8 from Channel "C" or "G"

b. Division 3 I solation Signals.

3. Division 3 1 n board Steam Line Isolation Valve F002 and Warm u p Valve F 1 00 do n ot close on the fol lowi ng signals:

a. Low Steam Line pressure b . H i g h Turbine exhaust diaphrag m pressu res.

c. H i g h Steam Line flow.

4 . Vacu u m Breaker I solation Valve F079 does not isolate with H i g h Drywel l Pressure a n d Low Steam Pressu re .

1 DJ481 DISTRIBUTION PANEL Automatic Plant Response 1 . TAGS Loop B outboard supply valve EG-HV-2522D fails closed . I F TAGS is o n the "B" Loop , it wi l l auto m atically swap to the "A" Loop.

2. RWCU pump sucti on outboard contain ment isolation valve HV-F004 fails closed d u e to a false SLC P u m p Start Signal. This causes RWCU isolation and p u m p tri p.

3 . Control Area C i rculating Water Pump B P400 trips , i f run n i ng , causing a trip o f Contro l Area Chiller B K400 and Control Room Venti lati on Train "B". Control Room Ventil ation Tra i n "A" automatically starts.

4. Loss of Reactor B u i l d i ng Ventil ation due to closure of S u pply and Exhaust Dampe rs . .

5 . " D" Channel P C I S i nitiation/actuation signals a s a result of loss o f power t o RFE/RBE radi ation m o n itors .

Control and Ind ication Failures General 1 . Channel "D" LOCA/LO P Sequencer is inoperative . Channel "D" PCIS Isolations wi l l not occu r.

2 . Loss of Division I V (Channels " D " and "H") ECCS/RC I C Auto Tri p U n its a n d Start Relays

- in genera l , process signal transm itter fai l u res affecting i n itiation signals, m i n i m u m flow valves, and pressu re perm issives .

3 . " D " FRVS Reci rcu l ation F a n receives tri p signal due t o false Deluge Actuatio n Signal i n put.

4. Loss of control for "D" Channel at RS P .

5 . Loss of voltage a n d am pe re transducers for 1 D D4 1 3 a n d 1 D D4 1 4 Battery Chargers .

6 . Channel " D " and "H" Trip U n it O utput fai l u res .

EDG D 1 . Loss of power to "D" EDG Rem ote Engine Panel .

2 . Diesel control a n d indication transm itters fai led .

3 . Electronic Governor is powered b y 1 25 VDC and not affected . Mechan ical G overnor i s not affected .

4 . T h e " D " EDG wi l l sta rt a n d breaker wil l close d u ring a LO P .

9

L R-N 1 8-0032 LAR H 1 8-02 E n closure Core Spray 1 . Channel "D" wi l l not automatical ly i nitiate on High Drywel l Pressure or Low RPV Leve l .

2 . PCI S Channel "D" LOCA Level 2 I solations d o not occur.

RHR 1 . Channel "D" wil l not automatically i n itiate on High Drywel l Pressu re or Low RPV Leve l .

2 . LPC I system injectio n valve F 0 1 7 D wi l l not automatically open when RPV pressure d rops below the perm issive setpoint with a LOCA Level 1 signal present.

3. F0 1 7 D cannot be opened m a n ually below the perm issive setpoint.

4. "D" pump m i n i m um flow valve wil l not automatically close.

ADS 1 . Channel "D" wi l l not automatically i n itiate.

2 . S RV " P " wil l not perform LO-LO Set Function .

RCIC 1 . RC I C wi l l not autom atically i n itiate on low RPV Level from a Channel "D" Level Transm itter.

2 . RC I C does not automatically trip on the following trip conditions:

a. RPV Level 8 from Channel "D" Leve l .

b . Division 4 Isolation Signals.

3. RC I C steam line I n board Isolation Valve F007 and Warm up Valve F076 do not close on the following signals:

a. Low Steam Line pressu re .

b . H i g h Tu rbine exhaust diaphragm pressu re .

c. High Steam Line flow.

4 . Vacuum Breaker I solation Valve F084 does not isolate with High Drywel l P ressure and Low Steam Line Pressure .

1 AJ482 DISTRIBUTION PANEL Automatic Plant Response 1 . TACS Loop A i n board supply valve EG-HV-2522A closes . I F TACS was o n the A Safety Auxi l iaries Cooling System (SACS) Loop, the standby SACS pu m p starts and the B and D TACS Su pply and Return valves ope n . Water sluices from B SACS Loop to A SACS Loop due to TACS Loop A i n board return valve HV-2496A fai l ing as is (open) . B and D TACS Supply and Return valves isolate when ' B' SACS Loop Expansion Tan k reaches Lo-Lo-Lo Setpoi nt.

2. RWC U pump suction i n board contain ment isolation valve HV-F00 1 closes due to false "A" S LC Pump operating sig n a l . Both RWCU P u m ps tri p.

3. FPCC Filter/Dem i n O utboard I n let Isolation Valve HV-4676A closes . If the fi lter/demin is i n service , then the B FPCC p u m p wi l l trip if it was i n service . The A F PCC p u m p wi l l not tri p d ue to loss of power to tri p logic, and the pump wi l l remain i nservice with no flow path .

Control and Ind ication Failures 1 . "A" E DG wi l l not respond to LOCA, LO P , or Control Room Manual Start Signals.

2. Loss of 1 E Analog Log ic Cabinet 1 AC655 wi l l result i n the loss of Division 1 /Channel "A" analog instrumentatio n . Analog indicators wil l fai l in the mid-scale positio n . Dig ital Status I ndicators (valve positions, pump status , etc.) wi l l be lost.

10

LR-N 1 8-0032 LAR H 1 8-02 Enclosure

3. Loss o f 1 E Digital Log ic Cabinet 1 AC652 wi l l res u lt i n t h e loss o f control a n d status indication for Non-ECCS Division 1 /Channei "A" components , including alarm and com p uter i n put.

4. Division 1 com ponents of HPCI , RHR and Core Spray wi l l lose status indication o n ly. All M a n u a l and Automatic Signals remain fu nctional .

5 . T h e "A" S LC P u m p wi l l not respond t o a Control Room m a n u a l start command.

6 . If F P C C fi lter/demin was i n service , A F u e l P o o l Cooling P u m p wi l l continue t o ru n but wi l l l ose ru n n i ng indication . EC-HV-4689B, Filter Demin Bypass Valve m ust be opened to establish a flow path.

1 BJ482 DISTRIBUTION PANEL Automatic Plant Response 1 . TACS in board su pply valve EG-HV-2522B closes . I F TACS was on the B Loop, the Stan d by SACS p u m p starts and the A and C TACS S upply and Retu rn valves ope n .

Water slu ices from A SACS Loop t o B SACS Loop d u e t o HV-2496B failing a s i s (open) .

A and C TACS S u pply and Retu rn va lves isolate when 'A' SACS Loop Expansion Tank reaches Lo-Lo-Lo Setpoint.

2 . FPCC Filter/Dem i n I n board I n let I solation Valve EC-HV-4676B and O utlet I solation Valve EC-HV-4678 close (the ru nning Fuel Pool Cooling pump wil l n ot have a discharge path)

3. RWCU pump suction outboard containment isolation HV-F004 closes due to false "B" SLC P u m p operating sig nal. Both RWCU P u m ps tri p .

Control and Ind ication Failures 1 . "B" EDG response to LOP , LOCA or Control Room Start Signals will be i n h i bited .

2 . Loss of 1 E Analog Logic Cabi net 1 BC655 wi l l result i n t h e loss of Division 2/Channel "B" analog i nstrumentatio n . Analog indicators wi l l fai l i n the m id-scale position. Dig ital status indicators (valve positions, pump status , etc.) wi l l be lost.

3 . Loss of 1 E Dig ital Log ic Cabi net 1 BC652 wi l l result i n t h e loss o f co ntro l a n d status i n d i cation for Non-ECCS Division 2/Channel "B" com ponents , i ncluding alarm and Com puter I n put.

4. Division 2 com ponents of RC I C , RHR and Core Spray wi l l lose status indication o n ly. All M a n u a l and Automatic Signals remain functional.

5 . T h e " B " S L C Pump wil l n ot respond t o a Control Room m a n u a l start com mand.

6. IF FPCC fi lter/demin was i n service , B Fuel Pool Cooling P u m p wi l l conti nue to ru n but wi l l l ose ru n n i ng indication . EC-HV-4689A, Filter Dem i n Bypass Valve m ust be opened to establish a flow path .

1CJ482 DISTRIBUTION PANEL Automatic Plant Response 1 . TACS Loop A outboard su pply valve EG-HV-2522C closes . I F TACS was on the A SACS Loop, the Standby SACS p u m p starts and the B and D TACS S u pply and Retu rn valves ope n . Water slu ices from B SACS Loop to A SACS Loop due to Loop A o utboard retu rn valve HV-2496C fai l i ng as is (open) . B and D TACS S upply and Retu rn valves isolate whe n 'B' SACS Loop Expansion Tank reaches Lo-Lo-Lo Setpoi nt.

2. Reactor building ventilation system (RBVS) exhaust outboard isolation damper G U - H D-94 1 4A fails closed , causing trips of RBVS .

11

LR-N 1 8-0032 LAR H 1 8-02 Enclosure Control and Ind ication Failures 1 . EDG "C" response to LOP, LOCA or Control Room Start Signals wil l be i n h i bited .

2 . Loss of 1 E Analog Logic Cabinet 1 CC655 wi l l result in t h e loss o f Division 3/Channei "C" analog i nstrumentatio n . Analog indicators wil l fai l i n the m id-scale positio n . Dig ital status indicators (valve positions, p u m p status , etc.) wi l l be lost.

3. Loss of 1 E Dig ital Log ic Cabinet 1 CC652 wi l l resu lt i n the loss of contro l and status ind ication for Non-ECCS Division 3/Channel "C" com ponents , includ i ng alarm and computer i nput.

4. Division 3 com ponents of H P C I , RHR and Core Spray wi l l lose status indication o n ly. All Manual and Automatic Signals remain functional .

1 DJ482 DISTRIBUTION PANEL Automatic Plant Response 1 . TAGS Loop B O utboard Supply Valve EG-HV-2522D closes . I F TAGS was on the B SACS Loop , the Standby SACS pump starts and the A and C TAGS S u pply and Return valves ope n . Water sluices fro m A SACS Loop to B SACS Loop due to TAGS Loop B outboard return valve HV-2496D fai l i ng as is (open) . A and C TAGS S u pply and Return valves isolate when 'A' SACS Loop Expansion Tan k reaches Lo-Lo-Lo Setpoi nt.

2 . Both RWCU P u m ps tri p d u e t o a false , HV-F004 not 1 00% open , s ig n a l .

Control and Ind ication Failures 1 . E DG "D" response to LOP , LOCA, or Control Room Sta rt Sig nals wi l l be i n h i bited .

2 . Loss of 1 E Analog Log ic Cabinet 1 DC655 wi l l result in t h e loss o f Division 4/Channel "D" analog i nstrumentatio n . Analog indicators wil l fai l i n the m id -scale positio n . Dig ital status indicators (valve positions, pump status , etc.) wil l be lost.

3. Loss of 1 E Dig ital Log ic Cabinet 1 DC652 wil l result i n the loss of contro l and status indication for Non-ECCS Division 4/Channei "D" com ponents , including alarm and computer i n put.

4 . Division 4 com ponents of RC I C , RHR a n d Core Spray wi l l lose status indication o n ly. Al l Manual and Automatic Signals remain fu nctional.

2.2 Current Tech n ical S pecification Req u i rements The cu rrent TS 3 . 8 . 3 . 1 , "Onsite Powe r D istri bution Systems, Distribution - Operati ng", Lim iting Condition for Operability (LCO) provides a l ist of AC power distri bution system chan nels wh ich shall be energ ized i n O P E RATI O NAL CON DITIONS 1 , 2 and 3. This list includes the fol l owi n g :

Channel A 1 20 volt A C distri bution panels 1 AJ48 1 /1 AJ482 a n d inverters AD48 1 /AD482 Channel B 1 20 volt AC distribution panels 1 BJ48 1 /1 BJ482 and i nverters B D48 1 /BD482 Channel C 1 20 volt AC distri bution panels 1 CJ48 1 /1 CJ482 and i nverters C D48 1 /CD482 Channel D 1 20 volt AC distri bution panels 1 DJ48 1 /1 DJ482 and i nverters D D48 1 /DD482 TS 3 . 8 . 3 . 1 ACTION d states , "With one or both i nverters in one chan n e l i n operable, energ ize the associated 1 20 volt AC d istribution panel(s) with i n 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months , and restore the inverter(s) to O P E RABLE status with i n 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months ; or be in at least HOT S H UTDOWN with in the next 1 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months and i n COLD SH UTDOWN with i n the followi ng 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . "

S U RVE I LLANCE REQU I RE M ENT 4 . 8 . 3 . 1 states, " Each of t h e above req uired power distri bution system channels shall be determ ined energ ized i n accordance with the S u rve i l lance 12

LR-N 1 8-0032 LAR H 1 8-02 Enclosure Freq uency Control Prog ram by verifying correct breaker/switch align ment and voltage on the busses/MCCs/panels . "

T h e O P E RABI LITY o f the A C and D C power sources and associated distri bution systems d u ring operation ensures that sufficient power wi l l be avai lable to su pply the safety related e q u i pment req uired for ( 1 ) the safe s hutdown of the faci l ity and (2) the m itigation and control of accident conditions with i n the faci lity. The m i n i m u m specified independent and red undant AC and DC power sou rces and d istri butio n systems satisfy the req u i rements of General Desig n Criteria 1 7 of Appendix "A" to 1 0 C F R 50.

"Energ ized" 1 20V AC distribution panels [A-D]J48[ 1 /2] req uire the panels to be energ ized to their proper voltage from the associated inverter via inverted DC voltage , inverter using the norm a l AC source , or Class 1 E backu p AC source via voltage reg ulator. O P E RABLE i nverters req u i re the associated 1 20 VAC distri bution panels ([A-D]J48 [ 1 /2]) to be powered by the i nverter with output voltage withi n tolerances , and power i n put to the i nverter from the associated station battery. Alternatively, the power su pply m ay be from an i nternal AC source via rectifier as l o ng as the O P E RABLE station battery is available as the u n i nterru ptible power su pply . "

2.3 Reason for the Proposed Change Consistent with the objectives of the N u clear Reg ulatory Comm ission's (N RC's) policy entitled "Use of Probabilistic Risk Assessment Methods i n N u clear Reg u l atory Activities; Final Policy Statement , " (PRA Policy Statement; Reference 1 4) , the proposed change provides ( 1 ) safety decision-m aking enhanced by the use of PRA insig hts , (2) more efficient use of resources , and (3) a red uction i n u n necessary burden . The proposed i nverter Allowed O utage Time (AOT) extension would provide these benefits by su pporting the abil ity to com plete on-line corrective or plan ned m a i ntenance of an i noperable i nverter. These benefits are described i n the fol lowi ng table:

N RC PRA Policy Statement Objective Anticipated Benefits of Proposed I nverter AOT Enhanced Efficient Redu ction I n Extension Decision- Use Of U n necessal)i making Resou rces B u rden Provide additional time to com plete repairs following X X an i nverter malfunction; Avert unplanned u n it sh utdowns and m i n i m ize the X X X potential need for NOED; I n crease the time to perform troubleshooti ng , repair, and testing following i nverter eq uipment problems, X X wh ich wi l l e n hance the safety and reliability of equ ipment and personnel ;

Allow time to perform routi ne maintenance activities on the i nverters in MODES 1 throug h 3, enhancing the ability to focus quality resou rces o n the activity X X X and the availability of the inverters d u ri ng refueling o utage periods.

TS 3 . 8 . 3 . 1 Action d currently allows o n ly 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months to troubleshoot and repai r one or both inoperable AC i nverters in one cha n n e l , perform post-mai ntenance testing , and return them to service . The 24-hour AOT was based on engi neeri ng j udgment , taking i nto consideration the 13

LR-N 1 8-0032 LAR H 1 8-02 E n closure time req uired to repair an inverter and the additional risk to wh ich the u n it is exposed because of the inverter i n o perabil ity.

M itigati ng strateg ies have been i m plemented to address emergent issues with i n the current 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months AOT. These include prepared safety tag outs for inverter trou bleshooting and repair, and mai ntai n i ng stocks of capacitors and burned-in replacement ci rcuit cards. However, as discussed below, the 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months AOT can be insufficient i n certai n instances to support on-l i n e trou bleshooting , corrective maintenance , and post-maintenance testing i n response t o emergent issues. H o pe Creek performs preventative maintena nce o n the safety related U PS u n its d uri ng each refueling outage. There are no current plans to perform routine preventive m a inte n ance on a sched u led basis at power. Should the need for such mai ntenance be identified as a res u lt of com po n e nt performance, the necessary preventive mai ntenance would be planned and sched uled i n accordance with PSEG proced u res for on-line work management.

If an i nverter becomes i noperable due to an emergent issue, the inverter troubleshooting and repair process requ i res proper electrical safety tag g i ng to be established. The trou bleshooti ng process beg ins with physical inspection of the U PS panels , and fuse and alarm checks . U pon com pletion of repairs , and depending on which ci rcuit card s have been removed and replaced, adj ustments are performed .

Post mai ntenance testi ng is req u i red before return i ng the U PS to service . Depending on the corrective m a i ntenance , an inverter fu nctional test m ay also be req u i red .

Experience both at HCGS and at other n uclear power plants h as shown that the current 24-hour AOT for restoration of a n inoperable inverter is i nsufficient i n certai n i n stances to s u pport on-line troubleshooti ng , corrective maintenance , and post-maintenance testing wh ile the u n it is at power. In 2008, Class 1 E inverter C D482 was inoperable for 1 7 hours8.101852e-5 days 0.00194 hours 1.157407e-5 weeks 2.6635e-6 months and 42 m i n utes d u e to a fai l u re of a power supply board . HCGS has entered TS 3 . 8 . 3. 1 LCO due to a n inoperable i nverter 3 times since 2 0 1 0. The actual durations were 5 hours5.787037e-5 days 0.00139 hours 8.267196e-6 weeks 1.9025e-6 months in 20 1 0, 1 3 hours3.472222e-5 days 8.333333e-4 hours 4.960317e-6 weeks 1.1415e-6 months and 1 5 m i n utes i n 2 0 1 3 , and 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months 35 m i n utes i n 20 1 5 . I n these i nstances, the causes of the fai l u res were q u ickly diagnosed and there were already conti ngency work orders i n place .

I n t h e 2 0 1 3 event, t h e 004 8 1 i nverter a utomatically swapped , as desig ned , t o t h e backu p AC su pply. I ns pection and i n itial troubleshooting determ ined there was a blown fuse in the inverte r i nput which led to the power loss. After the i n itial troubleshooting and replacement of the blown fuse, operators attem pted to restore the normal power su pply to the 004 8 1 inverter but the fuse blew aga i n . Additional troubleshooti ng determ ined the blown fuses were due to a fai led i nverter control circu it card . Six ci rcu it cards were replaced to restore the inverte r to O P E RABLE status.

The replacement cards were removed from another plant i nverter, not req u i red by LCO 3 . 8 . 3 . 1 ,

and installed i n 0048 1 .

I n each of the above i n stances , the inoperable i nverter was retu rned to OPERABLE status with i n the a l l owed outage time. The emergent issues were q uickly identified , replacement parts were read ily available, and extensive post-maintenance testing and com ponent tuning was not req uired . H owever, if the emergent issue had req u i red com plex troubleshooting or more extensive post-maintenance testi ng , or if backu p, b u rnt i n replacement com ponents were not available o n site , the process of return i ng the inverter to O P E RABLE status could have taken more than 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . The recommended burn-in period for replacement circu it ca rds is 50 hours5.787037e-4 days 0.0139 hours 8.267196e-5 weeks 1.9025e-5 months to properly ensure the i nteg rity of the card .

14

LR-N 1 8-0032 LAR H 1 8-02 E nclosure A review of 1 0 CFR 50 . 72 event notifications identified 3 instances s i n ce 2003 in which plant sh utdowns were i nitiated as req u i red by Tech nical Specifications whe n the time to com plete inverter trou bleshooting and repair exceeded the 24-hour allowed outage tim e . Other n u clear power plants have had similar instances of inverter fai l u res prompting req uests for enforcement d iscretion ( N O E D) and for License Amendments for inverter TS Completi on Time extensions from 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months to 7 days . Callaway was g ranted enforcement discretion i n 2 0 1 2 for an add itional period of 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months to restore an inverter to OPERABLE status . FPL Energy Seabrook, LLC received N RC approval of enforcement discretion for an additional 1 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months for a n inoperable (i . e . , fai led) d istri butio n panel inverter. The basis for the N O E D was that the 24-hour AOT did not provide adeq uate time to troubleshoot the problem , complete the repair activities, and perform post-maintenance testing to retu rn the inverter to operable status . The N i ne Mile Point U nit 2 and Watts Bar U n it 1 n u clear stations received enforcement discretion i n 2003 and 200 1 ,

respectively, to extend the Com pletion Time for an i noperable distri bution panel i nverter. The N RC approvals of the above N O E Ds and license amendments for the C l i nton , North Ann a ,

Braidwood , Byron a n d P a l o Verde Stations are detailed i n Section 4 . 2 of this evaluation. These approved amendments demonstrate that the cu rrent 24-hour Al lowed O utage Time for restoration of an i noperable i nverter can , i n some cases, be insufficient to support on-line troubleshooti ng, corrective m a i ntenance , and post-maintenance testing wh ich could lead to unplanned u n it sh utdowns and the potential need for NOEDs.

Conclusion The proposed AOT i ncrease does n ot i ncrease the potential for a loss of req u i red instru mentatio n . Wh ile operator actions are req u i red in response to the i n o perabil ity of one or both inverters i n a single ch anne l , the proposed change wil l reduce the i m mediate demands o n t h e operations staff prepari n g for a potential plant shutdown . Once approved , t h i s LAR wi l l better focus t h e operators on risk sign ificant actions , as com pared t o actions that are based u pon q ualitative com pletion times.

2.4 Descri ption o f t h e Proposed Change TS 3 . 8 . 3 . 1 ACTION d is being revised as shown below:

With one or both i nverters i n one cha n nel i noperable, energ ize the associated 1 20 volt AC distribution panel(s) wit h i n 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months , and resto re the i nverter(s) to O P E RABLE status with i n 24 7 days ; or be i n at least HOT S H UTDOWN withi n the next 1 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months and i n COLD S H UTDOWN with i n the fol l owi ng 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months .

3.0 TECHNICAL EVAL UATION

3. 1 Determ i n istic Assessment The proposed change i ncreases the allowed outage time for one or both i nverters i n one channel inoperable.

The trad itional engi neeri ng co nsiderations need to be addressed . These include defense-in depth and safety marg i n s . The fu ndamental safety pri nciples on wh ich the plant desig n is based can n ot be com prom ised . Design basis accidents are used to develop the plant desig n .

These are a com bi nation o f postu lated challenges a n d fai l u re events that are used i n t h e plant desi g n to demonstrate safe plant response. Defense-in-depth , the single fai l u re criterio n , and 15

LR-N 1 8-0032 LAR H 1 8-02 Enclosu re adeq uate safety marg i ns may be i m pacted by the proposed change and consideratio n needs to be g iven to these elements .

3. 1 . 1 Defense-I n-Depth

1) Preservation of a reasonable balance among the lay ers of defense The proposed l icensing basis change does n ot sig n ificantly reduce the effectiveness of a l ayer of defense that exists i n the plant desig n before the im plementation of the proposed l i censing basis change.

The defense i n depth approach to desig n ing and operating HCGS was and contin ues to be used i n o rder to prevent and m itigate accidents that could release radi ati on or h azardous m aterials. This approach provides for m u ltiple i ndependent and redundant l ayers of defense to com pensate for potential human and mech a nical fai l u res wh ich ensures that n o single l ayer, no m atter how robust, is exclusively rel ied u po n . Defense i n depth includes the use of access controls, physical barriers, red u ndancy, d iverse key safety fu nctions, and emergency response measures.

The robust plant desig n to survive hazards and m i n i m ize chal lenges that could res u lt i n the occu rrence of an event is not affected by the proposed change . The proposed extended AOT does not i ncrease the l i keli hood of i n itiating events or create new significant i n itiating events . It sim ply provides a risk-i nformed basis for the com pletion time. There are a n u m ber of actions that are com peted by the operations staff as req uired for the a utomatic response of the plant when there is a loss of vital instrumentation . This LAR has the effect of balanci ng some of the demands on the o perations staff. Once approved , the LAR wil l permit more focused operator and mai nten ance tech nician attention upon risk significant actions ,

as com pared to actions that are based u pon q u a litative AOTs.

The avai labi l ity and reliability of Systems, Structu res or Components (SSG) provid i ng the safety functions that prevent plant challenges from prog ressing to core damage are n ot sign ificantly i m pacted . The rem a i n i ng O P E RABLE 1 20 VAG inve rters are capable of s upplyin g the req u i red loads to safely sh utdown the plant.

The proposed extension of the AOT for o ne or both i nverters i n a channel from 24 h o u rs to 7 days does not sig n ificantly reduce the effectiveness of the emergency preparedness prog ram , including the ability to detect and measure releases of rad ioactivity, notify offsite agencies and the public, and shelter or evacuate the public as necessary.

2) Preservation of adequate capability of design featureswithout an overreliance on programmatic activities as compensatory measures The proposed l icensing basis change does n ot substitute prog ra m m atic activities for design features to an extent that sign ificantly red u ces the reliability and availabil ity of design features to perform their safety fun ctions without overreliance on progra m m atic activities.

N o prog ram m atic activities a re req u i red as com pensatory meas u res to preserve adequate capabil ity of design features d u ring the extended AOT. Only 3 i nverter chan nels , as described in Section 2 . 1 , are necessary to su pply the safety related eq u i pment req u i red for

( 1 ) the safe sh utdown of the facil ity and (2) the m itigation and control of accident cond itions 16

LR-N 1 8-0032 LAR H 1 8-02 Enclosure with i n the faci l ity. Therefore , one or both i nverters in a channel being inoperable do n ot i m pact the abil ity of the system to perform its req u i red fun ctio n .

HCGS uses abnormal operating procedures which provide d i rection for operator actions i n response t o a loss o f a 1 20 VAC inverter. Restoration o f power t o t h e associated 1 20 VAC distri bution panels and restoration of affected plant com ponents to normal lineup are also control led by plant proced u res as referenced by the abnorm a l operati ng procedure. While timely actions are req u i red when there is a loss of vital i nstrumentatio n , this LAR will red u ce the i m m ed i ate demands o n the operatio ns staff preparing for a potential plant sh utdown .

Adm i n i strative controls consistent with other l i censees that h ave received s i m i lar extensions of the i nverter allowed o ut-of-service time, as described i n Section 4 . 2 of this Enclos u re wi l l b e im plemented . T h e adm i nistrative controls described below are q u a l itative , prudent actions. Entry i nto the extended i nverter AOT wi l l not be plan ned concurrent with EDG mai ntenance , and entry i nto the extended i nverter AOT wil l not be plan ned concu rrent with planned mai ntenance on another ECCS/RC I C or isolation actuation instrumentation channel that cou l d resu lt i n that channel being i n a tripped conditi o n .

These actions are taken because i t is recog n ized that with a n inverter inoperable and the distri bution panel being powered by the backup AC distri bution system , conti n ued instru ment power for that train is dependent on power from the associated EDG following a loss of power event.

3) Preservation of sy stem redundancy , independence, and diversity commensuratewith the expected frequency and consequences of challenges to the sy stem, including consideration of uncertainty The proposed l i censing basis change does n ot sig n ificantly red u ce the red undancy, i ndependence, or d iversity of systems.

The proposed extended AOT makes no changes to the system operation or desig n and therefore has no effect on the expected freq uency of challenges or result in a decrease in red u nd ancy, independence , or d iversity of the 1 20 VAC power system . Also, redu ndant power suppl ies and operator actions are not i m pacted by these changes. If a red undant channel should fai l or be taken out of service d u ring the extended AOT, H ope Creek would be i n TS 3.0.3, req u i ring a plant s h utdown . This req u i rement is u nchanged by this LAR.

The proposed extended AOT is consistent with the ass u m ptions i n the plant's safety analysis, and does not resu lt in a sig n ificant i ncrease in risk.

4) Preservation of adequate defense against potential Common Cause Failures (CCFs)

The proposed l icensing basis change does not sig n ificantly red u ce defenses against CCFs that could defeat the red undancy, i ndependence , o r d iversity of the l ayers of defense; fission prod uct barriers ; and the desig n , operational, or m a i ntenance aspects of the plant.

The extension req uested does not red uce defenses ag ainst CC F . In fact, these extensions allow more deli berate and thoro ug h troubleshooting following an emerg i ng fai l u re , wh ich can i m prove the causal evaluations performed for eq uipment issues . Better understand i ng of any emergent fai l u re causes could lead to i nvestigations or actions to improve the rel iability of the u naffected inverters .

17

LR-N 1 8-0032 LAR H 1 8-02 E nclosure In additio n , the operating e nviro n ment for these com ponents remains u nchanged and there are no changes to the des i g n or operation of the i nverters associated with the proposed change, so new com m o n cause fai l u re modes are not i ntroduced . There are no changes to the common enviro n ment, inverter or support system desig n , therefore there are no changes to existing coupling factors . The extended allowed outage time affects none of these factors. The extent of con d ition performed as a part of any fai l u re of a safety-related piece of eq u i pment wil l address these issues as req u i red by plant adm i n i strative procedures.

Therefore , the defense against potentia l CCFs remains adeq uate .

5) Maintain multiple fission prod uct barriers The proposed l icensing basis change does not significantly reduce the effectiveness of the m u ltiple fission prod uct barriers .

The fission prod uct barriers (fuel cladding , reactor coolant system , and containment) and their effectiveness are maintained . The proposed changes do not affect the i ntegrity of fission prod uct barriers to l i m it leakage to the environment. Extending the AOT of the 1 20 VAC i nverters does not res u lt i n a significant increase i n the freq uency of existi ng chal lenges to the i nteg rity of the barriers, significantly increase the fai l u re probability of any individual barrier, or i ntrod uce new o r additional fai l u re dependencies among barriers .

6) Preserve sufficient d efense against human errors The proposed l icensing basis change does not significantly increase the potential for or create new human errors that m i g ht adversely i m pact one or more l ayers of defense.

The proposed extended AOT does not req u i re any new operator actions for the existing plant eq u i pment or introduce the potential for new human errors . G u i d ance wi l l be added to existing procedures to incorporate com pensatory meas u res which control what eq u i pment or systems wi ll not be allowed to be taken out of service concu rrent with a n i nve rter o ut of service for plan ned m a i nte nance . This is considered a m i n o r change to the Config u ration Risk Management Prog ra m wh ich wi l l not significantly i ncrease the potential for, or create new, h u m a n errors that m i g ht adversely im pact one or more l ayers of defense. No new operati ng , m a i ntenance , or test p rocedures are req u i red due to these changes , and no new at-power tests or maintenance activities are expected to occu r as a result of these changes .

The plant wi l l conti nue to be operated and mai ntained as before.

7) Continue to meet the intent of the plant's d esign criteria The proposed l icensing basis change does not affect the plant's ability to meet the intent of the desig n criteria referen ced i n the l icensing basis.

The i ntent of the Hope Creek design criteria is maintained . The plant wi l l continue to be operated and maintained as before. The proposed changes do not involve any physical changes to the desig n or operation of the 1 20 VAC Distri bution system . The abil ity of the remaining TS req u i red i nverters to perform thei r req u i red fu nctions is m a i ntained during the extended AOT.

18

LR-N 1 8-0032 LAR H 1 8-02 E n closure

8) Integrated Evaluation of the Defense-in-Depth Considerations There are no changes to the cu rrent plant desig n . The i ntent of each defense-in-depth consideration addressed above would sti l l be met following i m plementation of the proposed extended AOT. Therefore , the proposed l icensing basis change m a i ntains consistency with the defense-in-depth phi losophy.

3. 1 .2 Safety Marg i n T h e i m pact o f t h e pro posed change is consistent with t h e pri nciple that s ufficient safety m a rg i ns a re m a i ntai n ed .

Codes and Standards or alternatives approved for use by the N RC are met. The desig n and operation of the 1 20 VAC distributio n system is not changed by proposed i n crease of the AOT. The proposed change does not affect conformance with appl icable codes and standards.

Safety analysis acceptance criteria in the U FSAR are met. The safety analysis acceptance criteria, as stated i n the Hope Creek U FSAR, are not im pacted by these changes. Red undant channels wi l l be m a i ntained . D iversity , with regard to ensuri n g that s ufficient power wi l l be available to su pply the safety related equ i pment req u i red for ( 1 )

the safe shutdown of the facil ity and (2) the m itigation and contro l of accident con d itions withi n the facil ity wi l l be m a i ntained . The m i n i m u m specified i ndependent and red undant AC and DC power sources and distribution systems will conti nue to satisfy the req u i rements of General Desig n Criteria 1 7 of Appendix A to 1 0 CFR 50. The proposed changes wi l l not allow plant operation in a configuration outside the design basis.

3.2 Risk Assessment This risk assessment evaluates the pro posed extension of the i nverter Allowed O utage Ti mes (AOT) from the current 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months to 7 days using the Hope Creek Full-Power I nternal Events

( FP I E) PRA and Fire PRA Models of Record - H C 1 1 7A and H C 1 1 4FO, respectively.

The proposed Tech n ical Specification change is to i ncrease the AOT for one or both i nverters in o n e channe l . Conseq uently, this assessment postulates the conservative case of both i nverters associated with a single channel of AC power taken out of service s i m u ltaneously:

Channel A: i nverters AD4 8 1 & AD482

Channel 8: inverters 8D48 1 & 8D482

Channel C: i nverters C D48 1 & C D482

Channel D: i nverters D D48 1 & D D482 This g reatly simplifies the presentation of results and risk insig hts without loss of fidelity.

The j u stification for the i nverter extended Allowed Outage Time (AOT) is based upon risk i nformed and determ i n istic evaluations consisting of three main elements as cited i n Reg u latory G u ide 1 . 1 77:

1 . Tier 1 : Assessment of the i m pact of the proposed TS change using a valid and appropriate PRA m odel as compared with appropriate acceptance g u idelines.

19

LR-N 1 8-0032 LAR H 1 8-02 E nclosure

2. Tier 2 : Evaluation of eq uipment relevant t o plant ris k wh ile the i nverter(s) are in the extended AOT. Combinations of out-of-service eq u i pment can be eval u ated for their risk significance to determ ine if additional com pensatory measures may be requ i red .

3. Tier 3 : I m plementation of t h e Config u ration Risk Management Prog ram (C RMP) whi l e the inverter(s) is/are in the extended Allowed Outage Tim e . The CRMP is used for all work and helps ensure that there is no avo idable increase in plant risk while any inverter maintenance is performed . These prog rammatic measures provide additional assurance that critical plant safety fu nctions are preserved d u ring the extended i nverter AOT.

This section addresses the Tier 1 risk assessment for the p roposed extension of the i nverter AOT. Tier 2, a d iscussion of risk-sign ificant plant configurati ons, is add ressed in Section 3 . 2 . 5 .

Hope Creek's Mai ntenance Rule C R M P satisfies Tier 3 a s descri bed in Section 3 . 2 . 6 .

T h e N RC h a s issued Reg u latory G u ides t o specify t h e risk measures that s h o u l d b e calcu lated to provide i n put i nto the decision making process . These risk measures include the followi ng :

The change i n Core Damage Freq uency (L\C DF) (Reg . G u ide 1 . 1 74)

( Reference 1 )

The change i n Large Early Release Frequency (L\LE RF) Reg . G u ide 1 . 1 7 4

The I ncremental Core Damage Probability ( I CCDP) ( Reg . G u ide 1 . 1 77 )

( Reference 2)

The I ncremental Large Early Release Probabil ity ( I C L E RP)

( Reg . G u ide 1 . 1 77)

These val u es are all calculated with the latest H ope Creek Models of Record , as specified above .

H ope Creek P RA Model and Its Attributes The Hope C reek Generating Station (HCGS) PRA i ntern a l events at-power model and documentation has been m a i ntai ned cu rrent with the as-built , as-operated plant and is routi nely u pdated to reflect the curre nt plant config u ratio n , as wel l as the accum u l ation of additional plant operating history and com ponent fai l u re data. The Level 1 and Level 2 HCGS PRA analyses were orig i nally developed and subm itted to the N RC as the H ope Creek Generati ng Station I n d ivid ual Plant Examination (I P E E E) Subm ittal (Reference 9) i n response to N RC Generic Letter 88-20 (Reference 1 0) . The HCGS PRA has been u pdated many times since the orig inal I PE E E . Table 3- 1 summarizes these changes.

Table 3- 1 H I STORY O F HOPE CRE E K G E N E RATI N G STAT I O N P RA M O D E L U P DATES INTERNAL FIRE MODEL TRUNCAT ION DESCRI PT ION EVENTS CDF DATE NAME (N R)

CDF (N R) (N R) 1 IPE O ri g i n a i i P E S u b m ittal ( 1 994) 4 . 6 E-5 1 J - N ot Reported Apri l 1 994 2000 N U P RA M o d e l 8 . 89 E-06 - 1 E- 1 0 Dec. 2 0 0 0 F u l l P RA u pg rade incl u d i n g Pee r Review comme nts, AS M E P RA Aug ust 2003A 3 . 1 4 E-5 - SE-1 1 STD Gaps a n d convers i o n of 2003 model from N U P RA t o CAFTA Rev. 2 . 0A I nc l u d es P S E &G modificatio n s 2 . 78 E-5 - SE-1 1 Octo b e r 20

LR-N 1 8-0032 LAR H 1 8-02 E nclosure Table 3- 1 H I STORY O F HOPE C R E E K G E N E RATI N G STATION PRA M O D E L U P DATES INTERNAL FIRE MODEL TRUNCATION DESCRIPTION EVENTS CDF DATE NAME (IY R)

CDF (IY R) (IY R) o n 4 8 0V AC d e p e n d e n c i e s , 2005 SACS , s u ccess criteria, and SACS-SW H E P s . (Also referred to as the " O n the S pot Model" change . )

I nterim P RA model to add ress O ctober 2005A See 2 0 0 5 8 - See 2 0 0 5 8 conservatism i n Rev. 2 . 0A model . 2005 P RA model used as i n pu t for the EPU s u b m itta l . T h i s model rem oves conservati s m N ovember 2005 8 1 . 0 1 E-5 - 5E-1 1 i ntrod uced i n the Rev. 2 . 0A 2005 model (e. g . , SACS heat load m a n i p u lati o n H E Ps)

Mod ify 20058 EPU model to s u p po rt o n l i ne m a i n te n a n ce February 2005C 9 . 76 E-6 - 5E-1 1 eva l u ations a n d M S P I 2006

<2 >

calcu latio n s .

Add p l a n t mod ificati o n s , u pd ate Aug ust H C 1 08A H RA, u pd ate i ntern a l flood , 7 . 6 0 E-6 - 5 E- 1 1 2008 u p d ate d ata Add p roced u re c h a n g e to SSW/SACS h eat exch a n g e r discharg e valve opera ti o n i n

<3l AB. COO L-0002 a n d revis i o n to < 3> N ovember H C 1 08B 5 . 1 1 E-6 - 1 E- 1 2 i n tern a l flood fre q u encies based 2008 o n l atest E P R I P i pe R u ptu re Report, p l u s othe r model refi n e m e n ts .

H C 1 08BFO I n itial i s s u e of fi re m o d e l . - 3 . 1 2 E-5 1 E-9 Apri l 2 0 1 0 U pd ated to s u p port the H C 1 1 1 A Decem b er HC1 1 1 A 4 . 2 0 E-6 - 1 E- 1 2 mo d e l u pd ate. 201 1 U pd ated to reso lve open F&Os Dece m be r H C 1 1 4AFO - 2 . 1 8 E-5 1 E-1 1 from 2 0 1 0 P e e r Review. 201 5 U pd ated to s u p port the H C 1 1 7 A Decem b er H C 1 1 7A 5 . 9 1 E-6 - 1 E-1 2 model u p d ate . 201 7 (1) P S E G mod ified t h e s u ccess criteria fo r SACS/SSW and calc u l ated a revised va l u e of 1 . 3 E -05/yr.

(2) The o n l y P RA model c h a n g e from the 20058 EPU P RA model to the 2005C Base P RA model is to red uce the Turbine Trip i n itiat i n g event fre q u e ncy from 1 . 2 5/yr to 1 . 0 3/yr to reflect plant specific operati n g h istory.

(3) N ote that the tru n cati o n l i m it has decreased from the 2000 N U P RA model to the c u rre nt CAFTA model. This l ower tru n cati o n l i m it is needed to m eet the AS M E P RA Sta n d a rd .

T h e at-power PRA models o f t h e following hazards are considered :

I nternal Events : Model deve loped in accordance with the AS M E/ANS P RA Standard and Peer Reviewed 21

LR-N 1 8-0032 LAR H 1 8-02 Enclosure I ncremental conditional large early release probabil ity ( I C L E RP)

These calculated conditional probabilities com pared with the acceptance g uidelines provide a perspective on the risk change d u ri ng the proposed inverter extended AOT.

An i nteg rated assessment of the im pact of the AOT extension is calculated assig n i ng the "worst case" i nverter unavai labil ity. This calculation can then be used to calcu late the change in CDF and LERF in com parison with the criteria set in Reg u l atory G u ide 1 . 1 7 4.

Reg u l atory G u ide 1 . 1 7 4 has acceptance g u idelines wh ich are descri bed in S ECY 99-246 (Reference 1 5) as "trigger poi nts" at which q uestions are raised as to whether the proposed change provides reasonable assurance of adeq u ate protectio n .

I n preparation for the AOT submitta l , PSEG performed a n extensive review of the PRA mode l , particularly those seq uences that could be adversely i m pacted by inverter unavailabil ity. In add ition , external events with the possibility of affecting the PRA in puts were also exam ined for insights .

External events with potential quantitative influence on the resu lts of the AOT assessment are i ncorporated in the model q uantificatio n .

Add itionally, the PRA elements that may i m pact the inverters' function are also i nvestigated to assess whether they may be i nfl uenced by the AOT extensio n . These include the followi n g :

o Systems - no i m pact o Operator I nteractions - i ncreases dependence on other channels of AC power d u ring a loss of offsite power o S uccess Criteria - no im pact o Accident Seq uence prog ression - no i m pact o Data - no i m pact o Common Cause Fai l u re - no i m pact o Q u antification - no i m pact The Hope Creek i nternal events PRA is a thorough and detailed PRA model that is robust and capable of s u pporting the risk-i nformed decision to i ncrease the inverter AOT from 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months to 7 days . See Section 3 . 2 . 1 for a d iscussion of the PRA techn ica l adeq uacy.

3 . 2 . 2 . 1 . 1 Ass u m ptions The quantitative eval uation of the extended inverter AOT inco rporates a n u m ber of ass u m ptions , listed below. Refer to Section 3 . 2 . 4 for further d iscussion of assumptions and model uncertai nty.

C o m mon-cause fai l u re events are treated using the latest I N E E L com m o n cause data base developed u n d e r t h e auspices o f t h e N RC .

23

LR-N 1 8-0032 LAR H 1 8-02 E nclosure

Each of the four channels of AC power supplies different loads of plant safety equipment; therefore, it is expected that the risk profiles of each are d ifferent.

One case for each channel is quantified with the relevant i nverters' test-and mai ntenance basic events set to TRU E .

3 . 2 . 2 . 1 . 2 Model Changes The Base P RA Model of Record ( M O R} , H C 1 1 7A, has been reviewed for applicabil ity for the HCGS AOT. To study the i m pact of the extended inverter AOT, five different cases are q u antified - one base case with no changes, a nd one case for each of the fou r cha nnels of AC power. As the Technica l Specification change req uested involves extended mai ntenance windows on the i nverters (i . e . , the 1 20 VAC distri butio n panels wi l l remain energ ized by bypassing the inverters consistent with TS 3 . 8 . 3 . 1 Action d) , each case sets the channel's inverter test-and-maintenance (T&M ) basic events to TRU E . These are specified i n Table 3-2 :

Table 3-2 I NVERT E R BAS I C EVENTS S ET TO TRU E Case Basic Events Set to TRU E Base Case None

ACP-I NV-TM-AD48 1 , I NVERTER 1 AD48 1 U NAVAI LABLE D U E Channel A I nverters TO TEST AND MAI NT oos

ACP-I NV-TM-AD482 , I NVERTER 1 AD482 U NAVAI LABLE D U E T O TEST AN D MAI NT

ACP-I NV-TM-BD48 1 , I NVERTER 1 B D48 1 U NAVAI LABLE D U E Channel B I nverters TO TEST AN D MAI NT oos

ACP-I NV-TM-BD482 , I NVERTER 1 B D482 U NAVAI LABLE D U E T O TEST AN D MAI NT

ACP-I NV-TM-CD48 1 , I NVERTER 1 CD48 1 U NAVAI LABLE D U E Channel C I nverters TO TEST AN D MAI NT oos

ACP-I NV-TM-CD482 , I NVERTER 1 CD482 U NAVAI LABLE D U E T O TEST AN D MAI NT

ACP-I NV-TM- D D48 1 , I NVERTER 1 D D481 U NAVAI LABLE D U E Channel D I nverters TO TEST AN D MAI NT oos

ACP-I NV-TM-DD482 , I NVERTER 1 DD482 U NAVAI LABLE D U E T O TEST AN D MAI NT Observations reg ard i ng model fidel ity to the as-built, as-operated plant are tracked i n the PSEG U pdate Req uirement Evaluation (U RE) database as a resource for potentia l model enhancement i n the futu re . See Attachment 2 Section A. 1 . 5 . No open observations or model discrepancies to be resolved regard i ng the inverters , AC power, or offsite power h ave been identified .

3 . 2 . 2 . 1 . 3 I m pacted Power Loads Removi ng i nverters from service i m pacts the reliability of the associated AC busses . Section 2 . 1 of this describes some key Class 1 E loads suppl ied by each division of AC power that m ay be i m pacted (thoug h not necessarily d isabled) by the extended inverter AOT.

24

LR-N 1 8-0032 LAR H 1 8-02 Enclosure 3 . 2 . 2 . 1 .4 Calcu l ational Approach To determ i n e the effect of the proposed 7 day AOT for restoration of an inoperable inverter, the g u idance in Reg u l atory G u ides 1 . 1 7 4 and 1 . 1 77 is used .

. Fig u re 3-1 can be used to conceptually describe the terms used i n the risk metric calculati o n .

Thus, t h e fol lowi ng risk metrics are used t o eva l uate t h e risk impacts o f extending t h e i nverter AOT from 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months to 7 days :

Regulatory G u ide 1 . 1 7 4 LiCD FAVE = change i n the annual average C D F d ue to any i ncreased on-line maintenance u n availabil ity of the i nverter(s) that could result from the increased Al lowed O utage Time. This risk metric is used to com pare ag ainst the acceptance g u idelines of Regu l atory G u id e 1 . 1 74 to determ ine whether a change in C D F is regarded as risk sig n ificant. These criteria are a fu nction of the baseline a n n u a l average core damage freq uency, C D FsASE*

LiLERFAvE = change i n the annual average LERF due to any i ncreased on-line mai ntenance u n avai labil ity of the i nverter(s) that could result from the increased Allowed O utage Time. Reg u l atory G u ide 1 . 1 7 4 acceptance g u ideli nes were also applied to j udge the sig n ifica nce of changes i n this risk metric.

Regulatory G u ide 1 . 1 77 I C C D P1Nv = I ncremental conditional core damage probability with the i nverter(s) out-of service for an i nterval of time equal to the proposed new Al lowed Outage Time (7 days) . This risk metric is used as suggested in N U MARC 93-0 1 to dete rm i n e whether a proposed i ncrease i n Allowed Outage T i m e h a s an acceptably l ow ris k i m pact.

I n cremental core damage probabil ity is the d ifference in the "config u ratio n specific" C D F a n d t h e baseline ( o r t h e zero mai ntenance) C D F . The configuration-specific CDF is the annualized risk rate with the u navailabilities of the out-of-service SSCs set to o n e . The confi g u ration-specific C D F m ay also consider the zero mai ntenance model ( i . e . , the unavai labil ity of the out..:of-service SSC(s) is set to one, and the m a intenance u navailabil ity of the rem a i n i ng SSCs is set to zero) . This more closely reflects the actual config u ration of the plant d u ring the maintenance activity.

Plants should consider factors of d u ration i n setting the risk management thresholds. This m ay be either the d u ration of a particular out-of-service condition , or a specific defi ned work i nterval (e. g . shift , week, etc . ) . The product of the incremental C D F (or LERF) and duration is expressed as a probabil ity (e . g . , incremental core damage probability - ICCDP, incremental large early release probabil ity - I C LERP).

25

LR-N 1 8-0032 LAR H 1 8-02 Enclosure I C L E RP 1Nv = I n cremental conditional large early release probabil ity with the inverter(s) o ut-of service for an interval of time eq ual to the proposed new Al lowed Outage Time (7 days) . This risk metric from RG 1 . 1 77 is used to determ ine whether a proposed increase i n Allowed Outage Time h as a n acceptably low ris k impact.

The evaluation of the above risk metrics is performed as follows .

The change in the a n nual average CDF due to the extension of the i nverter Allowed O utage Time , A C DFAvE is evaluated by com puti ng the followi n g :

CDFA VE = (_!A_J TCYCLE CDFINV-OOS + ( _!A_J 1-TCYCLE CDFBase [Eq. 1]

where :

CDF aAsE = Base l i n e annual average CDF with average u navailabil ity of the inverters consistent with the cu rrent i nverter Allowed O utage Time.

CDF!N v-oos = CDF evaluated from the PRA model with the i nverter(s) out-of-service and appropri ate measures i m plemented . These measures i nclude, for example, pro h ibiti ng concurrent maintenance or inoperable status of the remaining AC power channels i n accordance with Tech nica l S pecifications.

TA = Total outage ti me proposed for the AOT req u i red for the m a i ntenance acti on and testing of the i nverter(s) (i . e . , 7 days) .

T cycle = For this AOT extension , the cycle is assumed to be a calendar year, 1 2 months of operation (365 days) 7 days 3 5 8 days CDFAVE = CDFINV-OOS X 3 65 days

+ CDFBase X ---

3 6 5 days

[Eq. 2]

iJCDFA vE = CDFA vE - CDFsAsE [Eq. 3]

where :

= Average CDF based on a 7 day i nverter OOS and " cycle" of one calendar year.

ACDFAvE = Difference between C D FsAs E ( i . e . the current Tech n ical S pecifications on the inverter(s)) and the CDF for an average 1 2-month cycle with the inverter Allowed Outage Time extended to 7 days .

Fig ure 3- 1 provides a g raphical d isplay of the cycle evaluation for the RG 1 . 1 74 risk evaluation.

26

LR-N 1 8-0032 LAR H 1 8-02 E n closure A s i m ilar approach was used to eva l u ate the change in the average LERF due to the req uested Allowed O utage Time, ilLERFAvE:

[Eq. 4]

where :

LERFsAs E = Baseline annual average LERF with an i nverte r unavailability consistent with the current Allowed Outage Time. This is the LERF res u lt of the current baseline PRA. (See d iscussion u nder CDFsAs E above . )

L E R F 1Nv-oos = LERF evaluated from the PRA model with the i nverter(s) o ut-of-service and appropriate meas u res i m plemented . These measures include, for exam ple ,

prohi biting concurrent maintenance or i noperable status of the rema i n ing AC power channels i n accordance with Technical Specifications.

&ERF = LERFA vE -LERFBASE [Eq. 5]

The evaluation was performed based o n the assu m ption that the extended Allowed O utage Time would be applied once per yea r (for each chan nel) , hence TA = 7 days . The cycle time is take n to be one year.

TcrcLE = 3 65 days The incremental conditional core d a m age probabil ity (I CCDP) and i n cremental conditional large early release probabil ity ( I C L E RP) are computed using their defi n itions from Reg ulatory G u ide 1 . 1 77 . In terms of the above defi ned parameters , the defi n ition of ICCDP is as follows :

ICCDP = (CDFINv-oos - CDFBAsE) TA o r [Eq. 6]

ICCDP = (CDFINv-oos - CDFBAsE) * (7 days) I (365 days/year) [Eq. 7]

ICCDP = (CDFINv-oos - CDFBAsE)

1 . 92E-02 years [Eq. 8]

N ote that i n the above form ula 365 d ays/year is merely a conversion factor to provide the Allowed Outage Time u nits consistent with the CDF frequency u n its . The I C C D P val ues are d i m e nsion less probabilities to evaluate the i ncremental probabi lity of a core damage event over a period of time eq ual to the extended Allowed Outage Time.

S i m ilarly, I C LERP is defined as fol l ows :

ICLERP = (LERFINv-oos - LERFBASE)

1 . 92E-2 years [Eq. 9]

Finally, it is noted th at ilC DFAvE and I CC D P , as defined above , are i n fact eq ual since TcvcLE is taken to be one year. The same is true of ilLE RFAvE and I C LERP.

27

LR-N 1 8-0032 LAR H 1 8-02 E n closure BEFORE TECH SPEC C HAN G E c

D C D F eAsE F

1' T

Refue l AFT E R TECH SPEC CHAN G E Tcycle c C D FAvE D

F C D F eAsE 1'

T Refu e l Fig u re 3-1 : Evaluation Used for Reg . G u ide 1 . 1 74 Calculation < 1 J 3.2.2.2 Resu lts a n d I m pacts 3 . 2 . 2 . 2 . 1 Quantified Results The H o pe Creek at-power Models of Record ( H C 1 1 7A and H C 1 1 4FO) we re quantified for five cases - one base case, and one for each channel's inverters set out-of-service (see Sectio n 3 . 2 . 2 . 1 .2). Both models were tru ncated as prescribed in their respective Quantification N otebooks ; FPI E to 1 . 00E-1 2/yr, and Fire to 1 . 00E-1 1 /yr ( References 1 7 & 1 8) . The resu lting C D F and LERF metrics for each case studied a re presented i n Table 3-3 and Table 3-4 respectively.

<1> C a l c u l ation ass u mes the i n verter o utage occu rs with i n o n e ( 1 ) ca l e n d a r year a n d that the AC D F is for that ca l e n d a r year.

28

LR-N 1 8-0032 LAR H 1 8-02 Enclosure Although the Fire model contributes larger absol ute values to the totals, the risk metrics calculated i n Section 3 . 2 . 2 . 2 . 2 depend on the deviation from the base case; therefore, the F P I E model is of m uch g re ater conseq uence.

Table 3-3 S U M MARY OF Q UANT I F I E D C D F I nternal Events Fire Total Case CDF (/yr) C D F(/yr) C D F (/yr)

Base Case MOR 5.91 E-06 1 . 80E-05 I 2 . 39 E-05 I

Channel A I nverters OOS 1 . 02 E-05 1 . 92 E-05 2 . 94 E-05 Channel B I nverters OOS 1 . 1 3 E-05 1 . 99 E-05 3 . 1 3 E-05 Channel C I nverters OOS 9 . 95E-06 1 . 88 E-05 2 . 87 E-05 Channel D I nverters OOS 1 . 02 E-05 1 . 82 E-05 2 . 85E-05 Table 3-4 S U M MARY OF Q UANTI F I E D LERF I nternal Events F i re Total Case LERF (/yr) LERF (/yr) LERF (/yr)

I Base Case M O R I 1 . 84E-07 I 2 . 2 5 E-06 I 2 . 44 E-06 I

Channel A I nverters OOS 4.43E-07 2 . 48 E-06 2 . 92 E-06 Channel B I nverters OOS 6 . 02 E-07 2 . 28 E-06 2 . 88 E-06 Channel C I nverters OOS 4 . 54E-07 2 . 45 E-06 2 . 90E-06 Channel D I nverters OOS 4. 85E-07 2 . 28 E-06 2 . 77 E-06 3 . 2 . 2 . 2 . 2 Calculated C D F and LERF Metrics Table 3-5 summarizes the calcu l ated values for the N RC-specified risk metrics (CD F , LERF, ICCDP, and I C LE RP) for the proposed change to the inverter AOT for each of the four inverter channels. These resu lts , calculated from the data in Table 3-3 and Table 3-4 as defi ned i n Section 3 . 2 . 2 . 1 .4 , are produced a s specified by the N RC i n R G 1 . 1 74 , a n d R G 1 . 1 77. Table 3-6 through Table 3-9 provide example calculations of these metrics .

29

LR- N 1 8-0032 LAR H 1 8-02 Enclosure Table 3-5 COM PARISON OF Q UANTITATIVE RESU LTS WITH ACCE PTANCE G U I D E L I N ES (TOTAL O F I NTE RNAL AN D EXTERNAL EVE NTS)

L\CD FAvE I ICCDP L\LERFAvE I ICLERP Acceptance Criteria 1 . 00 E-6 1 . 00 E-7 Chan nel A I nverters OOS 1 . 06 E-07 9 . 30E-09 Chan nel 8 I nverters OOS 1 . 4 1 E-07 8 . 54 E-09 Channel C I nverters OOS 9 . 1 9 E-08 8 . 93E-09 Chan nel D I nverters OOS 8 . 65E-08 6 . 3 1 E-09 Table 3-6 SAM PLE CD F CALCU LATI O N FOR HOPE CREEK - I NVERTERS OOS Average CDF after AOT Extension I n cluded . Channel A COFA vE = 2. 94E-051yr * (7 days I 365 days) + 2. 39E-051yr * (358 days I 365 days)

COFA vE = 2. 40E-051yr Change in C D F . C h a n n e l A L1COF = CDFA vE - CDFaASE L1CDF = 2. 40E-05/yr - 2. 39E-051yr1J L1 CDF = 1 . 06E-071yr Lege n d :

C D F = C h a n g e i n the a n n u a l average C D F d u e to any inc reased o n - l i n e m a i nte n a nce u nava i l a b i l ity of the i nverters that co u l d res u lt from the i ncreased Allowed O utag e T i m e . T h is risk m etric is used to com pa re ag a i n st t h e accepta nce g u id e l i nes of Reg u latory G u id e 1 . 1 74 to dete rm i n e whethe r a c h a n g e i n C D F i s rega rded as r i s k sig n ifica n t . These criteria a re a fu n ction of the base l i n e a n n ua l ave rag e c o re damage freq ue ncy, C D F eAS E

LERF = C h a n g e i n the a n n u a l average L E R F d u e to any i n c reased o n - l i n e m a i nte n a n ce u nava i l a b i l ity of the i n verte rs that cou l d res u lt from the i n creased Allowed O utag e T i m e . Reg u latory G u id e 1 . 1 7 4 acce pta nce g u id e l i n e were a l s o a p p l ied t o j u d g e t h e s i g n ificance o f c h a n g es i n t h is risk m etric.

C D F eAsE = Appl icati o n -s pecific C D F fo r ave rag e m a i ntenance.

30

LR-N 1 8-0032 LAR H 1 8-02 E nclos u re CDFA vE = Averag e C D F i n corporati n g a 7 day i nverter OOS a n d based o n a o n e cal e n d a r year.

Table 3-7 SAM PLE ALERF CALC U LAT I O N S FOR HOPE CRE E K - I NVERTERS OOS Average LERF after AOT Extension I n cluded . Channel A LERFA vE = LERF/N v-oos * (TA l TcvcLEJ + LERFaASE * (1 - TA l TcvcLE)

LERFA vE = 2. 92E-061yr * (7 days I 365 days) + 2. 44E-06 * (358 days I 365 days)

LERFA vE = 2. 45E-061yr Change in LERF. Channel A LJ.LERF = LERFA vE - LERFaA sE LJ.LERF = 2. 45E-061yr - 2. 44E-061yr LJ.LERF = 9. 30E-91yr Table 3-8 SAM PLE I CCDP CALCU LAT I O N - I NVERTERS OOS Channel A ICCOP = (COFINv-oos - CDFaA sEJ * (TA I TcvcLE)

/CCDP = (2. 94E-051yr - 2. 39E-051yr) * (7 days I 365 dayslyr)

JCCDP = 1 . 06E-07 Table 3-9 SAM PLE ICLERP CALCU LAT I O N - I NVE RTE RS OOS Channel A

/CLERP = (LERFINv-oos - LERFaA sE) * (TA I Tc YCLE)

JCLERP = (2. 92E-061yr - 2. 44E-061yr) * (7 days I 365 dayslyr)

/CLERP = 9. 30E-07 3.2.2.3 Risk I nsights The risk insights described i n this section are i ntended to be folded i nto the H o pe Creek Config u ration Risk Management Prog ram (CRM P).

3 . 2 . 2 . 3 . 1 D istri bution of Risk Contri butors The distri bution of i n itiati ng event and accident class contri butors for the resu lts generated by the H o pe Creek Application-Specific M odel (ASM) have been reviewed. As the risk metrics depend on the difference between each case and the base case, the im portance measures of i nterest a re those of the delterm cutsets , i . e . the difference i n the two cutset fi les. I n this 31

LR-N 1 8-0032 LAR H 1 8-02 Enclosure evaluation , the F P I E metrics are m u ch more risk-significant to the overall result than Fire, so these im portance measu res are presented for F P I E only. Table 3-1 0 and Table 3- 1 1 present the i nitiating events' i m portance meas u res for delterm FPI E CDF and LERF; Table 3- 1 2 and Table 3- 1 3 present the same for the various accident classes.

32

LR-N 1 8-0032 LAR H 1 8-02 Enclosure Table 3- 1 0 I N ITIATI N G EVENT CONTR I B UTORS TO D E LTA F P I E C D F Channel A Channel S C h a n nei C C h a n nei D I n itiator Descri ptio n CDF % CDF % CDF % CDF %

LOSS O F O F F S I T E POW E R I N ITIAT I N G

% 1 E-TE 4 . 36 E-06 95.0% 5 . 3 7 E-06 95.4% 4 . 1 4 E-06 96. 8 % 4 . 32 E-06 95. 3 %

EVE N T

% l E-TT T U R B I N E T R I P W I T H BYPASS 6 . 1 6 E-08 1 .3% 9 . 3 6 E-08 1 .7% 4 . 4 5 E-08 1 .0% 4 . 89 E-08 1 .1%

% F LTB-CW T U R B I N E B U I LD I N G F L O O D 3 . 36 E-08 0.7% 6 . 6 0 E-08 1 .2% 4 . 5 7 E-09 0. 1 % 7 . 4 9 E-09 0.2%

% 1 E-SO RV2 2 o r M o re S O RVs 2 . 05 E-08 0.4% 4 . 0 0 E-09 0. 1 % 3 . 5 9 E-09 0. 1 % 4 . 0 9 E-09 0. 1 %

LOSS O F S E RV I C E WATE R I N I TIATI N G

% 1 E-SWS 1 . 94 E-08 0 .4 % 1 . 59 E-08 0.3% O . O O E+ O O 0.0% 1 . 82E-1 0 0.0%

EVE N T

% F L F PS-R B U F P S R U PT U R E I N R B U P P E R LEVELS 1 . 54 E-08 0.3% 2 . 0 1 E-08 0.4% 1 . 57 E-08 0.4% 1 . 86 E-09 0.0%

% I E-SACS L O S S O F SACS I N I TIATI N G EVE N T 1 . 07 E-08 0.2% 8 . 7 8 E-09 0.2% O . O OE+OO 0.0% 9. 08E-1 1 0.0%

% 1 E-M L R H R M ed i u m LOCA - R H R 9 . 99 E-09 0.2% 1 . 35 E-09 0.0% 2 . 1 4 E- 1 0 0.0% 9. 08E-1 1 0.0%

% 1 E- M L R E C I RC M ed i u m LOCA - Reactor Recircu latio n 8 . 7 1 E-09 0.2% 1 . 6 9 E- 1 0 0.0% 4 . 2 7 E- 1 1 0.0% O . O O E+ O O 0.0%

%I E-TC LOSS O F C O N D E N S E R VAC U U M 8 . 1 1 E-09 0.2% 1 . 08 E-08 0.2% 5 . 1 7 E-0 9 0. 1 % 5 . 7 2 E-09 0. 1 %

F P S R U PT U R E I N C O N T R O L D I E S E L

% F L FPS-C D 6 . 79 E-09 0. 1 % 1 . 00 E-08 0.2% 5 . 2 5 E-08 1 .2% 1 . 35 E-07 3 . 0%

BUILDING Oth e r 3 . 30 E-08 0.7% 3 . 0 7 E-08 0.5% 9 .48 E-09 0.2% 1 . 1 4 E-08 0.3%

Tota l 4 . 58 E-06 1 00 % 5 . 6 3 E-06 1 00 % 4 . 2 7 E-06 1 00 % 4 . 54 E-06 1 00 %

33

LR-N 1 8-0032 LAR H 1 8-02 Enclosure Table 3- 1 1 I N ITIATI N G EVE NT CONTRI B UTORS TO D ELTA F P I E LERF C h a n n el A C h a n ne l S Channel C C h a n nei D I n itiator Descri pti o n LERF % LERF % LERF % LERF %

LOSS O F O F FS I T E POW E R I N ITIAT I N G

% 1 E-TE 2 . 59 E-07 95.5% 4 . 0 9 E-07 96. 1 % 2 . 6 7 E-07 96.4% 2 . 86 E-07 93. 1 %

EVE N T F P S R U PT U R E I N C O N T R O L D I E S E L

% F L F PS-C D 2 . 72 E- 1 2 0.0% 5 . 2 3 E- 1 0 0. 1 % 6 . 96 E-09 2.5% 1 . 83 E-08 6.0%

B U I LD I N G

% l E-TT T U R B I N E T R I P WITH BYPASS 3 . 4 7 E-09 1 .3% 5 . 66 E-09 1 . 3% 1 . 7 1 E-09 0.6% 1 . 9 1 E-09 0.6%

L O S S O F S E RVI C E WAT E R I N ITIAT I N G

% 1 E-SWS 1 . 88 E-09 0.7% 1 . 32 E-09 0.3% O . O O E+ O O 0.0% O. OOE+OO 0.0%

EVE N T

% I E-MS MAN UAL S H UTDOWN I N I TIATI N G EVE N T 1 . 79 E-09 0.7% 2 . 36 E-09 0.6% 3 . 6 8 E- 1 0 0. 1 % 4 . 6 0 E- 1 0 0.2%

% F LT B-CW TU RBI N E B U I L D I N G FLOOD 1 . 05 E-09 0.4% 1 . 7 1 E-09 0.4% 1 . 66E - 1 1 0.0% 3. 07E-1 1 0.0%

% I E-SACS L O S S O F SACS I N I TIATI N G EVE N T 1 . 00 E-09 0.4% 6 . 9 8 E- 1 0 0.2% O . O O E+ O O 0.0% O . O O E+OO 0.0%

% 1 E-SO RV2 2 o r M o re S O RVs 6 . 6 5 E- 1 0 0.2% 1 . 02 E- 1 0 0.0% 8 . 86 E- 1 1 0.0% 9 . 8 1 E-1 1 0.0%

Other 2 . 35 E-09 0.9% 4 . 1 3 E-09 1 .0% 7. 8 1 E - 1 0 0.3% 2 . 7 3 E- 1 0 0. 1 %

Total 2 . 72 E-07 1 00 % 4 . 26 E-07 1 00 % 2 . 7 7 E-07 1 00 % 3 . 0 7 E-07 1 00 %

34

LR-N 1 8-0032 LAR H 1 8-02 E nclosu re Table 3- 1 2 ACC I DENT C LASS CONTR I B UTORS TO D ELTA F P I E C D F Channel A Channel S C h a n n el C C h a n nel D Class Descriptio n CDF % CDF % CDF % CDF %

Loss of i nvento ry m a ke u p at h i g h reactor lA 1 . 7 1 E-06 37.3% 1 .4 1 E-06 25.0% 8 . 64 E-07 20.2% 9 . 1 4 E-07 20. 1 %

p ress u re Loss o f i nvento ry m a k e u p d u ri n g a n early statio n IBE 8 . 0 1 E-07 1 7.5% 1 . 2 5 E-06 22.2% 6 . 7 6 E-08 1 .6% 1 . 2 3 E-07 2.7%

blackout Loss o f i nvento ry m a ke u p d u ri n g a late statio n IBL 9 . 77 E-08 2.1 % 9 . 8 9 E-08 1 .8% 1 . 42 E-07 3.3% 1 . 47 E-07 3.2%

blackout L o s s of i nvento ry m a ke u p i n d u ced by a n ATWS ;

IC 8 . 30 E-09 0.2% 5 . 6 9 E-09 0. 1 % 2 . 1 4 E- 1 0 0.0% 1 . 82 E- 1 0 0.0%

conta i n ment i n tact Loss of i nvento ry m a ke u p at low reactor ID 7 . 73 E-07 1 6. 9% 2 . 1 4 E-06 38.0% 3 . 0 9 E-06 72. 3 % 3 . 24 E-06 71 .3%

p res s u re II Loss o f con ta i n m e n t heat rem oval 1 . 1 2 E-06 24.4% 7 . 1 3 E-07 1 2 . 7% 1 . 07 E-07 2 . 5% 1 . 1 5 E-07 2.5%

Loss of conta i n m e n t heat re mova l , core d a m a g e l iT 4 . 58 E- 1 0 0.0% O . O O E+ O O 0.0% O.OO E+OO 0.0% 4 . 54 E- 1 1 0.0%

post-re p ressu rizatio n S m a l l o r m ed i u m LOCA, reactor ca n n ot IliB 4 . 85 E-08 1.1% 5 . 6 3 E- 1 1 0.0% 4 . 2 7 E- 1 1 0.0% O. OOE+OO 0.0%

d e p ressu rize M ed i u m o r l a rg e LOCA, reactor h a s n o low-IIIC 4 . 36 E-09 0. 1 % 3 . 8 8 E-09 0. 1 % 3 . 8 9 E-09 0. 1 % 4 . 3 6 E-09 0. 1 %

p ressu re i nj ectio n LOCA o r R PV fai l u re, va p o r s u p p ression i s IliD 4 . 58 E- 1 1 0.0% 5 . 6 3 E- 1 1 0.0% O . O O E+ O O 0 . 0% O.OO E+OO 0.0%

i nadeq u ate , l oss of m a ke u p IV Fai l u re to scram 2 . 65 E-08 0.6% 1 . 35 E-08 0.2% 1 . 2 8 E- 1 0 0.0% 9 . 0 8 E- 1 1 0.0%

v U n isolated LOCA o utside conta i n m e n t O . OOE+OO 0.0% O . O O E+ O O 0.0% O . O O E+ O O 0.0% O . O O E+ O O 0.0%

Total 4 . 58 E-06 1 00 % 5 . 6 3 E-06 1 00 % 4 . 27 E-06 1 00 % 4 . 54 E-06 1 00 %

35

LR-N 1 8-0032 LAR H 1 8-02 Enclosure Table 3-1 3 ACC I DENT C LASS CONTRI B UTORS TO D E LTA F P I E LERF C h a n ne l A C h a n ne l S C h a n nel C C h a n n ei D C lass Descri ptio n LERF % LERF % LERF % LERF %

Loss of i nvento ry makeup at h i g h reactor lA 2 . 1 2 E-08 7.8% 1 . 52 E-08 3.6% 2 . 4 7 E-08 8.9% 2 . 62 E-08 8.6%

p ress u re Loss o f i nvento ry m a ke u p d u ri ng a n early station IBE 1 . 65 E-07 60.7% 2 . 8 5 E-07 67.0% 1 . 2 3 E-08 4.4% 1 . 67 E-08 5.5%

blackout Loss o f i nvento ry m a ke u p d u ri n g a late stati o n IBL O . OO E+ O O 0.0% O . O O E+ OO 0.0% O . O O E+ O O 0.0% O . O O E+ O O 0.0%

blackout Loss of i nvento ry m a ke u p i n d u ced by a n ATWS ;

IC 6 . 79 E- 1 1 0.0% 4 . 26 E- 1 1 0.0% O . O O E+ O O 0.0% O . O O E+OO 0.0%

conta i n ment i n tact Loss o f invento ry m a k e u p a t low reactor ID 6 . 72 E-08 24 . 8 % 1 . 1 7 E-07 27.5% 2 . 4 0 E-07 86. 6 % 2 . 6 4 E-07 86 . 0 %

pressu re II Loss o f con ta i n m e n t heat re m oval O . OOE+OO 0.0% O. OOE+OO 0.0% O.OO E+OO 0.0% O . O O E+ OO 0.0%

Loss of conta i n m e n t heat re mova l , core damage l iT O. OOE+OO 0.0% O. OOE+OO 0.0% O.OO E+OO 0.0% O. OOE+OO 0.0%

post-re p ressu rizati o n S m a l l o r med i u m LOCA, reactor can n ot 1118 1 . 75 E-09 0.6% O. OOE+OO 0.0% O. OOE+OO 0.0% O . OO E + O O 0.0%

depressu rize M ed i u m or l a rg e LOCA, reactor has n o low-I I IC 1 . 03 E- 1 0 0.0% 9 . 7 9 E- 1 1 0.0% 8 . 86 E- 1 1 0.0% 9 . 8 1 E-1 1 0.0%

p ressu re i nj ectio n LOCA o r R PV fai l u re , va p o r s u p p ression i s IliD 2 . 1 7 E- 1 1 0.0% 2 . 1 3 E- 1 1 0.0% O.OO E+OO 0.0% O . O O E+ O O 0.0%

inadeq uate , loss o f m a ke u p IV Fa i l u re t o scram 1 . 62 E-08 6.0% 8 . 05 E-09 1 . 9% 3. 88E-1 1 0.0% 3 . 68 E- 1 1 0.0%

v U n isolated LOCA o utsi d e conta i n ment O. OOE+OO 0.0% O. OOE+OO 0.0% O. OOE+OO 0.0% O . O O E+ O O 0.0%

Tota l 2 . 72 E-07 1 00 % 4 . 2 6 E-07 1 00 % 2 . 77 E-07 1 00 % 3 . 07 E-07 10 36

LR-N 1 8-0032 LAR H 1 8-02 Enclosure 3 . 2 . 2 . 3 . 2 O bservations from the Risk Metric Calculations Several observations may be m ade from the res u lts and im portance measures presented in the previous s ubsections.

First, a loss of offsite power (LOOP) is overwhel m i n g ly sig n ificant to the change i n plant risk metrics d u e to the considered AOT chang e . This i n itiator accou nts for about 95% of CD F and LERF for all fou r inverter channels. S uch a h i g h i m portance com ports with the i nverters ' sole, vital function as part of AC power distri bution to Class 1 E eq u i pment - any change i n plant risk due to thei r m a i ntenance m ust naturally proceed from a challenge to AC power. The othe r i n itiators contribute neg l ig i ble amou nts of risk.

Next , the difference i n risk-sig n ificant accident classes between the fou r chan nels is attri b uted to the d ifferen ce i n AC power loads they supply.

All four channels serve thei r respective trains of several plant systems; it is ass u m ed that these common systems do not g ive rise to the d ifferen ces in risk-sig n ificance :

o Emergency Diesel Generators (E DGs) o Residual Heat Removal (RH R) o Core Spray (CS) o Service Water (SW) o Safety Auxiliary Cooling System (SACS)

Channel A: This channel supplies the High Pressure Coolant I njection ( H PC I ) System and Suppression Pool Cooling Tra i n A (SPC A) . The CDF i ncrease fro m taki ng these i nverters out-of-service therefore resu lts most often i n a loss of inventory at h igh pressu re (Class lA - 37%) and a loss of containment heat removal (Class I I - 24%) Loss of i nventory at low pressure (Class I D

- 1 7%) i s less sign ificant com pared to other channels as core damage tends to occu r before depressu rizatio n . A station blackout is sig n ificant in the early timeframe (Class I B E - 1 8%) as this is when i njection is m ost critica l . Early station blackout is also the most l i kely to lead to a l arge early release (Class I BE - 6 1 %) due to a reliance on either the RC I C turb i ne d riven pump or prompt recovery of offs ite AC power.

Channel B : This channel su pplies the Reactor Core Isolati on Cooling ( RC I C) Syste m ,

as wel l a s S u ppression Pool Cooling Train B (SPC B ) a n d t h e Autom atic Depressurization System (ADS) . It has a similar accident profi le as Channel A, though core damage occurs less frequently due to loss of i nventory at high pressure (Class lA - 25%) and more freq uently at l ow pressure (Class I D - 38%) . This is because the plant is more l i kely to successfu lly depressurize with the H P C I System (supplied by Chan n e l A) in service . The successfu l operator action to i n h ibit ADS is a sig n ificant contri butor to this (Fussei-Vesely 24%) . Loss of containment heat re moval is somewhat less i m portant (Class I I - 1 3%) . Early station blackout is similarly significant reg ard i ng core damage (Class I B E - 22%) and large early releases (Class I B E - 67%) , ag ain due to the i m portan ce of early i njection , the H PC I turbine-driven p u m p , and prom pt offsite AC power recovery.

37

LR- N 1 8-0032 LAR H 1 8-02 Enclosure

Channel C : This cha n nel suppl ies the Low Pressu re Coolant I njection (LPC I ) System .

A large majority of both the C D F a n d L E R F i ncreases when removin g this channel from service is due to a loss of inventory at l ow pressu re (Class I D

- 72 % C D F , 87% LERF), which LPCI i s designed to m itigate . The rem a i nder is m ostly via loss of i nventory at h ig h pressure (Class lA -

20% C D F , 9% LERF) . Considering statio n blackout, it is notable that the late timeframe (Class I BL - 3 . 3%) is relatively m o re i m portant than the early (Class I B E - 1 . 6%) , i n contrast with Chan nels A and B. This re iterates the importance of low-pressure injection sources .

Channel D : This channel also suppl ies the Low Pressure Coolant I njection (LPCI)

Syste m , as wel l as the Automatic Depressurization System (ADS) . Its accident profi le is very s i m i lar to Channel C, with a large contribution com i ng from l oss of inventory at low pressu re (Class I D - 7 1 % C D F ,

86% LERF) and most o f t h e remainder from l o s s o f inventory a t h ig h pressu re (Class lA - 20% C D F , 9% LERF) .

Turning t o the Fire model , examination of the delterm cutsets reveals that the change i n fire risk is overwh e l m i ngly due to fires that damage the ADS logic tri ps, resulting i n a spurious ADS actuation and subseq uent Large LOCA. This u ltimately leads to core damage through a variety of d iffere nt accident seq uences, depending on which chan nel's i nverters are out-of-service . For Channel D , which shows the lowest i ncrease i n fire risk, this effect is less pronounced and is about eq ually sig nificant with a loss-of-feedwater induced by Condensate System fai l u res.

Overa l l , thoug h , these changes i n fire risk are significantly less i m portant than those noted above for i nternal events risk.

The PRA m odel resu lts were reviewed and it was determ i ned that the individual fai l u re of a -

482 i nverter has a risk i ncrease eq u ivalent to about 80% of the risk i ncrease for fai l u re of two i nverters on that channel. This approxi mation is fai rly consistent for LlCDF / ICCDP and LlLERF

/ I C LERP results and for each channel. An individ ual fai l u re of a -48 1 i nverter resu lts in a m uch lower risk increase com pa red to the risk i ncrease for the fai l u re of two i nverters on that channel .

This result is consistent with the res u lts described i n 3-1 0 through 3- 1 3 wh ich attribute m ost of the risk i ncrease to l oss of offsite power (LOOP) scenarios . Following a LOOP with only the -

482 i nverter alig ned to the backup power, the associated E DG wil l not automatically start and the higher voltage busses o n that channel will not be energ ized . Followi ng a LOOP with o n ly the -48 1 i nverter alig ned to the backup power, the u naffected -482 inverter wil l shift to battery su pplied power and start the E D G . The 1 20 VAC buses powered by the -48 1 inverter wi l l i n itially b e de-energ ized and wil l b e reenerg ized a s t h e E D G comes o n l i n e . Therefore , t h e risk i ncrease associated with o n ly the -48 1 inverter is m u ch lower than the risk i ncrease with o n ly the -482 inverter.

Fi nally, the values for LlCD F / ICCDP and LlLERF / ICLERP reported in Table 3-5 com pare favorably to the acceptance g u ideli nes establ ished by the N RC i n Reg u l atory G u ides 1 . 1 7 4 and 1 . 1 77 , standing about an order of magn itude below the l i m it across the board . Therefore , no matter which inverter is taken out-of-service for mai ntenance , there i s generous marg i n in the ris k metrics . Of the two m etrics , LlCDF / ICCDP is the most l i m iting ; of the fou r i nverter channels, Channel B is the m ost l i m iting . Removi ng this channel from service i m pacts the m ost safety systems, including RC I C , S PC B, and ADS , plus the E D G , R H R , CS, SW, and SACS systems common to all channels. It should again be noted that the Tech nical Specification 38

LR-N 1 8-0032 LAR H 1 8-02 E nclos u re the random ness of seism ic capacity) . Therefore, a g iven seismic event that fails one i nverter is highly l i kely to fai l all the others, as wel l . Qualitatively, the inverters are "all or n oth i ng " , and i ncreasing the m a i ntenance outage period of a single chan n e l wil l have a minimal effect o n plant seismic risk. Accord i ngly, the seism ic t.C DF / ICCDP and t.LERF / I C LERP for this risk evaluation a re expected to be negligible.

Additionally, a bounding esti mate of the change i n risk m etrics d ue to seismic hazards may be made based on the F P I E Model of Record , wh ich was developed to the standards set by Reg u l atory G u ide 1 . 200 (Reference 3). The incremental change i n seismic C D F ( i . e . , core damage d u e to a seismic i n itiati ng event) may be calculated by applying Bayes' Theorem to Equation 6 :

ICCDP = (CDFIN v-oos - CDFaA sEJ *TA oT [from Eq. 6]

Seismic ICCDP = [(CDFJNv-oos AND Seismic IE) - {CDFaA sE AND Seismic IE)J*TAoT Seismic ICCDP = [P(Seismic IE) *CDFJN v-oosi Seismic IE

- P(Seismic IE) *CDFaA sEI Seismic IEJ*TA oT Seismic ICCDP = P(Seismic IE) *[CDFtNv-oosi Seismic IE - CDFaAsEI Seismic IEJ *TA oT

[Eq. 1 0]

where P(Seismic IE) represents the probabil ity of a seismic i n itiating event, CDFtN v oosi Seismic IE is the CDF g iven a seism ic i n itiati ng event and the i nverters out-of service , CDFaAsEI Seismic IE is the C D F g iven a seismic i n itiating event for the base mode l , and TA oT represents the cycle fraction (i.e. 7 days d ivided by 365 days = 1 . 92 E-02) .

The eq uation above considers a l l seismic in itiators ; however, for the purposes of th is risk evaluatio n , the scope can be l i m ited to seismic l oss of offsite power (LOOP) i n itiati ng events .

F rom Table 3-1 0 and Table 3- 1 1 , it can be seen that such accident sequences are overwhelm i n g ly responsible for the change i n C D F and L E R F , contributing 95% of both risk metrics for all fou r ch annels. G iven that the inverters' sole function i s to protect the availabil ity of AC power, it is assu med that any change in seis m i c risk metrics wil l similarly arise from a seismic LOOP event. Specifying Equation 1 0 therefore yields :

Seismic ICCDP P(Seismic LOOP) *[CDFJNv-oosi Seismic LOOP

- CDFaAsE I Seismic LOOPJ *TA oT [Eq. 1 1]

A calculation for Seismic ICLERP is similarly developed :

Seismic ICLERP P(Seismic LOOP) *[LERFJN v-oosi Seismic LOOP

- LERFaA sEI Seismic LOOPJ*TA oT [Eq. 1 2]

The freq uency of a seismic LOO P can be calcu lated based on the peak g round acceleration exceedance curves from the most recent Seismic H azard and Screening Report ( Referen ce 23, E nclosure 1 , Table A- 1 ) . Conservatively taking the median frag i l ity of offsite power com ponents to be 0 . 1 5 g Peak G round Acceleration (compared to a determ i ned value of 0 . 3 1 g in the I PE E E seismic assessment) , this freq uency has a m e a n o f 6 . 6 7E-05 /yr a n d is considered bounding.

The C D F (or LERF) g iven a seism ic LOOP may be estimated by q u a ntifying the FPI E Model of Record ( H C 1 1 7A) with the LOOP i n itiator (%1 E-TE) set to TRUE and a l l other i n itiators set to 40

LR- N 1 8-0032 LAR H 1 8-02 Enclosure FALS E . This conseq uently fails all eq u i pment dependent on offsite power. It is co nservatively assu med that offsite power recovery is not possible - these basic events are also set to T RU E .

Additionally taki ng an inverter channel out-of-service (as detailed i n Section 3 . 2 . 2 . 1 . 2) allows a bounding calculation of the change i n seismic CDF or LERF due to the extended AOT.

This approach is conservative in two ways . First, in a seismic PRA developed per Reg ulatory G u ide 1 . 200 , s i m i lar eq u ipment i n s i m i lar plant locations would have h i g h ly correlated seismic fai l u re probabil ities (as noted above) . A seism ic event that fails one i nverter is highly l i kely to fai l a l l the others , as wel l ; the fact that one may be out-of-service is i rrelevant, and there would be no change i n risk metrics due to the extended AOT. Second, ass u m i ng offsite power recovery is not possible conservatively d iscredits m itigating actions for seis m i c accident seq uences with lower peak g round accelerations, wh ich are exponentially more l i kely g iven the hazard curves.

Table 3- 1 4 presents the esti m ated LOO P CDFs and LERFs resu lting from these model quantifications:

Table 3- 1 4 ESTI MATED LOOP CDF AN D LERF Case CDF (/yr) LERF (/yr)

Base Case M O R 2 . 25E-05 9 . 9 1 E-07 Channel A I nverters OOS 1 . 36E-04 2 . 53E-06 Channel B I nverters OOS 1 . 3 1 E-04 3 . 33 E-06 Channel C I nverters OOS 8 . 64E-05 2 . 5 1 E-06 Channel D I nverters OOS 1 . 1 1 E-04 3 .42E-06 41

LR- N 1 8-0032 LAR H 1 8-02 Enclosure Flood Protection Featu res H CGS relies on both passive and active i ncorporated flood protection features to establish its design basis flood protection .

Doors and penetrati ons i n exterior walls of the Auxi liary and Reactor B u i ld i ngs are protected against water i nflow u p to Elevation 1 27' for parts of the south exterior walls and u p to Elevation 1 2 1 ' of other exterior walls.

Penetrations i n exterior walls and slabs of the Stati on Service Water System i ntake structure are protected against water i nflow up to E levation 1 2 1 ' for the north and east exterior walls and up to Elevation 1 28 . 5 ' for other exterior walls and slabs .

These flood protection features include the buildings themselves , penetration seals, waterproofi ng , and watertig ht doors . These features are part of the desig n and l icensing basis of the plant and have clearly defi ned hyd raulic capabil ity characteristics . During HCGS's response to the Fukushima Near-Term Task Force's Reco m mendation 2 . 3 (References 24, 25 and 26) , H CGS's flood protection featu res were reviewed and demonstrated to show adeq uate marg i n above desig n basis flood elevations. The flood ing walkdown report provides additional i nformation on the flood protection features credited i n the HCGS l icensing basis. Performance of the wal kdowns provided confirm ation that flood protection featu res are i n place , are i n g ood conditi o n , and wi l l perform as credited in the current licensing basis. Minor issues were e ntered i nto the PSEG Corrective Action Prog ram (CAP) . No o perability concerns were identified .

As shown i n Table 2 . 1 -3 of PSEG's response to the su bseq uent req uest for i nform ation (Reference 27) , watertight door thresholds at H CGS are at Elevation 1 02 ' . The plant's des i g n basis flood protection featu res are established to m itigate the effects of a h u rricane storm surge event, with the flood protection elevations at Elevation 1 2 1 ' or higher.

HCGS flood protection featu res do not i nclude any tem porary elements that req u i re procedura lized manual actions i n order for the featu re to perform its i ntended flood protection fu nctio n . The watertight doors are the only active flood protection features at HCGS . The rem a i n i ng flood protection featu res are passive and conti n u ally maintain thei r fu l l hyd ra u l i c capabil ity.

I PE E E Screening The HCGS I P E E E (Reference 1 9) considered plant performance versus the feasible maxim u m h u rricane s u rge with a coincident ten-percent-exceedance h i g h tide . This postulated con d ition results in a m axi m u m wave ru n-up of 35.4 ft. Mean Sea Level (MSL) along the southeast face of the Reactor Building and a small corner face of the Auxi l i a ry Building . Additionally, the Service Water I ntake Structure may be s u bject to waves wh ich could overtop the roof of the western portion at 39 feet above M S L .

T h e H C I P E E E a l s o exami ned t h e N RC Probable Maxi m u m Precipitation (PMP) req u i rements associated with Generic Letter 89-22 (Reference 28) concern ing plant area flood ru noff depth, finding that the requ i rements delineated there i n are met. There are no new plant area flood ru noff depths to evaluate.

All "other external events" identified i n N U REG/CR-2300 h ave been screened out by bou nding probabilistic analyses that demonstrate a co re damage frequency of less than the I P E E E 43

LR-N 1 8-0032 LAR H 1 8-02 E nclosure screen i ng criteri on of 1 E-6/yr or by compliance with the 1 975 Standard Review Plan (SRP) criteria .

Re-evaluated Flood Hazard As discussed i n the Flood Hazard Reevaluation Report (FH RR) (Reference 27), HCGS is susceptible to flooding above plant g rade from Local I ntense P recipitati on ( L I P) and storm surge based flood ing events. Probable M axi m u m Flood events that address the effects of u pstream riverine flooding o n ly prod uce flood levels above plant g rade when com bined with storm s u rge events . Other flooding mechanisms postulated in N U REG/CR-7046 (Reference 30) do n ot produce sufficient water surface elevations i n the Delaware River and Bay to cause flood ing i n excess of plant g rade. Sectio n 1 . 3 of the F H RR additionally notes there h ave been no changes to the flood protection featu res themselves since i n itial licensing . Finally, procedural actions have been enhanced to respond to potentia l flood threats.

3 . 2 . 3 . 3 . 2 Qualitative Discussion of Extern al Flood i ng Risk This subsection provides a detai led qualitative assessment based o n recent analyses and current procedures that ind icate that the external flooding risk is very low. Acceptable marg i n to the risk evaluation acceptan ce criteria is preserved when accounting for flood ing hazards, g iven the current state-of-knowledg e .

Frequency of External Flood i ng Mechanisms LI P and storm surge based flood ing events that prod uce water levels that challenge the plant's design basis flood protection featu res are very rare - the associated exceedance probabilities are 1 E-6 or less , as discussed in Section 2.4 of Reference 27, and fu rther in References 3 1 , 32, and 33. The annual exceedance probabil ity of flood levels that cou l d exceed the watertig ht door thresholds did not need to be calcu lated for the FHRR; however, PSEG d i d assess these levels d u ring its development and s ubsequent activities (Reference 34) .

Based on a representative analysis performed by EPRI (Reference 35), the rai nfall rate u sed i n Section 2 . 1 of the F H R R t o evaluate the L I P event i s estimated t o h ave a n a n n ual exceed ance probability between 1 E-7 and 1 E-9. To support development of a trigger to i m plement watertig ht d oor closure for a LI P event, PSEG assessed the rate of rai nfall req u i red to exceed watertight door thresholds. Based on the same conservative m odeling a pp roaches described i n the FHRR, Section 2 . 1 , approxi mately 6 i n ches of rai n i n 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months could challenge the threshold .

Conservatively, a trigger of a pred icted 6 inches of rai n i n the next 24 h o u rs is now used to prompt watertight door closure in advance of a heavy rainfall event ( Reference 36) . After the critical rai nfal l th reshold was determ i ned , a simplified rainfall freq uency analysis was performed using historical gage d ata in the a rea to determ ine how often the critical threshold could be exceeded . The exercise was not i ntended to be a com prehensive statistical freq uency analysis or exhaustive review of area rai nfall records; rather, the intent of com piling rai nfall data was to get a general u nderstanding of how often the thresholds have been exceeded i n the past. Five inches of rainfall was conservatively used as the threshold and the recu rrence i ntervals were estimated to be approxim ately 25 years for a 24-ho u r storm and 50 years for the 6-hour storm .

I n 20 1 3, the US Army Corps of Engi neers (USAGE) com pleted a Storm S u rge Study for Federal Emergency Management Agency (FEMA) Reg ion I l l , wh ich encom passes the Delaware River and Bay areas (Referen ce 37) . This study estim ated sti l l water surface elevations of 1 0. 7 ft.

44

LR-N 1 8-0032 LAR H 1 8-02 E nclosure and 1 2 . 1 ft. above the North American Vertical Datum (NAVD) for recurrence intervals of 500 and 1 000 years, respectively. These elevati ons eq uate to approxi mately site g rade and the watertig ht door th reshold, respectively.

I mpact of External Flood ing Mechanisms on Plant Operation and Structures. I n cluding the Ability to Cope with Upset Conditions As discussed i n the FH RR, the reeval u ated flood i ng events could produce flood levels that are above the watertight door thresholds, b ut below the plant's m i n i m u m flood-protected elevation of 1 2 1 ft. The plant's design basis flood protection featu res are established to m itigate the effects of a h u rricane storm surge event. P rotection of safety related systems, structures , and components (SSCs) is ensured by i m plementing severe weather g uidance docu m e nt OP-AA-1 08- 1 1 1 - 1 00 1 , "Severe Weather and N atura l Disaster G u idelines" and abnorm a l operati n g proced u re H C . O P-AB . M I SC-000 1 , "Acts of N ature". Performance of t h e wal kdowns provided confi rmation that flood protection featu res are i n place , are i n good cond ition and wil l perform as cred ited in the cu rrent l icensing basis. M i n o r issues were identified and entered in the PSEG corrective action prog ram . No operability concerns were identified .

The overall strategy for protecting HCGS from a flooding event req u i res simple and straightforward actions . Response to a flood event beg ins with the Control Room S u pervisor mon itori ng the Nati onal Weather Service for storm warn i ngs once per shift per OP-HC-1 1 2- 1 0 1 -

1 00 1 -F2 , "Control Room Supervisor - Relief Checklist" . Plant safety is then ensured by i m plementing severe weather g u idance and an abnormal operati ng procedu re instructing o perators to close watertight doors . The FHRR provides additional d iscussion of the tem poral characteristics of these hypothetical events i n Section 2 . 1 0.6. PSEG operators should be a ble to execute these procedu res with no particu lar challenge.

Operating Experience Associated with Reliability of Flood Protection Measures Evaluation of the overall effectiveness of the H CGS flood protection features was performed and docu mented i n the Hope Creek Generating Station Response to Reco m m endation 2 . 3 :

Flooding Walkdown of the Near-Term Task Force Review o f I nsights from the Fukus h i m a D a i i c h i Accident ( Reference 24) . T h e review o f t h e flood protection features desig n a n d l icensing d ocumentati o n , a n d subseq uent field i nspection o f t h e applicable physical flood protection features was i m plemented per the g uidance provided with in N E I 1 2-07(Reference

40) . PSEG has i m plemented E R-AA-3 1 0- 1 " Condition Mon itori ng of Maintenance Rule Structu res" (Reference 4 1 }, for structu res such as flood control featu res - concrete walls and slabs, water-control structu re elements , penetration seal s , etc. S pecific instructio n s rega rding the inspection of penetratio n seals are addressed i n HC. FP-SV. ZZ-0026 , "Flood and Fire Barrier Penetratio n Seal I nspection". I nstruction regarding the inspecti on and m a i nte nance of the watertig ht doors is addressed i n H C . M D- P M . ZZ-0007 , "Missile Resistant and Watertight Door P . M . " .

HCGS safe sh utdown SSCs are cu rrently protected b y means of permanent passive a n d active features, i . e . , watertight doors . Watertig ht door closure can be performed with i n the warn ing time provided by proceduralized triggers , as shown by HCGS operating experience (e.g . , the floodi ng wal kdown report i n Reference 24 documents that closure can be performed with i n the req u i red period of time following exceedance of a high river water level trigger) . Therefo re, the manual actions req u i red to i m plement the flood response strategy ( i . e . , watertig ht door closure) are feasible and the overall i m plementation of the strategy is adeq uate .

45

LR-N 1 8-0032 LAR H 1 8-02 E nclosure Wal kdowns provided confirmation that flood protection features are in place , are in good conditi o n , and wi l l perform as credited i n the cu rrent licensing basis . Minor issues were identified and entered in the PSEG CAP . No operability con cerns were identified .

Reliabil ity of Operator Actions Operator actions req u i red for flood protection actions are contained i n H C . O P-AB . M I SC-000 1 ,

Acts of Nature . This proced u re would be entered for the fol l owing conditions that could res u lt i n onsite flood i n g :

A h u rricane or tropical storm watch for Salem Cou nty is issued

A h u rricane or tropical storm warn i ng for Salem Cou nty is issued

A coastal flood warn i ng for Salem County is issued

Observation of severe weather conditions

Delaware River Water Level is antici pated to reach 96 feet.

The National Weather Service P robabilistic Quantitative Preci pitation Forecast (PQPF) predicts Local I ntense Preci pitation (LI P) to exceed 6 inches over the next 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months

Notification of a fai l u re of the Francis E . Walter Dam (White Have n , PA) , the Cannonsvi lle Dam (Delaware Cou nty, NY) , or the Pepacton Dam (Delaware Cou nty , NY)

N otification of a tsunami to strike the New Jersey coast The abnorm a l procedure d i rects operators to increase m o n itori ng of river levels and perform closu re of water tig ht doors o nsite . Operators have indicatio n avai lable in the control room to m o n itor river conditions and the actions to close water tig ht doors can be com pleted by the m i n i m u m s h ift complement. Entry i nto the abnormal operating procedure u nder the conditions described above provides sufficient time to ensure com pletio n before water leve l s reach 1 02 ft.

and i m pact system operati ons. Periodic testing of the watertight doors ensures their contin ued flood protection capability and demonstrates operator proficiency at perform i n g this task.

3 . 2 . 3 . 3 . 3 Quantitative Treatment of External Flood i ng Risk A h i g h ly conservative bounding estimate for the change i n external flood risk may be i nferred with an approach s i m i lar to that used for seismic risk in Section 3 . 2 . 3 . 2 above . There is n ot enoug h data to state the overa l l , absol ute quantitative i m pact of external flooding events with certainty; h owever, this calculation demonstrates that flood i ng events are not a significant contri butor to the change in risk affected by the proposed i nverter AOT extensio n .

As reported i n Table 3-1 0 , the change i n plant CDF a n d L E R F due t o t h e AOT extension i s alm ost entirely due t o LOOP sequences - over 95% i n a l l cases - comporting with t h e inverters' single, dedicated fu nction i n mainta i n i ng the availability of AC power. Therefore , it is assu med that any additional change in risk due to flood i nitiators m ust similarly i nvolve a LOO P . That is, floods that do n ot cause a LOOP are taken to be negligible.

The extremely few documented cases of external floods i n the operati ng history of the n uclear industry s uggests that they a re a remote possibil ity, though this is n ot taken as a n evidentiary basis for this esti mate. I n stead , the severe weather LOOP freq uency developed i n the H o pe Creek I n itiating Events Notebook, wh ich cha racterizes LOOPs resu lting from storm s u rg e ,

tornadoes, l ig htn i ng stri kes , etc. , is considered . At H ope Creek, seasonal floods a n d d a m breaks along t h e Delawa re River are n ot credible, so externa l floods are a s ubset o f severe 46

LR-N 1 8-0032 LAR H 1 8-02 Enclosure weather events. Because only LOO P sequences are relevant to this eva l u ation , the severe weather LOOP freq uency appropri ately bounds the contri bution of external flood risk, as severe weather LOOPs are a superset of external flood LOOPs. This is visually i l l u strated i n Fig u re 3-2.

Figure 3-2 : The set of exte rna l flood LOOPs (checked) is bounded b y the set of severe weather LOOPs (striped) (not to sca le) .

Severe weather LOOP i n itiati ng events are one of the fou r sub-categ ories of LOO P events defi ned in the PRA. Split fractions for each are developed in the Hope Creek I n itiati ng Events N otebook:

= 0 . 5866 Grid-related (LOOP-I E-GR)

= 0 . 0387 Plant-centered (LOOP-I E-PC)

= 0 . 2778 Switchyard (LOOP-I E-SWYD)

Severe Weather (LOOP-I E-SW) = 0 . 0969 The external flood LOOP freq uency is therefore simply the overall LOOP frequency

(% 1 E-TE = 6 . 1 7 E-02 /yr) m u ltipl ied by the Severe Weather split fraction above (9.69%) , yielding 5 . 98 E-03 /yr.

Equations 1 1 and 1 2 were developed in Section 3 . 2 . 3 . 2 above to estimate the contri butio n of seis m i c LOO Ps to I CCDP and I C L E R P . They may be be s i m i larly re-written here for the contribution of externa l flood ing LOOP:

Ext. Flood ICCDP :::: f(Ext. Flood LOOP) *[CDF1N v-oosi Ext. Flood L OOP

- CDFaAsdExt. Flood LOOPJ*TAor [Eq. 1 3]

Ext. Flood ICLERP :::: f(Ext. Flood LOOP) *[LERF1N v-oos1 Ext. Flood L OOP

- LERFaAsE! Ext. Flood LOOPJ*TAor [Eq. 1 4]

The change in C D F and LERF for a generic LOOP event when the inverters are taken out-of-service is reported above in Table 3- 1 4. These values were q uantified conservative ly ass u m i ng that LOOP recovery is n ot possible. Applying the m , the external flood LOOP 47

LR-N 1 8-0032 LAR H 1 8-02 E n closure frequency, and the cycle fraction ( TAor = 7 days / 365 days = 1 . 92 E-02) to Eq uations 1 3 and 1 4 yields the estimates of flood ICCDP and I CLERP i n Table 3- 1 6 :

Table 3- 1 6 ESTI MATED EXTE RNAL F LOOD ICCDP A N D ICLERP Case Ext. Flood ICCDP Ext. Flood ICLERP Channel A I nverters OOS 1 . 30E-08 1 . 77E-1 0 Channel 8 I nverters OOS 1 . 25E-08 2 . 69E-1 0 Channel C I nverters OOS 7 . 34 E-09 1 . 74E- 1 0 Channel D I nverters OOS 1 . 02 E-08 2 . 79E- 1 0 It m ust be n oted that the risk fig u res deve loped above a re considered to be a substantial overestimate of the result of a detai led external flood evaluation . For one, the set of severe weathe r events that can actually cause a flood is expected to be very small, so the use of the severe weather LOO P freq uency is an overestimate of perhaps an order of m ag n itude or m ore .

F u rthermore , no credit has been assigned for passive flood protections, such as penetrati o n s e a l s , and n o consideration h a s been g iven t o possible flood paths, affected elevations, storm d rains, and other elements unique to externa l flooding .

While these fig u res lack realis m , it can be stated with confidence that they represent an u pper bound on the im pact of external flood scenarios . As they are approxi mately an order of m ag n itude s m a l ler than the ove rall resu lts presented i n Table 3-5 , this consideration

, of externa l flood risk d oes n o t change t h e conclusion o f t h i s risk evaluati o n .

3 . 2 . 3. 4 Other Extern al Hazards The I P E E E assessment either screened o ut o r found a neg ligible i m pact from the remai n i ng external events indicated i n N U REG-1 407, those bei n g :

Transportation and Nearby Faci l ity Accidents

Red uction of Secondary Heat S i n k

H i g h Winds and Tornadoes

Severe Weather Storms

Severe Tem peratu re Transients

Avalanche, Landslide, and Volcanoes

Lightning

Release of On-Site Chemicals

Soil Fai l u re

Turbine Missi les

and Extraterrestrial Activity 48

LR-N 1 8-0032 LAR H 1 8-02 Enclosure 3.2.4 U n certai nty Evaluation The evaluation of the CDF and LERF risk metric changes for the AOT assessment has been supported by a detai led qualitative and quantitative uncertai nty evaluation . U n certai nty is generally categorized i nto three types -- parametric, mode l , and com pleteness. These are each discussed in the following subsections.

3.2.4. 1 Parametric U ncertai nty The parametric u n certai nty study is developed with the Monte Carlo s i m u l ation utility U N C E RT.

This software estimates the confidence bounds of the cutsets' total CDF or LERF by repeated re-samplings of the co nstituent basic event values. Attachment 3 documents this methodology in deta i l .

T h e parametric u n certainty analysis was performed for both t h e F P I E and Fire m odels' C D F a n d LERF for each o f t h e four cases reported i n Section 3 . 2 . 2 . 2 . Each case's cutset fi le was re sampled 1 5 , 000 times with a u niform Monte Carlo method . Table 3- 1 7 , Table 3-1 8 , Table 3-1 9 and Table 3-20 s u m m arize the resulting descri ptive statistics. These are:

Point Esti m ate - the result of q uantifyi ng the indicated case

Estim ated Mean - the mean of the re-sam ples' com puted means

% D ifference - the percent difference between the Estim ated Mean and the Point Estim ate

95% Confidence I nterval - the interval esti mate of the Esti m ated Mean at the 95%

confidence level

Sam ple Standard Deviation - the mean of the resam ples' com puted standard deviations

Standard E rror of the Mean - the standard deviation of the Estimated Mea n 's sampling distri buti o n ; used to construct the 95% Confidence I nterval , and eq ual to the Sample Standard Deviation divided by the sq uare root of the n u m ber of re-sam ples ( 1 5 , 000)

The poi nt estimates used in the risk assessment are withi n the calculated 95% confidence intervals for all but the followi ng cases:

Channel C I nverters O ut-of-Service FPI E LERF

Channel B I nverters Out-of-Service Fire C D F

Channel C I nverters Out-of-Service Fire C D F However, even these cases' poi nt esti mates differ from t h e estimated m e a n by about o n l y 2% ,

indicati ng g ood ag reement between the Monte Carlo s i m u l ation and the PRA models. This is true of all the other cases , as wel l . Due to the m i n i m a l difference between the poi nt esti m ates and the Monte Carlo resu lts , use of the point estimates for C D F and LERF are deemed acceptable for this risk assessment.

49

LR-N 1 8-0032 LAR H 1 8-02 Enclosure Table 3- 1 7 PARAM ETR I C U N C E RTAI NTY OF T H E FPI E C D F RESU LTS E

FPIE CDF Sample Sta n d a rd Estim ated 95% Confi d e n ce Point % D ifference Sta n da rd E rror of Mean I nte rval Esti m ate D eviation the Mean Channel A 1 . 02 E-05 1 . 03 E-05 1.1% [9. 9 E-06 , 1 . 1 E-05] 2 . 82 E-05 2 . 3 0 E-07 I nverte rs OOS Channel S 1 . 1 3 E-05 1 . 1 5 E-05 1 . 8% [ 1 . 1 E - 0 5 , 1 . 2 E-05] 1 . 50 E-05 1 . 22 E-07 I nverters OOS Channel C 9 . 9 5 E-06 9 . 95 E-06 -0. 1 % [ 9 . 8 E-06 , 1 . 0 E-05] 8 . 80 E-06 7 . 1 9e-08 I nverters OOS Channei D 1 . 02 E-05 1 . 0 1 E-05 -1 .3% [9 . 9 E-06 , 1 . 0 E-05] 9 . 50 E-06 7 . 76 E-08 I nverters OOS N = 1 5 , 00 0 Table 3-1 8 PARAM ETRI C U N C E RTAI NTY O F T H E FPI E LERF RESU LTS c:J FPI E LERF Sample Sta n d a rd Estimated 95% Confide n ce Point % D iffere nce Sta n da rd E rror of the Mean I nterval Estim ate Deviation Mean Ch a n n e l A I nverters 4 . 4 3 E-07 4 . 3 7 E-07 -1 .2% [4 . 3 E-07 , 4 . 5 E-07] 6 . 8 5 E-07 5 . 59 E-09 oos Channel S I nverters 6 . 02 E-07 6 . 1 5 E-07 2.2% [6 . 0 E-07 , 6 . 3 E-07] 9 . 4 9 E-07 7 . 75 E-09 oos Channel C I nverters 4 . 54 E-07 4 . 6 5 E-07 2.3% [4 . 6 E-07 , 4 . 7 E-07] 6 . 2 0 E-07 5 . 06 E-09 oos Channei D I nverters 4 . 8 5 E-07 4 . 89 E-07 0.8% [4 . 8 E-07 , 5 . 0 E-07] 5 . 97 E-07 4 . 87 E-09 oos N = 1 5 , 000 50

LR-N 1 8-0032 LAR H 1 8-02 Enclosure Table 3- 1 9 PARAM ETR I C U N C E RTAI NTY O F THE F I R E C D F RES U LTS B

F i re C D F Sample Sta n d a rd Esti m ated 95% Co nfidence Point % D i fference Sta n da rd Error of t h e Mean I nte rval Esti m ate Deviation Mean Channel A I nverters 1 . 92 E-05 1 . 93 E-05 0.5% [ 1 . 9 E-05 , 1 . 9 E-05] 1 . 1 5 E-05 9 . 39 E-08 oos Channel S I nverte rs 1 . 99 E-05 2 . 02 E-05 1 .2% [2 . 0 E-05 , 2 . 0 E-05] 1 . 1 3 E-05 9 . 2 3 E-08 oos Channel C I nverte rs 1 . 88 E-05 1 . 9 1 E-05 1 . 5% [ 1 . 9 E-05 , 1 . 9 E-05] 1 . 56 E-05 1 . 2 7 E-07 oos Channei D I nverters 1 . 82 E-05 1 . 82 E-05 -0 . 2 % [ 1 . 8 E-05 , 1 . 8 E-05] 6 . 4 8 E-06 5 . 29 E-08 oos N = 1 5 ,000 Table 3-20 PARAMETR I C U NC E RTAI NTY OF THE F I R E LERF RESU LTS F i re L E R F Sample Sta n d a rd Esti mated 95% Co nfidence Case Point % D i fference Sta n d a rd E r ro r of the Mean I nte rval Esti m ate Deviation Mean Channel A I nve rters 2 . 4 8 E-06 2 . 4 3 E-06 - 1 . 9% [2 . 4 E-06 , 2 . 4 E-06] 8 . 2 8 E-07 6 . 76 E-09 oos Channel S I nverters 2 . 2 8 E-06 2 .2 3 E-06 -2 . 0 % [2 .2 E-06 , 2 . 2 E-06] 7 . 64 E-07 6 . 24 E-09 oos Channel C I nverters 2 . 4 5 E-06 2 . 4 0 E-06 -1 .9% [2 . 4 E-06 , 2 . 4 E-06] 7 . 6 0 E-07 6 . 2 1 E-09 oos Chan nei D I nverters 2 . 2 8 E-06 2 . 2 3 E-06 -2 . 1 % [2 . 2 E-06 , 2 . 2 E-06] 7 . 42 E-07 6 . 06 E-09 oos N = 1 5, 000 51

LR-N 1 8-0032 LAR H 1 8-02 Enclosure 3.2.4.2 Model U n certainty This evaluation uses the PRA Models of Record , without mod ificatio n , to quantify the change i n plant risk i ntrod uced by the i nverter AOT extensio n . A n extensive review of possible model uncertainties was performed i n the FPI E S u m mary N otebook ( Reference 45) . Of these , o n ly one item relevant to the inverters was determ i ned to be a candidate for further consideratio n ,

that being t h e state-of-knowledge regard i ng l ocal ized power g rid stabil ity a nd l oss of offsite power (LOOP) i n itiati ng event, conditional fai l u re , and recovery freq uencies . As LOOP seq uences are of high sign ificance to the change in risk metrics (see Section 3 . 2 . 2 . 3} , this is a potential source of model uncertai nty for this risk evaluatio n .

T h e PRA Models o f Record establish probabilities for these LOOP events with i nd ustry-wide data drawn from N U REG/CR-6890 (Reference 46) for fou r causal categories (plant-centered ,

switchyard-centered, weather-related , and g rid-related) . The i n itiati ng event and conditional fai l u re probabil ities are fu rther developed via a Bayesian update using plant-specific data for each of the four categ ories, wh ile the recovery probabilities are used directly. This overall approach incorporates l ocal plant cond itions and is considered an industry best practice; however, it is not yet a consensus approach , and the deg ree to wh ich the condition of the i m m ediate power g rid i nfrastructure matters has not been establ ished .

It is assumed that the industry-wide evidentiary basis for LOO P events is broadly reflective of H ope Creek, and that any specific deviation due to the localized g rid is u lti mately accounted for i n the Bayesian u pdate process .

3.2.4.3 Completeness U n certainty This su bsection reiterates the hazard g roups that a re treated quantitatively and the potential im pact associated with not quantifying certain hazard g roups.

The risk metric calcu lations perfo rmed to support the i nverter AOT extension include the explicit q u a ntification for the following hazard g roups:

I nternal Events

Fire

I nternal Flood Potential changes i n seismic risk are discussed i n Section 3 . 2 . 3 . 2 .

Other external events were previously screened from consideration i n t h e I PE E E a s havi ng extremely l ow ris k sig n ificance .

The risk analysis shows the risk i ncreases associated with on-line i nverter mai ntenance . The need for inverter m a i ntenance could emerge wh ile in Mode 3. The plant spends less time in Mode 3 than it does on line, thus the l i keli hood of needing m a i ntenance is lower. The ris k i ncreases associated with on-line maintenance b o u n d t h e risk i ncreases associated with M o d e 3 mai ntenance. Thus, the risk associated with sh utd own mai ntena nce is bounded and does n ot need to be q uantified i n this LAR .

52

LR-N 1 8-0032 LAR H 1 8-02 Enclosure 3 . 2 . 4.4 Sensitivity Analyses 3 . 2 .4 .4 . 1 Com pensatory Measures Credited Section 3 . 2 . 5 , below, considers the effect of several Com pensatory Meas u res. These Meas u res a re not req u i red to meet the acceptance criteri a .

3 . 2 .4 . 4 . 2 Common-Cause Fai l u res Per Reg u l atory G uide 1 . 1 77 , com m on-cause fai l u re (CCF) probabi lities for eq u ipment rel ated to the s u bject of a risk evaluation should be adj usted appropriate to the change considered.

Because data for inverters was not avai lable i n the N RC/I N L database (Reference 47) used to develop the model's common-cause basic events , no i nverter common-cause basic events exist i n the model to manipulate. However, the effect of common-cause fai l u res m ay be s i m u l ated with a sensitivity case using generi c data and post-processing the cutset data with a recovery fi l e .

It s h o u l d b e noted that incorporation o f com mon-cause fai l u res is considered to b e very conservative for the pu rposes of this risk evaluatio n . The CCF calcu lation methodology i s prem ised o n t h e random , unannou n ced fai l u re o f a particular piece o f eq u ipment. If an inverter should fai l or req u i re emergent mai ntenance, the other i nverters wi l l be verified to be operable and monitored freq uently d u ring the outage, and any com mon-cause fai l u re wi l l be quickly discovered . The inverters are well-i nstrumented and mon itored both locally and i n the Contro l Room . If an add itional i nverter s h o u ld become i noperable , Hope Creek enters i nto T S 3 . 0 . 3 ,

wh ich req u i res i m mediate shutdown actions.

There are eight i nverters considered i n this risk evaluation - two for each of the fou r chan nels of AC power. For each q uantificati on ru n , both i nverters of a single channel are take n out-of service ( i . e . their maintenance basi c events are set to TRUE), leaving the rem a i n i n g six subject to random fai lures. These fai l u res are independent i n the base model; it is des i red to q u antify them as a CCF g roup of size six, where an inci pient fai l u re of one m ay ind uce com m o n fai l u re of the others .

T h e alpha factors reported in t h e N RC/I N L C C F database represent conditional probabil ities of m u ltiple fai l u res in a CCF g roup, as meas u red from historical data . a1 represents the fraction of fai l u res i nvolving exactly one com ponent in a g roup of a g iven size , a 2 represents exactly two fai l u res, a3 exactly three , etc. Because these factors wi l l be applied to specific com bi nations of eq u ipment fai l u res instead of a s i ng le g rou p-representative basic event, they m ust be divided by the n u m ber of possible dependent combinations (i . e . , the "x of n" CCF g roup a l pha factor m ust be divided by (n- 1 ) choose (x-1 ) - the fi rst eq u i pment fai l u re is g ive n ) . M u ltiplying the resu lt by the i ndependent fai l u re probability of an inverter ( 1 . 20E-04) then g ives the joint CCF probabilities . Because the database does not specify alpha factors for i nverters , the generic pooled data for rate fai l u res was used . Table 3-2 1 calcu lates the appropriate j o i nt CCF probabilities .

53

LR-N 1 8-0032 LAR H 1 8-02 Enclosure Table 3-2 1 COMMO N-CAUS E FAI L U R E P RO BAB I LITIES APPL I E D

of App l i e d J o i n t Common- I nd e pe n d e n t A l p h a F acto r Dependent =

CCF Cause I nverter Fai l u re X I

( Pooled Rate Fai l u re) Com b i nati o n s 1 P ro b a b i l ity Fai l u re of . . . P ro b a b i l ity (lyr)

C ( n - 1 , x- 1 ) (lyr) 2 of 6 5

I nverters 6 . 34 E-03 1 . 52 E-07 3 of 6 10 I nverters 6 . 1 9 E-03 7 . 4 3 E-08 4 of 6 =

1 . 2 0 E-04 X I 10 I nverters 4 . 6 9 E-03 5 . 6 3 E-08 5 of 6 5

I nverters 2 . 58 E-03 6 . 1 9 E-08 6 of 6 1

I nverters 1 . 90 E-03 2 . 2 8 E-07

1. T h e a l p h a factors we re develo ped based on the n u m be r of dependent com b i nations g ive n a n i n d e pe n d e n t eq u i p ment fai l u re , n o t t h e ove ra l l n u m be r of com b i nation s . For exa m p l e , i n t h e case of 2 of 6 i nverters fa iled , the i n itial o n e fai l s i n d e p e n dently, a n d 1 of the 5 re m a i n i n g fai l s d e p e n d ently.

T h e refo re , there a re 5 d e pendent com b i nati o n s .

A modified version of the q uantification recovery file was developed to incorporate the above CCF probabilities by replacing coincident sets of i nverter fai l u res with an appropriate CCF basic event. Re-q uantifyi ng the model with this adj usted recovery fi le effectively conve rts the formerly i ndependent inverter fai l u res into CCFs . Table 3-22 and Table 3-23 compare the results of this q u antification with the FPI E Model of Record results (see Table 3-3 and Table 3-4) :

54

LR-N 1 8-0032 LAR H 1 8-02 Enclosure Table 3-22 CDF COMPAR I S O N OF COMMON-CAUSE S E N S I TIVITY A N D M O D E L OF RECORD Model of Record C C F S e n sitivity Case D ifference (/yr) ( % )

C D F (/yr) C D F (/yr)

Base Case 5 . 9 1 E-06 5 . 9 1 E-06 1 . 00E-1 1 (<0. 0 1 %)

C h a n n e l A I nverters O O S 1 . 02 E-05 1 . 02 E-05 3 . 0 0 E- 1 0 ( < 0 . 0 1 % )

C h a n n e l B I nverters O O S 1 . 1 3 E-05 1 . 1 3 E-05 1 . 1 0 E-09 ( 0 . 0 1 % )

C h a n n e l C I nve rters OOS 9 . 95 E-06 9 . 95 E-05 5.30E-1 0 (<0. 0 1 %)

C h a n n e l D I nve rters OOS 1 . 02 E-05 1 . 02 E-05 7 . 00 E- 1 0 ( < 0 . 0 1 % )

Table 3-23 LERF COMPARI SON OF COMMON-CAUS E S E N S I TIVITY AN D MODEL OF RECOR D Model of Record C C F S e n s itivity Case Differen ce (/yr)

L E R F (/yr) L E R F (/yr)

Base Case 1 . 84 E-07 1 . 84 E-07 O . OO E-00 C h a n n e l A I nverters OOS 4 . 4 3 E-07 4 . 4 3 E-07 O . O O E-00 C h a n nel B I nverters OOS 6 . 02 E-07 6 . 02 E-07 O . O O E-00 C h a n nel C I nverters OOS 4 . 54 E-07 4 . 54 E-07 O . OO E-00 C h a n n e l D I n ve rte rs OOS 4 . 85 E-07 4 . 85 E-07 O . O O E-00 The d ifference in C D F when q uantifying the mode l with the adj usted CCF probabil ities is approxim ately fou r orders of m ag n itude below the CDF itself. For LERF, the cutsets affected by the change are all below the tru ncation l i m it of 1 . 00E- 1 2 , res u lting i n no change. Common cause fai l u res affecting the inverters are therefore j udged to be n eg ligible.

3 . 2 . 4 . 4 . 3 Excl usion of FLEX Procedures and Eq uipment The base PRA Model of Record i n cl udes consideration of F LEX eq u i pment and operator actions. To determ i n e these elements' i m pact on the results , a sensitivity case was quantified with the fol l owing F L EX basic eve nts set to TRU E i n Table 3-24 to remove all credit:

55

LR-N 1 8-0032 LAR H 1 8-02 Enclosure Table 3-24 F L EX BAS I C EVENTS Bas ic Even t Descri pti o n P O R - D G N - F R - F L EX F L EX D I E S E L G E N E RATO R FAI LS TO R U N P O R-M D P-FR-1 O P 0 0 1 F L EX ALT H EAD E R P U M P 1 0 P 0 0 1 FAI LS T O R U N PO R-M DC-FR-F L EX F L EX C O M P R ES S O R FAI LS T O R U N P O R-XH 1 - E LAP- D E C L-Q O P E RATO R FAI LS TO D E C LA RE E LAP A N D P E R F O R M LOAD S H E D When re-q uantifying with these changes, C D F increases slightly, wh ile L E R F does n ot increase at a l l . Table 3-25 and Table 3-26 com pare the sensitivity resu lts to those presented in Table 3-3 and Table 3-4.

Table 3-25 C D F COMPARISON OF F L EX S E N S ITIVITY AND M O D E L OF RECORD M o d e l of Record F L EX Sens itivity Case D ifference (/yr) (%)

CD F (/yr) C D F (/yr)

Base Case 5 . 9 1 E-06 6 . 4 0 E-06 I 4 . 9 E-07 ( + 8 % )

I C h a n n e l A I nverters OOS 1 . 02 E-05 1 . 1 4 E-05 1 . 2 0 E-06 ( + 1 2 % )

C h a n n e l B I nve rters O O S 1 . 1 3 E-05 1 . 2 5 E-05 1 . 2 0 E-06 ( + 1 1 %)

C h a n n e l C I nve rters OOS 9 . 95 E-06 1 . 1 1 E-05 1 . 1 5 E-06 ( + 1 2 % )

C h a n n e l D I nverters O O S 1 . 02 E-05 1 . 1 4 E-05 1 . 2 0 E-06 ( + 1 2 % )

56

LR-N 1 8-0032 LAR H 1 8-02 E nclosure Table 3-26 LERF COMPARISON OF FLEX S E N S IT IVITY AN D M O D E L O F RECORD M o d e l of Reco rd C C F Sens itivity Case D iffe rence (/yr)

L E R F (/yr) L E R F (/yr)

Base Case 1 . 84 E-07 1 . 84 E-07 O . O O E-00 C h a n n e l A I nve rters OOS 4 . 4 3 E-07 4 . 4 3 E-07 O . O O E-00 C h a n n e l B I nve rters OOS 6 . 02 E-07 6 . 02 E-07 O . O O E-00 C h a n n e l C I nverters OOS 4 . 54E-07 4 . 54 E-07 O . O O E-00 C h a n n e l D I nve rters OOS 4 . 8 5 E-07 4 . 85 E-07 O . OO E-00 3.2.5 Tier 2 - Avoidance o f Risk-S ign ificant Plant Config u rations The risk metrics calcu lated in Section 3 . 2 . 2 . 2 demonstrate that Hope Creek is wel l with in the acceptance criteria for the proposed inverter AOT extension in its current configuratio n . The risk insights discussed i n Section 3 . 2 . 2 . 3 did not identify any equipment outage or plant confi g u ratio n with extremely high risk contri butions while an i nverter is out of service .

Therefore , n o plant configuration or eq u i pment o utage would req u i re enhancements to Tech n i cal S pecifications or plant procedures. Nevertheless , PSEG has identified a set of C o m pe nsatory Measu res that would i m p rove the plant's defe nse-in-depth with one channel of inverters in mai ntenance and fu rther i ncrease the available marg i n to the acceptance guidelines ,

should i t b e j udged necessary. These meas u res are presented below.

3.2.5. 1 Compe nsatory Measures Table 3-27 lists the identified Compensato ry Measures. These adm i nistrative controls are q ual itative , prudent actions , consistent with other l i censees that have received similar extensions of the inverter allowed o ut-of-service tim e , as described i n Section 4 . 2 .

Table 3-27 C O M P E N SATORY M EAS U RES FOR U S E D U R I N G P LAN E D I NVERTER O UTAG E S

1. E ntry i nto the extended i nverter AOT wi l l not be plan ned concurrent with EDG mai ntenance .

2. E ntry into t h e extended inverter AOT wil l n o t b e plan ned concurrent with plan ned mai ntenance on another ECCS/RC I C or isolation actuation instrumentation channel that could resu lt i n that channel being i n a tri pped condition .

57

LR-N 1 8-0032 LAR H 1 8-02 E nclosure Compensatory Meas u re 1 is not cred ited . The current PRA m odels do not cred it man ually starting and load i ng an EDG without 1 20 VAC power, wh ich is conservative .

This action wil l be taken because it is recogn ized that with an i nverter i noperable and the distribution panel being powered by the reg u lati ng tra nsformer, instru mentation for that channel is dependent o n power from the associated EDG followi ng a loss of offsite power event.

Com pensatory Measure 2 is not cred ited . The current PRA models do not include test and-maintenance basic events for RPS or ECCS/RC I C actuation logic so no q u antitative cred it can be assig ned. This is a conservative ass u m ption.

3.2.6 Tier 3 - Risk-I nformed Configuration Management I m plementation of the H o pe Creek Config u ration Risk Management Prog ra m , which meets the req u i rements i n Reg u l atory G u ide 1 . 1 77 Section 2 . 3 . 7 . 2 , helps to ensure there is no sign ificant risk i ncrease wh ile i nstru ment maintenance is being performed . This consideration is im portant because all possible risk-significant config u rations u nder Tier 2 can n ot be pred icted . Hope Creek i m plements the applicable portions of the Mai ntenance Rule by using the endorsed g u idance of Section 1 1 . 0 of N U MARC 93-0 1 .

Hope Creek uses the Equi pment O ut of Service (EOOS) Config u ration Risk Monitor prog ram from the Electric Power Research I nstitute (EPRI) to i mplement 1 0 C F R 50 . 65(a) (4) (Reference

8) . I n the spring of 2 0 1 8 , H ope Creek wil l com plete the transition to the Phoenix code , which is the EPRI replacement for EOOS . The followi ng descri ption genera l ly applies to both codes.

Phoenix uses the same fau lt trees and database as the i ntern a l events PRA mode l , so it is fu l ly capable of evaluating C D F and LERF for i nternal events . The load i n g and use of Phoenix is proced u rally controlled by the PSEG PRA procedures. H ope Creek p roced u res recog n ize that there are l i m itati ons i n P h oenix and specifically d i rect consideration of external events and site activities that can res u lt in significant plant events. Some conditions are evaluated in Phoenix through m ultiplicatio n facto rs; others procedurally lead to other actions, i n cluding plant color changes. Fire risk m anagement actions, which are governed by the same set of proced u res and i m plemented by the same staff, are determ ined from the determ i nistic fire safe sh utdown procedu res from 1 0 C F R 50 Appendix R.

When m a i ntenance or testing is sched u led , the Operations, Work Week Management, and S ite Risk Management staff perform and review weekly ris k analyses using the Phoenix prog ra m .

F o r u n planned or emergent equ i pment fai l u res, control room personnel wi l l enter the configurati on i nto Phoenix. In either case, the configuration wi l l be evaluated to assess and manage the risk.

Risk associated with u n available plant equipment is assessed at H o pe Creek as req u i red by 1 0 CFR 50. 65(a)(4) . PSEG work m anagement adm i n istrative procedu res govern on-line risk assessments, which featu re a blended approach using q ual itative or defense-in-depth considerations and q u a ntifiable P RA risk insights whe n avai lable to com plement the qualitative assessment. H ope Creek com m u n i cates on-line plant risk using three risk tiers : Green , Yellow, and Red . The defi n itions of these tiers are as follows :

58

LR-N 1 8-0032 LAR H 1 8-02 Enclosure Table 3-28 CON F I G U RATI O N R I S K MANAG E M E NT R I S K T I E RS Color Risk Threshold < 1 l Req u i red Action I CC D P < 1 E-06 for 7 -day d u ration AN D No specific actions are G reen I CLERP < 1 E-07 for 7-day d u ration req u i red AN D N o LOOP H ig h Risk Evo l ution ( H RE) 1 E-06 < I CC D P < 1 E-05 for 7-day Limit the u n avai labil ity ti m e by d u ration establishing a conti n uous work sched ule or provide OR justificatio n .

Yellow 1 E-07 < I CLERP < 1 E-06 for 7 -day Protect SSCs wh ich wou ld d u ration cause an unplan ned entry i nto OR a Red risk condition if lost concurrent with those LOOP H i g h Risk Evolution (H RE) unavai lable for m a i ntenance .

It is u nacceptable t o voluntari ly enter this conditio n .

!.E a n emergent condition or degradation causes an 1 E-05 < I CC D P for 7-day d u ration u n plan ned entry i nto this Red OR condition , i m mediate actions shall be taken to restore 1 E-06 < I CLERP for 7-day d u ration and/or protect SSCs relied upon to m itigate events, and the station d uty m a n ager shall be contacted for d i rection and support.

The on-line risk level H ope Creek wi l l remain G reen for an outage of one or both i nverters i n one channel affected b y t h i s proposed change. At t h i s leve l , risk is considered close t o baseline, a n d com pliance with Tech nical S pecificati on req u i rements would be considered adeq uate risk management. Nevertheless, PSEG maintenance practices i nvolve protecting other eq u i pment during a mai ntenance outage o n an i nverter per OP-AA- 1 08- 1 1 6 , Protected Equi pment Prog ram (Reference 48) . The PRA Model of Record d i rectly accou nts for this mai ntenance practice and reflects it i n the q u antitative analysis by excl uding cutsets that contai n unallowed mai ntenance combi nations.

Equi pment protection req uires posted sig ns and robust barriers to alert personnel not to approach the affected eq ui pment. Work on such eq u i pment is generally disal lowed . M i n o r exceptions exist for activities such as inspections, secu rity patrols, or emergency operations.

Other exceptions may be a uthorized by the station s h ift manager i n writing. If additional u n planned eq u i pment unavailabil ity occu rs , station proced ures direct that the risk be re-59

LR-N 1 8-0032 LAR H 1 8-02 Enclosure evaluated , and if found to be unaccepta ble, com pensatory actions are taken until such a t i m e that t h e ris k is red uced t o an acceptable leve l .

I n addition , OP-AA- 1 08-1 1 6 d i rects Operations and Work Management personnel t o routinely m o n itor various mai ntenance configurations and protect eq u i pment that could lead to an elevated ris k condition (e. g . , " Red") if it were to become unavai lable due to u n planned or emergent conditions. This is normally accomplished using the Phoenix P RA software too l ,

supplemented b y operations a n d work m anagement proced ures.

3.2.7 Risk S u m mary and Conclusion 3.2.7. 1 Reg u l atory G u ideli nes This risk eval uation demonstrates with reasonable ass u rance that the proposed Tech n ical S pecification change for the i nverters' Allowed O utage Times are with i n the acceptance g u ideli nes established i n Reg ulatory G u ides 1 . 1 74 and 1 . 1 77 . Com pensatory Measures h ave been identified to i ncrease the marg i n to the acceptance l i m its ; however, they are not req u i red .

3.2.7.2 P RA Model The resu lts of this ris k evaluatio n are based on q uantification of the H ope Creek Full-Power I nternal Events (FPI E) and Fire PRA Models of Record , H C 1 1 7A and H C 1 1 4FO, respectively.

These models are highly detai led , accu rately reflect the as-built, as-operated plant, and are supported by an extensive pedigree of self-assessment and peer review. Both have undergone successfu l peer review ag ainst the ASM E/ANS P RA Standard . There are no open Facts and Observations (F&Os) for the FPI E mode l . Open F&Os for the Fire m odel have been dispositioned i n Attachment 2 Section A . 2 .

3.2.7.3 Quantitative PRA Resu lts The risk m etrics calcu lated are presented in Sectio n 3 . 2 . 2 . 2 . 2 . Depending which channel the affected inverter serves, the req uested Tech nical S pecification change wi l l resu lt in a CDF / I CC D P of at most 1 .4 1 E-07, com pared to a n acceptance l i m it of 1 . 00E-06 . The LERF / I CLERP wi l l be at most 9 . 30E-09, com pared to an acceptance l i m it of 1 . 00E-07.

3 . 2 . 7.4 External Hazard Considerations The model adeq uately addresses external hazards. A peer-reviewed Fire PRA model was used to q u antify the risk due to internal fi res. The change in risk metrics for seismic i n itiators is j udged to be neg l ig i ble. I nternal flood ing is co nsidered in the FPI E mode l . The qual itative assessment found no plant vul nerabi l ity to any other h azards, including fi re and external flo od .

3.2.7.5 Conclusion The proposed change to Hope Creek's Tech nical S pecifications to extend the inverter Allowed O utage Ti m e fro m 1 day to 7 days is fou n d to be we l l within the acceptance criteria establ ished i n Reg ulatory G uides 1 . 1 74 and 1 . 1 77.

60

LR-N 1 8-0032 LAR H 1 8-02 E nclosure 4 .0 REGUL ATORY EVAL UATION

4. 1 Applicable Reg u l atory Req u i rements and Criteria 1 0 CFR 50.36, "Tech n ical Specifications , " identifies the req u i rements for the Tech nical S pecification categories for operating power plants : ( 1 ) Safety limits, limiting safety system settings, and limiting control settings, (2) Limiting conditions for operation, (3) Surveilla nce requirements, (4) Design features, (5) Administrative controls, (6) Decommissioning and (7)

Initial notification, and (8) Written Reports. For Lim iting conditions for operatio n , 1 0 CFR 5 0 . 36 states: Limiting conditions for operation are the lowest functional capability or performance levels of e q uipment re q uired for safe operation of the facility. When a limiting condition for operation of a nuclear reactor is not met, the licensee shall shut down the reactor or follow any remedial action permitted by the technical specifications until the condition can be met.

The O P E RAB I L ITY of the i nverters is consistent with the i n itial ass u m ptions of the accident analyses and is based on meeting the design basis of the u n it. The inverters are a part of the d istribution -system and , as such , satisfy Criterion 3 of 1 0 CFR 50. 36(d)(2)(i i) .

1 0 CFR 50 Appendix A, G DC 1 7 , " E lectric Power Syste m s , " requ i res the onsite electric power supplies, including the batteries, and the o nsite electric distribution system , to have sufficie nt independence , red undancy, and testability to perform their safety fu nctions assum ing a s i n g le fai l u re . Si nce no physical changes are being made, and cu rrent desig n bases are not bei ng affected , there is n o i m pact on com pliance with GDC 1 7 .

1 0 CFR 50, Appendix A, G DC 1 8 , " I nspection and testing of electric power system s , " req u i res that electric power systems that are i m portant to safety m ust be designed to permit appropriate period ic inspection and testi ng. The proposed change does not m ake changes to inverter inspections or testi n g . Therefore , i m plementation of the proposed Al lowed O utage Time extension wi l l have no s i g n ificant effect on the contin ued conform a n ce with G DC 1 8.

1 0 CFR 50 . 65 , " Req u i rements for m o n itoring the effectiveness of m a intenance at n uclear power plants , " req u i res that preventive m a intenance activities m ust be sufficient to provide reasonable assurance that SSCs are capable of fulfi l l i ng their intended fu nctio n s . As it relates to the proposed inverter Allowed O utage Time extension , 1 0 C F R 50. 65(a) (4) requ i res the assessment and management of the i ncrease in risk that may resu lt from proposed maintenance activities . As discussed previously, the HCGS Mai ntenance Rule prog ram monitors the reliabil ity and availabi l ity of the AC inverters and ensures that appropri ate management attention and goal setting are applied based on pre-establ ished performance criteria . The AC inverters are all currently i n the 1 0 CFR 50. 65(a)(2) Mai ntenance Rule categ ory (i. e . , the AC i nverters are meeting established performance criteria) . The HCGS CRMP is consistent with 1 0 CFR 50. 65(a) (4) , and is managed to ensure that risk-sig n ificant plant config u rations wi l l not be e ntered for planned maintenance activities , and that appropriate actions will be taken should u nforeseen events place the plant in a risk sign ificant config u ration d u ring the proposed extended AC inverter Al lowed Outage Time. Therefore , the proposed extension of the AC inverter Allowed Outage Time from 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months to 7 d ays are not anticipated to result in exceed ing the cu rrent establ ished Mai ntenance Rule criteria for the AC i nverters .

1 0 CF R 50.63, " Loss of all alternating current power, " req u i res that n uclear power plants m ust be able to withstand a loss of all AC power for an establ ished period of time and 61

LR- N 1 8-0032 LAR H 1 8-02 Enclosure recover from a station blackout. The proposed extension of the AC inverter Completion Time from 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months to 7 days has no sign ificant effect on the abil ity to withstand a loss of all AC power and recover from a station blackout.

In conclusion, based on the considerations discussed above , ( 1 ) there is a reasonable assurance that the health and safety of the public wil l not be endangered by operatio n i n the proposed manner, (2) such activities wil l be conducted i n com pliance with the N RC's reg u lations, and (3) the issuance of the amendment wil l not be i n i m ical to the com m o n defense and secu rity or to the health and safety of the public.

4.2 Precedent 4.2. 1 License Amendments The changes proposed here i n to the Al lowed O utage Time for restoration of an i n o perable i nverter are s i m ilar to those previously approved by the N RC for the Clinton Power Stati o n ,

North A n n a Power Station , Byron a n d Bra idwood Stations, a n d Palo Verde Statio n . These previous approvals are discussed below.

Palo Verde N uclear Generating Stati on By l etter dated September 28, 2009 (ADAMS accession M L0928 1 0227} , as s u pplemented by letters dated J u ne 24 , 2 0 1 0 (ML101880263} , September 3, 2 0 1 0 (ML102571398} , and Septe m ber 24, 2 0 1 0 (ML102720481 ) , Arizona Public Service req uested N RC approval of a Palo Verde N uclear Generati ng Stati on TS change to extend the inverter Al lowed O utage Time . The N RC approved the change i n License Ame ndment Nos. 1 80 for Palo Verde, U n its 1 , 2 a n d 3 ,

issued September 29, 2 0 1 0 (ML102670352) . T h e amendment issued for t h e P a l o Verde N u clear Generating Station was su bstantively eq u ivalent to the amendment req uested here i n for t h e HCGS, in that i t revised TS 3 . 8 . 7 , " I nverters - Operati ng , " t o change t h e Allowed O utage Time for restoration of an i noperable inverter from 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months to 7 days .

Cli nton Power Stati on By letter dated Apri l 26, 2004 (ADAMS Accession M L04 1 2 1 09 1 3) , as s u pplemented by letters dated Apri l 1 8 , 2005 (M L05 1 080395} , October 1 1 , 2005 (M L0529 1 0 1 84) , and May 1 9 , 2006 (ML061500124} , AmerGen Energy Com pany, LLC (AmerGen) req uested N RC approval of a C l i nton Power Stati on TS change to extend the Completion Time for N uclear System Protection System I nverters . The N RC approved the change i n License Amendment No. 1 74 for the C l i nton Power Station , U n it 1 , issued M ay 26 , 2006 (M L06 1 1 60 1 8 1 ). The amendment issued for the C l i nton Power Station was substantively equ ivalent to the amendment req uested here i n for the HCGS, in that it revised TS 3 . 8 . 7 , " I nverters - Operati ng , " to change the Com pletion Time for restoration of an inoperable i nverter from 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months to 7 days .

North An na Power Stati on By letter dated Decem ber 1 3, 2002 (ADAMS accession M L0236002 1 7} , as su pplemented by letters dated May 8 , 2003 (M L03 1 4000 1 9} , December 1 7 , 2003 (M L033580639} , February 1 2 ,

2004 (M L040550548) , and March 9 , 2004 (M L0407005 1 2) , Virg i n i a Electric and Power Com pany (VE PC) requested N RC approval of a North Anna Power Station TS change to extend the i nverter Allowed Outage Time. The N RC approved the change i n License Amendm e nt Nos.

62

LR-N 1 8-0032 LAR H 1 8-02 E nclosure 235 and 2 1 7 for the North Ann a Power Statio n , U n its 1 and 2, respectively, issued May 1 2 ,

2004 (M L04 1 380438) . The amendment issued for the North An na Power Station was substantively equivalent to the amendment requested here i n for the HCGS, in that it revised TS 3 . 8 . 7 , " I nverters - Operati ng , " to change the Allowed O utage Time for restoration of an inoperable i nverter from 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months to 7 days .

Byron and Braidwood Power Stations By letter d ated October 1 6 , 2002 (ADAMS accession M L02302006 1 ) , as supplemented by letters dated June 20, 2003, October 1 4 , 2003 (M L032900989) , and N ovem ber 7, 2003 (M L033 1 60 1 96) , Exelon Generation Co . , LLC (Exelon) req uested N RC approval of TS changes to extend the i nverter Com pletion Ti me for the Byron and Braidwood Stations. The N RC approved the changes i n License Amendment Nos . 1 35 for the Byron Statio n , U nits 1 and 2 ,

a n d Amendment Nos. 1 29 for the Braidwood Statio n , U n its 1 a n d 2 , issued Novem ber 1 9 , 2003 (M L032830455) . The amendments issued for the Byro n and Braidwood Stations were substantively eq u ivalent to the amendment requested herein for the HCGS , i n that they revised TS . 3 . 8 . 7 , " I nverters - Operati ng , " to change the Completion Time for restoration of an i noperable i nverter from 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months to 7 days .

4.2.2 N otice of E nforce ment Discretion (NOED)

N u clear power plants with instances of inverter fai l u res prompti ng req uests for NOEDs to extend the Com pletion Time for an inoperable distri bution panel inverter.

N RC Letter to U nion E lectric Company, " N otice of E nforcement Discretion for U n i o n Electric Com pany Regarding Callaway Plant U n it 1 [TAG N O . M E9277, N O E D N o . 1 2 002] , " dated Aug ust 23, 20 1 2 (ADAMS Accession N o . ML12237A010) . This N O E D g ranted enforcement discretion fo r an additional 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months .

N RC Letter to F P L Energy Seabrook, LLC, " N otice of Enforcement Discretion for F P L Energy Seabrook, L L C , Reg ard i ng Seabrook Statio n , N O E D N o . 2005-0 1 -0 1 , " dated Dece m ber 5, 2005 (ADAMS Accession N o . M L053400372) . Th is N O E D g ranted enforcement discretion for an additional 1 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months .

N RC Letter to N i n e M i le Point N uclear Station , L LC , "Notice of E nforcement Discretion Reg ard i ng N i ne Mile Poi nt U n it 2 , NOED N o . 2003-03-0 1 -002 , " dated Aug ust 1 8, 2003 (ADAMS Accession No. M L0323 1 0080) . This N O E D g ranted enforcement discreti on for an additional 1 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months .

N RC Letter to Tennessee Valley Authority, " N otice of Enforcement Discretion for Ten n essee Val ley Authority Regarding Watts Bar N u clear Plant U nit 1 , N O E D N o . 200 1 -

2-00 1 , " dated March 8 , 200 1 (ADAMS Accession N o . M L0 1 06802 1 1 ) . This N O E D g ranted enforcement discretion for an add itional 2 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months .

4.3 N o S i g n ificant H azards Considerati on PSEG N u clear LLC (PSEG) req uests approval of a change to the H ope Creek Generating Station ( HCGS) Tech n ical Specifications (TS) concerning Alternati ng Current (AC) I nverters .

The proposed change would extend the Allowed O utage Time (AOT) for an inoperable inverte r from 24 h o u rs to 7 days . The proposed new allowed outage time (AOT) is based on application of the Hope Creek Probabilistic Risk Assessment (PRA) i n support of a risk-informed extension, and on additional considerations and com pensatory actions. The risk evaluation and determ i nistic engi neering analysis su pporting the pro posed change were developed i n 63

LR-N 1 8-0032 LAR H 1 8-02 Enclosure accordance with the g u ideli nes establ ished in Regu latory G u ide 1 . 1 77 , "An Approach for Plant Specific Risk-i nformed Decision-maki ng : Tech nical S pecifiqati ons , " and Reg ulatory G u ide 1 . 1 7 4 , "An Approach for Using Probabil istic Risk Assessment i n Risk-I nformed Decisions on Plant-Specific Changes to the Licensing Basis . "

PSEG h a s evaluated whether or not a sign ificant h azards consideratio n is involved with the proposed amendment by focusing on the th ree stand ards set forth i n 1 0 C F R 50 . 92 , " I ssuance of amendment," as d iscussed below:

1. Does the proposed amend ment involve a significant increase in the probability or consequences of an accid ent previously evaluated?

Response : N o .

T h e proposed T S amendment does not affect t h e desig n o f t h e A C inverters , the operational characteristics or function of the i nverters , the i nterfaces between the inverters and other plant systems, or the reliability of the inverte rs. An inoperable AC i nverter is not considered an i nitiator of an analyzed event. I n addition , TS Actions and the associated Allowed O utage Times are not i n itiators of p reviously eva l u ated accidents . Extending the Al lowed Outage Time for an inoperable AC inverter wou l d not have a significant i m pact on the freq uency of occu rrence of an accident previously evaluated . The proposed amendment wil l not result i n modifications to plant activities associated with i nverter maintenance, but rather, provides operational flexi bil ity by allowing additional time to perform i nverter troubleshooti n g , corrective maintenance , and post-mai ntenance testing on-line.

The proposed extension of the Com pleti on Time for an i n o perable AC i nverter wi l l not sign ificantly affect the capability of the inverters to perform thei r safety functio n , wh ich is to ensure an u n interru ptible su pply of 1 20-volt AC electrical power to the associated power distribution su bsystems. An evaluatio n , using PRA m ethods, confirmed that the i ncrease in plant risk associated with i m plementation of the proposed Allowed Outage Time extension is consistent with the N RC's Safety Goal Policy Statement , as fu rther described i n RG 1 . 1 74 and RG 1 . 1 77 . In additio n , a determ i nistic evaluation concluded that plant defe nse-in-depth philosophy wi l l be m a i ntai ned with the proposed Allowed Outage Time extension .

There wil l be n o i mpact on the source term or pathways assu med i n accidents previ o usly evaluated . N o analysis ass u m ptions wil l be changed and there wi l l be n o adverse effects on onsite or offsite doses as the result of an accident.

Therefore , the proposed ch ange does not i nvolve a sign ificant increase in the probabil ity or conseq uences of an accident previously evaluated .

2. Does the proposed amend ment create the possibility of a new or d iff erent k ind of accid ent from any accid ent previously evaluated ?

Response : N o .

T h e proposed amendment does not i nvolve physical alteration of t h e H C G S . No new eq u i pment is being i ntrod uced , and instal led eq u ipment is not being operated in a new or 64

L R-N 1 8-0032 LAR H 1 8-02 Enclosure d ifferent manner. There is no change being made to the parameters withi n wh ich the HCGS is operated . There are n o setpoints at which protective or m itigati ng actions are i n itiated that are affected by this proposed actio n . The use of the alternate Class 1 E power source for the AC d istribution panel is consistent with the HCGS plant desig n . The change does not alter ass u m ptions m ade in the safety analysis. This proposed action wi l l not alter the man ner in which equi pment operati on is i n itiated , nor wil l the fu nctional dem ands on credited eq uipm e nt be changed. No alteration is proposed to the proced u res that ensure the HCGS remains withi n analyzed l i m its , and no change is being made to procedures re l ied u po n to respond to an off-normal event. As such , no new fai l u re modes are being i ntroduced.

Therefore , the proposed changes do not create the possibility of a new or d ifferent kind of accident from any previously evaluated .

3. Does the proposed amend ment involve a significant red uction in a margin of safety?

Response : No.

Marg i n of safety is related to the confidence i n the ability of the fission prod uct barriers to perform their desig n fu nctions d u ring and following an accident. These barriers i n clude the fuel claddi n g , the reactor coolant system , and the contain ment system . The proposed change, which wou ld i ncrease the AOT from 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months to 7 days for one inoperable inverter, does not exceed or alter a setpoi nt, design basis or safety l i m it .

Therefore , t h e proposed amend ment does not i nvolve a sig n ificant red u ction i n a m a rg i n of safety.

Based u po n the above , PSEG N u clear concludes that the proposed amendment presents no sig n ificant h azards consideration u nder the standards set forth i n 1 0 CFR 50 . 92 (c) , and, accord i ng ly , a finding of "no significant h azards considerati on" is justified.

4.4 Conclusion In conclusion, based on the considerations discussed above , ( 1 ) there is reasonable ass u rance that the health and safety of the public wil l n ot be endangered by operation i n the pro pose d m a n ner, (2) such activities will be conducted i n com pliance with t h e Comm ission's reg ulations, and (3) the issuance of the amendment wi l l not be i n i m ical to the common defe nse and security or to the health and safety of the public.

5. 0 ENVIRONMENTAL CONSIDERATION A review h as determ i ned that the proposed amendment would change a req u i rement with respect to installation or use of a facil ity com ponent located with in the restricted area, as defi ned in 1 0 CFR 20, or would change an i n s pection or surveillance req u i rement. H owever, the proposed amendment does not i nvolve (i) a s ig n ificant hazards consideratio n , (ii) a s i g nificant change in the types or significant i ncrease in the amou nts of any effl uent that m ay be released offsite, or (iii) a sig nificant increase in i n d ivid ual or cu m u lative occu pational radiatio n exposu re .

Accord i n g ly , the proposed amendment meets t h e eligibility criterion for categorical exclusion set forth in 1 0 C F R 5 1 . 22(c) (9) . Therefore , pursuant to 1 0 CFR 5 1 . 22(b) , no environmental i m pact 65

LR-N 1 8-0032 LAR H 1 8-02 Enclosure statement or environmental assessment need be prepared in connection with the proposed amendment .

6.0 REFERENCES

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[ 1 0] U S N RC , "Generic Letter 88-20, I nd ivid ual Plant Exa m i n ation for Severe Accident Vu l nerabilities - 1 0 CFR 50. 54(f) , " Nove m ber 23, 1 988.

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I ndependent Assessment Report Using N E I 05-04/07- 1 2/1 2-06 , Appendix X, " Aug ust 20 1 7 .

[ 1 2] PSEG , "HC-PSA- 1 04 , Hope Creek Fire Probabilistic Risk Assessment S u m m ary and Quantification Notebook, Rev. 2," Dece m ber 2 0 1 5 .

[ 1 3] PS E G , "Hope Creek Generati ng Station Fire P RA Peer Review Report U s i n g ASME/ANS PRA Standard Req u i rements , " Nove m ber 2 0 1 0 .

[ 1 4] US N RC , "Use o f Probabil istic R i s k Assessment Methods i n N u clar Reg u latory Activities; Final Policy State ment," Aug ust 1 6 , 1 995.

[ 1 5] U S N R C , "SECY-99-246 , Proposed G u idelines for Applying Risk-I nformed Decisionmaking in License Amendment Reviews , " October 1 2 , 1 999.

[ 1 6] PSEG , "H C-005 . 020, AC Power System N otebook, Revision 3," December 2 0 1 1 .

[ 1 7] PS E G , "HC-0 1 4 , Hope Creek Generati ng Station Proba bilistic Risk Assessment Quantification Notebook, Model H C 1 1 7A, Rev. 4 , " Dece m ber 2 0 1 7 .

[ 1 8] PSEG , "HC-PSA- 1 04 , Hope Creek Fire Probabil istic Risk Assessment S u m mary and Quantification N otebook, Rev. 2," December 2 0 1 5 .

[ 1 9] PS E G , "Hope Creek Generati ng Station I ndividual Plant Exa m i nation for External Events , "

J u ly 1 997.

[20] U S N RC , "Generic Letter 88 I ndividual Plant Exa m i n ation of Exte rna l Eve nts (I PEE E) for Severe Accident Vu lnerabilities - 1 0 CFR 50. 54(f) , S u pplement 4," J u ne 1 99 1 .

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[2 1 ] USNRC, " N U REG-1 407, Procedural and S u bm ittal G u idance for the I nd ivid ual Plant Examination of External Events ( I P E EE) for Severe Accident Vulnerabilities , " J u ne 1 99 1 .

[22] USNRC, " N RC Staff Evaluation Report (S E R) of I nd ivid ual Plant Exa m i n ation for External Events (I P E E E) S u b m ittal for H o pe Creek Generati ng Statio n , " J u ly 1 999.

[23] PSEG , "LR-N 1 4-0035, PSEG N uclear LLC's Seismic H azard and Screening Report (CE U S Sites) Response t o N RC Request for I nformation Pursuant t o 1 0 C F R 50. 54(f) Regard i ng Recom mendation 2 . 1 of the Near-Term Task Force Review of I ns ig hts from the Fukush i m a Dai-ich i Accident - H ope Creek Generating Station" March 28, 20 1 4 .

[24] PSEG , "LR- N 1 2-0369, Hope Creek Generating Station Response to Recommendatio n 2 . 3 :

Flood ing Walkdown o f the Near-Term Task Force Review o f I nsig hts from the Fukus h i m a Dai-ich i Accident , " N ovem ber 26, 2 0 1 2 .

[25] US N RC , "Hope Creek Generati ng Station - Audit Report Reg ard i n g Flooding Wal kdowns to Support I m plementation of Near-Term Task Force Recomm e nd ation 2 . 3 Related to the Fukushima Dai-ichi N u clear Power Plant Accident (TAC No. M F0236} , " Nove m ber 1 8 ,

20 1 3 .

[26] U S N RC , "Hope Creek Generati ng Station - Staff Assessment of Flood i ng Walkdown Report Supporting I m plementation of Near-Term Task Force Recom mendation 2 . 3 Related to the Fukushima Dai-ichi N u clear Power Plant Accident (TAC N o . M F0236} , " J u ne 1 6 ,

20 1 4 .

[27] PSEG , " LR-N 1 4-004 1 , PSEG N uclear LLC's Response to Req uest for I nformation Reg ard i ng Flooding Aspects of Recommendation 2 . 1 of the Near-Term Task Force Review of I nsights from the F u kushima Dai-ichi Accident - Hope Creek Generating Station Flood Hazard Reeval u atio n , " March 1 2 , 2 0 1 4 .

[28] U S N RC , "Generic Letter 89-22 , Potential for I ncreased Roof Loads and P lant Area F lood Runoff Depth at Lice nsed N uclear Power Plants d ue to Recent Change i n Probable Maxi m u m Precipitation Criteria Developed by the National Weather Service , " October 1 9 ,

1 989.

[29] U S N RC , " N U REG/CR-2300 , N U REG/CR-2300, PRA P rocedu res G uide: A G u ide to the Performance of Probabilistic Risk Assessments for N uclear Power Plants , " January 1 983.

[30] USNRC, " N U REG/CR-7046, Desig n-Basis Flood Estimation for Site Characterization at N uclear Power Plants in the U n ited States of America , " Nove m ber 2 0 1 1 .

[3 1 ] PSEG, "LR-N 1 4-0 1 70, PSEG N u clear LLC's 30-day Response to Req uest for Additional I nformatio n Reg ard i ng Flooding Aspects of Recommendation 2 . 1 of the Near-Term Task Force Review of I nsig hts from the F ukushima Dai-ichi Accident , " J u ly 28, 20 1 4 .

[32] PSEG , "LR-N 1 4-0207, PSEG N uclear LLC's 90-day Response to Req uest for Additional I nformation Reg ard i ng Flood ing Aspects of Recommendatio n 2 . 1 of the Near-Term Task Force Review of I nsig hts from the F ukushima Dai-ichi Accident , " Septem ber 23, 20 1 4.

[33] PSEG , " LR-N 1 5-0 1 00 , Hope Creek Generati ng Station's Response to Req uest for Additional I nformation Regarding Flooding Aspects of Recommendation 2 . 1 of the Near Term Task Force Review of I nsights from the Fukus h i m a Dai-ichi Accident , " May 7 , 20 1 5 .

[34] PSEG , "LR-N 1 6-0 1 1 2 , Hope Creek Generati ng Station's Flood H azards M itigati ng Strategies Assessment (MSA) Report Subm itta l , " Dece m ber 29 , 2 0 1 6 .

[35] EPRI , "Report 3002004400, Local Preci pitation-Freq uency Studies, Development of 1 -

Hour/1 -Sq uare Mile P recipitation-Freq uency Relationships for Two Example N u clear Power Plant S ites , " 20 1 4.

[36] PS EG , "PSEG Docu ment H C . O P-AB . M I SC-000 1 , "Acts of N ature", Rev. 30".

67

LR-N 1 8-0032 LAR H 1 8-02 Enclosure

[37] USAC E , "Report E RDC/C H L TR- 1 1 - 1 , Report 5, Coastal Storm Surge Analysis: Storm S u rge Resu lts, " November 20 1 3 .

[38] PSEG , "PSEG Docu ment OP-AA- 1 08- 1 1 1 - 1 00 1 , Severe Weather and Natural Disaster Guideline, Rev. 1 4" .

[39] PSEG , " P S E G Docu ment OP-HC-1 1 2- 1 0 1 - 1 00 1 -F2 , Control Room S u pervisor - Rel ief Checkl ist, Rev. 1 ".

[40] N E I , " N E I 1 2-07 , G u ideli nes for Perform ing Verification Walkdowns of Plant Flood Protection Features, Rev. 0-A , " May 2 0 1 2 .

[4 1 ] PSEG , "PSEG Docu ment E R-AA-3 1 0- 1 0 1 , Condition Mon itori ng of Mai nte nance Rule Structures, Rev. 0" .

[42] PS E G , "PSEG Docu ment HC . F P-SV. ZZ-0026, Flood and Fire Barrier Penetration Seal I nspection, Rev. 7".

[43] PSEG , "PSEG Docu ment H C . M D-PM . ZZ-0007 , M issile Resistant and Watertight Doors P.M.".

[44] PSEG , "HC-00 1 , Hope Creek Generating Station (HCGS) Probabilistic Risk Assessment I n itiating Events Notebook, Rev. 4," Dece m ber 2 0 1 7 .

[45] PSEG , "HC-0 1 3 , Hope Creek Generating Station Probabilistic Risk Assessment S u m mary Notebook, Rev. 3 , " December 20 1 7.

[46] U S N RC , " N U REG/CR-6890 , Reevaluation of Station Blackout Risk at N u clear Power Plants , Analysis of Loss of Offsite Power Events , " N ove m ber 2005.

[47] U S N RC , "CCF Parameter Esti m ations, 2 0 1 5 U pdate , " October 20 1 6 .

[48] PSEG , "PSEG Document OP-AA- 1 08- 1 1 6 , Protected Eq u i pment Prog ra m , Revis i o n 1 2 , "

May 2 0 1 6 .

[49] PSEG , "HC-004 , Hope Creek Generating Station Probabilistic Risk Assessment H u man Rel i a b i l ity Analysis (HRA) Notebook, Rev. 5," December 20 1 7 .

[50] PS E G , "HC-000, Hope Creek Generating Station Probabil istic Risk Assessment Docum entation and Roadmap N otebook, Rev. 3," Dece m ber 2 0 1 7 .

[5 1 ] PSEG , "HC-0 1 6 , Hope Creek Generating Station Probabil istic Risk Assessment Self Assessment Notebook, Rev. 2 , " December 20 1 7 .

[52] N E I , " N E I 00-02 , Probabilistic Risk Assessment (P RA) Peer Review Process G u id e , Rev.

A3 , " March 2000.

[53] BWR Owner's G roup, " Hope Creek PRA Peer Review Certification , " October 2000.

[54] N E I , "NEI 00-02 Appendix D , Self Assessment Process for Add ressing ASM E P RA Standard RA-S b-2005, as endorsed by N RC Reg u latory G u ide 1 . 200 , " October 2006.

[55] US N RC , " N U REG-1 855, G u idance o n the Treatment of U n certai nties Associated with PRAs in Risk-I nformed Decision Maki n g , Rev. 1 , " March 20 1 7 .

[56] PSEG , "HC-0 1 0 , Hope Creek Generating Station Probabil istic Risk Assessment Com ponent Data N otebook, Rev. 4 , " December 20 1 7 .

[57] U S N RC , " N U REG/CR- 1 278, Hand book of H RA, " Aug ust 1 983.

[58] U S N RC , "Reg u l atory G u ide 1 . 1 82 , Assessing and Managing Risk Before M a i ntenance Activities at N uclear Power Plants , Revision 1 , " M ay 2000.

[59] Boil i n g Water Reactors Owners' G ro u p (BWROG), "PSA Peer Review Certification I m plementation G u idelines (DRAFT} , " J u ly 1 997.

[60] E P R I , "N P-6395-D, Probabil istic Seismic Hazard Evaluation at N uclear Power Plant S ites in the Central and Eastern U n ited States , " January 1 989.

68

LR-N 1 8-0032 LAR H 1 8-02 Enclosure

[6 1 ] E P R I , " 1 0 1 6737 , Treatment of Parameter and Modeling U n certainty for Probabilistic Risk Assessments , " December 1 9, 2008.

[62] U S N RC , "CCF Parameter Esti mations, 2009 U pdate , " Apri l 2 0 1 1 .

[64] E P R I , " 1 009652 , G u ideline for the Treatme nt of U n certainty i n Risk-I nformed Applications , "

Dece m ber 2004 .

69

LR-N 1 8-0032 Attachment 1 Technical Specification Page with Proposed Changes

LR-N 1 8-0032 LAR H 1 8-02 TECHNICAL SPECIFICATION PAGES W ITH PROPOSED CHANGES The followi ng Techn ical Specifications for Renewed Facil ity Operating License N P F-57 are affected by this change req uest:

Technical Sp ecification 3.8.3. 1 3/4 8-20

EL ECTRI CAL POWE R SYST EMS L I M ITI NG CONDITION F O R OPERATION (Contin u ed)

A P P L I CAB I LITY: O P E RATIO NAL CON DIT I O N S 1 , 2 and 3 .

ACTIO N :

a. With o n e of t h e a b ove req uired A. C . distri bution system c h a n nels n ot energ ized ,

re-e nerg ize t h e channel within 8 h o u rs o r be i n at least HOT S HUTDOWN within the n ext 1 2 ho u rs a n d i n COLD S H U TDOWN with i n t h e fol l owing 24 h o u rs.

b. With o n e o f t h e above req u i red 1 25 volt D . C . d i stribution syste m channels not e n e rg ized , re-energ ize the d ivision wit h i n 2 h o u rs o r be in at least H OT S H UTDOWN w it h i n the next 1 2 h o u rs and in COL D S H UTDOWN wit h i n t h e fol l owing 24 h ours .

c. With a n y o n e o f t h e a bove req uired 250 volt D . C . d i stri b ution systems not energized , declare the associ ated H PCI or R C I C system i nopera ble and apply the a ppropriate ACTION req u i red by t h e a p p l i cable S pe cificat i o n s .

d. With one o r both i n verters i n one cha nnel i nopera b l e , energ ize the associated 1 20 volt A. C. d i stri bution pa nel(s) with i n 8 h o u rs , a n d resto re t h e inverter(s) to O P E RABLE status wit h i n 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months ; o r be i n at least HOT S H UTDOWN within the n ext 1 2 h o u rs a n d in COl:. S H UTDOWN wit h i n the following 24 h o u rs .

S U RVEI LLANCE REQU I REMENTS 4 . 8 . 3 . 1 Each of the above req u i red power dist ri bution system channels s h a l l be d eterm i ned energ ized i n accord a n ce with the S u rveil l an ce Frequency Control Prog ram by verifying correct breake r/switch a l i g n m e nt a n d voltage on the busses/MCCs/pa nels .

HOPE CREEK 3/4 8-20 Amendment N o . 1 87

LR-N 1 8-0032 LAR H 1 8-02 Attachment 2 Technical Ad equacy of the PRA Mod els

LR-N 1 8-0032 LAR H 1 8-02 A.1 Q UAL ITY OF THE PRA MODEL OF RECORD A. 1 . 1 I NTRO D UCTI O N The H ope C reek F P I E model has the needed q u a l ity and scope to support this AOT extensio n .

I t i s h i g h ly detailed , including a wide variety o f i nitiating events (e. g . , transients , i nternal floods, LOCAs inside and outside containment , su pport system fai l u re i n itiators) , modeled syste m s ,

operator actions, a n d common-cause events . Furthermore, i t is t h e e n d prod uct o f over 2 5 years of analysis effort. As part of its m ost recent revision in 2 0 1 7 (i . e . , H C 1 1 7A) , the model was reviewed against the American Society of Mechan ical Eng ineers/American N u clear S ociety (ASM E/ANS) P RA Sta ndard with the i ntent of m eeti ng Capability Category I I .

PSEG's risk management procedures and best practices provide the details describing the use of the PRA model at H o pe Creek to support Mai ntenance Rule activities . The model serves an inva l uable role in establishing performa nce criteria , balancing unavailability and reliability for ris k-sig n ificant SSCs , and provides in put to the Expert Panel for the risk-sign ificance determ i n ation process when revisions to the P RA take place .

Because t h e PRA is actively used a t Hope Creek, a formal process is i n place t o evaluate and resolve PRA model-related issues as they are identified . This is referred to as the U pdate Req u i rements Evaluation (U RE) process.

The HCGS PRA has been u pdated to ensure that the model's level of detail, its fidelity with the as-operated , as-bu i lt plant, and the techn ical q uality of its results all are acceptable to s u pport its use for risk-i nformed applications.

To ensure the PRA addresses fidel ity and q uality, the H C 1 1 7A model u pdate i n cluded recent operating experience , plant modifications, changes to key plant procedu res, changes in operator training , system success criteria , engineering analyses , u pdated industry and plant specific event and fai l u re data, and more defensible success criteria based on enhanced MAAP calculations.

A sign ificant amount of effort was expended to provide a fu lly-documented and traceable basis for all elements of the PRA. Overa l l , the Hope Creek PRA may be considered a m ajor accomplishment for PSEG i n bring ing the q u a l ity of the m odel and su pporting basis d ocuments to the needed level of sophistication for support of P RA applications such as Extended Power U prate (EPU) and Allowed Outage Time (AOT) extensions.

The q u a l ity of the HCGS PRA model used i n perform i ng risk assessment applications for the HCGS is evidenced by the following:

S ufficient scope and level of detai l i n PRA

Active mai ntenance of the P RA models and i nputs

Com prehensive Critical Reviews P RA quality is assured for the H ope Creek m odel and its d ocumentation through a com b i n ation of the following :

Confi rmation of the fidel ity of the model with the as-built, as-operated plant (see Section A. 1 . 2) 1

LR-N 1 8-0032 LAR H 1 8-02

Use of i nternal reviews , i nterviews with the system eng inee rs and the operati ng crew mem bers

Use of experienced PRA practitioners qualified under the PSEG P RA Program

A self-assessment of the PRA against the ASM E/ANS P RA Standard (see Section A. 1 . 4 . 4)

The P RA Peer Review Process using the ASM E/ANS PRA Standard . (see Section A. 1 . 4 . 5)

Use of an U pdate Req u i rement Evaluation (U RE) database to track potential model enhancements (See Section A. 1 . 5)

PRA mai ntenance and u pdate are governed by a set of PSEG procedures.

U pd ate req uirements are specifically listed i n PSEG procedures for FPI E and Fire PRAs A. 1 . 2 ACC U RACY O F T H E M O D E L T h e fidel ity o f the PRA m o d e l with t h e as-bu i lt, as-operated plant is assu red b y the followi ng steps :

The Site Risk Management E ng i neer (S RME) has reviewed the plant design modifications that could affect the risk profile and h as identified those mod ifications to be explicitly accounted for i n the PRA. These m od ifications have been incl uded .

The S R M E has reviewed the proced ure changes that could affect the risk profile and has identified those procedu re changes to be explicitly accounted for i n the PRA. These have been included .

Operati ng crews have been interviewed to assess their interpretation of procedu res for key operator actions and the list of i n itiating events . These resu lts are folded back i nto the H u m a n Reliabil ity Analysis ( H RA) , docu mented in the H RA N otebook (Reference 49) , and then incorporated i nto the P RA mode l .

System Managers have been i nterviewed to assess any changes i n the plant, the operating history , or system usage that would i nfluence the PRA systems or i n itiating events. These resu lts have been i ncorporated i nto the system models.

The latest plant-specific Mai ntenance Rule d ata has been exa m i ned and the res u lts have been i ncorporated i nto the PRA data base using a Bayesian u pdate process to calculate com ponent fai l u re data .

A. 1 . 3 MAI NTENANCE O F M O D E L , I N PUTS , AN D DOC U M E NTAT I O N T h e H C G S PRA m o d e l a n d documentation h a s been u pdated to reflect t h e cu rrent plant configuratio n and to i ncorporate the accu m u l ated additional plant operating history and com ponent fai l u re data.

The 20 1 7 u pdate m ade significant changes to the fol l owing P RA elements to respond to the PRA Peer Review and real ize the ASM E/ANS PRA Standard . These incl ude the followi n g :

U pd ated data (initiati ng events , com ponent fai lure data, and u navailabil ity data)

Mod ified system models

U pdated com mon-cause fai l u res incorporati ng the latest N RC data

U pdated i nternal flood i n itiati ng freq uencies and refi nement of scenarios 2

LR-N 1 8-0032 LAR H 1 8-02 A. 1 .4 PRA S E LF-ASS ESS M E NT AN D P E E R REVI EWS Followi ng the issuance of the 2009 ASM E PRA Standard and its endorseme nt by the N RC i n R G 1 . 200, Rev. 2 , PSEG u ndertook a detai led review of the Hope Creek P RA m odel and documentation. This review was performed using the NEI recommended self-assessment process as endorsed by the N RC i n RG 1 . 200.

The objective of the Hope Creek P RA maintenance program is to identify g a ps i n the PRA with respect to Capability Category I I for all supporting req u i rements and to correct any deficiencies .

The HCGS P RA U pdate process incl udes the self-assessment of the 20 1 7 P RA model

( H C 1 1 7A) , data, and docu mentation using the 2009 ASM E PRA Standard as endorsed by RG 1 . 200 , Rev. 2. The identified items were then resolved as part of the update process. The HCGS Roadmap Document (Reference 50) provides the reference sections of the HCGS documentation that su pport the individual S u pporti ng Req u i rements .

The Road map Document provides the l i n k between the ASM E PRA Standard S u p porting Req u i rements and the HCGS PRA. The self-assessment developers then use their assessment of the P RA and its documentatio n to cite a Capability Categ ory.

The resu lts of the self-assessment and a s u m mary and a disposition of the gaps from the 2008 u pdate were documented i n the PRA self-assessment notebook (Reference 5 1 ) .

A. 1 .4 . 1 I nputs for PRA Self-Assessment The following information was com pi led for review and use i n the assessment:

2 0 1 7 Hope Creek PRA and associated documentation

AS M E/ANS PRA Standard - RA-Sa-2009

N E I Peer Review G u idelines, N E I 00-02

H CGS PRA Peer Review Report (Reference 53)

Appendix 1 of N E I S u pplementary G uidance (Reference 54)

Appendix 2 of N E I S u pplementary G u idance , Subtier Criteria for peer review process A. 1 . 4 . 2 Self-Assessment Standards It can be anticipated that the ease of application and confidence held in a P RA would be best served if the PRA can be consistently demonstrated to meet a m i n i m u m Capability Category of the ASM E/ANS PRA Standard . Because Capability Category I I com pares to the N E I 00-02 evaluated categ ory of "Grade 3" and because HCGS meets at least G rade 3 for each sub element following the 2 0 1 7 PRA u pdate, it makes sense to demonstrate the H CGS PRA capabil ity relative to ASM E/ANS PRA Standard Capabi l ity Categ ory I I .

A. 1 . 4 . 3 Supporting Requirements Review Process Using Section 4 . 5 of the AS M E/ANS PRA Sta ndard , the followi ng steps were performed relative to the HCGS H C 1 1 1 A PRA u pd ate docu ment to provide i nput to the 20 1 7 m odel u pdate:

3

L R- N 1 8-0032 LAR H 1 8-02 F i rst, beg i n n i ng with I n itiati ng Events Analysis (Section 2-2 . 1 of the ASM E/ANS PRA Standard ) ,

and u s i n g Appendix 1 o f t h e N E I S u pplementary G u idance , identify t h e Su pporting Req u i rements of the ASM E/ANS PRA Standard (corresponding to Capabi l ity Category I I) that are indicated as " partially addressed" or " n ot addressed" by the peer review process . For each req u i rement so identified , the fourth col u m n of the table notes the specific acti on to be taken as part of the self-assessment process.

N ext, for each Su pporting Req uirement so identified , review the above l isted i nfo rmatio n , as appropriate, to make a determ i nation as to whether the supporting requ i rement was addressed in the HCGS PRA. Document the basis for the determ i n ation that the supporting req u i re ment is addressed , or not. This incl udes the u pdate of the PRA i n 2 0 1 1 to specifically address the s u pporting req u i rements .

The n , for S u pporting Req u i rements identified i n Appendix 1 as "addressed" by the peer review process , review the peer review report to determ ine if these sub elements were assigned a g rade of 3 o r h ig her. If a g rade less than 3, or a conditional g rade 3 was provided , or if s i g n ificant facts and observati ons need to be reconciled , then a determ i nation is made of which capabil ity level i n the ASM E/ANS PRA Standard is met, and this determ i nation shou ld be documented . This i ncl udes consideration of the resolutio n of Facts and Observations (F&Os) wh ich are i n corporated in the 2008 PRA u pdate . The resoluti on of F&Os from the PRA Peer Review includes all of the "A" and " B" F&Os.

Finally, fol l owing assessment of the Su pporting Req u i rements , the i nform ation prod uced is reviewed and a determination is m ade whether the hig h-level objective for the in itiati ng events analysis section is met. This determ i n atio n is documented in a s u m mary at the beg i n n i n g of each element. Appendix A of the Peer Review d ocument provides the resol ution of the P RA Peer Review F&Os that have been incl uded i n the 2008 HCGS PRA U pdate . The resolution of F&Os from the PRA Peer Review i n clude all of the "A" and " B" F&Os.

A repeat of the above process for Sections 2-2 . 2 (Accident Seq uence Analysis) through 2 -2 . 8

( L E RF Analysis) of the ASM E/ANS Standard i s also performed t o evaluate each of the n i n e areas .

4

LR-N 1 8-0032 LAR H 1 8-02 A. 1 .4.4 Conclusion of the 2 0 1 7 Self-Assessment The ASM E/ANS P RA Standard identifies 3 1 6 Tech nical Supporting Req u i rements plus 1 0 Maintenance and U pdate Supporting Req uirements . The 2 0 1 7 self-assessment of the model agai nst these req u i rements identified the followi ng items to resolve :

Resolution Pend ing Pr ior ity ( Number of Supp or ting Req uir ements)

High 0 Med i u m 0 Low 0 There were 3 1 6 tech nical S u pporting Req u i rements that were eva l uated as part of the self-assessment. Of these 3 1 6 Su pporting Req u i rements, the documentation and the model were j udged to meet the ASM E/ANS PRA Standard to support Capability Category I I for 3 1 4. Of the two (2) S u pporti ng Req u i rements that did not meet Capabil ity Category I I , both are considered l ow tech nical priority.

It is recog n ized that there are open q uestions about the scope and level of detail expected for the resolution of the m odel uncertainty treatment i n each of the elements. H owever, the HCGS eva luation uses the approach developed by EPRI to exa m i n e and eva luate these uncertai nties .

This approach is j udged to be consistent with N RC g uidance i n N U REG/CR- 1 855 (Reference

55) .

The 2 0 1 7 H ope Creek PRA update (HC 1 1 7A) i ncorporated a l l recent plant modifications, including those for the EPU, through the freeze date of 1 2/3 1 /20 1 6. As such , the H C 1 1 7A Hope Creek PRA model is an accu rate and real istic representation of the as-bu i lt, as-operated H ope Creek Generating Station for the risk profile from i nternal events occu rri ng at-power.

The result of these activities is that the H CGS PRA is found s u itable to support risk-informed PRA applications that req u i re ASM E/ANS PRA Capabil ity Category I I .

A. 1 . 4 . 5 Peer Reviews There have been two peer reviews and one F&O closu re review of the HCSG F P I E PRA:

A peer review i n 1 999 by BWR Owner's G ro u p (BWROG) using N E I 00-02, u lti m ately resu lting i n the H C2005C model

A peer review i n 2008 by BWROG using N E I 05-04 (Process for Perform i ng I nternal Events PRA Peer Reviews Using the ASM E/ANS P RA Standard) and the 2007 ASM E PRA Standard , resulting i n the H C 1 08A m odel

An F&O closure review i n 20 1 7 to resolve the open items of the 2008 peer review, resu lting i n the H C 1 1 7A model 5

LR-N 1 8-0032 LAR H 1 8-02 1 999 Peer Review I n 1 999, PSEG partici pated in a P RA Peer Review Certification of the H ope Creek PRA ad m i n i stered under the auspices of the BWROG Peer Certification Comm ittee (Reference 53) .

The purpose of the PRA peer review process is to establish a method of assessing the tech nical q uality of the PRA for the spectrum of its potential applications.

The evaluation process uti l ized a tiered approach using standardized checklists allowing for a detailed review of the elements and the sub-elements of the Hope Creek PRA to ide ntify strengths and areas that needed i m provement. The review system used allowed the Peer Review team to focus on tech n ical issues and to issue their assessment resu lts in the form of a "grade" of 1 through 4 on a P RA su b-element leve l . To reasonably span the s pectrum of potential P RA applications, the fou r g rades of certification as defined by the BWROG document

" Report to the I ndustry on PRA Peer Review Certificatio n Process - Pilot Plant Results" were em ployed . All of the "A" a nd " B" pri ority comments were addressed by PSEG i n the HCGS PRA 2005C model , as appropriate .

The overall conclusion of the 1 999 Hope Creek PRA Peer Review was positive , and the P RA Peer Review Team stated that the H o pe Creek PRA can be effectively used to support applications involvi ng risk-i nformed applicati ons.

The F&Os for Hope Creek were evaluated and addressed by the H ope Creek PRA Prog ra m as part of previous PRA u pdates . There were n o "A" Facts and Observations and 84 " B" Facts and Observations identified in the P RA Peer Review report. All 84 F&Os were resolved by m odel changes i n the 2003 u pdate. N o outstanding "A" or " B" priority F&Os remai ned at this time.

2008A Peer Review Because of the sign ificant changes in PRA methods (e. g . , H RA, I nternal Flood i n g , Common Cause , LOOP treatment, and Level 2} , a com plete PRA Peer Review of the H o pe Creek P RA H C 1 08A m odel was req uested by PSEG. The PRA Peer Review was performed i n October 2008 using the 2007 ASM E PRA Standard as endorsed by the N RC i n Reg . G u ide 1 . 200 ,

Rev. 1 .

The PRA Peer Review process confi rmed the adeq uacy of the H ope Creek P RA m odel for use i n PRA appl ications based on both the exit interview and the Draft PRA Peer Review Report.

The PRA Peer Review using the ASM E PRA Standard resu lted i n the identification of some m i n o r numerical changes to basic events and several additions to model log ic. These changes led to a re-q uantification of the H ope Creek PRA model resulting i n the H C 1 08B m odel . I n additi o n , the H C 1 08B model used the FTREX quantification engine wh ich allowed efficient quantification at a lower truncation l i m it, i . e . , 1 E-1 2/yr.

2 0 1 7 F&O Closure Review An F&O closure review was co nducted in Aug ust 2 0 1 7 to reso lve the open F&Os identified by the 2008 peer review. The review used the process descri bed Appendix X to N E I 05-04 , N E I 07- 1 2 (Fire Probabil istic Risk Assessment (FPRA) Peer Review Process G u idelines} , N E I 1 2-06 (Diverse and Flexi ble Coping Strategies (FLEX) I m plementation G u ide} , and the ASM E P RA 6

LR-N 1 8-0032 LAR H 1 8-02 Standard , with clarifications provided in Reg . G u ide 1 . 200, Rev. 2 and N RC Staff Expectations for an I ndustry Facts and Observations (F&O) I ndependent Assessment Process.

This review compared the H C 1 1 1 A model against the AS M E PRA Standard and assessed the reso l utions to fifteen Findings , as wel l as one S uggestion that the m odel had met only at Capabi l ity Category I . The pee r reviewers concu rred with all resolutions and closed o ut a l l sixteen F&Os . These resolutions are carried over into t h e H C 1 1 7A mode l , wh ich h a s no rem a i n i ng open F&Os against it.

A. 1 . 4 . 6 Ped igree of the PRA Model The flowchart i n Figure A- 1 summarizes the h istory of HCGS self-assessments and peer reviews .

The H CGS PRA review process includes all of the steps identified i n the N E I supplementary g uidance and l ater, the ASM E/ANS P RA Standard .

7

LR-N 1 8-0032 LAR H 1 8-02 ASME PRA NEI Peer Review 1 999 STD Self Assessment Process PRA 2002 Process Guideline 1 997 Model I I Revised Peer Review Application of Results of Interim PRA

..... S elf r--. __.. Disposition of PRA __..

Process Peer Review PRA Self 2005 c Assessment Changes 2003 A 2000 to PRA 1 999 Assessment Model Model Self ASME/ANS F&O Closure Assessment PRA STD Review Changes 2009 HC 1 08 A PRA Peer HC 1 08 B S elf HC l l l A Self HC 1 1 7A Model Review Model Assessment Model Assessment Model Update Oct 2008 Update Update Update F i g u re A-1 : HCGS P RA Self-Assessment H istory 8

LR-N 1 8-0032 LAR H 1 8-02 A 1 .5 U R E STATUS In addition to the PRA self-assessment, a n u m ber of observations were also recorded in the PSEG U pdate Req uirement Evaluation (U RE) database to serve as a resou rce for potential model enhancement i n the future . This allows the Risk Management team to ensure that the PRA accu rately reflects the as-b u i lt , as-operated plant by identifyi n g , trackin g , and resolving these observations.

Approximately 1 68 U REs were addressed as part of the 2 0 1 7 u pd ate . Of these , - 1 30 were res olved and closed out; leaving 39 U REs postponed or left ope n . None of these postponed U REs are considered to have the potential to significantly affect the resulting M odel of Record

( i . e . H C 1 1 7A) or any potential applications envisioned for the PRA.

Table A- 1 presents a s u m m ary of model changes and U REs addressed in the u pdate. Because some U REs had l ittle or n o effect on the q uantification or d id not apply to the P RA m odel , not a l l resolved U REs are listed i n Table A- 1 . Detai led records reg ard i ng t h e status o f U REs are tracked in the URE database .

Table A- 1 S U M MARY O F H O P E C R E E K 2 0 1 7 MODEL (HC 1 1 7A) U R E C HANG E S Change URE C h a n g e o r U R E Descri pti o n

- - H C 1 1 1 A base model fi les 1 H C2 0 1 2-00 1 O S P gate 2 H C2 0 1 2-006 Co n t Ven t R u ptu re Disk d u p l icate B E 3 H C2 0 1 2-0 1 1 B E m is n a m ed 4 HC20 1 2-0 1 3 XVM-CO p ro b a b i l ity 5 HC20 1 2-0 1 4 Waste Evaporator 6 HC20 1 4-00 1 CW Valve c h a n g e fro m H OV t o M O V 7 H C2 0 1 5-0 0 5 M S I V g ate e rro r 8 H C2 0 1 2-0 1 2 O S P ( H C-AS M -0 0 1 )

9 HC-AS M-002 UV Relays 10 HC20 1 2-0 1 0 SAC S HX Bypass valves 11 H C2 0 1 6-022 S RV leakage B E 12 HC20 1 2-0 1 4 Waste Evaporator 13 H C2 0 1 7-008 C I S-AOV C C F name HC20 1 2-0 1 0 14 SAC S HX Bypass valves H C2 0 1 5-006 15 HC20 1 5-0 1 0 SWIS HVAC TM terms 16 HC20 1 5-0 1 0 SWI S HVAC TM terms adj ustm ent i n M UT EX 17 H C 2 0 1 2-00 1 L O O P/S BO ET changes from Ed/Larry 18 N/A Add C lass Tags 19 N/A Ad d Seq u e ncer Tags 20 N/A Recovery fi l e to set tags to T R U E and S U B S U M E 21 N/A Add L2 Release Tags 22 N/A Ad d ADS-XH 1 -VF-I N H I B to Recovery fi l e 23 HC2008-02 1 C h a n g e S B0-006 t o l iT 24 HC2009-027 SWS yard d ischa rg e U R E 25 HC20 1 5-0 1 2 S L C B Es d e lete d fro m H C-STI-007 9

LR-N 1 8-0032 LAR H 1 8-02 Table A- 1 S U M MARY O F HOPE CREEK 2 0 1 7 M O D E L ( H C 1 1 7A) U RE CHANG ES Change URE C h a n g e o r U R E Descri pti o n 26 H C2009-028 Replace C ST-T N K-FAI L with CST-T N K- R P-CST0 1 H C 2 0 1 4-007 27 H C20 1 3-00 1 Add SWS-XH 1 -FO-HVAC H C2 0 0 9-02 9 28 N/A U pd ate p l a n t ava i l a b i l ity factor B E Deleted % 1 E- F I R Exx i n itiato rs a n d re lated g ates from model a n d 29 N/A R R database.

Revised SACS valve mode l i n g t o b e cons istent w it h AS M , U V 30 H C-AS M -0 0 3 relay mode l i n g s i m p l ificati o n , a d d F L EX powe r to A&B c h a rg e rs 31 H C-AS M-003 C reate n ew F LAG fi l e to turn F L EX o n/off a n d GTG o n/off I n BE ADS-XH D-H P I , ca lc type is an eq uatio n : " 0 . 05*3 . 8 E -4 " .

32 H C-ASM-003 C h a n g ed 3 . 8 E-04 i n t h i s eq u ation to 3 . 7 E-04, which g e n erates a calcu l ated p ro b a b i l ity of 1 . 8 5 E- 05 .

C h a n g ed the fol l owi ng basic eve nts t o cal c u l ati o n me t hod 1 -

M u lt i p ly (exposu re*rate) , then c h a n g ed the facto r to 2 4 :

33 H C-AS M-003 R C I -STR-P L-O F20 9 , H P I -STR-PL-O F2 1 0 , R H S-STR-P L - P C ,

R H S-STR-P L-P D , R H S-STR-P L-PA, R H S-STR- P L- P B , CSS-STR-P L-C , CSS-STR-P L-A, CSS-STR-PL-D, CSS-STR-PL-B 34 - S LOCA-ST a n d S L OCA-WA ET revision 35 H C 2 0 1 2-004 Add exte rna l i nj nod e to L L OCA-WA ET.

36 H C200 9-022 Ad d 2496 va lve isolation to TACS/SACS isolation g ates .

Revise conta i n m e n t ve nt FT logic to m a ke eas i e r to read , d e l ete 37 -

d u p l icates, a n d s i m p l ify logic.

H C 2 0 1 6-02 0 38 Revise RACS recove ry a n d T ACS recovery co n necti o n s .

H C20 1 2-020 39 H C20 1 1 -006 Replace C R C S 1 0 0 with GZCS 1 00 .

40 HC20 1 6-006 Revise RRCS loQ i c to o n ly h ave A, B , C , a n d D A P R M s .

Revised u nd e r g ate GGT based on H C . O P -A B . ZZ-0 1 35 a n d 41 H C 2 0 1 7-004 S 1 . 0 P-AB . LO O P-000 1 U pd ated n o rm a l and a ltern ate OSP feeds g ates to 4KV busses for 42 H C 2 0 1 6-028 consistency.

43 H C2 0 1 6-002 Deleted FW g ate from u nd e r H P C I - I N J -LOCA.

C h a n g e SSW-XH 1 -0C-VLV1 to o n l y be for S SW crosstie for o p pos ite SACS loop coo l i n g (and renamed to SAC-XH 1 -F O -XT I E ) .

44 H C2 0 1 2-020 M a ke RAC-XH 1 -RS-24-0 1 a n d TAC-XH 1 -RS-24-0 1 t h e H E Ps fo r RACS a n d TACS cool i n g resto ratio n after L O C A isolati o n .

45 - Revise 6" conta i n ment vent path to be s i m i la r to 1 2 " ve nt path U pd ate I E freq u e n cies; u pd ated L O O P recove ry p ro b a b i l ities; 46 -

ren a m e recovery B Es to be m o re accu rate with t ime period 47 - Upd ated I S LOCA freq u encies 48 - Set DG-ABC D TM term to False i n F lag fi le ( later remove d )

Add n ew conseq uential LOOP p ro b a b i l ity for m a n u a l scra m 49 -

i n itiator.

Revised DWV node to reflect p roced u re ; revised SWI S HVAC H E P 50 p ro b ; a d d e d X-GTR-TBV t o G T R d e p ress n o d e .

C reated n ew H P I -GTR tree fo r transient H P I . Conta i n s RC I C/C R D 51 -

combo a n d d e l etes H C P I m i n flow va lve .

10

LR-N 1 8-0032 LAR H 1 8-02 Table A- 1 S U M MARY O F HOPE CREEK 2 0 1 7 MODEL ( H C 1 1 7A) U R E C HAN GES Change URE C h a n g e o r U R E Descri ptio n S BO ET - add T DV-N L to O S P - L d own branch to create n ew S B O -

52 -

006 a n d S B0-007 U pdated tra ns a n d L conseq u e n t i a l LOO P to 6928 d ata with Ed's 53 -

com m ents 54 - U n-do #34 .

C reate X-S LOCA-ST g ate for S LO CA-ST d e p ress n o d e with S P C 55 -

with n e w H E P for P S P L d e p ressu rizati o n .

56 - Reca l c u l ated I S LOCA frequencies.

57 - SAC S HX TM a n d leakage terms for A loop were swa p ped .

Delete Gate GVSS54 0 , GVS P 1 60 , GVSS543 from u nd e r 58 H C 2 0 1 3-005 GVS P 1 5 0 a n d fro m u nd e r GVS S 5 3 0 .

59 H C 2 0 1 3-008 Delete G C N S-XH 1 -RS-CO N DS from u nd e r GVSS2 0 0 .

60 - Revise S LO CA-ST ET to s p l i t i nto l a rge and s m a l l 61 - Revise S LOCA-WA ET to cred i t OW S p rays and d e l ete RC I C .

62 - C hange the one C lass IE seq u e n ce to C lass l A p e r E d a n d La rry.

D elete SWS P re-I n itiators, rem ove DG-A B C D TM term from Flag 63 HC20 1 7-0 1 1 fi l e U pd ate I S LOCA fre q u e n cies based o n fi n a l a n alys i s ; rem ove 64 -

D G N -ABCD T M term from Flag fi l e .

C h a n g e G S LC 1 50 t o A N D g ate ; c h a n g e S LC-C KV-CC-F006A a n d 65 - B to S LC-SCV-CC-F006A a n d B ; C h a n g e Type Code to SCV-CC for both 66 H C 2 0 1 7-009 Delete CSS-XH P-R E-XV0 0 1 and CSS-XH P-R E-XV00 5 .

U pd ated the P re-I n itiato r H E P val u e s i n R R d atabase to be 67 -

cons istent with Calc u l ator Deleted AC P-XH P-RE-GTS from model fi les H C 1 1 7A-L 1 -SYS . caf 68 H C2 0 1 7-0 1 0 and H C 1 1 7A. caf.

Change g ates SP1 a n d S P 2 i n S P . caf L2 n o d a l FT based o n Ed's 69 H C2 0 1 1 -003 m a rk u ps.

U pd ate O S P R B E's i n L2 n o d a l FTs to be cons iste n t with L 1 70 -

cha nges in BE names.

H C 2 0 1 2-008 71 I ncorpo rate STI -004 m a n u a l EDG sta rt i n to H C 1 1 7A-SYS . caf H C2 0 1 2-009 72 H C 2 0 1 2-007 Changed AC P-LOG-N O-* type code to R LY-F O in H C 1 1 7A. rr Added GZGA360 u n d e r GA4 K 1 3 3 . Added L O O P - LOCA g ate u n d e r G B4 K 1 3 0 a n d G B 4 K 1 3 3 (same for C a n d D) to be s i m i l a r to 73 STI -004 A. C h a n ged C g ate names to b e cons iste nt with othe r th ree fo r GC4K1 30 a n d GC4K1 3 3 . Ad ded UV com m o n cause terms from STI-004 Rev 1 .

Add C C F terms and n ew B Es from STI -007, i n c l u d i n g RPT0 0 1 74 STI-007 (exc luded DC power depe n d e n cies to prevent c i rcu l a r l o g i c ) .

75 - U pd ate M UAs in H C 1 1 7 A. rr based on 6/2/ 1 7 75 - U pd ate I F frequencies i n H C 1 1 7A. rr based on 5/2/ 1 7 a n a lysis d ata 11

LR- N 1 8-0032 LAR H 1 8-02 Table A- 1 S U M MARY O F HOPE C R E E K 2 0 1 7 M O D E L ( H C 1 1 7A) U R E C HANGES Change URE C h a n g e o r U R E Descri pti o n Added VS LOCA I E ( % 1 E-VS LOCA) u n d e r G - I E- MS g ate ( n ow O R g ate) . Also c h a n g ed % I E-MS u n d e r g ate I E- L O O P -C N D-MAN S C R to G-I E- MS i nstead o f j ust MS i n iti ato r. VS LOCA be low TAF s h o u l d a lso fai l C R D consistent with PB m o d e l . Ad ded n ew g ate 76 - G-CRD-I N I T u nd e r C R D - E N H and p u t % 1 E-VS L O CA u nd e r n ew gate. S h o u l d a lso h ave s p l i t fraction such that o n l y VS LOCA b e l ow TAF s h o u l d fai l C R D , b u t don't h ave s p l it fractio n in m o d e l c u rrently. A d d 0 . 5 facto r ( N E E D T O A D D TO D O C U M E N TAT I O N )

. (XH OS-VS LOCA- B E LOW-TAF)

F o l l ow-u p to Item #60 . S p l it % 1 E-S2-ST-L a n d % 1 E-S2-ST-U i n to 77 -

5 0 % each .

Added n ew H E P AC P -XH 1 -E LAP-D E C L u nd e r n ew g ate G -

78 -

O PACT-F L EX-ACP with 0 . 1 based o n M O M a n d P B .

U pd ate F L EX model i n g for Batt Chg and F L EX C o m p ressor; 79 -

u pd ate proba b i l ities from H RAC .

80 H C2 0 1 1 -0 1 2 D e lete room cool i n g req u i rements from SWG R roo m s .

R eq u ant with o l d H C 1 1 1 A I F freq ue ncies ; p u t n ew I F freq u e ncies 81 -

i n to F LAG fi le but not u sed for this l i n e e ntry .

82 - I F c h a n g es for RACS room SW floods 83 - C redit for R H R A fo r flood sce narios u s i ng RS P .

84 - Q u a n t with n ew I F frequen cies for six RACS room floods o n ly.

U pd ate p ro b a b i l ity of M C R - P H E-DOO R to 0 . 0 1 based on e n g i n ee ri ng j u d g e ment a n d Bob Wolfg a n g's paper. U pd ated 85 - H RAC for R S P -XH 1 - FC-S H T D N to adj ust t i me to 78 m i n .

Reca l c u l ated t o 1 . 5 E-2 (from 1 . 6 E-2) based o n H RAC note b oo k e ntry 3 . 1 04 ; Q u antify with a l l n ew flood freq u e ncies.

86 - D e leted seq u e n ces S LSTL-0 1 1 and -0 1 8 .

87 - U pd ated TM te rm and TC proba b i l ities C h a n g ed a l l R R entries that were type 1 ( m issi on*rate) a n d 24 h rs 88 -

to type 3 a n d 24 h o u rs (same as P B2 1 4A mod el ) .

89 - Review A ppx G a n d update some va l u es .

Revise C S T swapove r leve l i n d ication fai l u re typ e cod e s ; add 5 0 0 kV ri ng b u s 6 2X b reaker a n d 62X 1 0 d iscon n ect B Es; s p l it RC I -

H C2 0 1 1 -0 0 8 X H 1 -FO-X F E R i n to H PC I a n d RCI C ve rs i o n s ; added % F LT B-CW 90 HC20 1 7-0 1 5 u nd e r g ate LOOP2 a n d I E- L O O P ; ren amed % F L- F P S

to H C2 0 1 7-0 1 6

% F L F PS* for consiste ncy ; p u t I F freq u e n cies d i rectly i n RR a n d d e l eted F LAG fi le fo r I F freq uencies.

Add F L EX g ate 1 E480VSWG R F L EX under BAT- C H G with AN D ;

d e l ete % 1 E-SWS from u nd e r transient con d ition a l L O O P g ate ( I E -

91 -

L O OP - CN D-T R) a n d keep o n l y u n d e r LOCA co n d iti o n a l L O O P g ate ( I E-LOO P-CN D-LOC) .

Redo S B O ET fo r E LAP; add TDV-E LAP AN D B 5 B- F L EX- I N J 92 -

F FTs 93 - U pd ate F L EX-I N J F FT a n d S B O ET U pd ate Appx G . 1 1 fo r Vacu u m B reaker p ro b a b i l ities a n d u pd ated 94 -

RR d atabase 95 - U pd ate H RA d ependency_to modern {method 4) 12

L R-N 1 8-0032 LAR H 1 8-02 Table A- 1 S U M MARY OF HOPE CREEK 2 0 1 7 M O D E L ( H C 1 1 7A) U R E CHANGES Change U RE C h a n g e or U RE Descripti o n Refi n e H RA d e p e n d e ncy; revised SWS-XH 1 actio n s t o be m o re s pecific, i ncorp o rated the fact that SACS HX o utlet valves a re 96 -

normally open a n d open u p o n SW p u m p start; same fo r SAC S i n let valves a n d SACS p u m ps.

97 - Remove ZQQQ Q Q ; use opti m ized seeds in F LAG fi le .

Add G F L EX- R PV- D D P u n d e r EXT-C N D- 8 5 8 , ZZ-VNT-EXT-A, a n d 98 -

ZZ-VNT - EXT -A-C P ; fix 407 f a n powe r dependency to C&D tra i n s 99 - Add c h i l l e r a n d fa n com bos to D isal l ow.

Delete g ate GZF D 1 42 fro m u nd e r GZFD 1 30 ; also delete G ZFD200 1 00 -

from u n d e r GZF D 1 3 3 .

Redo depen d e n cy with 1 E - 1 0 C D F tru ncation a n d 1 E-9 L E R F 1 01 -

tru n catio n for D E P a n a lys i s .

1 02 - Fix i ncorrect R C I -T D P - F R type code Deleted C N S 1 7 86 , V034 a n d V 1 1 7 valves from cond e nsate flow 1 03 -

path . Can sti l l i nject th ro u g h i d l e R F P a n d FWHs .

1 04 - U p d ate co n d iti o n a l LOO P fo r a l l t h ree 8 Es .

1 05 - Redo d e p e n d e n cy Add ed F L EX-P OW E R - F LAG u n d e r o n ly 3 g ates : G F L EX-R PV-1 06 - M O P , G F L EX-CO M P- 1 0 0 , 1 E4 8 0VSWG R F L EX. These a re a l l O R g ates .

C h a n g e flag fi l e t o u s e AC P -GTS - F R a s flag i nstead o f TM term ;

del ete F L EX-POW E R - F LAG a n d j u st add F L EX com po n e n ts to 1 07 - flag fi l e ; red o S 8 0 ET to h ave E LAP a n d n o n - E LAP seq u e n ces.

Redo X-S 80 node a n d E LAP - D E C L nodes; fix e rror i n D I SALLOW for 8 c h i l le r and C EDG (was D E D G )

F ix some H E Ps that d i d n't h ave J H E P fla g s , es pecia l ly a few i n L2 1 08 -

m o d e l . Redo d e pe n d e n cy.

1 09 - Fix con d e n sate p u m p bypass logic for PRI and SEC 1 10 - Adj ust L2 d e p e n d e n cies in H RAC 111 - Add G F L EX-RPV- D D P u n d e r ZZ-FAI L-I N - M U4-LP 1 12 - Recalcu late d e p e n d e n cies 113 - Use FTREX 1 . 8 Clean u p P C P a n d S C P l o g i c , s p l it o u t P CS and EXT I N J g ates 1 14 -

separate l y .

1 15 - C h a n g e E D G ru n t ime from 6 h rs . t o 8 h rs .

C h a n g e FW flow path A a n d 8 g ates t o R PV i n to " a l ready r u n n i n g "

g ate which has fai l to rem a i n open valves , a n d " need to restart" 1 16 -

which has fa i l to o p e n valves GVSS360 a n d GVSS380 turned i nto GVS S360 R U N/380 a n d GVSS360RST/3 8 0 .

Delete g ate G - N R-ECCS from u nd e r C R D - E N H . The E C C S H E Ps a re for actuation of ECCS systems g iven a utomatic actuati o n s h ave failed . C R D h as n o a u to m atic actuation a n d is n ot a n E C C S system . C R D has its o w n H E P ( C R D -XH 1 -FO-C R D E N ) . Also 1 17 - d e l ete G-N R-ECCS-S ET , G S ET-250V, GWTLVL-S ET, X-X H E-SET, GS ET-CST, GS ET-CV, G S ET-CD-S EQS, G R H R I N I T-S ET, GSACS-SSWS-SET, G C O N -X H E-S ET, GS ET-S LOCA, G S ET-LOO P-SLOCA, G S ET-I E S , GS ET-TRA N S , GHVAC-XH E-S ET, GS ET- L O O P (seis m ic g ates) .

13

LR-N 1 8-0032 LAR H 1 8-02 Table A- 1 S U M MARY O F HOPE C R E E K 2 0 1 7 MODEL ( H C 1 1 7A) U RE C HANG ES Change URE C h a n g e o r U R E Descri pti o n C h a n g e a l l LOCA ET nod e F FTs for EXT I N J to n ew EXT-****-

1 18 -

LOCA which req u i re hotwel l refi l l from CST if co nd e nsate is used .

Delete G I AS 1 00 fro m u nd e r G C I C S -IA-A a n d G C I CS-IA- 8 . 5029 119 - a n d 503 1 valves fai l closed on loss of a i r per P & I D . Redo L2 dependency and Flag/Recovery fi l es .

Seco n d cutset review: U pd ated I E- S B O node with mod ified E D G fai l u res t o remove inverter roo m coo l i ng a n d also use s i m p l ified SACS fai l u res; added 5 3 02 flood i n itiator to PC-SCP node; fixed 1 20 -

R C I C a uto i n itiation logic AN D/O R g ates ; c h a n g es % 1 E -SWS conditional LOO P to TR i n stead of LOCA; red o H RA d e p e n d e n cy a n d u pd ate severa l CD to M D fo r L 1 a n d L2 121 - Seco n d cutset review red o d e pe n d e n cy 1 22 - C h a n g e L O P ET C R D F FT from H P I t o H P I -C R D 1 23 - l n corQ_o rate changes from the c h a l l e n g e review 14

LR-N 1 8-0032 LAR H 1 8-02 A.2 RESOLUTI O N OF O P E N FACTS AN D OBSERVAT I O N S A.2. 1 O P E N F U L L-POWER I NTERNAL EVENTS PRA M O D E L FACTS AN D OBSERVATIONS N o F&Os are considered open for the FPIE Model of Record .

A.2.2 O P E N F I RE PRA M O D E L FACTS AND OBSERVATIONS The open F&Os from the Nove m be r 2 0 1 0 Fire PRA Peer Review ( Reference 1 3) were reviewed for possible im pacts to the resu lts of this risk evaluation - in particular, items rel ati ng to ris k s i g n ificant SSCs (including the inve rters and emergency d iesel generators) , the fault tree mode l ,

im portant accident sequences ( i . e . LOOP), external events , h u m a n reliability, model q uantificatio n , and sources of model u n certainty. The F&Os fal l i ng i nto these categories are docu mented in Table A-2 . Each has been add ressed i n the Fire PRA Model of Record (HC 1 1 4 FO) used i n this ris k evaluatio n .

15

LR-N 1 8-0032 LAR H 1 8-02 Table A-2 RESOLUTI ON O F RELEVANT FPRA P E E R REVI EW F&Os S u p porti n g F&O F&O Descri ption Resol u t i o n Req u i re m ent(s)

Software util ized i n q u antificatio n of the F i re P RA is F RAN C , XI N IT ,

a n d CAFTA (as part of the R & R Software s u ite ) . An overview of t h e use of these codes is p rovided i n H C-PSA-2 1 . 06 Sectio n 3 . 1 4 .

Th ese codes a re accepted as P RA i nd u stry sta n d a rd codes for q ua ntification of F i re P RA. In the 20 1 4 F P RA u p d ate , a d iscuss i o n H oweve r, n o d iscussion i s p rovided as t o the l i m itati o n s o r featu res reg a rd i n g F RANX a n d its l i m itatio n s a n d use QU-8 1 of the codes that cou ld i m pact res u lts. In fact, Append ix E s hows was added to th e d o c u m entatio n . The 1 -20 Q U-F5 that there a re d ifferences i n the use of F RA N C vs. XI NIT fo r co ncerns raised a p p l y to the older E P R I FQ-8 1 q u a n tificatio n , b u t n o d iscu ssion is p rovided as t o t h e reason for the codes F RAN C a n d XI N IT, which FRANX q ua ntification d iffe re n ce . S o m e d ifferen ces a re attri buted to M i n -C u t re place d . N o i m p ortant l i m itatio n s were U p per b o u n d a p p roxi m atio n . identified .

Exa m ples of i m pacts d u e to the codes chosen i n c l u d e :

I m pacts o f the M i n-Cut-U ppe r bou n d q u a n tification method a n d Rare Even t Approxi mati o n when u sed i n q u a ntify i n g h i g h pro b a b i l ity fa i l u res.

In the 20 1 4 F P RA u pd ate , CDF a n d L E R F H C-PSA-2 1 . 06 Section 5 . 3 were req u a ntified with a n ew tru n cati o n study to d e m o n strate convergence. T h i s A tru n cati o n sensitivity is performed t o va l i d ate the reaso n a b l e n ess w a s i n cl u ded i n the documentation . The of the chosen tru n catio n l i m it. The c h a n g e i n C D F from the chosen tru n cation l i m it affects the absolute va l u e of Q U-F2 tru n catio n level to the n ext h ig h e r tru n cati o n level i s less than 5 % .

t h e C D Fs a n d L E R Fs q u a ntified ; h owever, F o r L E R F t h i s i s less than 1 % c h a n g e .

1 -2 1 QU-83 the r i s k m etrics developed fo r this risk H owever, only two p o i n ts a re q ua n tified wh ich only p rovide one data eva l u ation d e p e n d o n the c h a n g e in these FQ-8 1 point for the c h a n g e i n CDF ( L E R F ) . No converg en ce of res u lts i s when the i nverters a re taken out-of-se rvice.

d e m o n strated , wh ich wou ld req u i re q u a n tificatio n of at least th ree Any add iti o n a l releva nt cutsets fa l l i n g below s uccessive tru n cati o n s to p rovid e m o re than o n e d elta CDF ( L E R F ) t h e tru n cation l i m it ( 1 E- 1 22 ) wo u ld be o n the a n d thus d e m o n strate a tre n d in d ecreasi n g c h a n g e i n CDF ( L E R F) . o rd e r o f 1 E-1 2 , s i x o rd e rs of m a g n itude smaller than the risk m etrics consid ered .

16

LR-N 1 8-0032 LAR H 1 8-02 Table A-2 RESOLUTI O N O F RELEVANT FPRA P E E R REVI EW F&Os S u p po rti n g F&O F&O Descri ptio n Resolution Req u i re me n t(s)

Sectio n 1 . 2 . 4 of the H o p e C reek F i re P ro b a b i l istic Risk Assessment S u m m a ry a n d Q u a ntification N otebook ( H C-PSA-2 1 . 06) d o c u ments I n the 20 1 4 F P RA u pd ate , a d iscussion of the res u lts of the se ismi c fi re i n te ractio n a n a lys is i n c l uded i n the seis m ic-fire i n te ra ctio n s con s i d e r i n g a l l 1 99 7 I P E E E . T h i s d iscussion a d d resses t h e res u lts a n d i nsig hts ava i l a b l e g u i d a n ce was a d d ed to the g a i ned fro m the I P E E E eva l u atio n . H owever it is n ot consid ered docu m e ntatio n to m eet the SR 3-8 S F-8 1 sufficient to fac il itate F i re P RA a p p l ications, u p g rades, and peer req u i re ments. T h i s does n ot affect revi ew s i n ce the I P E E E does not document a l l of the req u i red q u a ntificatio n o r risk i n s i g h t co n c l u s i o n s .

S e i s m i c/ F i re I nteractio n s req u i red by the S F req u i re m ents. S eis m ic-fi re i n teractio n s a re not Accord i n g ly this S R is co n s i d e red n ot met a n d a n F&O has been exacerbated with i n verter(s) o u t-of-service.

p repared .

Sectio n 4 . 8 . 1 . 3 of the I P E E E docu m ents an eval u ation of the seis m i c d eg radatio n of fi re s u p p ression syste m s . The eva l u ation In the 20 1 4 F P RA u p d ate , a d iscussion of perfo rmed was l i m ited to fi re s u p p ression system s locate d in safety se i s m i c-fi re i n teractio n s co n s i d e r i n g a l l related areas, th e fi re water p u m phouse , a n d wate r storag e ta n ks . ava i l a b l e g u i d a n ce was added t o t h e T h i s a n a lysis acknowledges t h a t the primary conce rn is fai l u re of t h e docu m e ntatio n t o m eet the S R 3-9 S F-A3 n o n -se i s m i c fi re wate r p u m p h o use a n d water storage ta n ks h owever req u i re m e nts . T h i s does n ot affect the assessm e n t does not exten d beyo n d d eve l o p m e n t of t h i s o n e q u a ntification o r r i s k i n s i g h t co n c l u s i o n s .

com m o n -ca use fa i l u re. D u e to the l i m ited n a t u re of this assessment Seismic-fi re i n te ractio n s a re n ot th i s S R is con s i d e red not met a n d a fi n d i n g is g e n e rated to expan d exacerbated with i n ve rter(s) o u t-of-service.

the eva l u ation performed .

17

LR-N 1 8-0032 LAR H 1 8-02 Table A-2 RESOLUTI O N O F RELEVANT FPRA P E E R REVI EW F&Os S u p p o rti n g F&O F&O Descri ption Reso l u t i o n Req u i re m e n t(s)

The S e i s m i c F i re I nteractio n s stu dy performed for the I P E E E d i d n ot look at the fol l owi n g :

1 ) R EVI EW of t h e p l a n t seismic response p roced u res a n d Q u a l itatively ASS E S S the potential t h a t a seismically i n d u ced fi re , o r I n t h e 20 1 4 F P RA u pd ate , a d i scussion of the s p u ri o u s operatio n of fi re s u pp ressi o n syste m s , m i g h t se i s m i c-fi re i n teractio n s co nsideri n g a l l com p rom ise post-earthq ua ke p l a n t response. ava i l a b l e g u i d a n ce was a d d ed to the S F-A4 5-1 2 2 ) R EVI EW of a) p l a n t fi re brigade tra i n i n g p roced u res a n d ASS ESS d ocu m e ntatio n wh ich a d d ressed the two S F -AS the exten t to wh ich tra i n i n g has prepared fi refig hti n g person nel to specified ite m s . S eis m ic-fi re i n teractions respond to potential fi re a l a rm s a n d fi res i n the wa ke of a n a re n o t exacerbated with i n verter(s) out-of-earthq uake a n d b) the storage a n d place me nt of fi refig hti n g s u p port service.

eq u i p m e n t a n d fi re brigade access routes , a n d c) AS S E S S the potential that a n ea rth q u a ke might com p ro m ise o n e o r m o re of these featu res.

Events added to the F i re P RA a re i n c l u d ed i n Ta b l e 1 - 1 of the model In the 2 0 1 4 F P RA u pdate, a d iscuss i o n of deve l o p m e n t calcu latio n . H owever, the basis for the expos u re t i m e basic eve nt p ro b a b i l ities and fa i l u re rates o r othe r parameters a re n ot p rovided. F or exa m p l e , m ost of the has been added to the docu m e ntatio n eve n ts a re M OV F a i l to R e m a i n Open/C losed . These eve nts use the i n cl u d i n g j u stification for fa i l u re rates of new g e n e ric fa i l u re rate a n d a 24 h o u r m ission t i m e . T h i s mission t i m e is DA-M basic events. Also the treatment of s p u rious typ ically a p p l ied to a co m po n e n t that is verified ava i la b le o r a l a rmed 5-1 7 P R M- 8 1 3 operation was u pdated to the N U R EG-7 1 50 prior to the event occu rri n g . H owever, there i s n o docu m entatio n of P R M-C 1 cu rre nt data . This risk eva l u ation d oes n ot the verification of the M OV position o r a l a r m . I t may i n fact be that m a n i p u late basic event freq u e n ci e s , oth e r the n o n-a la rmed M OVs m ay h ave s p u ri ousl y operated s i n ce the last t h a n i n o n e of t h e s ens itivity cases , a n d the test, o r s i n ce t h e last time the operator verified the positi o n .

concerns raised a re n ot affected by the Add itio n a l ly, event H P I -TD P-SS is set to 1 E-0 5 , witho u t refe re n ce or i nve rters .

basis p rovided .

18

LR-N 1 8-0032 LAR H 1 8-02 Table A-2 RESOLUTI O N OF RELEVANT FPRA P E E R REVI EW F&Os S u p po rti n g F&O F&O Descri ption Reso l u ti o n Req u i re m ent(s)

Two ha rdwa re re p a i r events we re carried over from the i ntern a l I n t h e 20 1 4 F P RA u pd ate, a m o re deta i led even ts P RA model : R H S - R E PAI R-L and R H S- R E PAI R-TR. These d iscussion of these rep a i r events a n d the i r eve n ts h ave p ro b a b i l ities based u po n mean times to repa i r for p ro b a b i lity ca lcu latio n s were added to the n o r m a l ra n d o m fa i l u res (fo r s u p p ression pool coo l i n g ) a n d d o not SY-A24 docu m e ntati o n . This was reviewed a lso 5-22 acco u n t for the potentially damaging effects of fi re eve nts . These P R M-89 d u ri n g the cutset reviews with p l a n t recovery eve n ts a p pear in 8 of the top 1 0 fi re C D F cutsets and a re operatio n s . These risk-s i g n ifica nt re p a i r a m o n g the most risk s i g n ifica nt basic events i n the fi re P RA resu lts.

actio n s a re n ecessary to include i n this risk I nc l u d i n g t h e s e eve n ts a n d the associated p ro b a b i l ities from the eva l u atio n .

i ntern a l events model was n ot j u stified .

For the 2 0 1 4 F P RA u pd ate, thermal M S O s were i n c l ud e d i n the F P RA model witho u t co nsideration for hyd ra u l i c calculations u s i n g MAAP were actual flow rates o r t i m i n g affecting C D F or co re u ncovery. performed to confirm s p u ri o u s o pe ration SY-87 For exa m p l e , M S O of the head ve nts was conservatively modeled , p l a n t response, such as s p u ri o u s M S I V 5-24 P R M-89 a n d may n ot l e a d t o a core damage event i n 24 h o u rs. M u ltiple S RV o pe n i n g , a n d s p u ri o u s s i n g le or m u ltiple open i n g s was conservatively modeled (e. g . , for 2 S RVs) as a Large S RV o p e n i n g s . The res u lts were LOCA, witho u t d iscussion on the expected flow rates . i n corporated i nto the F P RA a n d th i s risk eva l u atio n .

N o o p e rator I nte rviews o r tal k t hro u g h s were performed for t h e H E Ps ide ntified as a p p l ica b l e t o t h e F i re P RA.

H R-E3 I n the 20 1 4 F P RA u pd ate , operator N o o p e rator I nte rviews o r tal k t hro u g h s were performed for H R-E4 i n terviews were performed a n d added t o the i n terpretation of the p roced u res with p l a n t o p e ratio n s or tra i n i n g H R-G 5 docu me ntati o n . P l a n t operators were also 5-30 person n e l to confirm that i n terpretati o n i s consiste nt with plant H RA-A2 i n vo lved with cutset reviews . Th is add itio n a l operati o n a l a n d tra i n i ng p ractices.

H RA-A4 d ocu m e ntatio n has no q u a ntitative i m pact N o s i m u lator o bservatio n s o r ta l k-th rou g h s with o p e rators were o n t h i s risk eva luation .

H RA-C 1 performed to confirm the response models for sce n a rios modeled 19

LR-N 1 8-0032 LAR H 1 8-02 Table A-2 RESOLUTI O N O F R E L EVANT FPRA P E E R REVI EW F&Os S u p porti n g F&O F&O Descri ptio n Reso l ution Req u i re m ent(s)

In the 2 0 1 4 F P RA u p d ate, deta i l ed H E P calcu lati o n s , i n cl u d i n g u nce rta i n ty facto rs ,

h ave been deve loped with H RA Calcu lato r U n ce rta i nty factors fo r the J H E P values do not appear to have been fo r the 2 0 1 4 F P RA u pd ate . The val ues of H R-G8 5-40 i n c l uded in the F P RA. Ad d ition a l ly, the new H E P added to the model J H E Ps we re u pdate d , b u t u n ce rta i n ty H RA-C 1 (TWC-XH E-I S O L) d i d n ot h ave a n y u nce rta i n ty val ues added . facto rs were n ot ca lcu lated . Q u a l itative u n ce rta i n ty was assessed a n d docu mente d .

J H E P s a re n ot risk-s i g n ifica n t for t h e i nverte rs o r i n t h i s r i s k eva l u atio n .

LE-F2 Q U-D2 I n t h e 20 1 4 F P RA u pd ate , a consiste n cy Q U-F2 The Resu lts of the F P RA C D F a n d L E R F a re p resente d i n the review of i n s i g n ifica nt seq u e n ces a n d S u m m a ry a n d Q u a ntification N otebook, a l o n g with the i m portance QU-D5 cutsets was performed d u ri n g the c utset 5-5 1 meas u res. Top C u tsets a re also p resented . H oweve r, a consiste n cy U N C-A 1 reviews . T h i s additional docume ntatio n has revi ew a n d review of i n s i g n ifica nt seq u e n ces o r cutsets does n ot FQ-D 1 no q u a n titative i m pact on t h i s risk appear to h ave been perfo rmed .

eva l u atio n .

FQ-E 1 FQ-F1 QU-E1 Sectio n 3 . 1 7 a n d 3 . 1 8 o f t h e F P RA S u m m a ry a n d Qua ntificatio n LE-F3 Analysis p rovides a d iscussion of assu m ptions a n d sou rces o f I n the 20 1 4 F P RA u p d ate, a l l identified u n ce rta i n ty in th e F P RA. H owever, the s o u rces of u n ce rta i n ty is not LE-G4 s o u rces of u n ce rta i n ty were i n cl u ded i n the com plete , a n d not fu l l y d iscussed. See Appe n d ix V of N U R EG/C r-5-52 LE-G5 docu m e ntati o n . S o u rces of u n certa i n ty 6850 for a n exa m ple of potential so u rces of u n ce rta i n ty to be U N C-A 1 s pecific t o the i nverters a n d t h i s ris k con s i d e re d .

FQ-E 1 eva l u ation a r e d iscussed i n Sectio n 3 . 2 . 4 .

Add itio n a l ly , the l i m itati o n s of t h e L E R F a nalysis ( a s req u i red by L E -

F Q- F 1 G S ) a re n o t i d e ntified i n the F P RA resu lts.

20

LR-N 1 8-0032 LAR H 1 8-02 Table A-2 RESOLUTION OF RELEVANT FPRA PEER REVI EW F&Os S u pp o rti n g F&O F&O Descri ption Reso lution Req u i re m ent(s)

T h e F P RA d oc uments the resu lts of a sens itivity o n cred iti n g ( n ot d a m ag i n g ) the com po n e n ts whose ca ble locatio n s a re u n k n own (table 6 . 1 ) -- H owever, a sensitivity case wh e re com po n ents whose cable locatio n s a re u n known b u t a re ass u med to n ot be d a m aged in certai n com partment sce n a rios a re d amaged (fai l e d ) is not docu m en ted .

Refe re n ces:

In the 20 1 4 F P RA u pd ate , this sensitivity FS S-E4 A q u a l itative d iscussion of the u n ce rta i nty associated with the case was performed a n d d o c u m e nted . The 6-5 excl u s i o n of Y3 ca bles is p rovided i n A ppe n d ix D of H C-PSA-2 1 . 06 .

U N C-A2 i n ve rters' ca ble locatio n s a re k nown , so they Table 6-1 s h ows that if ca ble selection was perfo rmed for all cred ited a re u naffected i n this sensitivity case .

P RA eq u i p me nt the C D F wou ld decrease by a maxi m u m of a p p roximately 1 7% . C red iti n g the com po n ents whose ca ble locations a re u n kn own was fou n d to h ave a moderate i m pact o n C D F q ua n titatively. T h i s C D F red u cti o n , h owever, i s the m axi m u m red u ctio n ach ievable a n d i t wou l d be expected that t h e actua l red u ctio n wou l d be less t h a n th is va l u e s i n ce s o m e u n kn own location ca bles wo u l d be expected to be i m pacted by fi re events.

21

LR-N 1 8-0032 LAR H 1 8-02 Atta c h ment 3 Parametri c U n certai nty Meth odolog y

LR-N 1 8-0032 LAR H 1 8-02 The assessment documented in this section addresses q u antitative parametric uncertainty analysis (i . e . , Monte Carlo analysis of the core damage accident seq uence cutset basic events) .

The sources of uncertainty assessed include the following :

I n itiating event freq uencies

Com ponent fai l u re probabilities

Com ponent mai ntenance u n availabil ities

H u m a n error probabi l ities

Com mon-cause fai l u res

Recovery fail u re probabilities (e. g . , offsite power, main condenser, station air)

Phenomenological events (e.g . , enviro n m e ntal ly-i nduced eq u i pment fai l u re post conta i n ment fai l u re)

Consistent with the ASM E/ANS PRA Stand ard , parametric uncertainty is characterized using Monte Carlo s i m ulation . For the resu lts of this analysis , see Attach ment 1 Section 3 . 2.4. 1 .

The parametric uncertai nty propag ation for this risk eval uation is performed using the com mercially avai lable software U N C E RT Version 4.0 (part of the R&R Workstation) developed by the Electric Power and Research I nstitute ( E P R I ) . U N C E RT Version 4 . 0 is a 32-bit Windows based prog ram that uses CAFTA-generated cutset fi les and databases as inputs to q u antify the u n certai nty distri bution of a g roup of cutsets .

CAFTA core damage accident seq uence cutset i nformation (cutset fi les and database files) from the developed configurations (see Attach ment 1 Section 3 . 2 . 2 . 1 . 2) of the C D F and LERF m odels are i m ported into U NCERT. Probabil ity d i stri bution types and associated vari an ce parameters (e . g . , E rror Factors (E Fs) in the case of log norm a l d istributions) are assigned to each of the basic events. These distri b utions and E Fs are assigned in the CAFTA database. < 1 >

U N C E RT randomly re-sam ples from each of the i n put distri butions, based on the type code database , and uses the CAFTA cutset eq u ations to re-com pute the new CDF or LERF. The res ults are stored and the i nput distri butions are again re-sam pled many additional times. After all the re-sam ples are com pleted , the stored resu lts are processed to form a probabil ity d istri bution for the Hope Creek PRA C D F and LERF.

A M onte Carlo evaluation of PRA logic can be perforiT)ed using correlated or u n correlated probabil ity d istributions to represent the i n puts for the basic events . The probability density distri bution describing the uncertai nty in a com ponent fai l u re probability is characterized as a state-of-knowledge abo ut an assumed fixed va lue; the same state-of-knowledge (that is. , the same distri bution) may i n fact u nderlie many d isti nct basic events. For example, the knowledge of the fai l u re rate of one particular m otor operated valve (e . g . , a LPCI i njection valve) is typically based on experience with all MOVs . Therefore , the various basic events that i nvo lve the fai l u re of a n MOV are all i n fact estim ated from a single com m o n d istribution and are m apped to a the same data variable (type code) to ensure pro pe r state-of-knowledge correlati on in the M o nte Carlo process. A type code is assig ned to every u nique basic event. For more i nform atio n o n t h e u s e o f type codes, see t h e H ope Creek P RA FPI E Com ponent Data N otebook (Referen ce

56) .

<1>

Type c o d e i nfo rmatio n (sto red i n T C tab l e o f t h e H C 1 1 1 A. R R fi le) is cu rrently u s e d t o acco u n t for the state-of-knowled g e depende nce a m o n g corre lated i n p u t d istribut ions.

1

LR-N 1 8-0032 LAR H 1 8-02 The uncertai nty bounds for basic events are defined by the use of log normal distribution E rror Factors (E Fs) , wh ich are defi n ed as the sq uare root of the ratio of the 95 1h and 51h percentiles.

They are assigned as follows :

I n itiating Events :

When available, E Fs obtained from the i n itiating event freq uency Bayesian analysis res ults

When such i nformation is not available, the ge neral E F g u ideli nes below are used .

Random Component Fail u res:

When available, E Fs obtai ned from the com ponent fa i l u re data Bayesian analysis resu lts

When such i nform ation is not available, the general E F g u idelines below are used .

M a intenance U navailabilities :

The general E F g u ideli nes below are used .

CCF Terms:

The general E F g u ideli nes below are used .

H uman E rror Probabilities :

The followin g g u idelines are based on information i n Section 7 of N U R EG/CR- 1 278.

E rror Factor Pre- I n itiator H E Ps Estim ated H E P < 0 . 0 0 1 10 Estim ated H E P 0 . 0 0 1 t o 0 . 0 1 3 Estimated H E P > 0 . 0 1 5 Post- I n itiator H E Ps Esti mated H E P < 0 . 0 0 1 10 Esti m ated H E P > 0 . 0 0 1 5

For high probability H EPs (i . e . , >0. 1 ) , refer to general E F g u ideli nes below.

2

LR-N 1 8-0032 LAR H 1 8-02 General E F G u idelines:

The following E F assig nments a re used u n less other d istribution i nformation is available as described above :

Basic Event (BE) Value Error Factor BE 0.25 1 0 . 1 0 BE < 0 . 25 2 1 E-4 B E < 0. 1 0 3

< 1 E-4 10 3

LR-N 1 8-0032 LAR H 1 8-02 Attachment 4 Single L ine Drawing of Ty pical Inverter

LR-N 1 8-0032 LAR H 1 8-02 Single L ine Drawing of Ty pical Invert er BACK-UP NORMAL POWER SuPPL Y POWER SuPPLY 1-2/C *2 ITYP,)

480V, 1¢ !TYP.) 1-3/C *4

<TYPJ 480V, 3¢ tTYP,) 4-1/C<TCMIL

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£ LOW IMPEOANCE VOLTAGE REGULATOR STATIC SW LINE VOLTAGE/

REGULATOR TRANSFER SWITCHES CLASS lE INSTRUMENTAT ION AC POWER SUPPLY 1A0481 20KVA [B) .sLU.::fN 1

v t e Letter Sequence Request
EPID:L-2018-LLA-0101, License Amendment Request: Inverter Allowed Outage Time (AOT) Extension (Approved, Closed)
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