ML20249A531

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Rev 4 to PRA-REV-001, PRA Model Rev Procedure
ML20249A531
Person / Time
Site: San Onofre  Southern California Edison icon.png
Issue date: 01/07/1997
From: Chung G, Hook T
SOUTHERN CALIFORNIA EDISON CO.
To:
Shared Package
ML20249A528 List:
References
PRA-REV-001, PRA-REV-1, NUDOCS 9806170016
Download: ML20249A531 (35)
v • d • e


Text

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ATTACHMENT #2 1 i l

PRA MODEL REVISION PROCEDURE 9806170016 980612 'E PDR ADOCK 05000361 P PDR

PRA-REV-001 Revision 4,12/17/96,.

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PRA MODEL REVISION 4

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Prepared By: S 8% //7/p7

[^# / 6m' Reviewed By: [M l /7 /97 NSG SW D.de l of l9 .

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Attachment #2

!' PRA-REV-001 l Revision 4,12/17/96

! TABLE OF CONTENTS 1'

SECTION 'PAGE

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1.0 - P U R P O S E .. ...... ............... .. .... .... ..... ....... . ... .. .... .. ........ . .. .... .. . .. .2 '

2.0 APPL I C AB I L IT Y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 2 3.0 ' REFE RENC ES . . . .. . .. . . . .. . . . . . . . . . . . . .. . .. . .. . . . . . . . . . . . . . . . . . . . . . . . . . ...............2 I

4.0 . -

RESPONSIBILITIES .... .... ... . . . ... . .... . . . . . . . . . . . . . . . . . . . . . . . ................4 I

5.0 . PROCE D URE . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..... .. . . 5 1.

l. . 6.0 RECORDS...............................................................................8 i

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l Attachment #2 PRA-REV-001 Revision 4,12/17/96 1.0 PURPOSE-1.1 This procedure establishes the administrative controls and provides the guidelines for performing updates to maintain current the PRA models and their documentation for San Onofre Nuclear Generating Station Units 2 and 3.

1.2 This procedure applies to all personnel who perform or support the updates of the documents and models mentioned in section 2 of this procedure.

1.3 This procedure implements QA Procedure N3.06 Revision 1; Plant PRA Model Revision.

1.4 The procedure is in accordance with the following sections of the Topical Quality Assurance Manual:

1-C Quality Planning (Instructions and Procedures) 1-D Document Management 1-J Electronic Data Processing Controls 5-A Procedures and Instmetions 2.0 APPLICABILITY 2.1 This procedure is applicable to the update / revision of all the SONGS 2/3 Living PRA models. The SONGS 2/3 Living PRA models includes all documentation, models, and software pertaining to the internal and external initiating events analysis for full power and other operating modes.

3.0 REFERENCES

3.1 Individual Plant Examination Report for San Onofre Nuclear Generating Station Units 2 and 3 in Response to Generic Letter 88-20; Submittal Document, April 1993, and the Computer Model.

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Attachment #2

' PRA-REV-001 Revision 4,12/17/96 3.0 ' REFERENCES (Continued) 3.2 Individual Plant Examination of External Events for San Onofre Nuclear Generating Station Units'2 and 3 in Response to Generic Letter 88-20,

l. Supplement 4; Submittal Document, December 1995, and the Computer Model.

3.3 San Onofre Topical Quality Assurance Manual 3.4 / PSA Applications Guide, EPRI TR-105396, August 1995.

3,5 PRA Procedure PRA-IPE-010, PRA Living Database Update, Maintenance and Application.

3,6 Individual Plant Examination Procedure PRA-IPE-003, System Fault Tree Development and Analysis.

3.7 Individual Plant Examination Procedure PRA-IPE-004, Initiating Event Data Collection and Analysis.

3.8 Individual Plant Examination Procedure PRA-IPE-005, Accident Sequence Analysis.

3,9 Individual Plant Examination Procedure PRA-IPE-006, Data Collection and Analysis.

-3.10 Individual Plant Examination Procedure PRA-IPE-006A, Supplemental Guidance on Dependent Failures.

3.11 Individual Plant Examination Procedure PRA-IPE-007, Human Reliability

- Analysis.

3.12 Individual Plant Examination Procedure PRA-IPE-008, Internal Flood Analysis.

-3.13 Individual Plant Examination Procedure PRA-IPE-009, Plant Model Quantification.

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3 Attachment #2 PRA-REV-001 :

Revision 4,12/17/96 '

3.0 REFERENCES

_', (Continued) 3.14 Individual Plant Examination Procedure PRA-IPE-009A, Sensitivity Analysis.

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3.15 QA Procedure N5.06, General Document Review Procedure 3.16 S0123-XXIV-5.1, Engineering, Construction and Fuel Services Sofiware Quality

- Assurance -

~4 0 RESPONSIBILITIES

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.~4' 1 - - The' Supervisor, Nuclear Safety. Group (NSG) is responsible for implementing and ~

updating as necessary, this procedure. The NSG Supervisor or his designee is

responsible for assigning responsibility of reviews and appropriate actions in this '

procedure to PRA Engineers and must review and approve any changes to the PRA recommended by the PRA Engineers.

- 4.2 Nuclear Safety Group staff trained in PRA technology (hereaRer referred to as PRA Engineers) are responsible for gathering the information on plant changes and document revisions, performing the screening and review of plant changes as they relate to the Living PRA models, databases, and associated documents, and for providing the recommendations regarding the necessity to incorporating the changes.

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Attachment #2 PRA-REV-001 Revision 4,12/17/96 4.0 RESPONSIBILITIES (Continued)

Additionally, the PRA Engineers are also responsible for performing the necessary analysis and calculations for the purpose ofincorporating the changes, in )

accordance with the procedures controlling the existing documents, software and j computer models.

5.0 PROCEDURE The PRA documents may be updated for various reasons. These reasons include plant modifications, crror corrections, procedural changes, plant data update, improved methods, etc. The update frequency for changes other than data will be as near real time  ;

as practical. Initiating events and component reliability / availability data will be updated at periods no longer than once every two refueling cycles.

The following provides guidelines for the steps taken to ensure that updates are performed per the quality assurance requirements:

5.1.a Monitorine and Collectine Plant Chance In#qrmation. Table 1 provides a list of documents that shall be reviewed by PRA Eagineers as they are issued by CDM, for their potential impact on the PRA. The haclear Safety Group should be on the distribution list for all of these documents (either hardcopy or electronic). The Supervisor, Nuclear Safety Group or his designee is responsible for designating a PRA Engineer to review each document. New documents issued by CDM should i be reviewed on a near real time basis as they are obtained to determine potential impact and priority for incorporation. An Information Evaluation Form  ;

(Attachment 1) shall be completed for each document reviewed.

The collection ofinformation to support the update ofinitiating event and component reliability / availability data will utilize References 3.7 and 3.9 and be documented in accordance with those procedures.

5.1.b Other Causes of PRA Model Revision. In addition to plant change information, other sources could cause a PRA model revision including: PRA review comment,

! plant specific data update, change in NRC requirements, change in NSG procedures. In these cases, an Information Evaluation Form is unnecessary since it l

' has already been determined that a revision to the PRA is required. l 6 of 19

Attachment #2 PRA-REV-001 Revision 4,12/17/96 5.0 PROCEDURE (Continued) 5.2 Screen New Information. Table 1 provides guidance on which key elements of the PRA may be impacted by the changes defined in the documents gathered in step 5.1. Table 2 defines the key elements of a PRA. The review in this step only -

determines whether the information has the potential to impact the PRA.

If the change is believed to have an impact on the ranking of the top 200 components in the latest risk increase or risk achievement worth list for plant components, then the change shall be identified as high priority and implemented before other pending lower priority changes. If there is no potential impact on the  ;

PRA, the completed Information Evaluation Form (Attachment 1) shall be  ;

reviewed by the Supervisor, Nuclear Safety Group or his designee and then the form given to the Secretary, Nuclear Safety Group for filing.

The plant change information reviewed in this step can be discarded if the change does not affect the PRA.

The review ofinformation to support the update ofinitiating event and component reliability / availability data shall utilize References 3.7 and 3.9.

I 5.3 Uodate Reauired Evaluation. If the reviewed plant change documents have a potential to impact the PRA, then the information must be evaluated further. The evaluation and the proposed change is given an unique number by the Secretary, Nuclear Safety Group. The numbering scheme for the PRA Change Packages  !

should be PRACP-YY-XXXX where XXXX is a consecutive number from 1 to  !

9999 in each year YY.bThis number is recorded on the Information Evaluation Form as well as in the PRA Change Package form (Attachment 2) by the .

Secretary, Nuclear Safety Group. I 1

The information may have an impact on one key element of the PRA and the change in this element may result in cascading impacts on other key elements of l the PRA. Table 2 provides a guide of how changes in each element may impact other elements of the PRA. Only the primary impact of each element on other elements has been indicated, not the cascading impacts.

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Attachment #2 PRA-REV-001 L Revision 4,12/17/96 l

5.0 PROCEDURE (Continued)

! A PRA Engineer, designated by Supervisor, Nuclear Safety Group or his designee l shall review the subject plant documentation and prepare a complete PRA Change l Package that includes details of all the changes required to each key element of the l PRA (computer model and documentation). The package must contain all the calculations and identify all the changes to be implemented. Table 3 provides a recommended format for the PRA Change Package. The calculations for each key PRA element will be based on their respective procedures (Ref. 35 through 3.14).

Attachment 3 provides the list of the key PRA elements and their governing procedures.

The proposed changes may be implemented only after the review of the entire PRA Change Package by the Supervisor, Nuclear Safety Group or his designee. The PRA Change Package must include the PRA computer model and the appropriate marked up data in the Living PRA Database. The review of the Change Package

._ must be conducted, and comments and resolutions recorded in accordance with the  !

QA requirements of Reference 3.15. j j

The Supervisor, Nuclear Safety Group shall determine if a PRA Peer Review Panel and/or Expert Review Panel review of the subject PRA Change Package is required prior to approval for implementation. l 5.4 Perform Update. Only after approval of the PRA Change Package by the Supervisor, Nuclear Safety Group may the proposed change be implemented. The Supervisor, Nuclear Safety Group or his designee shall designate a PRA Engineer l to implement the change in the PRA models and documentation. The updating must be performed on a model and documentation that is copied from the current controlled model, leaving the current controlled model and documentation intact.

I The PRA software to be used for analysis of the updated model must be installed on a PC, verified, validated and the installation report completed in accordance with the QA requirements of Reference 3.16.

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Attachment #2 PRA-REV-001 I Revision 4,12/17/96 5.0 PROCEDURE (Continued)

5.5 Review 1moact on PRA. After the PRA Engineer has implemented the changes to . 3 the relevant models and documents, the implementation of the changes and the j results must be reviewed by the Supenisor, Nuclear Safety Group or his designee.

The review of the results will be based upon Appendix B of Reference 3.4 and any subsequent NRC guidance issued regarding PRA content and quality. The review comments shall be documented in accordance with the QA requirements of-Reference 3.15. .

l 5.6 Install Updated Model and File PRA Change Package. Only upon approval of the update by the Supervisor, Nuclear Safety Group, will the existing controlled model be replaced by the new updated model. Once installed for use as the current

. controlled model, the new updated model and documentation shall be backed up in l accordance with Records requirements in Section 6.0. The completed PRA Change Package shall be given to the Secretary, Nuclear Safety Group for filing.

6.0 RECORDS 6.1 A copy of the entire Liv'mg PRA model documentation shall be maintained in electronic format accessable to the Nuclear Safety Group. The Supervisor, Nuclear Safety Group shall designate a person to maintain the documentation.

, 6.2 All Information Evaluation forms and PRA Change Packages shall be maintained in the Nuclear Safety Group work area and a copy provided to CDM. The information evaluated in the Information Evaluations (e.g., DCPs, EOls, etc.) need not be retained since it is always available from CDM. The Secretary, Nuclear Safety Group shall be responsible for maintaining the documentation in this step.

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ll Attachment #2 PRA-REV-001 l Revision 4,12/17/96 EO . RECORDS ' (Continued) 6.3 An electronic copy of the current Living PRA Models, databases, and PRA analysis software shall be maintained on a network drive or other suitable means to be available to Nuclear Safety Group PRA Engineers. A backup copy of the current Living PRA Models and databases shall be retained on suitable electronic storage media (e.g., tapes). The electronic storage media shall be clearly labeled with the revision numbers and dates. All prior versions of the Living PRA Models and databases shall be retained on suitable storage media in the Nuclear Safety i

Group work area for the remaining life of the plants. The Supervisor, Nuclear Safety Group or his designee shall be responsible for implementing this step.

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' Attachment #2 PRA-REV-001 Revision 4,12/17/96 Figure 1. MAINTENANCE OF THE PRA MODELS Monitor and Collect l Plant Change Information l

Screen New Information l

Update Required?

If no, Stop here.

I Perform Update l

Assess Impact on PRA I

Evaluate Results l

Install Updated Model l

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Attachment #2 PRA-REV-001 Revision 4,12/17/96

- TABLE 1. SOURCES AND DOCUMENTS TO BE REVIEWED Key PRA Type Description 3 d (See Table 2) l l

AOI- Abnormal Operating Instruction 4,5,8 DCP Design Change Package 2,3,4,5,7,8, 9,10 DCN Design Change Notice 2,3,4,5,7,8, j 9,10 l

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EOI Emergency Operating Instruction 4, 5, 8 FCN Field Change Notice 2,3,4,5,7,8, 9,10 FIDCN Field Interim Design Change Notice 2,3,4,5,7,8, 9,10 IDCN Interim Design Change Notice 2,3,4,5,7,8, 9,10 OP Operating Procedure 4,5,8 PCN Procedure Change Notice 4,5,8 LER Licensee Event Report 2, 4 l

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Attachment #2 PRA-REV-001 Revision 4,12/17/96 TABLE 2. KEY ELEMENTS OF A LIVING PRA

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1 Other Primary PRA j

"'I Elements Impacted if Description of Key Element Element No. . Key Element Modified l 1

1 Basic Event Database (in software) -- i 2 Initiating Events 1 3 Dependency Matrices 2,4,5 l

4 Event Tree and Plant Models 5 5 System Success Criteria / System Analysis 1, 2, 4 6 Component Failure and Unavailability Data Analysis 2, 5 7 Thermo-Hydraulic Analysis 4,5,8 8 Human Actions Analysis 1, 2, 4, 5 9 Seismic Analysis 1 10 Fire Analysis 1 11 Other External Events 1 12 Containment Model 1 i I

13 Release Model 1 l

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Attachment #2 PRA-REV-001 Revision 4,12/17/96 TABLE 3. FORMAT FOR PRA CHANGE PACKAGE TITLE SHEET I TABLE OF CONTENTS l

' l.0 INTRODUCTION

..2,0 MODEL CHANGES FOR REVISION 20 RESULTS 4.0 VERIFICATION VALIDATION Appendix A Databases forModel

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Appendix B ' Detailed calculations, models, from Section 2.0 14 of 19

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Attachment #2 PRA-REV-001 Revision 4,12/17/96

- TAllLE 4. DOCUMENTS USED IN TIIE PRA MODELS FOR INITIATING EVENTS

' AND COMPONENT DATA INITIATING EVENTS 1, Monthly Reports

2. LERs
3. Systems Analyses Documents for Loss of Suppon Systems Initiated Events i
4. Seismic Analysis Repons from Section 3.10 in Reference 3.2, )
5. Fire Analysis Report from Section 4.9 in Reference 3.2.
6. OH' site liazards Reports l

PLANT COMPONENT DATA ANALYSIS

1. Work Orders / Action Reports
2. Maintenance Requests / Maintenance Orders / Tag-out Orders l 1
3. Trouble Reports / Discrepancy Reports
4. Component Operating Experience I
5. Component IIistories 6, Monthly Repons 15 of 19 i

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i' Attachment #2 PRA-REV-001 Revision 4,12/17/96 TABLE 4. DOCUMENTS USED IN THE PRA MODELS FOR INITIATING EVENTS ~

AND COMPONEN.T DATA (continued) l - 7. - LERs -

8.- Plant Power History

9. ' Control Room Logs
10. System Operating Procedures l

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Attachment #2 PRA-REV-001

'- Revision 4,12/17/96 I

l-ATTACilMENT 1 INFORMATION EVALUATION FORM Information Identification No; Impact on PRA:

IfNo 0:

Provide form to Secretary, Nuclear Safety Group for filing.

If Yes 0:

Assigned PRA Change Package No.

(PRACP-YY-XXXX)

Potentially affects ranking of top 200 components on latest plant component risk increase listing?

Yes O No O If Yes, this is a high priority change and should be implemented prior to pending non-high priority changes.

Reviewed by: Date:

Approved by: Date:

Supervisor, Nuclear Safety Group 17 of 19

Attachment #2 PRA-REV-001 Revision 4,12/17/96 ATTACIIMENT 2 PRA CIIANGE PACKAGE

Title:

Punch List item #:

(inapplicable)

Change No. PRACP-(PRACP-YY-XXXX) where XXXX is consecutive from 1 to 9999 Reason for change:

Proposed change:

Prepared by: Date:

PRA Engineer i

1 NSG Supervisor Review. j

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PRA Review Panel Required: No O Yes O j l

Expert Review Panel Required: No O Yes O  ;

i Proposed Change reviewed by: Date:

Supervisor, Nuclear Safety Group or designee 4

Change Implemented by: Date:

PRA Engineer PRA Living Database Updated: Date:

PRA Engineer Implementation. .Teviewed by: Date:

Supervisor, Nuclear Safety Group or designee (Ensure Punch List Database resolution date entered if applicable.)

Approved by: Date: ,

Supersisor, Nuclear Safety Group 18 of 19 I

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Attachment #2 PRA-REV-001 Revision 4,12/17/96 ATTACHMENT 3 RELEVANT PROCEDURES FOR EVALUATION OF KEY PRA NLEMENTS .

pg Applicable PRA esenPt:,on Procedures from Element No.

Section 2 1- Database for plant model References 3.5 through 3.14 2 Initiating Events Reference 3.7 -

3 Dependency Matrices References 3.5, 3.6, 3.8 4 Event Tree and Plant Models Reference 3.8 5 System Success Criteria / System Analysis References 3.5, 3.6 6 Basic Events Database and Data Analysis Reference 3.9, j 310  :

7- Thermo-Hydraulic Analysis  !

8 Human Actions Analysis Reference 3.11 i 9 Seismic Analysis --

10 Fire Analysis --

i l1 Other External Events --

i 12 Containment Model --

13 - Release Model --

14 Plant Model Quantification Reference 3.13 15 Sensitivity Analysis Reference 3.14 19 of 19

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A TTACHMENT#3 LOSS OF OFFSITE POWER & STATION BLACKOUT EVENT TREES l

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A TTACHMENT#4 LOSS OF OFFSITE POWER AND l STATION BLACKOUT EVENTS TOP 50 CUTSETS 1

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Attachment #4 Top 50 LOP /SBO Cutsets Safety Monitor 5.27a Configuration

Title:

LOP & SB0 INITIATING EVENT CUTSETS (CROSS-T!E MOD CREDITED)

CutSet Number 1 CutSet frequency = 6.10E-07 INIT LOP - 1.07E 01 INITIATING EVENT - LOSS OF OFFSITE POWER L HCNSBOMANU 6.50E 02 DP FT MAN CTL AFW FLOW VALVES W/! 2.5 TO 8.0 HOURS M-HCBCBFAILU 5.00E-01 OPER FT RESPOND TO BATT CHRG B2 FAILURE GIVEN PREV RESP FAIL M HCHITEMP-U 1.00E+00 NO OPER RESPONSE TO ECCS HI TEMP ALARM GIVEN PREV RESP FAIL M HCNOSIAS-U 1.50E 03 NO OPRT RESPONSE TO HIGH TEMPERATURE ALARM ESF SWGR/DIST U HCOSPWR60U 1.17E-01 NDNRECOVERY OF OFFSITE POWER IN 60 MINUTES Cutset Numbers 2 Cutset Frequency a 4.04E-07 INIT LOP- 1.07E-01 INITIATING EVENT LOSS OF OFFS!1E POWER L HCTP140- U 4.30E-02 DPER FT MANUALLY OPERATE TD AFW FJMP (NO DC PWR S 8H)

M HCBCSFAILU 5.00E 01 OPER FT RESPOND TO BATT !NRG B2 FAILURE GIVFN PREV RESP FAIL M HCHITEMP U 1.00E+00 NO OPER RESPONSE TO ECCS H! TEMP ALARM GIVEN PREV RESP FAIL M HCNOSIAS U 1.50E 03 NO DPRT RESPONSE TO HIGH TEMPERATURE ALARM-ESF SWGR/DIST

.U HCOSPWR60U 1.17E 01 NONRECOVERY OF OFFSITE POWER IN 60 MINUTES

^ Cutset Numbers 3 Cutset Frequency = 3.15E 07 INIT LOP 1.07E 01 INITIATING EVENT - LOSS OF OFFSITE POWER

'L HCNROSP8HU 1.00E+00 ADJ FACTOR FOR OSP RECOVERY WITH T121 FAILURES DURING LOP L HCCSTMU- U 3.00E 05 OPERATOR FAILS TO PROVIDE T121 (CST) MAKEUP PER PROCEDURE ,

U HCOSPWRH1U- 9.80E 02 NONRECOVERY OF OFFSITE POWER AT T=8 HOURS j Cutset Number 4 ~ CutSet Frequency

  • 1.07E 07 INIT LOP 1.0TE 01 INITIATING EVENT - LOSS OF OFFSITE POWER L-HCTP140--U 4.30E 02 OPER FT MANUALLY OPERATE TD AFW PUMP (NO DC PWR G 8H)

L-MP504--1DR ' 9.57E-03 MTR-DRIVEN PP 504 FT RUN FOR 24 HR - TRAIN 8 U CZA0418- P 3.00E 03 BCR (CNTL) 4160V A0418 FT OPEN ON DEMAND U-00PCLOOP-Z 8.12E-01 LOOP EVENT PLANT- CENTERED LOOP NO NON 1E PWR AVAILABLE CutSet Numbe 5 Cutset Frequency = 9.67E-08 INIT-LOP 1.07E 01 INITIATING EVENT - LOSS OF OFFSITE POWER L TP140- 1DR 1.03E-02 TURBINE DRIVEN PP 140 FT RUN FOR 24 H

- L*TP140NR1DR 1.00E+00 . TURBINE DRIVEN PP 140 FT TO RUN IS NOT RECOVERABLE

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M-HCBCBFAILU 5.00E 01 OPER FT RESPOND TO BATT CHRG B2 FAILURE GIVEN PREV RESP Fall M-HCHITEMP-U 1.00E+00 NO DPER RESPONSE TO ECCS HI TEMP ALARM GIVEN PREV RESP FA!L M HCNOSIAS-U 1.50E-03 NO OPRT RESPONSE TO HIGH TEMPERATURE ALARM-ESF SWGR/DIST U-HCOSPWR60U 1.17E 01 NONRECOVERY OF OFFSITE POWER IN 60 MINUTES .

I cutset Numbers 6 Cutset Frequency = 7.66E 08 )

INIT LOP 1.07E 01 INITIATING EVENT LOSS OF OFFSITE POWER U-C2A0418--P 3.00E-03 BKR (CNTL) 4160V A0418 FT OPEN ON DEMAND U-C2A0618- P 3.00E-03 BKR (CNTL) 4160V A0618 FT OPEN ON DEMAND U HCOSPWRH1U 9.80E 02 NONRECOVERY OF OFFSITE POWER AT T=8 HOURS U-00PCLDOP 2 8.12E-01 LOOP EVENT PLANT- CENTERED LOOP NO NON-1E PWR AVAILABLE ,

1 Cutset Number: 7 Cutset Frequency = 6.54E 08 INIT-LOP 1.0TE 01 INITIATING EVENT - LOSS OF OFFSITE POWER L TP140- M 6.97E-03 TURBINE-DRIVEN PP 140 DOS FOR MAINTENANCE i' l , M-HCBCBFAILU' 5.00E-01 OPER FT RESPOND TO BATT CHRG B2 FAILURE GIVEN PREV RESP FAIL

l. M HCHITEMP-U 1.00E+00 NO OPER RESPONSE TO ECCS HI TEMP ALARM GIVEN PREV RESP FAIL M-HCNOSIAS-U 1.50E-03 NO OPRT RESPONSF TO HIGH TEMPERATURE ALARM ESF SWGR/DIST U HCOSPWR600 1.17E-01 NONREC0VERY OF OFFSITE POWER IN 60 MINUTES Cutset Number: 8 Cutset Frequency 6 5.38E-08

_ INIT-LOP 1.07E 01 INITIATING EVENT LOSS OF OFFSITE POWER

< L HCHV4716PU '1.00E+00 DPERATOR FAILS TO MANUALLY OPEN NV4716 LOCALLY AFTER FAULT l L MV4716-- P 5.73E-03 MTR-OPERATED VLV 4716 FT DPEN ON DEMAND M-HCBCBFAILU' 5.00E-01 OPER FT RESPOND TO BATT CHRG B2 FAILURE GIVEN PREV RESP FAIL M HCHITEMP U L1.00E+00 NO OPER RESPONSE TO ECCS H! TEMP ALARM GIVEN PREV RESP FAIL M HCNOSIAS-U 1.50E-03 NO OPRT RESPONSE TO HIGH TEMPERATURE ALARM-ESF SWGR/DIST l U-HCOSPWR600 1.17E 01 NONRECOVERY OF OFFSITE POWER IN 60 MINUTES k ..

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Attachment #4 Top 50 LOP /SBO Cutsets CutSet Nunber '9 Cutset Frequency = 4.00E-08 INIT-LOP 1.07E-01 INITIATING EVENT - LOSS OF OFFSITE POWER

- L-TP140NR"S 4.26E 03 P140 FAILS TO START AND 15 NOT RECOVERABLE M HCBCBFAILU 5.00E-01 OPER FT RESPOND TO BATT CHRG B2 FAILURE GIVEN PREV RESP FAIL M NCHITEMP U 1.00E+00. NO OPER RESPONSE TO ECCS HI TEMP ALARM GIVEN PREV RESP FAIL' M HCNOSIAS D 1.50E 03 NO OPkT RESPONSE TO HIGH TEMPERATURE ALARM ESF SWGR/DIST-U HCOSPWR60U J1.17E-01 'NONRECOVERY OF OFFS!TE POWER IN 60 MINUTES Cutset Number 10 CutSet Frequency = 3.75E-08 INIT* LOP 1.07E 01 INITIATING EVENT - LOSS OF OFFSITE POWER

-L-HCTP140" U 4.30E 02 OPER FT MANUALLY OPERATE TD AFW PUMP (NO DC PWR S 8H)

-L*MP504 ~-M 3.35E-03 MTR-DR!vEN PP 504 005 FOR MAINTENANCE - TRAIN B U C2A0418" P 3.00E-03 'BKR (CNTL) 4160V A0418 FT OPEN ON DEMAND U-00PCLOOP 22 8.12E 01 LOOP EVENT PLANT CENTERED LOOP NO NON 1E PWR AVA!LABLE Cut $et Numbers li- CutSet Frequency = 3.36E 08 INIT-LOP 1.07E 01 INITIATING EVENT Loss OF OFFSITE POWER

.L-C2A0603"N' 3.00E 03 BKR (CNTL) 4160V 2A0603/3A0612 FT CLOSE ON DEMAND L-HCTP140"U 4.30E 02 OPER FT MANUALLY OPERATE TD AFW PUMP (No DC PWR S 8H)

U-C2A0418"P 3.00E 03 BKR (CNTL) 4160V A0418 FT OPEN ON DEMAND U+00PCLOOP 2 8.12E-01.. LOOP EVENT PLANT CENTERED LOOP - No NON 1E PWR AVAILABLE

-Cut $et Number: 12 Cutset Frequency = 2.70E 08

-IN!T LOP 1.07E 01 INITIATING EVENT + LOSS OF OFFSITE POWER L HCHV4716PU. 1.00E+00 OPERATOR FAILS 70 MANUALLY OPEN HV4716 LOCALLY ALTER FAULT L-MV4716 " M '2.88E 03 MTR OPTD VLV 4716 00$ FOR MA!NTENANCE M-HCBCBFAILU 5.00E 01 OPER FT RESPOND TO BATT CHRG B2 FAILURE GIVEN P6EV RESP FAIL M-HCHITEMP-U.1.00E+00 NO OPER RESPONSE TO ECCS HI TEMP ALARM GIVEN PREV RESP FAIL l M HCNOSIAS-U 1.50E 03 NO OPRT RESPONSE TO HIGH TEMPERATURE ALARM-ESF SWGR/DIST U-HCOSPWR600 1.17E-01 NONRECOVERY OF OFFSITE POWER lN 60 MINUTES CutSet Number 13 < CutSet frequency = 2.57E-08 INIT LOP 1.07E 01 INITIATING EVENT - LOSS OF OFFSITE POWER L MP504"1DR 9.57E-03 MTR DRIVEN PP 504 FT RUN FOR 24 HR - TRAIN B L-TP140~1DR 1.03E-02 TURBINE DRIVEN PP 140 FT RUN FOR 24 H L TP140NR1DR -1.00E+00 TURBINE DRIVEN PP 140 FT TO RUN IS NOT RECOVERABLE U C2A0418-*P 3.00E-03 BKR (CNTL) 4160V A0418 FT OPEN ON DEMAND U-00PCLOOP 2. 8.12E 01 LOOP EVENT PLANT

  • CENTERED LOOP - No NON-1E PWR AVAILABLE CutSet Number 14 ' Cutset frequency = 2.54E-08 INIT-LOP 1.07E 01 -INITIATING EVENT - LOSS OF OFFSITE POWER

'H-HASMPLT " X 7.90E 04 EMERGENCY SUMP LATCH LEFT OPEN-

' Y 00RV DEM 2 1.00E 01 POST TRIP PRESSURIZER SAFETY VALVES DEMANDED T RV0200~ N. 3.00E 03L RELIEF VLV SPRlWG LOAD 0200 FT CLOSE ON DEM  ;

' CutSet Nun 6ers.15 Cutset Frequency = 2.54E 08

! NIT-LOP 1.07E 01 INITIATING EVENT LOSS OF 0FFSITE POWER H HASMPLT"X 7.90E 04 EMERGENCT SUMP LATCH LEFT OPEN iT 00RV DEM-2 1.00E 01' POST-TRIP PRESSURIZER SAFETY VALVES DEMANDED Y-RV0201-"N 3.00E*03 RELIEF VLV SPRING LOAD 0201 FT CLOSE ON DEM CutSet Number 16 Cutset Frequency = 2.02E-08 INIT-LOP 1.07E 01 INITIATING EVENT LOSS OF OFFSITE POWER L HCTP140 "U 4.30E-02 OPER FT MANUALLY OPERATE TD AFW PUMP (N0 DC PWR S BH)

L-MP504 " " S- 1.80E-03 MTR-DRIVEN PP 504 FT START ON DEMAND - TRAIN B U C2A0418 " P' 3.00E 03. BKR (CNTL) 4160V A0418 FT OPEN ON DEMAND ~

U 00PCLOOP-2. 8.12E 01 LOOP EVENT PLANT- CCNTERED LOOP - NO NON 1E PWR AVAILABLE CutSet Nunbers 17 Cutset Frequency a 1.88E 08 i

.lN!T LOP ' 1.07E*01 INITIATING EVENT LCSS OF OFFSITE POWER

- L*SV4700 bJ 2.00E 03 ~ SOLENOID VALVE 4700 FT ACT/DE-ACT ON DEMAND l M HCBCBFAILU 5.00E 01 OPER FT RESPONO TO BATT CHRG B2 FAILURE GIVEN PREV RESP FAIL 1

-M-HCHITEMP-U 1.00E+00 No JPER RESPONSE TO ECCS HI TEMP ALARM GIVEN PREV RESP FAIL I M HCNOSIAS U.1.50E 03 NO OPRT RESPONSE TO HIGH TEMPERATURE ALARM-ESF SWGR/DIST j

) U HCOSPWR60U- 1.17E 01' NONRECOVERY OF OFFSITE POWER IN 60 MINUTES ;l l

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Attachment #4 Top 50 LOP /SBO Cutsets cutSet Number 18 Cutset Frequency = 1.81E 08 INIT-LOP 1.07E 01 INITIATING EVENT - LOSS OF OFFSITE POWER L*HCNSBOMANU 6.50E 02 OP FT MAN CTL AFW FLOW VALVES W/I 2.5 TO 8.0 HOURS M CHCC0001 $ 4.44E 04 COMMON CAUSE FAILURE -CH S-->E-335,E 336 M HCGASFANSZ 5.00E 02 OPERATOR FAILS TO ESTABLISH ALTERNATE COOLING IN ESF ROOMS U-HCOSPWR60U 1.17E-01 NONRECOVERY OF OFFSITE POWER IN 60 MINUTES CutSet Numbers 19 CutSet Frequency = 1.80E 08 INIT LOP 1.07E-01 INITIATING EVENT - LOSS OF OFFSITE POWER L-MP141 1DR 6.72E-03 MTR DRIVEN PP 141 FT RUN FOR 24 HR - TRAIN A L TP140 1DR 1.03E-02 TURBINE DRIVEN PP 140 FT RUN FOR 24 H L TP140NR1DR 1.00E+00 TURBINE DRIVEN PP 140 FT TO RUN IS NOT RECOVERABLE U C2A0618 P 3.00E 03 BKR (CNTL) 4160V A0618 FT OPEN ON DEMAND U-00PCLOOP-Z 8.12E-01 LOOP EVENT PLANT CENTERED LOOP - NO NON 1E PWR AVAILABLE CutSet Ntsnber: 20 Cutset Frequency = 1.74E-08 INIT LOP 1.07E 01 INIT!ATING EVENT LOSS OF OFFSITE POWER L-MP504--1DR 9.57E-03 MTR DRIVEN PP 504 FT RUN FOR 24 HR - TRAIN B L TP140 M 6.97E 03 TURBINE-DRIVEN PP 140 00$ FOR MAINTENANCE U-C2A0418--P 3.00E-03 BKR (CNTL) 4160V A0418 FT OPEN ON DEMAND

'U 00PCLOOP-Z 8.12E 01 LOOP EVENT PLANT CENTERED LOOP - No NON 1E PWR AVAILABLE CutSet Nunber 21 Cutset Frequency = 1.63E-08 INIT LOP 1.07E 01 INITIATING EVENT - LOSS OF OFFSITE POWER L TK120-- -D 1.30E-06 CONDENSATE STORAGE TANK T120 UNAVAILABLE U HCOSPWR60U 1.17E 01 NONRECOVERY OF OFFSITE POWER IN 60 MINUTES Cutset Number: 22 Cutset Frequency = 1.63E 08 INIT-LOP 1.07E-01 INITIATING EVENT - LOSS OF OfFSITE POWER L-TK121 -D 1.30E-06 CONDENSATE STORAGE TANK UNAVAILABLE U HCOSPWR60U 1.17E 01 NONRECOVERY OF OFFSITE POWER IN 60 MINUTES Cutset NLsnber: 23 Cutset Frequency = 1.48E-08 INIT-LOP 1.07E-01 INITIATING EVENT - LOSS OF OFFSITE POWER L-HCNSBOMANU 6.50E-02 OP FT MAN CTL AFW FLOW VALVES W/I 2.5 TO 8.0 HOURS M-CHE 335 M 1.75E-02 CHILLER E-335 00S FOR MAINTENANCE LOOP B ESF HVAC M HCGASFANSZ 5.00E 02 OPERATOR FAILS TO ESTABLISH ALTERNATE COOLING IN ESF ROOMS U C2A0418--P 3.00E 03 BKR (CNTL) 4160V A0418 FT OPEN ON DEMAND U 00PCLOOP-Z 8.12E 01 LOOP EVENT PLANT- CENTERED LOOP NO NON-1E PWR AVAILABLE Cutset Ntsnber: 24 CutSet Frequency = 1.48E-08 INIT-LOP 1.07E 01 INITIATING EVENT - LOSS OF OFFSITE POWER L-HCNSBOMANU 6.50E-02 OP FT MAN CTL AFW FLOW VALVES W/! 2.5 TO 8.0 HOURS M-CHE-336- M 1.75E 02 CHILLER E-336 OOS FOR MAINTENANCE LOOP A ESF HVAC M HCGASFANSZ 5.00E 02 OPERATOR FAILS TO ESTABLISH ALTERNATE COOLING IN ESF ROOMS U C2A0618 -P 3.00E 03 BKR (CNTL) 4160V A0618 FT OPEN ON DEMAND U 00PCLOOP Z 8.12E 01 LOOP EVENT PLANT CENTERED LOOP - NO NON 1E PWR AVAILABLE

- CutSet Number: 25 Cutset Frequency = 1.43E-08 INIT LOP 1.07E 01 INITIATING EVENT - LOSS OF OFFSITE POWER L HCHV4716PU 1.00E+00 OPERATOR FAILS TO MANUALLY OPEN HV4716 LOCALLY AFTER FAULT L MP504 1DR 9.57E-03 MTR DRIVEN PP 504 FT RUN FOR 24 HR

  • TRAIN B L MV4716-- P 5.73E-03 MTR-OPERATED VLV 4716 FT OPEN ON DEMAND l U C2A0418 -P 3.00E-03 BKR (CNTL) 4160V A0418 FT OPEN ON DEMAND U-00PCLOOP 2 8.12E 01 LOOP EVENT PLANT
  • CENTERED LOOP - NO NON*1E PWR AVAILABLE Cutset NLsnber 26 Cutset Frequency = 1.43E-08 INIT-LOP 1.07E-01 INITIATING EVENT LOSS OF OFFSITE POWER M CHCC0001 S 4.44E-04 COMMON CAUSE FAILURE -CH-S-->E-335,E-336 Y-00RV DEM Z 1.00E 01 POST TRIP PRESSURIZER SAFETY VALVES DEMANDED Y RV0201 --N 3.00E 03 RELIEF VLV SPRING LOAD 0201 FT CLOSE ON DEM Page 3 of 6 l

l l

4 Attachment #4 Top 50 LOP /SBO Cutsets Cutset Nu ser 27 CutSet Frequency = 1.43E 08 INIT LOP 1.07E-01 IN!?!ATING EVENT - LOS$ OF OFFSITE POWER M CHCC0001-5 '4.44E 04 COMMON CAUSE FAILURE -CH 5- >E 335,E-336 Y 00RV-DEM Z 1.00E-01 POST TRIP PRESSUR:ZER SAFETY VALVES DEMANDED Y-RV0200"*N 3.00E-03 RELIEF VLV SPRING LOAD 0200 FT CLOSE ON DEM Cutset Nunber: 28 Cutset Frequency = 1.39E 08

! INIT LOP 1.07E 01 INITIATING EVENT LOSS OF OFFSITE POWER

l. H MPCC0001-$ 4.33E 04 COMMON CAUSE FAILURE -MP-S " > 017, 018, AND 019 Y 00RV DEM Z 11.00E 01 POST TRIP PRESSURIZER SAFETY VALVES DEMANDED Y RV0200"*N 3.00E-03 RELIEF VLV SPRING LOAD 0200 FT CLOSE ON DEM CutSet Number: .29 CutSet Frequency = 1.39E 08 -

INIT LOP 1.07E-01 INITIATING EVENT - LOSS OF OFFSITE POWER H MPCC0001 S 4.33E 04 COMMON CAUSE FAILURE -MP-S ~ > 017, 018, AND 019 Y 00RV DEM-Z 1.00E-01 POST-TRIP PRESSURIZER SAFETY VALVES DEMANDED Y-RV0201" M 3.00E-03 RELIEF VLV SPRING LOAD 0201 FT CLOSE ON DEM Cutset Number:- 30 CutSet Frequency = 1.38E-08 INIT-LOP 1.07E-01 INITIATING EVENT - LOSS OF OFFSITE POWER L-MPCC0001 $ 1.07E-04 COMMON CAUSE FAILURE -MP-S ~ > 141 AND 504 (AFW MDPS)

L TP140" 1DR 1.03E 02 TURBINE DRIVEN PP 140 FT RUN FOR 24 H L TP140NR1DR 1.00E+00 TURBINE DRIVEN PP 140 FT TO RUN IS NOT RECOVERABLE U HCOSPWR60U 1.17E-01-NONRECOVERY OF OFFSITE POWER IN 60 MINUTES Cut $st Numbers 31 Cutset Frequency = 1.29E-08 INIT LOP 1.07E 01 INITIATING EVENT - LOSS OF OFFSITE POWER U HCOSPWR60U 1.17E-01 NONRECOVERY OF OFFSITE POWER IN 60 MINUTES

' U 00GWLOOP Z 1.88E-01 LOOP EVENT GRID RELATED LOOP - NO OFFSITE PWR AVAILABL U DGCC0001 S 1.12E-04 COMMON CAUSE FAILURE -DC-S-->2G2,2G3,3G2,3G3 U HCEDGRECV 5.00E-01 NON* RECOVERY OF COMMON CAUSE EDG FAILURE WITHIN 8 HOURS U HCOSPWRH1U 9.80E 02 NONRECOVERY OF OFFSITE POWER AT T=8 HOURS Cutset Numbers 32 Cutset Frequency = 1.22E 08

. IN!T-LOP .1.07E-01 INITIATING EVENT - LOSS OF OFFSITE POWER L-MP141"1DR 6.72E 03 MTR-DRIVEN PP 141 FT RUN FOR 24 HR TRAIN A L TP140- "M 6.97E-03 TURBINE DRIVEN PP 140 OOS FOR MAINTENANCE U-C2A0618 P ~3.00E-03 BKR (CNTL) 4160V A0618 FT OPEN ON DEMAND U-00PCLOOP 2' 8.12E 01 LOOP EVENT PLANT CENTERED LOOP NO NON 1E PWR AVAILABLE CutSet Number 33 'Cutset Frequency = 1.20E 08 INIT LOP 1.07E 01. INITIATING EVENT - LOSS OF OFFSITE POWER L HCTP140 -U 4.30E 02 OPER FT MANUALLY OPERATE TD AFW PUMP (No DC PWR S BH)

M CHCC0001 S '4.44E 04 COMMON CAUSE FAILURE -CH-S a>E-335,E-336 M HCGASFANSZ 5.00E 02 OPERATOR FAILS TO ESTABLISH ALTERNATE COOLING IN ESF ROOMS U HCOSPWR60U 1.17E 01 NONRECOVERY OF OFFSITE POWER IN 60 MINUTES Cutset Nueer: 34 Cutset Frequency = 1.12E-08 INIT LOP '1.07E 01 INITIATING EVENT LOSS OF OFFSITE POWER L CV547" " N 1.00E 03 CHECK VLV 547 FT CLOSE ON DEMAND L HCTP140 -U 4.30E-02 OPER FT MANUALLY OPERATE TD AFW PUMP (No DC PWR S BH)

U C2A0418- P 3.00E-03 BKR (CNTL) 4160V A0418 FT OPEN ON DEMAND U-00PCLOOP Z .8.12E 01 LOOP EVENT PLANT- CENTERED LOOP - NO NON-1E PWR AVAILABLE Cutset Nunbers 35 Cutset Frequency = 1.10E-08 INIT LOP 1.07E-01 INITIATING EVENT LOSS OF OFFSITE POWER K HCEFAS a-U 1.00E+00 OP FT MANUALLY ACTUATE EFAS PER PROCDURE K-00EFAS 2BZ 9.80E 04 EFAS 2B INDEPENDENT $1GNAL FAILURE

. L-HCTP140"U 4.30E-02 OPER FT MANUALLY OPERATE TD AFW PUMP (NO DC PWR S BH) 4 U-C2A0418--P 3.00E-03 BKR (CNTL) 4160V A0418 FT OPEN ON DEMAND U-00PCLOOP-Z 8.12E 01 LOOP EVENT PLANT- CENTERED LOOP - NO NON 1E PWR AVAILABLE Page 4 of 6

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./itinChnient #4 l . Top 50 LOP /SBO Cutsets i.

( ' Cutset Numbers . 36 Cut $st Frequency = 1.07E 08 l INIT LDP 1.07E-01 INITIATING EVENT LOSS OF OFFSITE POWER M-HCBCBFA!LU 5.00E-01 OPER 77 RESPOND TO BATT CHRG B2 FAILURE GIVEN PREV RESP FAIL M HCHITEMP-U 1.00E+00 NO OPER RESPONSE TO ECCS HI TEMP ALARM GIVEN PREV RESP FAIL M HCNOSIAS-U- 1.50E-03 NO OPRT RESPONSE TO HIGH TEMPERATURE ALARM-ESF SWGR/DIST T-AVCC0001-N 1.14E-03 COMMON CAUSE FAILURE -AV N **> 8419 AND 8421 l T HCSOADV U .1.00E+00 OPERATOR FAILS 70 ISOLATE STUCK OPEN ADV U HCOSPWR60U 1.1TE-01 NONRECOVERY OF OFFSITE POWER IN 60 MINUTES Cutset Ntabers 37 CutSet Frequency = 1.06E-08 l INIT LOP 1.07E-01 IN!T!ATING EVENT LOSS OF OFFSITE POWER L-MP504 1DR 9.57E 03 MTR DRIVEN PP 504 FT RUN FOR 24 HR - TRAIN B L-TP140NR S 4.26E 03 P140 FAILS TO START AND IS NOT RECOVERABLE U C2A0418 -P 3.00E-03 BKR (CNTL) 4160V A0418 FT DPEN ON DEMAND U-00PCLOOP Z 8.12E 01 LOOP EVENT PLANT CENTERED LOOP - NO NON 1E PWR AVAILABLE

-.Cutset Number: 38 Cutset Frequency a 1.00E-08 INIT-LOP 1.07E-01 INIT!ATING EVENT - LOSS OF OFFSITE POWER L-HCHV4716PU 1.00E+00 OPERATOR FAILS TO MANUALLY OPEN HV4716 LOCALLY AFTER FAULT L MP141* 1DR 6.72E 03 MTR-DRIVEN PP 141 FT RUN FOR 24 HR - TRAIN A L*MV4716---P 5.73h*03 MTR-OPERATED VLV 4716 FT OPEN ON DEMAND U C2A0618 -P 3.00E-03 BKR (CNTL) 4160V A0618 FT OPEN ON DEMAND U 00PCLOOP Z' 8.12C 01 LOOP EVENT PLANT CENTERED LOOP - NO NON-1E PWR AVAILABLE CutSet Nunbers 39 Cutset Frequency = 9.81E-09 INIT LOP 1.07E 01 INITIATING EVENT LOSS OF OFFSITE POWER L-HCTP140- U 4.30E-02 OPER FT MANUALLY OPERATE TD AFW PUMP (No DC PWR a 8H)

M-CHE 335--M 1.75E 02 CHILLER E 335 005 FOR MAINTENANCE - LOOP B ESF HVAC M*HCGASFANSZ 5.00E 02 OPERATOR FAILS TO ESTABLISH ALTERNATE COOLING IN ESF ROOMS U C2A0418 -P 3.00E 03 BKR (CNTL) 4160V AD418 FT OPEN ON DEMAND U-00PCLOOP Z 8.12E-01 LOOP EVENT PLANT CENTERED LOOP - NO NON 1E PWR AVAILABLE I

Cutset Numbers 40 Cutset Frequency = 9.81E-09 '

INIT LOP 1.07E-01 INITIATING EVENT - LOSS OF OFFSITE POWER L HCTP140 U 4.30E-02 OPER FT MANUALLY OPERATE TD AFW PUMP (NO DC PWR S OH)

M-CHE 336 -M 1.75E 02 CHILLER E-336 003 FOR MAINTENANCE - LOOP A ESF HVAC M HCGASFANSZ 5.00E-02 OPERATOR FAILS TO ESTABLISH ALTERNATE COOLING IN ESF RDOMS U C2A0618--P 3.00E 03 BKR (CNTL) 4160V AD618 FT OPEN ON DEMAND U 00PCLOOP Z 8.12E-01 LOOP EVENT PLANT CENTERED LOOP - NO NON 1E PWR AVAILABLE CutSet Number 41 CutSet Frequency = 9.34E 09 IN!T LOP 1.07E 01 INITIATING EVENT - LOSS OF OFFSITE POWER

~L-MPCC0001 S 1.07E 04 COMMON CAUSE FAILURE MP-S --> 141 AND 504 (AFW MDPS) ,

L-TP140 - M 6.97E 03 TURBINE-DRIVEN PP 140 00S FOR MAINTENANCE

' U*HCOSPWR60U 1.17E 01 NONRECOVERY OF OFFSITE POWER IN 60 MINUTES CutSet Number: 42 . Cutset Frequency a 9.23E-09

!N!T LOP 1.07E 01 INITIATING EVENT - LOSS OF OFFSITE POWER L-HV4762 -M 4.87E 02 CONTROL VALVE 4762 00S DUE TO MAINTENANCE

'L-HV4763- M 4.87E 02 CONTROL VALVE 4763 CLOSED DUE TO MAINTENANCE L-MVCC0012 P 3.11E-04 COMMON CAUSE FAILURE -MV P -> 4705, 4706, 4712 AND 4713 U HCOSPWR60U '1.17E-01 NONRECOVERY OF OFFSITE POWER IN 60 MINUTES Cutset Number: 43 Cutset Frequency = 8.99E INIT-LOP 1.07E-01 INITIAT!NG EVENT - LOSS OF OFFSITE POWER L MP504 M 3.35E 03 MTR-DRIVEN PP 504 00S FOR MAINTENANCE - TRAIN B

L TP140--1DR '1.03E 02 .. TURBlNE DRIVEN PP 140 FT RUN FOR 24 H

~ L-TP140NR1DR 1.00E*00 TURBINE DRIVEN PP 140 FT TO RUN !$ NOT RECOVERABLE U 02Au418 P 3.00E 03' BKR (CNTL) 4160V AD418 FT DPEN ON DEMAND-

.U 00PCLOOP Z 8.12E 01 LOOP EVENT PLANT- CENTERED t00P - NO NON-1E PWR AVAILABLE Page 5 of 6

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/(ttachulent #4 Top 50 LOP /SBO Cutsets CutSet Nwbers 44 Cutset Frequency = 8.99E-09 INIT LOP 1.07E 01 INITIATING EVENT - LOSS OF OFFSITE POWER L-MP141 --M 3.35E-03 MTR-DRIVEN PP 141 005 FOR MAINTENANCE TRAIN A L TP140- 1DR 1.03E-02 TURBINE DRIVEN PP 140 FT RUN FOR 24 H L-TP140NR1DR 1.00E+00 TURBINE DRIVEN PP 140 FT TO RUN IS NOT RECOVERABLE U C2A0618 -P 3.00E 03 BKR (CNTL) 4160V A0618 FT OPEN ON DEMAND U 00PCLOOP Z 6.12E 01 LOOP EVENT PLANT CENTERED LOOP - NO NON 1E PWR AVAILABLE CutSet Numbers 45 Cutset Frequency = 8.29E 09 INIT LOP 1.07E-01 INITIATING EVENT LOS$ OF OFFSITE POWER L-MP141 1DR 6.72E-03 MTR-DRIVEN PP 141 FT RUN FOR 24 HR - TRAIN A L-MP504 1DR 9.57E 03 MTR-DRIVEN PP 504 FT RUN FOR 24 HR TRAIN 8 L-TP140 1DR 1.03E 02 TURBINE DRIVEN PP 140 FT RUN FOR 24 H L TP140NR1DR 1.00E+00 TURBINE DRIVEN PP 140 FT TO RUN IS NOT RECOVERABLE U HCOSPWR600 1.17E-01 NONRECOVERY OF OFFSITE POWER IN 60 MINUTES CutSet Numbers 46 CutSet Frequency = 7.68E-09 INIT LOP 1.07E-01 INITIATING EVENT LOSS OF OFFSITE POWER

'L HCHV4716PU 1.00E+00 OPERATOR FAILS TO MANUALLY OPEN HV4716 LOCALLY AFTER FAULT L MPCC0001 S 1.07E 04 COMMON CAUSE FAILURE MP S > 141 AND 504 (AFW MDPS)

L-MV4716-- P 5.73E 03 MTR-OPERATED VLV 4716 FT OPEN ON DEMAND U-HCOSPWR60U 1.17E 01 NONRECOVERY OF OFFSITE POWER IN 60 MINUTES Cutset Number: 47 Cut $et Frequency = 7.21E 09 INIT LOP 1.0TE 01 INITIATING EVENT LOSS OF OFFSITE POWER L HCOVRSP U 9.00E 02 OP FAILS TO RESET OVRSPD TRIP L-TP140RR S 8.53E 03 TD AFW PUMP TRIPS ON OVRSPD AND IS RECOVERABLE M HCBCBFAILU 5.00E-01 OPER FT RESPOND TO BATT CHRG B2 FAILURE GIVEN PREV RESP FAIL M HCHITEMP-U 1.00E+00 NO OPER RESPONSE TO ECCS HI TEMP ALARM GIVEN PREV RESP FAIL M HCNOSIAS-U 1.50E 03 NO OPRT RESPONSE TO HIGH TEMPERATURE ALARM ESF SWCR/DIST U HCOSPWR60U 1.17E 01 NONRECOVERY OF OFFSITE POWER IN 60 MINUTES Cutset Numbers 48 CutSet Frequency = 6.76E 09 INIT-LOP 1.07E 01 INITIATING EVENT LOSS OF OFFSITE POWER L FLP140-1DC 7.20E-04 FILTER P140 PLUGGED / FOULED W/I 24 H M HCBCBFAILU 5.00E-01 OPER FT RESPONO TO BATT CHRG B2 FAILURE GIVEN PREV RESP Fall M HCHITEMP U 1.00E+00 NO OPER RESPONSE TO ECCS HI TEMP ALARM GIVEN PREV RESP FAIL M HCNOSIAS-U 1.50E-03 NO OPRT RESPONSE TO HIGH TEMPERATURE ALARM-ESF SWGR/DIST U-HCOSPWR60U 1.17E 01 NONRECOVERY OF OFFSITE POWER IN 60 MINUTES CutSet Numbers 49 CutSet Frequency = 6.65E 09 INIT LOP 1.07E 01 INITIATING EVENT LOSS OF OFFSITE POWER L-MVCC0011 P 7.08E-04 COMMON CAUSE FAILURE -MV P - > 4715 AND 4730 M HCBCBFAILU 5.00E 01 DPER FT RESPOND TO BATT CHRG B2 FAILURE GIVEN PREV RESP FAIL H+HCHITEMP-U 1.00E+00 NO OPER RESPONSE TO ECCS HI TEMP ALARM GIVEN PREV RESP Fall M HCNOSIAS U 1.50E 03 NO OPRT RESPONSE TO HIGH TEMPERATURE ALARM-ESF SWGR/DIST U HCOSPWR600 1.17E-01 NONRECOVERY OF OFFSITE POWER IN 60 MINUTES CutSet Number: 50 CutSet Frequency = 5.71E-09 INIT-LOP 1.07E-01 INITIATING EVENT - LOSS OF OFFSITE POWER L MPCC0001 S 1.07E-04 COMMON CAUSE FAILURE MP-S - > 141 AND 504 (AFW MDPS)

L TP140NR- S 4.26E 03 P140 FAILS TO START AND IS NOT RECOVERABLE U HCOSPWR60U 1.17E 01 NONRECOVERY OF OFFSITE POWER IN 60 MINUTES RESULTS:

Unit 2 core damage risk = 2.7BE 06/yr Unit 2 offsite large, early release risk = 5.19E-08/yr Page 6 of 6

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A TTACHMENT#5 SAN ONOFRE LIVING PRA MODEL UPDATES i

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e Attachment #5 San Onofre Units 2/3 UPDATES TO TIIE SAN ONOFRE IPE PRA MODEL The San Onofre Individual Plant Examination (IPE) was submitted to the NRC in May 1993. Since that time, San Onofre has maintained a living PRA model current with plant design and operation.

Also, use of the living PRA model in the Safety Monitor has resulted in a hundreds of modifications to improve the capability of the model to assess the risk ofspecific plant configurations. Most of the changes indicated below were included in the model used for the San Onofre Individual Plant Examination for External Events submitted to the NRC in December 1995. Listed below are the major changes made to the living PRA mode since the IPE submittal to the NRC.

1. Updated plant specific failure data.
2. Updated plant specific test and maintenance data.
3. Revised the reactor coolant pump (RCP) seal LOCA model to incorporate more conservative RCP seal failure assumptions based on updated CE guidance on the potential for seal failure given a loss of component cooling water. The revisions considered the potential for seal failure to be approximately 1.5E-3 in the event ofloss of component cooling water and 1.0 in the event of a loss of component cooling water coupled with a failure to trip the RCPs ,

within 30 minutes l

4. Added more detail to loss of normal ESF switchgear and distribution room HVAC scenarios. )
5. Added a model for control room HVAC.
6. Added a more detailed model of plant protection systems. ,
7. Improved modeling ofintake and heat exchanger heat treatment configurations. )
8. Revised LOCA initiating event frequencies to be consistent with CE Owners Group standards.  !'
9. Incorporated common cause failure events directly into the fault trees to ensure truncation ofindependent failure does not occur.
10. Added detailed fault tree modeling for support system initiators.

I 1. Added dominant sequences from seismic, fire, and flooding PRAs.

12. Revised interfacing system LOCA modeling to account for plant specific features (e.g., l pressure indicators and alarm on piping between RCS boundary isolation valves).  ;
13. Added Level 2 PRA sequences having contributions above 0.5% to the Safety Monitor.
14. Revised post-initiator operator recovery actions based on more detailed analyses. I
15. Added all high safety significant SSCs to the Safety Monitor.
16. Incorporated switchyard maintenance impact in model.
17. Revised secondary heat removal model to credit feedwater makeup and steaming of a faulted and well as an unfaulted steam generator consistent with design features and the emergency operator instructions.

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s' ATTACHMENT #6 INTERNAL EVENTS QUANTITATIVE LEVEL 2 RISK RESULTS

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e Attachment #6 Internal Events Level 2 Risk Results Table 1-1 CORRECTIVE MAINTENANCE DISSEL GENERATOR AOT CONDITIONAL INTERNAL EVEICS RISK CONTRIBUTION PARAMETER Core Damage Large Early Frequency Release Frequency EDG Success Criteria 1 of 4*

Present ACT, days 3 Proposed AOT, days 14 A1. Conditional Risk, per year 5.85E-05 7.13E-07 (1 EDG unavailable)

A2. Conditional Risk, per year 2.67E-05 4.73E-07 (1 EDG never out for T/M)

A3. Increase in Risk, per year 3.18E-05 2.40E-07 A4. Single AOT Risk, Current 2.61E-07 1.97E-09 A5. Single AOT Risk, Proposed 1.22E-06 9.21E-09 14 day A6. Downtime Frequency, per year 0.63 per diesel A7. Yearly AOT Risk, Current, 1.65E-07 1.24E-09 per yr/ diesel j I

A8. Yearly AOT Risk, Proposed, 7.68E-07 5.80E-09 I l

per yr/ diesel A9. Actual Duration, hrs / event 23.8 A10. Single AOT Risk (based on 8.64E-08 6.52E-10 ]

actual data)

All. Yearly AOT Risk /yr/ diesel 5.44E-08 4.11E-10 (based on actual data)

Utilizing EDG cross-tie under 10CFR50.54X for non-LOCA events. j

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-o Attachment #6 Internal Events Level 2 Risk Results Table 1-2 PREVENTIVE MAINTENANCE DIESEL GENERATOR AOT CONDITIONAL INTERNAL EVENTS RISK CONTRIBUTION PARAMETER Core Damage Large Early Frequency Release Frequency EDG Success Criteria 1 of 4 2 Present AOT, days 3 Proposed AOT, days 14 Bl. Conditional Risk, per year 2.83E-05 4.95E-07 (1 EDG unavailable)

B2. Conditional Risk, per year 2.67E-05 4.73E-07 (1 EDG Never out for T/M)

B3. Increase in Risk, per year 1.60E-06 2.20E-08 B4. Single AOT Rick, Current 1.32E-08 1.81E-10 B5. Single AOT Risk, Proposed 6.14E-08 8.44E-10 14 day i l

B6. Downtime Frequency, per year 1.0 per diesel B7. Yearly AOT Risk, Current, per 1.32E-08 1.81E-10 yr/ diesel B8. Yearly AOT Risk, Proposed, 6.14E-08 8.44E-10 i per yr/ diesel B9. Proposed Downtime 224 1 (avg hrs / train /yr) l B10. Proposed Duration, hrs / event 224 Bil. Single AOT Risk (based on 6.14E-08 8.44E-10 proposed 14 day AOT)

B12. Yearly AOT Risk /yr/ diesel (based on average annual 4.09E-08 5.63E-10 proposed downtime) l

' Utilizing EDG cross-tie under 10CFR50.54X for non-LOCA events.

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, Attachment #6 l Internal Events Level 2 Risk Results l

t Table 1-3 AVERAGE RISK RESULTS l DIESEL GENERATOR AOT CONDITIONAL INTERNAL EVENTS ]

RISK CONTRIBUTION  ;

PARAMETER Core Damage Large Early Frequency Release Frequency EDG Success Criteria 1 of 4' Present AOT, days 3 Proposed AOT, days 14 C1. Proposed Downtime, hrs /yr/ diesel 239 i

C2. Average Risk (current) , 2.67E-05 4.73E-07 per yr C3. Average Risk (proposed) , 2.68E-05 4.73E-07 per yr C4. Change factor from baseline < 1.004 < 1.001 Risk

' Utilizing EDG cross-tie under 10CFR50.54X for non-LOCA events.

8 CE NPSD-996 incorrectly indicated the proposed downtime as 220 hr/yr/ diesel.

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