TMI-11-077, Supplemental Response to Request for Additional Information Related to Technical Specification Change Request No. 351: Maximum Allowable Power with Inoperable Main Steam Safety Valves.

Supplemental Response to Request for Additional Information Related to Technical Specification Change Request No. 351: Maximum Allowable Power with Inoperable Main Steam Safety Valves.

ML111920354
Person / Time
Site:	Three Mile Island
Issue date:	05/27/2011
From:	Jesse M Exelon Generation Co, Exelon Nuclear
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
TAC ME4808, TMI-11-077
Download: ML111920354 (141)

Text

10 CFR 50.90 TMI-11-077 May 27,2011 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Three Mile Island Nuclear Station, Unit 1 Renewed Facility Operating License No. DPR-50 NRC Docket No. 50-289

Subject:

Three Mile Island Unit 1 Supplemental Response to Request for Additional Information Related to Technical Specification Change Request No. 351:

"Maximum Allowable Power with Inoperable Main Steam Safety Valves"

References:

(1) Letter from P. B. Cowan (Exelon Generation Company, LLC) to U.S. NRC, "Technical Specification Change Request No. 351: Maximum Allowable Power with Inoperable Main Steam Safety Valves" dated September 24, 2010 (2) Letter from P. Bamford (U.S. Nuclear Regulatory Commission) to M. J. Pacilio (Exelon Generation Company, LLC), 'Three Mile Island Nuclear Station, Unit 1

- Request for Additional Information Regarding License Amendment Request Proposing Changes to the Number of Required Operable Main Steam Safety Valves (TAC NO. ME4808)" dated March 25,2011 (3) Three Mile Island Unit 1 Response to Request for Additional Information Related to Technical Specification Change Request No. 351: "Maximum Allowable Power with Inoperable Main Steam Safety Valves" dated April 21, 2011 By letter dated September 24,2010 (Reference 1), Exelon Generation Company, LLC (Exelon),

requested an amendment to the Technical Specifications (TS) for Three Mile Island Nuclear Station, Unit 1 (TMI, Unit 1) to revise TS 3.4.1.2.3 to allow up to two (2) Main Steam Safety Valves (MSSVs) per steam generator to be inoperable with no required reduction in power level, and to revise the required maximum overpower trip setpoints for any additional inoperable MSSVs.

The USNRC staff provided draft RAI questions to Exelon on March 2, 2011 and then formally requested the second round of additional information on March 25, 2011 (Reference 2). Exelon submitted a partial response to the second round of USNRC questions on April 21, 2011 (Reference 3) and agreed to submit a supplemental response by May 27,2011.

The supplemental response is provided in the Attachment to this letter. The Attachment is Revision 5 to the previously provided Reference 1, Attachment 3, AREVA Document No. 86-9054640-002, "TMI-1 MSSV Operability Phase 2 Results." The revision to the AREVA document includes a newly added "Appendix B: RAI Support" that provides the supplemental

U Nuclear Regulatory Commission May 27,2011 Page 2 information for the RAI responses. This information finalizes Exelon's response to the second round of questions.

Exelon has determined that the information provided in response to this request for additional information does not impact the conclusions of the No Significant Hazards Consideration or Environmental Consideration as stated in Reference 1.

There are no regulatory commitments contained in this submittal.

In accordance with 10 CFR 50.91, "Notice for public comment; State consultation," paragraph (b), EGC is notifying the Commonwealth of Pennsylvania of this response by transmitting a copy of this letter and its attachment to the designated State Official.

Should you have any questions concerning this letter, please contact Ms. Wendy E. Croft at (610) 765-5726.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 2th day of May 2011.

Michael D. Je se Director - Lice . g and Regulatory Affairs Exelon Generation Company, LLC

Attachment:

AREVA Document No. 86-9054640-005, TMI-1 MSSV Operability Phase 2 Results" cc: USNRC Region I, Regional Administrator USNRC Project Manager, TMI, Unit 1 USNRC Senior Resident Inspector, TMI, Unit 1 Director, Bureau of Radiation Protection, PA Department of Environmental Resources Chairman, Board of County Commissioners, Dauphin County, PA Chairman, Board of Supervisors, Londonderry Township, PA R. R. Janati, Commonwealth of Pennsylvania

ATTACHMENT AREVA Document No. 86-9054640-005 "TMI-1 MSSV Operability Phase 2 Results" Three Mile Island Nuclear Station, Unit 1 Renewed Facility Operating License No. DPR-50

• • • ACTION REQUEST *** PAGE: 27 AIR TYPE AIR NUMBER : A2148778 REQUEST ORG AIR STATUS : PLNNED REQUEST DATE:=Q24MA~U~GaO~6Q:=- ~ STATUS DATE: 290CT08 REQUESTED BY: LAST UPDATE: 16MAYll PRINT DATE : 16MAYll

=================================================================

EVALUATION NBR: ORIG DATE ASSIGNED: __

EVALUATING ORG: EVAL DUE DATE:~~~~ __

EVAL ASIGND TO: DATE ASSIGNED:~~~~ __

EVAL REQUEST ORG:~~~

EVAL REQUESTOR: EVAL STATUS EVAL RETURNED BY: __

IMPORTANCE CODE: OEAP: SCHEDULE CODE:~~~ DATE FIXED:

=========================END OF ACTION

A2148778 E25 Attachment #1 Page 1 of 4 1.0 Reason For Evaluation I Scope AREVA Calculation No. 86-9054640-005 analyzes the effects of a turbine trip without runback or an ARTS trip for different scenarios where Main Steam Safety Valves (MSSVs) were inoperable. The analysis supports TMI-TSCR #351 "Maximum Allowable Power with Inoperable MSSVs." The calculation will not be incorporated into the license basis (I.e. not issued as a design calculation) until the License Amendment Request (LAR) is approved by the NRC. This Technical Evaluation addresses the limitations of the applicability of this analysis to LAR

1. 351 and any other design basis use at TMI. This evaluation specifically addresses the recommendations in Section 7.0 of the report and explains which of these recommendations are appropriate. Furthermore, this evaluation completes the owner's acceptance review of AREVA 86-9054640-005.

This Technical Evaluation has been prepared in accordance with CC-AA-309-101 "Engineering Technical Evaluations." A risk assessment has been completed in accordance with HU-AA-1212. The consequence risk level is High for section C.1. Combined with a low probability of error for the 2 human performance risk factors identified, a risk ranking of 2 was determined. An independent review by the station is required. This evaluation is approved as the independent review requirement will be met by the Technical Verification Team review and PORC review of the TSCR.

This evaluation supersedes A2148778 E18 which documented owner's acceptance of AREVA 86-9054640-002 and underwent a PORC review. There is low consequence risk associated with the revision of this evaluation and normal process reviews apply.

2.0 Detailed Evaluation The description of plant design and assumptions used in the analysis described in this report was found to be accurate or conservative. The analyzed event, an event where turbine steam flow is isolated without actuating the RPS turbine trip function, is the event which results in the highest Main Steam system or OTSG pressures. The following event analysis assumptions do not reflect actual plant design but conservatively bound the "expected system pressure transient condition" which is required for compliance with ASME Section III 2001 for OTSG Overpressure Protection and USAS B31.1 1967 for main steam piping protection.

• The model assumed no reduction in reactor power due to reactivity feedback or plant control action

• The Turbine Bypass Valves are assumed to fail closed

• The Atmospheric Dump Valves are assumed to fail closed The analysis was completed to support a future uprate of reactor power to 2772 MWt. The peak OTSG and main steam line pressures were compared to an

A2148778 E25 Attachment #1 Page 2 of 4 acceptance criteria of 11 O%of 1050 psig. This acceptance criteria was conservative. The OTSG acceptance criteria per ASME Section III 2001 edition is 110°10 of 1150 psig, and the main Steam Une acceptance criteria per USAS B31 .1 1967 (for events expected less than 1% of the operating period) is at least 120%

of 1050 psig.

Section 7.0 of 86-9054640-005 includes the AREVA recommendations for a Tech Spec change. The following explains where our proposed Tech Spec change differs from the AREVA recommendation:

(1) In this analysis, AREVA recommends reduced power overpower trip setpoints to ensure normal operation is restricted to power levels that are less than the acceptable analyzed power levels with inoperable MSSVs. The recommended Maximum Overpower Trip Setpoint at reduced power outlined in section 6.0 of 86-9054640-005 has been adopted for the TMI-TSCR #351; however, they are recognized as being overly conservative. The basis for reducing the analyzed power level by 6.9% to establish an overpower trip setpoint comes from the difference between 112% full power, and the 105.1 % overpower trip setpoint applied to normal operations at 100% power. The function of the 105.1%

overpower trip setpoint is to prevent core thermal power from exceeding 112% to protect against fuel damage in a reactivity transient. The normal function of the overpower trip setpoint is not to protect against secondary side overpressure.

Therefore 6.9% margin for the overpower trip setpoint is not applicable to the administrative method used to keep steady state reactor power below the analyzed power level for conditions with inoperable MSSVs. Secondary side overprotection can be accomplished by setting the overpower trip at 2% below the analyzed power level. A margin of 2% is appropriate because the maximum uncertainty in the measurement of reactor power is less than 2% at 100% power (Reference UFSAR Table 3.2-11). This 2% margin for measurement uncertainty was properly applied where the 102% power condition was analyzed to support full power operation. The AREVA recommended overpower setpoint is more conservative than necessary; however, TMI has decided to accept the recommended overpower trip setpoints.

(2) TMI has not adopted the suggested change in 86-9054640-005 section 7.0 which states "At lease one (1) OPERABLE MSSV on each steam generator must have a nominal lift setpoint S 1050 pisg ...." One safety valve per OTSG is required to open at the design pressure of the protected component per ASME section 1112001 edition. While the EOTSGs are designed to meet ASME section III, they have a design pressure of 1150 psig. All safety relief valves lift below 1150 psig. The main steam line, between the steam generators and safety relief valves has a design pressure of 1050 psig. This piping is designed to 831.1, 1967 edition "Power Piping," not to ASME section III. There is no requirement for 831.1 piping to have at least 1 safety valve set at the pipe design pressure.

A2148778 E25 Attachment #1 Page 3 of 4 The acceptance criterion used to demonstrate sufficient overpressure protection is the ability to remain under 110% of rated design pressure during any anticipated transient The analysis is bounding in that it demonstrates overpressure protection when the most limiting combinations of MSSVs are out of service. No additional requirement specific to the number of operable MSSVs with lift setpoints s 1050 pisg is necessary to remain within 110% of the system design pressure.

In addition, AREVA 86-9054640-005 includes an evaluation of the effects of raising the setpoint of safety valves MS-V-21 A and MS-V-21 B to 1050 psig.

There is no plant initiative to change any MSSV setpoint at this time. The proposed Tech Spec change is independent of any change in MS-V-21A & B setpoint to 1050 psig. For the approval and future implementation of TMI-TSCR

1. 351, any analysis or discussion regarding increasing the setpoints of MS-V-21A and MS-V-21 B does not apply.

3.0 Conclusions I Findings The analysis supports proposed TMI TSCR #351 "Maximum Allowable Power with Inoperable MSSVs."

Upon approval of the LAR, the analysis will be issued as part of the implementing ECR. The implementing ECR will facilitate how the results of the analysis are incorporated into the plant design basis consistent with this technical evaluation.

The independent reviewer of this Technical Evaluation concurs with the analysis of 86-9054640-005 included in attachment #1 only. The preparer of this evaluation has signed as the reviewer on CC-AA-1 03-1 003 Attachment #2, "Owners Acceptance Review Checklist for External Design Analysis" for AREVA calculation 86-9054640-005. The checklist documents acceptance of the calculation upon manager approval of this Technical Evaluation.

4.0

References:

2.1 ASME Boiler and Pressure Vessel Code Section 1112001 edition.

2.2 TMI-1 TSCR #351 "Maximum Allowable Power with Inoperable MSSVs."

2.3 TMI Updated Final Safety Analysis. Table 3.2-11.

2.4 CC-AA-309-101 "Engineering Technical Evaluations" 2.5 HU-AA-1212 'Technical Task/Rigor Assessment, Pre-Job Brief, Independent Third Party Review, and Post-Job Brief.

2.6 USAS B31.1, 1967 Edition "Power Piping"

A2148778 E25 Attachment # 1 Page 4 of 4 5.0 Approvals Prepared =M=ic=h=ae=I~H=a.:.:.L- ~~~~_ Date 5/16/11 Prepared =B=iIl..:..:M=c=S=or:..:.:;le::..J.v. ~----f-+--~-- Date 5/16/11

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CC-AA-1 03-1 003 Revision 6 Page 8 of 9 ATTACHMENT 2 (Sample) Owner's Acceptance Review Checklist for External Design Analyses Page 1 of 2 /

No Question Instructions and Guidance Yes/No I N/A 1 Do assumptions have All Assumptions should be stated In clear terms with enough ~ D D sufficient documented justification to confirm that the assumption is conservative.

rationale?

For example, 1) the exact value of a particular parameter may not be known or that parameter may be known to vary over the range of conditions covered by the Calculation. It is appropriate to represent or bound the parameter with an assumed value. 2) The predicted performance of a specific piece of equipment in lieu of actual test data. It is appropriate to use the documented opinion/position of a recognized expert on that equipment to represent predicted equipment performance.

Consideration should also be given as to any qualification testing that may be needed to validate the Assumptions. Ask yourself. would you provide more justification if you were Are assumptions performing this analysis? If yes, the rationale is likely incomplete.

Ensure the documentation for source and rationale for the I

M U U 2 compatible with the assumption supports the way the plant is currently or will be way the plant is operated post change and they are not in conflict with any operated and with the design parameters. If the Analysis purpose is to establish a 3

licensing basis? ~

Do all unverified new licensing basis. this question can be answered yes. if the assumption supports that new basis.

If there are unverified assumptions without a tracking D D ~

I assumptions have a mechanism indicated. then create the tracking item either tracking and closure through an ATI or a work order attached to the implementing mechanism in place? WOo Due dates for these actions need to support verification 4 Do the design inputs prior to the analysis becoming operational or the resultant plant chanqe beinq op authorized.

The origin of the input. or the source should be identified and

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IEf D D have sufficient be readily retrievable within Exelon's documentation system.

rationale? If not, then the source should be attached to the analysis. Ask 5 Are design inputs yourself. would you provide more justification if you were performing this analysis? If yes. the rationale is likely incomplete.

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/'D D correct and reasonable clearly understand which input parameters are critical to the with critical parameters outcome of the analysis. That is, what is the impact of a identified. if change in the parameter to the results of the analysis? If the 6

appropriate?

Are design inputs impact is large. then that parameter is critical.

Ensure the documentation for source and rationale for the [g

/D D compatible with the inputs supports the way the plant is currently or will be way the plant is operated post change and they are not in conflict with any operated and with ~ design parameters.

licensing basis? /

7 Are Engineering See Section 2.13 in CC-AA-309 for the attributes that are EI D D Judgments clearly sufficient to justify Engineering Judgment. Ask yourself.

documented and would you provide more justification if you were performing justified? this analysis? If ves. the rationale is likely incomplete.

CC-AA-1 03-1 003 Revision 6 Page 9 of 9 AITACHMENT 2 (Sample) Owner's Acceptance Review Checklist for External Design Analyses Page 2 of2 No tion Instructions and Guidance Ye'4f{ No I N/A 8 Are Engineering Ensure the justification for the engineering judgment ~ U U Judgments compatible supports the way the plant is currently or will be operated with the way the plant is post change and is not in conflict with any design operated and with the parameters. If the Analysis purpose is to establish a new licensing basis. then this question can be answered yes. if 9

licensing basis?

Do the results and

-~ the iudqment supports that new basis.

Why was the analysis being performed? Does the stated L1

/U 0 conclusions satisfy the purpose match the expectation from Exelon on the proposed purpose and objective of application of the results? If yes. then the analysis meets the Desiqn Analysis? the needs of the contract. /

10 Are the results and Make sure that the results support the UFSAR defined S 0 0 conclusions compatible system design and operating conditions. or they support a with the way the plant is proposed change to those conditions. If the analysis operated and with the, supports a change. are all of the other changing documents 11 Iicensinq basis?

Have any limitations on

.7\\ included on the cover sheet as impacted documents?

Does the analysis support a temporary condition or [0'

/o 0 the use of the results procedure change? Make sure that any other documents been identified and needing to be updated are included and clearly delineated in transmitted to the the design analysis. Make sure that the cover sheet appropriate includes the other documents where the results of this 12 orqanizations?

Have margin impacts analysis provide the input.

Make sure that the impacts to margin are clearly shown lV U U

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been identified and within the body of the analysis. If the analysis results in documented reduced margins ensure that this has been appropriately appropriately for any dispositioned in the EC being used to issue the analysis.

negative impacts 13 (Reference ER-AA-2007)?

Does the Design Are there sufficient documents included to support the B

/o 0 Analysis include the sources of input. and other reference material that is not applicable design basis readily retrievable in Exelon controlled Documents?

14 documentation?

Have all affected design Determine if sufficient searches have been performed to l0

/U 0 analyses been identify any related analyses that need to be revised along documented on the with the base analysis. It may be necessary to perform 15 Affected Documents List (ADL) for the associated Configuration Chanqe?'*

Do the sources of inputs some basic searches to validate this.

Compare any referenced codes and standards to the current

/'

g- O 0 and analysis design basis and ensure that any differences are reconciled.

methodology used meet committed technical and regulatory req uirements?

If the input sources or analysis methodology are based on an out-of-date methodology or code. additional reconciliation may be required if the site has since committed to a more recent code

//

16 Have vendor supporting Based on the risk assessment performed during the pre-job ~ 0 0 technical documents brief for the analysis (per HU-AA-1212). ensure that and references sufficient reviews of any supporting documents not provided (including GE DRFs) with the final analysis are performed.

been reviewed when necessary?

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0402-01-FOl (Rev. 016, 03/31/2011)

A CALCULATION

SUMMARY

SHEET (CSS)

AREVA Title TMI-1 MSSV -

PURPOSE AND

SUMMARY

OF RESULTS:

Reference 11 summarizes an evaluation of MSSV operability for TMI-1 with the OTSGs and the current rated thermal power level of 2568 MWt. Reference 11 specifies the maximum overpower trip setpoint and maximum nominal operating power level that is acceptable as a function of the number of MSSVs out of service per steam generator.

Reference 1 used evaluations of the Turbine Trip without runback or ARTS trip for TMI-1 with the E-OTSG to demonstrate that the table of MSSVs out of service versus the maximum allowed power level and the overpower trip setpoint developed in Reference 11 for the OTSGs remains applicable for the E.QTSGs. The purpose of this document is to summarize the analyses methods and results of the E-OTSG evaluations in Reference 1. The evaluations in Reference 1, which used calculations from References 5 and 6, were performed at a stretch rated power level of 2772 MWt, but are applicable to the current rated power level of 2568 MWt.

The Reference 1 results support a revision to TS 3.4.1.2.3 for the E-OTSGs. Suggested changes to the existing TS and Bases are provided in this document, and are the same as was provided in Reference 11.

The calculation in Reference 1 also evaluated the setpoint of MSSVs MS-V21A and MS-V21B. These MSSVs currently have a nominal setpoint of 1040 psig. Evaluations were performed in Reference 1 to support increasing the setpoint of these two MSSVs to 1050 psig with the E.QTSGs. The results of those evaluations are discussed in this document. Note that Reference 8 Section 3.2.3.5 currently requires that at least one MSSV on each steam generator has a nominal setpoint of 1040 psig. This document does not address the potential revision needed to Reference 8 or any other design basis documentation in order to increase the setpoint of MSSVs MS-V21A and MS-V21B.

THE DOCUMENT CONTAINS ASSUMPTIONS THAT SHALL BE THE FOLLOWING COMPUTER CODES HAVE BEEN USED IN THIS DOCUMENT: VERIFIED PRIOR TO USE CODENERSION/REV CODENERSION/REV DYES None

[g] NO Page 1 of 131 Im;lud\~Q Pgq~s A~l to A.-11. aN! Pr1tnB*eA

A 0402-01-F01 (Rev. 016. 03/31/2011)

AREVA Document No. 86-905464Q..005 TMI-1 MSSV Operability Phase 2 Results Review Method: Design Review (Detailed Check)

AItemate Calculation Signature Block Name and Title P/RIA (printed or and Pages/Sections typed) Signature LPIlR Date Prepared/Reviewed/Approved WilliarnF.

Walters 1r'~ZI/l~ P l5-/)-1.~11 All Revision 5 Changes Prin. Engineer cJ?/~ R ~7/.v-J Phil Boylan R 5-13-2011 All Revision 5 Changes Contractor 1'1(~ ~

K. E. Higar Manager A 5/13/tl All, Reviewer Independence v

Note: P/RIA designates Preparer (P), Reviewer (R), Approver (A);

LPILR designates Lead Preparer (LP), Lead Reviewer (LR)

Project Manager Approval of Customer References (N/A if not applicable)

Name Title (printed or typed) (printed or typed) Signature Date R. J. Baker ~ ~ Project Manager f>t:v~ ~d\- ~~ 6-/3-/1 Mentoring Information (not required per 0402-01)

Name Title Mentor to:

(printed or typed) (printed or typed) (PIR) Signature Date N/A Page 2

A. 0402-01-F01 (Rell. 016.03/3112011)

AFt.VA Document No. 86-9054640-005 TMI-1 MSSV Operability Phase 2 Results Record of Revision Revision Pages/Sections/Paragraphs No. Changed Brief Description / Change Authorization 000 All Initial Release 001 All Changes made to address customer comments. Additional changes made to update references and use latest document form. Addition of Page 2 changes the page numbering of all subsequent pages, requiring a complete reissue. Rev. bars are provided on right hand side next to text affected by customer comments.

002 All Changes made to address customer comments. Additional changes made to update references and use latest document form. Added Figures 4-1 through 4-25. Rev. bars are provided on right hand side next to text affected by customer comments. Revision 002 is a complete reissue.

003 Appendix A Appendix A adds suggested license amendment request (LAR) input.

004 Pages 1-3 Modified to add Revision 4.

Pages 4 - 6 Added Appendix B to Table of Contents, List of Tables, and List of Figures Page 55 Updated References 7 and 9 Appendix B Added Appendix B to support RAJ responses 005 Pages I - 3 Modified to add Revision 005 Page 6 Added Figures B-32 through B-58 Page 55 Increased revision level on Reference I Pages B-6, B-7, B-38 to B-64 Added results of 77%FP case with 4 MSSVs out of service

A ARaVA Document No. 86*9054640*005 TMI*1 MSSV Operability Phase 2 Results Table of Contents Page SIGNATURE BLOCK 2 RECORD OF REVISION 3 LIST OF TABLES 5 LIST OF FIGURES 6 LIST OF ACRONyMS 7

1.0 INTRODUCTION

/BACKGROUND 8 2.0 PURPOSE 10 3.0 ANALYTICAL INPUT

SUMMARY

REVIEW I METHOD OF ANALYSIS 11 3.1 Analytical Input Summary Review 11 3.2 Event Description 11 3.3 Methodology Employed 12 3.4 Computer Code Utilized 13 4.0 FULL POWER RESULTS 15 4.1 Full Power with Two MSSVs Out of Service 15 4.2 Full Power with Three MSSVs Out of Service 41 4.3 Additional Full Power Analyses 41 5.0 REDUCED POWER RESULTS 43 5.1 92% of 2772 MWt with Three MSSVs Out of Service 43 5.2 92% of 2772 MWt with Four MSSVs Out of Service 44 5.3 62% of 2772 MWt with Four MSSVs Out of Service 44 5.4 62% of 2772 MWt with Five MSSVs Out of Service 45 5.5 Limits at Intermediate Power Levels 45 6.0 OVERPOWER TRIP SETPOINTS AND NOMINAL OPERATING POWER .47 7.0

SUMMARY

OF SUGGESTED CHANGES .49 8.0 DISPOSITION OF EVENTS 51 8.1 Technical Bulletin TB*07*6 54

9.0 REFERENCES

55 APPENDIX A: SUGGESTED LICENSE AMENDMENT REQUEST (LAR) INPUT.. A*1 APPENDIX B : RAI SUPPORT B-1

'.tU 4

A A FUEVA Document No. 86-9054640-005 TMI-1 MSSV Operability Phase 2 Results List of Tables Page Table 1-1: TMI-1 Main Steam Safety Valve Size, Current Nominal Lift Setpoint, and Capacity 9 Table 4-1: Turbine Trip at 102% of 2772 MWt, Two MSSVs Out of Service, E-OTSG 15 Table 4-2: Turbine Trip at 102% of 2772 MWt, Three MSSVs Out of Service, E-OTSG 41 Table 4-3: Turbine Trip at 102% of 2772 MWt, Additional Evaluations 42 Table 5-1' Turbine Trip at 92% of 2772 MWt, Three MSSVs Out of Service 43 Table 5-2: Turbine Trip at 92% of 2772 MWt, Four MSSVs Out of Service, E-OTSG 44 Table 5-3: Turbine Trip at 62% of 2772 MWt, Four MSSVs Out of Service, E-OTSG 44 Table 5-4: Turbine Trip at 62% of 2772 MWt, Five Full-Sized MSSVs Out of Service per E-OTSG 45 Table 5-5: Maximum Analyzed Power Level versus Number of MSSVs Allowed Out of Service 46 Table 6-1: Overpower Trip Setpoint and Maximum Nominal Power Level versus Number of MSSVs Allowed Out of Service 48 Table 6-2: Overpower Trip Setpoint and Maximum Nominal Power Level versus Number of Required Operable MSSVs 48 Table 8-1: Correspondence between Nominal Lift Setpoint and Analyzed Setpoints 8-3 Table 8-2: Comparison of Cases at 102% of 2772 MWt with Two MSSVs Out of Service 8-6 Table 8-3: Turbine Trip at 77% of 2772 MWt, Four MSSVs Out of Service, E-OTSG 8-7 PZII'S

A A FUEVA Document No. 86-9054640-005 TMI-1 MSSV Operability Phase 2 Results List of Figures Page Figure 4-1. RCS Pressure 16 Figure 4-2: Reactor Power 17 Figure 4-3: RCS Temperatures 18 Figure 4-4: RCS Flow 19 Figure 4-5: Indicated PZR Level 20 Figure 4-6: Core Average Moderator Temperature 21 Figure 4-7: Core Average Fuel Temperature 22 Figure 4-8: EOTSG Secondary Side Liquid LeveL 23 Figure 4-9: EOTSG Secondary Side Inventory 24 Figure 4-10: Core Reactivity 25 Figure 4-11: Maximum RCS Pressure 26 Figure 4-12: Maximum EOTSG Pressure 27 Figure 4-13: Maximum Steam Line Pressure 28 Figure 4-14: Main Feedwater and Steam Flow 29 Figure 4-15: PZR PSV and PORV Flow Rates 30 Figure 4-16: MSSV Steam Line 1 Flow 31 Figure 4-17: MSSV Steam Line 2 Flow 32 Figure 4-18: MSSV Steam Line 3 Flow 33 Figure 4-19: MSSV Steam line 4 Flow 34 Figure 4-20: MFW Integrated Flow 35 Figure 4-21: Steam Line Integrated Flow 36 Figure 4-22: Integrated MSSV Steam line 1 Flow 37 Figure 4-23: Integrated MSSV Steam line 2 Flow 38 Figure 4-24: Integrated MSSV Steam line 3 Flow 39 Figure 4-25: Integrated MSSV Steam line 4 Flow 40 Figure 8-1: Normalized MSSV Area vs. Steam Pressure Logic Diagram 8-2 Figure 8-2: TM 1-1 Main Steam Line Nading Arrangement. B-8 Figure 8-3: Steam line Pressure at MSSV Inlet - SG A, psia B-9 Figure 8-4: Steam Line Pressure at MSSV Inlet - SG 8, psia 8-1 0 Figure 8-5 to 8-31: TMI-1 Turbine Trip at 102% of 2772 MWt with 178 and 188 Out of Service 8-11 Figure B-32 to 8-58: TMI-1 Turbine Trip at 77% of 2772 MWt with 170, 180, 190,200 Out of Service 8-38

A A FUEVA Document No. 86-9054640-005 TMI-1 MSSV Operability Phase 2 Results List of Acronyms AIS Analytical Input Summary AOR Analysis of Record ARTS Anticipatory Reactor Trip System ASME American Society of Mechanical Engineers ATWS Anticipated Transient Without Scram DNB Departure from Nucleate Boiling ECCS Emergency Core Cooling System E-OTSG Enhanced Once Through Steam Generator FP Full Power ICS ~rated Control System LOCA ss of Coolant Accident MSIV Main Steam Isolation Valve MSSV Main Steam Safety Valve NRC Nuclear Regulatory Commission NSSS Supply System OTSG Once Through Steam Generator PORV Pilot Operated Relief Valve PSV Pressurizer Safety Valve RCP Reactor Coolant Pump RCPB Reactor Coolant Pressure Boundary RCS Reactor Coolant System RPS Reactor Protection System R51M2-B&W RELAP5/MOD2-B&W SG Steam Generator TMI-l Three Mile Island Unit I TCV Turbine Control Valve TS Technical Specifications TSV Turbine Stop Valve UFSAR Updated Final Safety Analysis Report

A A FU£VA Document No. 86~9054640-005 TMI-1 MSSV Operability Phase 2 Results

1.0 INTRODUCTION

/BACKGROUND The limiting transient for evaluating the secondary side overpressure protection is the Turbine Trip accident without power runback and without credit for the ARTS trip signal coincident with turbine trip.

One of the key parameters for the Turbine Trip accident relates to the operability of the MSSVs.

Specitically, TMI-I TS 3.4.1.2.3 [Reference 7] defines the operability requirements tor the MSSVs. In particular, the TS requires a reduction in the overpower trip setpoint (and a corresponding reduction in core power) if even one MSSV is declared to be out of service. This requirement is different from what is currently applied to the other B&W-designed plants. In addition, if more than 3 valves are inoperable at TMI- I, the plant is in an action statement to restore at least 15 valves to operable status or be in hot shutdown. The other plants remain operating with as few as 2 operable valves on any SG.

Scoping analyses have been performed for the TMI-I E-OTSGs at a core power level of 102% of 2772 MWt [Reference 5]. Those results indicate that it may be possible for up to 2 valves on each E-OTSG to be declared inoperable with no required reduction in core power. In addition, with a third valve out of service, the power may only need to be reduced to -90% [Reference 6]. These results indicate that there is a sufficient basis to revise TS 3.4.1.2.3 for the E-OTSGs to be less restrictive.

Table I-I li.sts the location, size, current nominal lift setpoint, and capacity for the TMI-I MSSVs. This information was obtained from Reference 5 Table 7-3.

Pa~e8

A A FUEVA Document No. 86-9054640-005 TMI-1 MSSV Operability Phase 2 Results Table I-I: TMI-I Main Steam Safety Valve Size, Current Nominal Lift Setpoint, and Capacity Steam Valve Size Lift Rated Generator I (inches) Setpoint Capacity I Steam Line (psig) (Ibmlhr)

SG-AI MS-VI7A 6 by 10 1050 792,610 Line I MS-VI8A 6 by 10 1060 799,990 MS-VI9A 6 by 10 1080 814,955 MS-V20A 6 by 10 1050 792,610 MS-V2IA 3 by 6 1040 194,900 SG-AI MS-VI7B 6 by 10 1050 792,610 Line 2 MS-VI8B 6 by 10 1060 799,990 MS-V19B 6 by 10 1080 814,955 MS-V20B 6 by 10 1092.5 824,265 SG-BI MS-V17C 6 by 10 1050 792,610 Line 3 MS-VI8C 6 by 10 1060 799,990 MS-V19C 6 by 10 1080 814,955 MS-V20C 6 by 10 1092.5 824,265 MS-V21B 3 by6 1040 194,900 SG-BI MS-V17D 6 by 10 1050 792,610 Line 4 MS-V18D 6 by 10 1060 799,990 MS-V19D 6 by 10 1080 814,955 MS*V20D 6 by 10 1050 792,610 I Rated capacity is based on saturated steam at the nominal lift setpoint plus 3% accumulation.

A A FUIVA Document No. 86-9054640-005 TM 1-1 MSSV Operability Phase 2 Results 2.0 PURPOSe Reference II summarizes an evaluation of MSSV operability for TMI- I with the OTSGs and the current rated thennal power level of 2568 MWt. Reference II specifies the maximum overpower trip setpoint and maximum nominal operating power level that is acceptable as a function of the number of MSSVs out of service per steam generator.

Reference I used evaluations of the Turbine Trip without ronback or ARTS trip for TMI-I with the E-OTSG to demonstrate that the table of MSSVs out of service versus the maximum allowed power level and the overpower trip setpoint developed in Reference II for the OTSGs remains applicable for the E-OTSGs. The purpose of this document is to summarize the analyses methods and results of the E-OTSG evaluations in Reference I. The evaluations in Reference 1, which used calculations from References 5 and 6, were perfonned at a stretch rated power level of2772 MWt, but are applicable to the current rated power level of 2568 MWt.

The Reference I results support a revision to TS 3.4.1.2.3 for the E-OTSGs. Suggested changes to the existing TS and Bases are provided in this document, and are the same as was provided in Reference II.

The calculation in Reference I also evaluated the setpoint of MSSVs MS-V21 A and MS-V21 B. These MSSVs currently have a nominal setpoint of 1040 psig. Evaluations were perfonned in Reference 1 to support increasing the setpoint of these two MSSVs to 1050 psig with the E-OTSGs. The results of those evaluations are discussed in this document. Note that Reference 8 Section 3.2.3.5 currently requires that at least one MSSV on each stearn generator has a nominal setpoint of 1040 psig. This document does not address the potential revision needed to Reference 8 or any other design basis documentation in order to increase the setpoint ofMSSVs MS-V2IA and MS-V2IB.

A AREVA Document No. 86-9054640-005 TMI-1 MSSV Operability Phase 2 Results 3.0 ANALYTICAL INPUT

SUMMARY

REVIEW I METHOD OF ANALYSIS 3.1 Analytical Input Summary Review Reference 4 is the AIS for the Turbine Trip event with E-OTSGs. Reference 4 was reviewed for applicability to the evaluation of the Turbine Trip event with the E-OTSGs and MSSVs out of service.

No substantive changes were required.

Reference 4 states that pressurizer spray should be modeled and that a sensitivity study should be run for the limiting event to determine the effects of pressurizer spray on the peak SG pressure. References I and 5 performed sensitivity studies on the effects of pressurizer spray and determined that at full power, the peak SG pressure for the Turbine Trip was more limiting without pressurizer spray. Therefore, the E-OTSG analyses in Reference I and Reference 5 do not model pressurizer spray. References I and 6 performed sensitivity studies on the effects of pressurizer spray and determined that at reduced power, the peak SG pressure was higher with pressurizer spray modeled but that the effect of pressurizer spray was less than minimal (0.34 psi or less.) Nevertheless, the Reference 6 evaluation modeled pressurizer spray. All other inputs in Reference 4 were deemed applicable to the Turbine Trip analysis with the E-OTSGs. Therefore, a revision to Reference 4 is not warranted for this analysis.

Note that the power level for partial power cases will be conservative for a specified number ofMSSVs that are inoperable at that power level.

The event description and methodology are based on the discussion provided in Reference 4.

3.2 Event Description A loss of electric load event can result from faults within the turbine generator, but more often are caused by circuit breaker operation somewhere within the power grid. Nonetheless, a loss of electric load and/or turbine trip can exist without a loss of emergency power. This type of event may be the result of the inadvertent closure of a main steam isolation valve (MSIV), a turbine control valve (TCV),

or a turbine stop valve (TSV).

As a result of the load reduction, the secondary system pressure rapidly increases until the MSSVs lift, allowing for the continued removal of heat through the SGs. The diminished heat removal capability of the SGs causes the reactor coolant temperature to increase, which reduces the fluid density and causes an insurge of reactor coolant into the pressurizer. As the pressurizer level increases, the system pressure also increases due to compressing the steam bubble within the pressurizer. If available, the pressurizer sprays are actuated in an attempt to reduce the pressure increase. Depending on the severity of the loss of heat sink, the actions of the pressurizer spray may be insufficient to prevent the pressurizer pressure and level from increasing. If the system pressure continues to increase to the High Reactor Coolant System (RCS) Pressure trip setpoint, the Reactor Protection System (RPS) will trip the reactor. Further pressure increases are ameliorated by the pressurizer Pilot Operated Relief Valve (PORV) and/or the Pagt! 11

A A FUEVA Document No. 86*9054640-005 TMI-1 MSSV Operability Phase 2 Results Pressurizer Safety Valves (PSVs). The PSVs have sufficient relieving capacity to prevent the system pressure from exceeding the accident acceptance criterion.

At this point during the transient the heat removal capability of the SGs is sufficient to reduce the reactor coolant temperature. Thus, the Turbine Trip event analysis is terminated at this time.

Section 14.1.2.8.2 of the TMI-I UFSAR [Reference 9] describes a loss of electric load event in which the power is ronback to 15 %FP without a reactor trip. This event is not limiting in terms of peak secondary pressure because of the immediate power reduction. Furthermore, this event can not presently occur because the rcs can not reduce power quickly enough to prevent a reactor trip with the current high pressure reactor trip and PORV setpoints.

Section 14.1.2.8.3 of the TMI-I UFSAR [Reference 9] describes a loss ofload event in which the ARTS trip on turbine trip function is credited. This event is not limiting in terms of secondary pressure because of the immediate reactor trip signal coincident with the turbine trip.

The Turbine Trip event analyzed in Reference I for determining the number of MSSVs that can be inoperable at a given power level does not take credit for the rcs runback or the ARTS trip signal on turbine trip function. As a result, the Turbine Trip event analyzed in Reference I is the limiting event in terms of the peak secondary pressure response.

3.3 Methodology Employed The Turbine Trip analyses were performed in accordance with methodology [Reference 2] approved by the Nuclear Regulatory Commission (NRC). Where possible, this methodology utilizes the plant design bases to establish acceptance criteria and input boundary conditions. The approved methodology includes the manner for determining the responses of the primary system, the secondary system, and the core to postulated accidents. In addition, the methodology requires the use of conservative setpoints, valve and pump capacities, and reactivity coefficients to demonstrate adequate margin to the applicable limits. With respect to the inoperable MSSVs, the valve setpoints and sensitivity studies were used to determine the valve or combination of valves that produce the limiting secondary pressure for a given number of valves out of service.

A combined representation of the TMI-I nuclear steam supply system (NSSS) is used to perform the Turbine Trip analysis. This representation includes the:

• reactor vessel and core;

• hot legs, cold legs, and reactor coolant pumps;

• pressunzer;

• replacement steam generators;

• main steam piping and valves; and,

• reactor protection system.

PaQe 12

A AAEVA Document No. 86~9054640~005 TMI~1 MSSV Operability Phase 2 Results Fuel damage is not postulated for the Turbine Trip event because thermal power will remain less than 112% of full power for the duration of the event With the reactor coolant pumps (RCPs) operating throughout the event, an excessive power-to~f1ow ratio is also avoided. Hence, the fuel pins will not experience a Departure from Nucleate Boiling (DNB).

Consistent with typical safety analysis assumptions, the core heat generation rate after reactor trip is based on 1.0 times the ANS-1971 decay heat standard for fission plus the B&W heavy actinides. This comhination of decay heat curve and multiplier has been shown to produce more energy than the ANS-1979 decay heat curve plus 20 uncertainty. While this assumption is conservative for RCS overpressure transients, it does not contribute significantly to secondary side overpressurization since the event is initiated by a turbine trip and the peak secondary pressure is reached soon thereafter just prior to lifting of the MSSVs.

Excessive pressurization of the Reactor Coolant Pressure Boundary (RCPB), i.e. pressurization of the RCS to a pressure that is much greater than the design pressure, is not postulated for the Turbine Trip event Although the peak RCS pressure will exceed the design pressure of 2500 psig, the peak RCS pressure is significantly less than the peak pressure of 2707.69 psia for the Startup Accident Thus, the RCPB will not experience excessive pressurization.

The integrity of the RePB is also maintained because consequential damage to the SG tubes from excessive tube loads will not occur for the Turbine Trip event Accordingly, the radiological doses to operating personnel (onsite) or to the public (offsite) will remain significantly less than the allowed values provided the integrity of the secondary pressure boundary remains intact.

The applicable acceptance criterion evaluated to determine the number of MSSVs that can be out of service for a given initial power level is the peak secondary side pressure in the SG and steam lines. The maximum steam line pressure is taken at the EOTSG steam outlet nozzle where the pressure is greatest.

The pressure drop to the MSSVs is assumed to be negligible because the length of piping is not substantial enough to create any significant pressure drop to the MSSVs. ASME code requirements for the SG and attached piping require the pressure to be limited to 110% of the design pressure. The design pressure for the E-OTSG is 1150 psig, which gives a pressure limit of 1279.7 psia for the E-OTSGs. The design pressure for the steam lines is 1050 psig, which gives a pressure limit of 1169.7 psia for the steam lines for this limited duration transient The RCS pressure limit is 2764.7 psia, however this limit will not be challenged.

3.4 Computer Code Utilized The RELAP5/MOD2-B&W (R51M2-B&W) computer code [Reference 3] was used for the analysis of the Turbine Trip event. This code has been approved by the NRC for use in non-Loss of Coolant Accident (LOCA) safety analyses [Reference 2]. Furthermore, this code is recognized as providing a conservative prediction of the overheating that will occur during the Turbine Trip event [Reference 2].

The code simulates RCS and secondary system operation. The reactor core model is based on a point kinetics solution with reactivity feedback for control rod assembly insertion, fuel temperature changes, and moderator temperature changes. The ReS model provides for heat transfer from the core, transport of the coolant to the SGs, and heat transfer to the SGs. The secondary model includes a detailed Page 13

A ARIlEVA Document No. 86-9054640-005 TMI-1 MSSV Operability Phase 2 Results depiction of the main steam system, including steam reHefto the atmosphere through the MSSVs and simulation of the TSVs. The secondary model also includes the delivery offeedwater, both main and emergency, to the SGs.

A ARIIVA Document No. 86-9054640-005 TMI-1 MSSV Operability Phase 2 Results 4.0 FULL POWER RESULTS Reference 5 developed a TMI- I model at 102% of 2772 MWt with the E-OTSGs. The model is consistent with Reference 4, with the exception of the pressurizer spray model and the RCS average temperature. Reference 5 determined that the peak secondary pressure was higher without pressurizer spray and therefore did not use pressurizer spray for the base analysis. The RCS average temperature used in the Reference 5 model is conservative.

4.1 Full Power with Two MSSVs Out of Service The scoping analysis done for the E-OTSG at 102 %FP [Reference 5] evaluated the limiting combination of two MSSVs out of service. Table I-I shows that Steam Line I and Steam Line 3 each have five MSSVs whereas Steam Line 2 and Steam Line 4 each have only four MSSVs. Therefore, the limiting combination will occur if two MSSVs are removed from service on Steam Line 2 or Steam Line

4. On Steam Line 2, valves MS-V I7B and MS-VI 8B were disabled because they are the lowest setpoint valves on that steam line. Similarly, on Steam Line 4, valves MS-V I70 and MS-V200 were disabled because they are the lowest setpoint valves on that steam line. Reference 5 determined that the limiting combination of two MSSVs out of service occurred when valves MS-V 170 and MS-V200 were inoperable. The results from the limiting case are summarized in Table 4-1.

Table 4-1: Turbine Trip at 102% of 2772 MWt, Two MSSVs Out of Service, E-OTSG Valves Out of Service MS-VI70, MS-V200 Maximum RCS Pressure (osia) 2581.11 Maximum SG Pressure (psia) 1170.97 Maximum Steam Line Pressure (psia) 1159.06 The resulting maximum RCS pressure is 2581.11 psia, which is well below the maximum RCS pressure 2707.69 psia in the Startup Accident. The maximum SG pressure is 1170.97 psia, which is less than the 1279.7 psia Code requirement for the E-OTSGs. The maximum steam line pressure is 1159.06 psia, which is less than the 1169.7 psia Code requirement for the steam lines. The results demonstrate that no reduction in power is required for continued operation with the E-OTSGs with as many as two MSSVs out of service.

Pi.II915

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_23

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_25

A ARaVA Document No. 86-9054640-005 TMI-1 MSSV Operability Phase 2 Results 4.2 Full Power with Three MSSVs Out of Service Since there was psi of margin to the SG pressure limit with two MSSVs out of service, additional evaluations of the Turbine Trip event were performed in References I and 5 at 102% of 2772 MWth and three MSSVs out of service. The limiting case for three MSSVs out of service occurs when valves MS-V17D, MS-VI8D, and MS-V20D are inoperable. Table I-I shows that these three valves are aU on same steam line. Furthermore, two of the valves have a nominal setpoint of 1050 psig and one valve has a nominal setpoint of 1060 psig. This case leaves only one 6 by 10 valve on Steam Line 4 with a nominal setpoint of 1080 psig. Furthermore, of the MSSVs remaining on SG-B, only one 6 by 10 valve has a nominal setpoint of 1050 psig. Two other cases were evaluated which disable the three 6 by 10 MSSVs on each SG with a nominal setpoint of 1050 psig. The results from these analyses are summarized in Table 4-2.

Table 4-2: Turbine Trip at 102% of 2772 MWt, Three MSSVs Out of Service, E-OTSG Valves Out of Service MS-VI7D, MS-VI7C, MS-VI 7A, MS-VI8D, MS-VI7D, MS-V20A, MS-V20D MS-V20D MS-VI7B I Maximum RCS Pressure (psia) 2584.43 2585.56 2583.04 Maximum SG Pressure (psla) 1181.86 1177.13 1176.94 Maximum Steam Line Pressure (psia) 1172.76 1164.69 1163.83 AU cases in Table 4-2 had a maximum RCS pressure that is well below the maximum RCS pressure from the Startup Accident. All cases in Table 4-2 also had a maximum SG pressure that is well below the 1279.7 psia Code requirement for the E-OTSGs. In two cases, having three MSSVs inoperable produced acceptable results when compared to the 1169.7 psia Code requirement for the steam lines.

Although two cases had acceptable results with three MSSVs out of service, the case with MS-V 170, MS-V18D, and MS-V20D out of service resulted in a maximum steam line pressure of 1172.76 psia, which exceeds the Code requirement and is unacceptable. Therefore, fun power operation should not be allowed ifmore than two MSSVs are out of service on a single SG.

4.3 Additional Full Power Analyses Reference 11 summarizes full power OTSG analyses that demonstrate that the number of MSSVs out of service on one steam generator does not affect the number of MSSVs that can be out of service on the other steam generator. Reference II also demonstrated that for the OTSG, increasing the nominal setpoint for MSSVs MS-V2IA and MS-V2IB to 1050 psig has a less than minimal effect on the peak secondary pressures experienced during the Turbine Trip event initiated from 102 %FP.

Reference I includes an evaluation of the Turbine Trip event at 102% of 2772 MWt with the E-OTSG that evaluates MSSVs out of service on both steam generators and the increase in the nominal setpoint for MS-V2IA and MS-V2IB to 1050 psig. The results are summarized in Table 4-3 along with the results from similar transients listed in Table 4-2.

Paqe 41

A AAI!£VA Document No. 86-9054640~005 TMI-1 MSSV Operability Phase 2 Results Table 4*3: Turbine Trip at 102% of 2772 MWt, Additional Evaluations Valves Out of Service MS-VI7C, MS-VI7A, MS-VI7A, MS-VI7C, MS-VI70, MS-V20A, MS-V20A, MS-VI70, MS-V20D MS-VI7B MS-VI7B, MS-V200, Increased Setpoint Maximum RCS Pressure (psia) 2585.56 2583.04 2584.32 Maximum sa Pressure (psia) 1177.13 1176.94 1176.60 Maximum Steam Line Pressure (psia) 1164.69 1163.83 1164.19 All three cases in Table 4-3 meet the applicable acceptance criteria. The peak steam line pressure is comparable in all three cases. The results contirm that having MSSVs out of service on one steam generator does not affect the number that can be out of service on the other steam generator. The results also demonstrate that it is acceptable to increase to the nominal setpoint for MS-V21 A and MS-V21 B to 1050 psig.

Page 42

A ARl!VA Document No. 86-9054640-005 TMI-1 MSSV Operability Phase 2 Results 5.0 REDUCED POWER RESULTS Reference 6 developed a TMI-I model at 92% of 2772 MWt with the E-OTSGs. Reference I developed a TMI-I model at 62% of 2772 MWt with the E-OTSGs. Both models are consistent with Reference 4.

5.1 92% of 2712 MWt with Three MSSVs Out of Service The Turbine Trip event was evaluated in Reference 6 using an initial power level of 92% of 2772 MWt for three MSSVs out of service. The full power analysis determined that the limiting combination of three MSSVs out of service occurred when valves MS-VI7D, MS-VI8D, and MS-V20D were removed from service. This combination was repeated in Reference 6 at 92 %FP with and without pressurizer spray. The Reference 6 results for peak RCS pressure and peak SG pressure are presented in Table 5-1.

The peak steam line pressure results from Reference 6 were adjusted in Reference I to remove excess conservatism and provide a consistent basis for comparison to other Reference 1 evaluations. Table 5-1 contains the adjusted peak steam line pressures from Reference I. Table 5-1 also contains the results from an analysis in Reference I, which has the same MSSVs out of service but with the nominal setpoint for MS-V21 A and MS-V21 B increased to 1050 psig.

Table 5-1: Turbine Trip at 92% of 2772 MWt, Three MSSVs Out of Service Valves Out of Service MS-VI7D, MS-VI7D, MS-VI7D, MS-VI8D, MS-VI8D, MS-VI8D, MS-V20D, MS-V20D, MS-V20D, Pressurizer No Pressurizer No Pressurizer Spray Spray Spray, Increased Setpoint Maximum RCS Pressure (psia) 2568.13 2578.82 2578.30 Maximum SG Pressure (psia) 1174.42 1174.08 1174.28 Maximum Steam Line Pressure (psia) 1165.19 1164.85 1164.87 The resulting maximum RCS pressure is well below the maximum RCS pressure 2707.69 psia in the Startup Accident. The maximum SG pressure is significantly less than the 1279.7 psia Code requirement for the E-OTSGs. The maximum steam line pressure of 1165.19 psia is less than the 1169.7 psia Code requirement for the steam lines and is therefore acceptable. The results show that pressurizer spray increases the maximum steam line pressure by 0.34 psia and increasing the nominal setpoint for MSSVs MS-V2IA and MS-V21B to 1050 psig increases the maximum steam line pressure by 0.02 psia. The results demonstrate that operation is acceptable at 92% of2772 MWt with the E-OTSGs, as many as three MSSVs out of service, and an increase in the nominal setpoint for MSSVs MS-V2IA and MS-V2l B to 1050 psig.

A ARIEVA Document No. 86*9054640-005 TMI-1 MSSV Operability Phase 2 Results 5.2 92% of 2772 MWt with Four MSSVs Out of Service Since there was margin to the limit with only three MSSVs out of service, the Turbine Trip event was evaluated in Reference I using an initial power level of92% of2772 MWt for four MSSVs out of service. The combination ofMSSVs removed from service completely removes all MSSVs from a single steam line while also removing two full-sized MSSVs with the lowest nominal setpoint of 1050 psig. Since the peak pressure the steam lines is more limiting than the peak pressure in the E-OTSG, the combination chosen is the limiting combination for tour MSSVs out of service. Table 5-2 shows the results.

Table 5-2: Turbine Trip at 92% of 2772 MWt, Four MSSVs Out of Service, E-OTSG Valves Out of Service MS-VI7D, MS-VI9D, MS-VI8D, MS-V20D Maximum RCS Pressure (psia) 2583.80 Maximum SG Pressure (psia) 1194.62 Maximum Steam Line Pressure (psia) 1187.43 The maximum RCS and SG pressure were less than the applicable limits, however, the steam line pressure of 1187.43 psia exceeded the 1169.7 psia Code requirement for the steam lines and is therefore unacceptable. As a result, operation at 92% of 2772 MWt should not be allowed if more than three MSSVs are out of service on a single SG.

5.3 62% of 2772 MWt with Four MSSVs Out of Service The Turbine Trip event was evaluated in Reference 1 using an initial power level of 62% of 2772 MWt tor four MSSVs out of service. The combination of valves chosen represents the limiting combination tor tour MSSVs out of service, as explained in Section 5.2. Table 5-3 shows the results.

Table 5-3: Turbine Trip at 62% of 2772 MWt, Four MSSVs Out of Service, E-OTSG Valves Out of Service MS-VI7D, MS-VI9D, MS-VI8D, MS-V20D Maximum RCS Pressure (psia) 2578.72 Maximum SG Pressure (psia) I 153.43 Maximum Steam Line Pressure (psia) 1149.36 The maximum RCS and SG pressure were less than the applicable limits. Furthermore, the steam line pressure of 1149.36 psia is considerably less than the 1169.7 psia Code requirement for the steam lines.

The results demonstrate that operation at 62% of 2772 MWt is acceptable with the E-OTSGs with as many as four MSSVs out of service.

Paoe44

A API_VA Document No. 86~9054640~005 TMI~1 MSSV Operability Phase 2 Results 5.4 62% of 2772 MWt with Five MSSVs Out of Service With four MSSVs out of service at of2772 MWt, the peak steam line pressure from a Turbine Trip still had 20 of margin to the limit. Therefore, the Turbine Trip event was evaluated with additional MSSVs out of service. For conservatism, the evaluation removed five full sized MSSVs from service on both steam generators and also removed MS-V2IA and MS-V21B from service. The evaluation bounds the case with five MSSVs out of service per steam generator and the nominal setpoint increased in MS~

V21A and MS~V21B to 1050 psig. The results are shown in Table 5~4.

Table 5-4: Turbine Trip at 61% of 1771 MWt, Five Fnll-Sized MSSVs Out of Service per E-OTSG Valves Out of Service MS-V17A, MS-V21B, MS-VI8A, MS-V17C, MS-V19A, MS-V17D, MS-V20A, MS-V18D, MS-V21A, MS-V19D, MS-V 17B MS-V20D Maximum RCS Pressure (psia) 2598.09 Maximum SO Pressure (psia) 1169.01 Maximum Steam line Pressure (psia) 1164.94 The RCS pressure of 2598.09 psia is well below the maximum RCS pressure for the Startup Event. The maximum SO pressure of 1169.01 psia remained below the 1279.7 psia Code requirement for the E-OTSGs. The maximum steam line pressure of 1164.94 psia is also less than the 1169.7 psia Code requirement for the steam lines. Since acceptable results are obtained when MS-V21 A and MS-V21 B are completely removed from service, it follows that the results would also be acceptable if the nominal setpoint is increased to 1050 psig.

5.5 Limits at Intermediate Power Levels Reference 1 used explicit evaluations of the Turbine Trip event with the E-OTSO to determine that two MSSVs can be out of service per SG at 102% of 2772 MWt, that three MSSVs can be out of service per SG at 92% of 2772 MWt, and that five MSSVs can be out of service per SG at 62% of 2772 MWt.

Reference I determined that for the OTSO, four MSSVs can be out of service at 77 %FP. Reference 1 used a linear relationship between the power and the peak SG pressure to verify that 77 %FP is conservative for allowing four MSSVs out of service per SG with the E-OTSGs.

The Turbine Trip at 92% of 2772 MWt with MS-V17D, MS-V18D, MS-V19D and MS-V20D out of service resulted in a peak steam line pressure of 1187.43 psia. The Turbine Trip at 62% of 2772 MWt with MS-V 17D, MS-V 18D, MS-VI9D and MS-V20D out of service resulted in a peak steam line pressure of 1149.36 psia. Based on a linear relationship, the peak steam line pressure would be less than or equal to the 1169.7 psia Code requirement for the steam lines for power levels less than or equal to 78% of 2772 MWt. Therefore, the 77 %FP maximum power determined for four MSSVs out of service

A AFtEVA Document No. 86-9054640-005 TMI-1 MSSV Operability Phase 2 Results for the OTSGs is applicable for the E-OTSGs with a I %FP of margin. The I %FP margin is more than sufficient to account for the effects of pressurizer spray and the increase in the nominal setpoint for MS-V21 A and MS-V21 B to 1050 psig.

Table 5-5 summarizes the maximum analyzed power levels shown to be acceptable as a function of the number of MSSVs that can be out of service per SG.

Table 5-5: Maximum Analyzed Power Level versns Number of MSSVs Allowed Out of Service Maximum Number of Total Number of MSSVs Maximum Acceptable MSSVs Allowed Out of Service Power Level Analyzed Allowed Out of Service (%FP) per Steam Generator 2 4 102 3 6 92 4 8 77 5 10 62 The licensing basis of the plant ensures that full power operation will not exceed 102% of the rated thermal power level. Therefore, analyzing the full power case at 102% of the rated power level is sufficient for verifying that two MSSVs can be out of service at full power. For more than two MSSVs out of service on a single SG, the overpower trip setpoint should be reset as described in Section 6.0 to ensure that the analyzed power level is protected.

Pa~46

A ARIEVA Document No. 86-9054640-005 TMI-1 MSSV Operability Phase 2 Results 6.0 OVERPOWER TRIP SETPOINTS AND NOMINAL OPERATING POWER The analyzed power levels of 102%, 92%, 77%, and 62% of 2772 MWt represent the max.imum power that the plant can be at when a Turbine Trip occurs with as many as 2, 3, 4, and 5 MSSVs out of service per SG, respectively. The licensing basis of the plant ensures that normal full power operation will occur at 100% of the rated thermal power level and wilJ not ex.ceed 102% of the rated power level. Therefore, allowing 2 MSSVs out of service per SG at full power is protected by the analyzed power level of 102%

of rated thermal power and the plant licensing basis. For more than two MSSVs out of service on a single SG, normal operation should be restricted to power levels that are less than the acceptable analyzed power level to provide margin to the limit. Furthermore, if more than two MSSVs are out of service on a single SG, the overpower trip setpoint should be adjusted to ensure that the plant does not exceed the maximum acceptable analyzed power level for a given number of MSSVs out of service on a single SG.

The overpower trip setpoint should be reduced in the event that more than 2 MSSVs are out of service on a single SG. The overpower trip setpoint is listed in TMI-I TS [Reference 7 Table 2.3-1] as 105.1

%FP. Reference 1 notes that the 105.1 %FP overpower trip setpoint ensures that a reactor trip will occur during a transient prior to the core power reaching 112% FP when all uncertainties are considered.

Using the 6.9 %FP string error for the overpower trip setpoint (112 %FP 105.1 %FP = 6.9 %FP), the overpower trip setpoint becomes 85.1 %FP (92 %FP 6.9 %FP) with three MSSVs out of service per SG, 70.1 %FP (77 %FP 6.9 %FP) with four MSSVs out of service per SG, and 55.1 %FP (62 %FP-6.9 %FP) with five MSSVs out of service per SG.

The normal operating power should also be adjusted with more than 2 MSSVs out of service on a single SG. Normal full power operation is 100 %FP, which has 5.1 %FP of margin between the nominal operating power and the overpower trip setpoint. This margin will be preserved for the reduced power cases. The recommended nominal power level is therefore 80 %FP (85.1 %FP 5.1 %FP) with three MSSVs out of service per SG, 65 %FP (70.1 %FP - 5.1 %FP) with four MSSVs out of service per SG, and 50 %FP (55.1 %FP 5.1 %FP) with five MSSVs out of service per SG.

Table 6-1 summarizes the overpower trip setpoints and the recommended maximum nominal operation power level as a function of the number of MSSVs that can be out of service per SG. Table 6-2 presents the same information in Table 6-1, but lists the information by the number of MSSVs that must be in service instead of the number that can be out of service. Table 6-1 and Table 6-2 do not restrict which MSSVs are removed from service on a SG. However, the ASME code requires each SG to have an operable MSSV with a nominal setpoint that is:s 1050 psig. Table 6-1 and Table 6-2 are applicable for the E-OTSGs and a rated power level of:S 2772 MWt.

Page 47

A AREVA Document No. 86-9054640-005 TMI-1 MSSV Operability Phase 2 Results Table 6-1: Overpower Trip Setpoint and Maximum Nominal Power Level versus Number of MSSVs Allowed Out of Service Maximum Number of Total Number of Maximum Overpower Maximum Nominal MSSVs MSSVs Allowed Out Trip Setpoint (%FP) Operating Power Out of Service per of Service (%FP)

Steam Generator 2 4 See TS Table 2.3-1 100 3 6 85.1 80 4 8 70.1 65 5 10 55.1 50 Table 6-2: Overpower Trip Setpoint and Maximum Nominal Power Level versus Number of Required Operable MSSVs Minimum Number of Minimum Number of Maximum Overpower Maximum Nominal MSSVs MSSVs Operable Trip Setpoint (%FP) Operating Power Operable per Steam (%.FP)

Generator 7 14 See TS Table 2.3-1 100 6 12 85.1 80 5 10 70.1 65 4 8 55.1 50 Pa.<<je 48

A ARBVA Document No. 86-9054640-005 TMI-1 MSSV Operability Phase 2 Results 7.0

SUMMARY

OF SUGGESTED CHANGES The following are the suggested changes to TMI-l TS 3.4.1.2.3 and the associated bases. These are the same changes suggested for the OTSG in Reference ll, except for the power level (2772 MWt) in the bases.

3.4.1.2.3 Except as provided in Specification 3.4.1.2.2 above, when the Reactor is above HOT SHUTDOWN, seven (7) MSSVs per steam generator shall be OPERABLE. If either Steam Generator has less than seven (7) MSSVs that are OPERABLE, then reduce the power and reset the overpower trip setpoint (see Table 2.3-1) as follows:

Maximum Minimum Number of Overpower Trip MSSVs Operable on each Setpoint Steam Generator (% of Rated Power) 7 see Table 2.3-1 6 85.1 5 70.1 4 55.1 With less than four (4) MSSVs OPERABLE per steam generator, restore at least four (4)

MSSVs on each steam generator to OPERABLE status within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> or be in HOT SHUTDOWN within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

At least one (l) OPERABLE MSSV on each steam generator must have a nominal lift setpoint S 1050 psig. If either steam generator does not have at least one (l) OPERABLE MSSV with a nominal lift setpoint S 1050 psig, restore at least one (1) MSSV with a nominal setpoint S 1050 psig on each steam generator to OPERABLE status within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> or be in HOT SHUTDOWN within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

3.4 Bases The MSSVs will be able to relieve to atmosphere the total steam flow if necessary. Below 5% power, only a minimum number of MSSVs need to be operable as stated in Specifications 3.4.l.2.1 and 3.4.1.2.2. This is to provide steam generator over pressure protection during hot functional testing and low power physics testing. Additionally, when the Reactor is between hot shutdown and 5% full power operation, the overpower trip setpoint in the RPS shall be set to less than 5% as is specified in Specification 3.4.l.2.2. The minimum number of MSSVs required to be operable allows margin for testing without jeopardizing plant safety. Plant specific analysis shows that one MSSV is sufficient to relieve reactor coolant pump heat and stored energy when the reactor has been subcritical by 1% delta K/K for at least one hour. Other plant analyses show that two (2) MSSVs on either OTSG are more than sufficient to relieve reactor coolant pump heat and stored energy when the reactor is below 5% full power operation but had been subcritical by I % delta K/K for at least one hour subsequent to power operation above 5% full power. According to Specification 3.l.1.2a, both steam generators shall be Paqe49

A ARIIVA Document No. 86-9054640-005 TMH MSSV Operability Phase 2 Results operable whenever the reactor coolant average temperature is above 250 degrees F. This assures that all four (4) MSSVs are available for redundancy.

During power operations at 5% full power or above, if more than two MSSVs are inoperable on a single steam generator, the power level and overpower trip setpoint must be reduced, as stated in Specification 3.4.1.2.3 such that the remaining MSSVs can prevent overpressure on a turbine trip. The turbine trip event is the limiting event in terms of peak secondary pressure. Analyses have shown that overpressure will not occur if a turbine trip occurs with two or less MSSVs out of service on each steam generator and an initial power level less than or equal to 102% of 2772 MWth. Having MSSVs out of service as allowed by Specification 3.4.1.2.3 does not adversely impact the transient progression of the remaining Safety Analysis events. The Code requires that at least one MSSV on each steam generator be set at or below the MS System design pressure. Therefore, Specification 3.4.1.2.3 requires that each steam generator has at least one operable MSSV with a nominal setpoint ~ 1050 psig.

A AAI!VA Document No. 86*9054640*005 TMI-1 MSSV Operability Phase 2 Results 8.0 DISPOSITION OF EVENTS Reference 1 reviewed the UFSAR [Reference 9] Chapter 14 events with respect to having MSSVs out of service as allowed by Table 6-1. Reference 1 also considered the potential increase in the nominal setpoint for MSSVs MS-V21 A and MS-V21 B from 1040 psig to 1050 psig. The results of the Reference 1 disposition of events as applicable to the E-OTSGs are summarized here.

The Turbine Trip event without ICS power runback and without credit for the ARTS trip signal coincident with turbine trip is the limiting transient in terms of secondary pressure for the following reasons:

• Reactor power continues at the initial power level for several seconds after the turbine has tripped, resulting is a large amount of heat transferred to the secondary side.

• Reactor coolant pumps continue to operate, adding heat and providing forced primary coolant flow that maintains a high heat transfer to the secondary side.

• Main feedwater is isolated coincident with reactor trip and emergency feedwater does not have time to initiate before the peak secondary side pressure is reached.

All other UFSAR Chapter 14 events are less limiting in tcrms of the peak secondary pressure response.

Since the Turbine Trip event without ICS power runback and without credit for the ARTS trip signal coincident with turbine trip was used to determine Table 6-1, it follows that the peak secondary pressure for all UFSAR Chapter 14 events will also be acceptable with the MSSVs out of service as allowed by Table 6-1. Furthermore, since the Turbine Trip event without ICS power runback and without credit for the ARTS trip signal coincident with turbine trip was used to justify an increase in the nominal setpoint for MS-V21A and MS-V21B to 1050 psig, it follows that the peak secondary pressure for all UFSAR Chapter 14 events will also be acceptable with an increase in the nominal setpoint for MS-V21 A and MS-V21 B to 1050 psig.

In addition to the peak secondary pressure considerations, the UFSAR Chapter 14 events were reviewed in Reference 1 to determine if having MSSVs out of service as allowed by Table 6-1 or increasing the nominal setpoint for MS-V21 A and MS-V21 B would affect the ability of the AOR to meet the applicable acceptance criteria.

For the following UFSAR Chapter 14 events, the MSSV characteristics do not have any bearing on the ability of the transient to meet the applicable acceptance criteria. This is true for both OTSGs and E-OTSGs. Therefore, MSSV characteristics are not considered in the AOR:

• UFSAR Section 14.1.2.1 - Uncompensated Operating Reactivity Changes

• UFSAR Section 14.1.2.2 - Startup Accident

• UFSAR Section 14.1.2.5 - Cold Water Accident

• UFSAR Section 14.1.2.6 - Loss of Coolant Flow

• UFSAR Section 14.2.2.1 - Fuel Handling Accident

• UFSAR Section 14.2.2.5 - Maximum Hypothetical Accident

• UFSAR Section 14.2.2.6 - Waste Gas Tank Rupture

A AAIEVA Document No. 86-9054640-005 TMI-1 MSSV Operability Phase 2 Results

• UFSAR Section 1.4.2.2.8 Fuel Cask Drop Accident For the foUowing UFSAR Chapter 14 events, the MSSVs may open following reactor trip, but the abi lity of the transient to meet the acceptance criteria is limited by the system characteristics that occur betore the MSSVs open. This is true for both OTSGs and E-OTSGs. Therefore, the MSSV characteristics do not change the ability of the following events to meet the applicable acceptance criteria.

• UFSAR Section 14.1.2.3 Rod Withdrawal at Rated Power Operation

• UFSAR Section 14. 1.2.4 Moderator Dilution Accident

• UFSAR Section 14.1.2.7 - Stuck-Out, Stuck-In, or Dropped Control Rod Accident

• Reference 10 Dropped Rod without leadscrew

• UFSAR Section 14.1.2.11 - Anticipated Transients Without Scram (Loss of Main Feed Water)

• UFSAR Section 14.2.2.2 Rod Ejection Accident

• UFSAR Section 14.2.2.7 and Reference 12 - Loss of Feedwater Accident

• UFSAR Section 14.2.2.9 and Reference 1.5 - Feedwater Line Break Accident The remaining Chapter 14 events are dispositioned separately as summarized below.

The Loss of Electric Power event with ICS unit runback, described in UFSAR Section 14.1.2.8.2, is not possible with the current RPS high pressure trip setpoint and PORV setpoint. Nevertheless, if the analysis were performed with the original RPS and PORV setpoints, MSSVs out of service as allowed by Table 6-1, and an increase in the nominal setpoint for MS-V21A and MS-V21B to 1050 psig, the effect on the AOR would be less than minimal. By definition, this transient maintains the RCS pressure below the RPS trip setpoint and therefore does not challenge the RCS pressure acceptance criteria.

Similarly, the ICS runback on unit power ensures that fuel damage does not occur from an excessive power-to-flow ratio. There is no effect on the dose consequences of the AOR because the steam relief to the condenser and atmosphere through the turbine bypass valves and the MSSVs can be accomplished with the MSSV capacity available with MSSVs out of service as allowed by Table 6-1. and with the increased setpoint for MS-V21 A and MS-V21 B. This event was not re-analyzed for E-OTSG since it is no longer credible.

The Loss of Electric Power event with reactor trip via the ARTS trip signal coincident with turbine trip, described in UFSAR Section 14.1.2.8.3, does not challenge the UFSAR acceptance criteria and is bounded by the Turbine Trip event without the ARTS trip signal analyzed in References 1,5, and 6.

The Station Blackout event, described in UFSAR Section 14.1.2.8.4, results in immediate reactor trip and therefore ensures that fuel damage does not occur from an excessive power-to-flow ratio. The dose consequences of the Station Blackout event are bounded by the Loss of Electric Power event with ICS unit runback. The peak primary pressure in the Station Blackout event does not occur until after the MSSVs have opened. However, the peak primary pressure in the Station Blackout event is driven by the PSV setpoint and capacity, which is not being changed. Therefore, MSSVs out of service as allowed by Table 6-1 and an increase in the nominal setpoint for MS-V2IA and MS-V2IB do not affect the ability of the AOR for the Station Blackout event to meet the applicable acceptance criteria. The effect of Page 52

A ARI!VA Document No. 86-9054640-005 TMI-1 MSSV Operability Phase 2 Results MSSV characteristics on the Station Blackout event is not dependent on the steam generator design and is therefore true for both the OTSGs and E-OTSGs.

The Steam Line Break event, described in UFSAR Section 14. 1.2.9 and analyzed in Reterence 13 for the E-OTSG, uses MSSVs in the untaulted loop after the repressurization occurs. The Steam Line Break transient progression is dominated by the blowdown and post-trip overfeed of the faulted steam generator and is less than minimally impacted by the MSSV characteristics. Theretore, MSSVs out of service as allowed by Table 6-1 and an increase in the nominal setpoint tor MS-V21 A and MS-V21 B do not atfect the ability of the AOR for the Steam Line Break event to meet the applicable acceptance criteria.

The Steam Generator Tube Rupture event, described in UFSAR Section 14.1.2.10 and analyzed for both the OTSG and E-OTSG in Reterence 14, uses the MSSVs after reactor and turbine trip to provide steam relief. The MSSV capacity with MSSVs out of service as allowed by Table 6-1 is sufficient for steam relief during the Steam Generator Tube Rupture event. The Steam Generator Tube Rupture event results in a less limiting dose consequence if the MSSV setpoint is increased or if higher setpoint MSSVs are used for steam relief. Therefore, the dose release from the AOR is bounding for a case with MSSVs out of service as allowed by Table 6-1 and an increase in the nominal setpoint for MS-V21 A and MS-V21 B.

I.n addition, MSSVs out of service as allowed by Table 6-1 and an increase in the nominal setpoint for MS-V21A and MS-V21 B have a less than minimal impact on the temperature gradients that might result in additional tube failures.

The Loss of Main Feedwater event is identified in UFSAR Section 14.1.2.11 as the most limiting ATWS event, particularly in terms of peak RCS pressure. As noted above, the peak RCS pressure in a Loss of Main Feedwater ATWS is based on the primary side conditions that occur prior to the turbine trip.

Therefore, the MSSV characteristics do not atlect the ability of the AOR for the Loss of Main Feedwater to meet the acceptance criteria. The Turbine Trip event is also a possible ATWS event. Since the ATWS analyses utilize more realistic assumptions than those typically assumed in standard safety analyses, such as realistic MSSV lift setpoints and the ICS power runback upon turbine trip, the Turbine Trip event without rcs power run back and without credit for the ARTS trip signal that was used to determine Table 6-1 is bounding in terms of secondary pressure response.

The Large Break LOCA transient, described in UFSAR Section 14.2.2.3 and verified as applicable to the E-OTSGs in Reference 16, is driven by the primary side conditions, the break size, the core decay heat, the fuel pin properties, the metal-water reaction, and the ECCS flow rates. Note that the evaluation performed in Reference 16 is based on a smaller tube plugging level for the EOTSG than the OTSG, however, the MSSVs don't playa significant role in mitigating the consequences of this event regardless of the tube plugging level. For the larger break sizes, the secondary pressure never reaches the MSSV lift setpoint and the MSSV characteristics have no affect on the Large Break LOCA transient. For those break sizes that do use the MSSVs, the MSSV characteristics have a less than minimal effect on the parameters that dominate the transient progression. Therefore, MSSVs out of service as allowed by Table 6-1 and an increase in the nominal setpoint for MS-V21 A and MS-V21 B have a less than minimal impact on the AOR for the Large Break LOCA.

Paqe 503

A A FUIVA Document No. B6~9054640~005 TMI~1 MSSV Operability Phase 2 Results The Small Break LOCA transient, described in UFSAR Section 14.2.2.4 and verified as applicable to the E~OTSGs in Reterence 16, utilizes the MSSVs for steam relief and to control secondary side pressure. Note that the evaluation performed in Reference 16 is based on a smaller tube plugging level for the EOTSG than the OTSG, however, the MSSVs don't playa significant role in mitigating the consequences of this event regardless of the tube plugging leveL For a significant portion of the Small Break LOCA transient, the secondary pressure is maintained at or near the lift setpoint for the lowest setpoint MSSVs. The AOR modeled the lift setpoint for the lowest setpoint MSSVs as 1065 psia.

MSSVs out of service as allowed by Table 6-1 and an increase in the nominal setpoint for MS-V21 A and MS-V21 B to 1050 psig does not invalidate the lift setpoint for the lowest setpoint MSSVs modeled in the Small Break LOCA AOR. The capacity of the MSSVs is sutlicient to maintain the secondary side pressure at or near 1065 psia during the Small Break LOCA even with MSSVs out of service as allowed by Table 6-1 and an increase in the nominal setpoint for MS-V21A and MS-V21 B to 1050 psig.

Therefore, MSSVs out of service as allowed by Table 6-1 and an increase in the nominal setpoint for MS-V21 A and MS-V21 B have a less than minimal impact on the AOR for the Small Break LOCA.

This concludes the disposition of events. For all UFSAR Chapter 14 events, MSSVs out of service as allowed by Table 6-1 and an increase in the nominal setpoint for MS-V2IA and MS-V2IB was shown to have a less than minimal impact on the ability of the AOR and E-OTSG specific analyses to meet the applicable acceptance criteria. Furthermore, the Turbine Trip event without ICS power runback and without credit for the ARTS trip signal coincident with turbine trip is the limiting transient in terms of secondary pressure. Therefore all UFSAR Chapter 14 events will have an acceptable peak secondary pressure with MSSVs out of service as allowed by Table 6-1 and an increase in the nominal setpoint for MS-V21 A and MS-V21 B to 1050 psig.

8.1 Technical Bulletin TB-01-6 Westinghouse Electric Company TB-07-6 is a technical bulletin concerning the credited relief capacity of the atmospheric steam relief system in Westinghouse designed NSSS. The atmospheric relief system in Westinghouse designed NSSS most closely correlates to the Atmospheric Dump Valves at TMI-I.

Although TB-07-6 does not mention B&W designed NSSS or the MSSVs, the main concerns identified in TB-07-6 were evaluated in Reference I with respect to the MSSV operability study.

The main concern ofTB-07-6 is that some Westinghouse analyses credited steam relief capacity ofSG the atmospheric steam relief without considering the following:

• The length of piping between the main steam line and the steam relief valves

• The actual size of the installed inlet and outlet piping valves

• The diffuser being smaller than the nominal size of the valves Reference I explains that the length of piping between the main steam line and the MSSVs is negligible.

Any pressure drop that might occur in the connecting piping is bounded by the conservatisms in the model, such as the conservative form loss added to account for flow turning from the steam line into the MSSVs. Reference 1 also determined that the MSSV flow areas used in the model are conservative relative to the size of the inlet and outlet piping and flanges. Therefore, the capacity of the MSSVs in the Reference I analysis is conservative.

A AFt.VA Document No. 86-9054640-005 TMI-1 MSSV Operability Phase 2 Results

9.0 REFERENCES

I) AREVA Document No. 32-9045537-001, "TMI-I MSSV Operability."

2) AREVA Document No. 43-10193PA-00, "RELAP5IMOD2-B&W For Safety Analysis ofB&W-Designed Pressurized Water Reactors."

3) AREVA Document No. 43* 10 I64PA-06, "RELAP5/MOD2-B&W An Advanced Computer Program tor Light Water Reactor LOCA and Non-LOCA Transient Analysis."

4) AREVA Document No. 51-9007375*003, "TMI-I Turbine Trip with E-OTSG AIS."

5) AREVA Document No. 32-9017996-000, "TMI-I E-OTSG Turbine Trip at Full Power."

6) AREVA Document No. 32-9020126-000, "TMI-I Turbine Trip at Reduced Power with E-OTSG."

7) *Three Mile Island, Unit I, Technical Specifications, Amendment 272.

8) *TMI Document SDBD-T 1-411 Revision 3, "System Design Basis Document for Main Stearn System. (with postings)"

9) *TMI-I Updated Safety Analysis Report, Revision 20 (with postings).

10) AREVA Document No. 86-9020266-00 I, "TMI Dropped Rod wlo Leadscrew Analysis Summary."

II) AREVA Document No. 86-9052402-00 I, "TMI-I MSSV Operability Phase I Results."

12)AREVA Document No. 32*9016024-000, "TMI-I EOTSG Loss of Feedwater Analysis."

13) AREVA Document No. 32-9012205-002, 'TMI-I EOTSG - MSLB Analysis."

14) AREVA Document No. 32-9028274-00[, "TMI-I EOTSG/OTSG Stearn Generator Tube Rupture."

15) AREVA Document No. 32-9019665-001, "TMI-I EOTSG Feedwater Line Break (FWLB)

Analysis."

(6) AREVA Document No. 51-9007383-003, "TMI-I EOTSG LOCA Safety Evaluation."

• The project manager signature on page 2 documents approval to use this reference.

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A AAItVA Document No. 86-9054640-005 TMI-1 MSSV Operability Phase 2 Results APPENDIX A: SUGGESTED LICENSE AMENDMENT REQUEST (LAR) INPUT The purpose of this Appendix is to provide suggested input for the TMI-1 license input request to support the Technical Specification changes related to MSSV operability. The following pages provide the LAR inputs based on the format outlined in Attachment B of Reference A-1. The bold, italicized portions of the LAR input indicate that these sections were not completed by AREVA and require input from Exelon.

Appendix A

References:

A-1.

• TMI Document LS-AA-101-1000, Rev. 007, "Ucense Amendment and Technical Specifications Change Request Process".

• The project manager signature on page 2 documents approval to use this reference

• • Additional supporting references for the LAR input are listed on page A-9.

Page A-1

A A FUEVA Document No. 86*9054640*005 TMI-1 MSSV Operability Phase 2 Results 1.0

SUMMARY

DESCRIPTION This evaluation supports a request to amend Operating License [Exe/on Input -license number(s)) for Three Mile Island. Unit 1.

The proposed change would revise the Operating License to maintain a higher power level in the event that main steam safety valves (MSSVs) are declared inoperable. The proposed amendment would allow at least one MSSV per steam generator to be inoperable with no required reduction in power.

providing greater operational flexibility to the plant. The proposed schedule for implementation is.....

2.0 DETAILED DESCRIPTION Technical Specification 3.4.1.2.3. as currently written. requires that all eighteen (18) MSSVs be operable above 5% power. or if any are not operable. the maximum overpower trip setpoint must be reduced from the nominal operating value of 105.1 % power to the value described in the table below.

Maximum Number of MSSVs Disabled on Any OTSG Maximum Overpower Trip Setpoint

(% of Rated Power) 1 92.4 2 79.4 3 66.3 With more than three (3) MSSVs inoperable. restore at least fifteen (15) MSSVs to operable status within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> or be hot shutdown within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

As written. the loss of a single MSSV results in a required reduction in the overpower trip setpoint.

which must be preceded by a decrease in reactor power. The purpose of the MSSVs is to proVide overpressure protection for the OTSG and the main steam lines. It has been determined by analysis that a lesser power reduction is required for overpressure protection than implied by the table above.

The analysis showed that a number of inoperable MSSVs can be allowed with no reduction in power.

The license amendment proposes to revise the table above based on recent analysis results.

As the current TS 3.4.1.2.3 is written. a reduction in power is required even for a single inoperable MSSV. This condition is overly restrictive and the proposed amendment resolves the restrictive nature of the TS and allows more operational flexibility for the plant.

The proposed amendment is an improvement to provide operational flexibility. Historically. there have been occasions where one or more MSSVs has failed operability testing. requiring a reduction in power. This is burdensome to the plant. requiring unnecessary maneuvering of the plant and reduced output. The proposed amendment will bring the TMI-1 plant more in-line with the other B&W plants and with the standard technical specifications for B&W plants (Reference 1).

A A FU£VA Document No. 86-9054640-005 TMI-1 MSSV Operability Phase 2 Results

3.0 TECHNICAL EVALUATION

The design pressure of the main steam (MS) system is 1050 psig, with the exception of the secondary side of the steam generators (SGs) which have a design pressure of 1150 psig. The MSSVs are provided for overpressure protection of the SGs and the MS system. The "A" loop of piping from the "A" SG and the "C" loop of piping from the "B" OTSG both have five MSSVs. The "B" loop of piping from the "A" OTSG and the "0" loop of piping from the "B" OTSG both have four MSSVs. The lowest MSSV setpoint is required to be set equivalent to the design pressure of the systems it protects, and accounts for a 10 psi pressure loss between the SG and the MSSV location, resulting in a lowest setpoint value of 1040 psig (one per SG). The remainder of the valve setpoints are staggered up to the highest value of 1100 psig. The MSSV setpoints and capacities are described in the following table.

Nominal Number Rated Capacity Lift Setpoint perSG per Valve pSig Ibm/hr

• 1040 1 194,900 1050 3 792,610 1060 2 799.990 1080 2 814,955 1092.5 1 824.265

• Rated capacity is based on saturated steam at the nominatli/t selpoint plus 3% accumulation The main steam system also includes Turbine Bypass Valves (TBVs) with a total capacity of about 21.4% of VWO steam flow, and Atmospheric Dump Valves (ADVs) with a total capacity of about 6.3%

of the VWO steam flow. However, only the MSSVs are credited in the analyses to demonstrate overpressure protection for the SGs and MS system.

The main steam system is discussed in Section 10.3.1 of the UFSAR. The overpressure protection provisions for the main steam system are described in Section 10.7.4 of the UFSAR.

The Turbine Trip analyses were performed in accordance with methodology [Reference 2J approved by the Nuclear Regulatory Commission (NRC). Where possible, this methodology utilizes the plant design bases to establish acceptance criteria and input boundary conditions. The approved methodology includes the manner for determining the responses of the primary system, the secondary system. and the core to postulated accidents. In addition. the methodology requires the use of conservative setpoints. valve and pump capacities, and reactivity coefficients to demonstrate adequate margin to the applicable limits. With respect to the inoperable MSSVs. the valve setpoints and sensitivity studies were used to determine the valve or combination of valves that produce the limiting secondary pressure for a given number of valves out of service.

A combined representation of the TMI-1 nuclear steam supply system (NSSS) is used to perform the Turbine Trip analyses. This representation includes the:

• reactor vessel and core;

• hot legs. cold legs. and reactor coolant pumps;

• pressurizer;

• once-through steam generators;

A ARIiVA Document No. 86-9054640-005 TMI-1 MSSV Operability Phase 2 Results

• main steam piping and valves; and,

• reactor protection system.

The RELAP5/MOD2-B&W (R5/M2-B&W) computer code (Reference 3) was used for the analysis of the Turbine Trip event. This code has been approved by the NRC for use in non-Loss of Coolant Accident (LOCA) safety analyses (Reference 2). Furthermore, this code is recognized as providing a conservative prediction of the overheating that will occur during the Turbine Trip event (Reference 2).

The code simulates RCS and secondary system operation. The reactor core model is based on a point kinetics solution with reactivity feedback for control rod assembly insertion, fuel temperature changes, and moderator temperature changes. The RCS model provides for heat transfer from the core, transport of the coolant to the SGs, and heat transfer to the SGs. The secondary model includes a detailed depiction of the main steam system, including steam relief to the atmosphere through the MSSVs and simulation of the TSVs. The secondary model also includes the delivery of feed water, both main and emergency, to the SGs. The key input assumptions for the analyses that demonstrate overpressure protection are:

• The core power is conservatively modeled to be at an uprated value compared to the current nominal plant nominal power level of 2568 MWt. The core power level is increased further to account for heat balance uncertainty.

• The heat addition from the reactor coolant pumps is modeled.

• The initial RCS pressure and Tavg are set to their nominal values, in accordance with the Reference 2 methodology.

• The initial pressurizer level is set to a minimum value, delaying reactor trip and maXimizing the heat addition to the secondary.

• The pressurizer spray function is credited, which likewise delays reactor trip.

• The pressurizer code safety valves are modeled to lift at 103% of their nominal setpoint.

• The MSSVs as described in the table above.

• A conservatively fast closure time is assumed for the turbine admission valves.

• Beginning-of-cycle kinetics parameters are chosen which maximizes RCS heatup.

• The reactor protection system actuates on high RC pressure. The analysis setpoint was adjusted for instrument uncertainty and a conservative response time is assumed prior to control rod insertion. No credit is taken for the anticipatory reactor trip system (ARTS) trip upon turbine trip.

• The tripped rod worth is calculated assuming the minimum technical specification shutdown margin of 1.0%dk/k at hot zero power.

A AAEVA Document No. 86-9054640-005 TMI-1 MSSV Operability Phase 2 Results

• The decay heat addition is based on 1.0 times the ANS 1971 standard and includes consideration of heavy actinides. The decay heat assumption bounds the 1979 ANS standard with 20 uncertainty.

• Offsite power is assumed to be available since control rod insertion is delayed, and reactor coolant pumps remain in operation maximizing heat heat addition to the reactor coolant system and heat transfer to the secondary plant.

• Single failures were considered, but no credible failures were identified that would produce more limiting consequences.

• No operator actions were modeled due to the short duration of the event.

For each of the chosen power levels, the limiting secondary side pressurization event, the turbine trip, was analyzed with various combinations of MSSVs out-of-service. The turbine trip is the event initiator, and after a short delay to close the tUrbine admission valves, the turbine sink is unavailable, and the MS system pressurizes due to the mismatch between the continued heat generation in the core and the secondary plant. The MSSVs begin to lift within 2 to 3 seconds after initiation of the event. The analyses demonstrate the number of in-service MSSVs that are required to meet the acceptance criterion to limit MS system pressure to less than 110% of the design pressure. Sufficient combinations of MSSVs were removed from service that allowed for identification of the most limiting valves to remove from service, generally the lowest setpoint, largest capacity valves. Thus the results ensure that any combination of MSSVs out of service will allow the desired overpressure protection. The results of the analysis were as follows:

Powel Level MSSVs Inoperable Maximum Steam Maximum SG

(% of 2772 MWt) (per SG) Line Pressure Pressure (psia) (psia) 102 2 1159.1 1171.0 92 3 1165.2 1174.4 62 5 1164.9 1169.0 The acceptance criteria for the analysis is that peak steam line pressure remains below 110% of 1050 psig (1169.7 psia), and that peak SG pressure remains below 110% of 1150 psig (1279.7 psia). Based on these analyses, a revision to Technical Specification 3.4.1.2.3 was developed that accounts for instrument uncertainty to arrive at maximum Technical Specification power levels for a given number of MSSVs out-of-service.

The nuclear overpower setpoint, with all MSSVs available, is 105.1% per Technical Specification Table 2.3-1. The analyses that credit the nuclear overpower trip assume 112% power after accounting for uncertainties for steady-state, transient operation, bistable measurement errors and heat-balance errors. The maximum power level for a given number of inoperable MSSVs has been established by analysis. An additional breakpoint was developed for four MSSVs out-of-service based on the results reported in the table above.

Page A-5

A ARIlVA. Document No. 86-9054640-005 TMI-1 MSSV Operability Phase 2 Results For a given number of inoperable MSSVs, the recommended nuclear overpower setpoint is determined by reducing the analyzed power level values by the maximum possible uncertainty. Then a recommended power level for operation was determined by further reducing power to allow margin between the operating power level and setpoint, such that small variations in reactor power will not result in inadvertent reactor scram. The table below summarizes the proposed Technical Specification changes to address inoperable MSSVs.

Number of Analyzed Overpower Trip Operating Power Inoperable Power Setpoint Level MSSVs per SG Level (%RTP) (%RTP)

(% RTP) 2 102 Per TS Table 100 2.3-1 3 92 85.1 80 4 77 70.1 65 5 62 55.1 50 Note that the overpower trip setpoint is not relied upon for overpressure protection during full power operation. Reactor trip occurs due to high reactor coolant system pressure, and the operating license requires that the power level remain at the licensed power level, accounting for heat balance uncertainty. At the reduced power breakpoints, there are no administrative controls to maintain the reduced power level, and therefore resetting the overpower trip setpoint provides a control to ensure the analyzed values are never exceeded for a given number of MSSVs out-of-service.

The UFSAR discusses a loss of load with reactor trip in Section 14.1.2.8.3. The acceptance criteria are related to fuel damage, excessive RCS pressure, and radiological consequences. Therefore, the discussion in this UFSAR section will be unaffected by the proposed amendment.

As described in Section 4.2, other Babcock and Wilcox (B&W) NSSS plants allow inoperable MSSVs with no reduction in power. The MSSVs are provided to prevent overpressurization, and the LCO provides assurance that the MSSVs will perform the design safety function. The precedent for is based upon the guidance of the B&W Standard Technical Specifications (Reference 1).

The function of the MSSVs is to prevent overpressurization of the MS system and the secondary side of the SGs. Analyses for TMI-1 have established the number of MSSVs required (as a function of power level) in order to satisfy the design function. Further, the analysis results demonstrate that the requirements of TS 3.4.1.2.3 are overly restrictive. In order to provide greater operational flexibility and to maximize output, the MSSVs required as a function of power level are proposed to be revised.

A ARIlVA Document No, 86~9054640~005 TMI-1 MSSV Operability Phase 2 Results

4.0 REGULATORY EVALUATION

4.1 Applicable Regylalorv Regulrements/Crlterla

[Exe/on Input .. This section describes in detail how the licensee's technical evaluation, which may 0' may not include risk infomlation, satisfies all applicable regulatory requi,ements and crite,ia. Any formal commitments to administrative controls needed to ensu,e compliance should be included in this section. The Regulatory Evaluation provides a basis that the NRC may use to find the proposed amendment acceptable.}

[Exe/on Input .. To assist the NRC, the licensee may choose to include an optional table of applicable ,egulatory requirements/criteria.}

4,.2 Precedent The ANO-1 nuclear plant, operated by Entergy, is a S&W NSSS that is very similar in design to the TMI-1 plant. The proposed amendment for TMI..1 will bring the MSSV operability requirements in-line with the current ANO..1 Technical Specification for MSSVs (3,7,1), LCO 3,7,1 for ANO..1 reqUires that seven MSSVs per SG be operable. Table 3.7.1-1 defines the maximum allowable power level, and the nuclear overpower trip setting to be implemented with multiple MSSVs out-of-service.

4.3 Ng SIgnificant Haurds Consideration

[Exe/on Input .. Provide a paragraph containing a few descriptive sentences suitable fo, use by the NRC in the Fede,al Register notice that will be published to seek public comment on the proposed amendment. Avoid slang words or undefined abbreviations 0' acronyms. This summary may duplicate wording in the licensee's cover letter and should bound the detailed changes being proposed.}

Exelon has evaluated whether or not a significant hazards consideration is involved with the proposed amendment(s) by focusing on the three standards set forth in 10 CFR 50.92, "Issuance of amendment,"

as discussed below:

1. Does the proposed amendment involve a significant increase in the probability or consequences of an accident previously evaluated?

Response: No The proposed amendment is not a change to the plant structures, systems, or components. There is no increase to the likelihood of MSSV-related failures. The MSSVs are relied upon to mitigate the effects of UFSAR Chapter 14 events including the loss of electric load, the limiting event for secondary overpressure. Analyses have successfully shown that, with reduced MSSV availability and following the power level restrictions provided in Section 3.0, the MSSVs will continue to limit the secondary pressure to less than 110% of the design pressure of the SGs and main steam system as required by ASME code. Therefore, the proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.

A AFtEVA Document No. 86*9054640*005 TMI*1 MSSV Operability Phase 2 Results

2. Does the proposed amendment create the possibility of a new or different kind of accident from any accident previously evaluated?

Response: No The proposed amendment is not a change to the plant structures, systems, or components.

Furthermore, within the current licensing basis MSSVs are accident mitigation SSCs. The current licensing basis does not include consideration of a MSSV failure as an event initiator. The proposed amendment will not fundamentally alter or create any new operator actions. Therefore, the proposed change does not create the possibility of a new or different kind of accident from any accident previously evaluated.

3. Does the proposed amendment involve a significant reduction in a margin of safety?

Response: No The limiting event forsecondary side overpressure is a loss of load event (turbine trip). The event has been analyzed for varying MSSVs out of service. The results of the analysis demonstrate that the acceptance criterion (MS and SG pressure remain less than 110% of the design pressure) is met for all combinations of inoperable MSSVs and initial power levels described in the proposed change.

Therefore, the proposed change does not involve a significant reduction in a margin of safety.

Based on the above, EGC concludes that the proposed amendment(s) does (do) not involve a significant hazards consideration under the standards set forth in 10 CFR 50.92(c), and, accordingly, a finding of no significant hazards consideration is justified.

4.4 Conclusions In conclusion, based on the considerations discussed above, (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.

5.0 ENVIRONMENTAL CONSIDERATION

[Exe/on Input. The identification of licensing and regulatory actions eligible for categorical exclusion or otherwise not requiring environmental review is the subject of 10 CFR 51.22. The categories of actions deemed "categorical exclusions" are specified by 10 CFR 51.22(c}.

Consideration of environmental factors should include sufficient detail to support a finding of categorical exclusion. For the majority of changes, it is clear that the environment will not be affected (e.g., extending a surveillance interval). Therefore, a simple statement (see below) is sufficient. If appropriate, provide more detailed information to strengthen the justification of categorical exclusion.}

Pa~e A-8

fA AREVA Document No. 86-9054640-005 TMI-1 MSSV Operability Phase 2 Results A review has determined that the proposed amendment would change a requirement with respect to installation or use of a facility component located within the restricted area, as defined in 10 CFR 20, or would change an inspection or surveillance requirement. However, the proposed amendment does not involve (i) a significant hazards consideration, (ii) a significant change in the types or a significant increase in the amounts of any effluent that may be released oftsite, or (Iii) a significant increase in individual or cumulative occupational radiation exposure.

Accordingly, the proposed amendment meets the eligibility criterion for categorical exclusion set forth in 10 CFR 51.22(c)(9). Therefore, pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the proposed amendment.

[and/or]

The proposed amendment is confined to (i) changes to surety, Insurance, and/or indemnity requirements, or (Ii) changes to recordkeeplng, reporting, or administrative procedures or requirements. Accordingly, the proposed amendment meets the eligibility criterion for categorical exclusion set forth in 10 CFR 51.22(c)(10). Therefore, pursuant to 10 CFR 51.22(b),

no environmental impact statement or environmental assessment need be prepared in connection with the proposed amendment.

6.0 REFERENCES

1. NUREG-1430, Revision 3, Standard Technical Specifications - Babcock and Wilcox Plants.

2. AREVA NP Topical Report BAW-10193PA-OO, "RELAP5/MOD2-B&W for Safety Analysis of B&W-Designed Pressurized Water Reactors".

3. AREVA NP Topical Report BAW-10164PA-06, "RELAP5/MOD2-B&W--An Advanced Computer Program for Light Water Reactor LOCA and Non-LOCA Transient Analysis".

A AREVA Document No. 86*9054640*005 TMI*1 MSSV Operability Phase 2 Results Suggested Modifications for Current TMI-1 Technical Specifications The following section repeats the suggested modifications for the current TMI-1 Technical Specifications as provided in Section 7.0 of this document

A ARIEVA Document No. 86~9054640*005 TMI*1 MSSV Operability Phase 2 Results 3.4.1.2.3 Except as provided in Specification 3.4.1.2.2 above, when the Reactor is above HOT SHUTDOWN, seven (7) MSSVs per steam generator shall be OPERABLE. If either Steam Generator has less than seven (7) MSSVs that are OPERABLE, then reduce the power and reset the overpower trip setpoint (see Table 2.3~ 1) as follows:

Maximum Overpower Minimum Number of Trip Setpoint MSSVs Operable on each (% of Rated Power)

Steam Generator 7 see Table 2.3-1 6 85.1 5 70.1 4 55.1 With less than four (4) MSSVs OPERABLE per steam generator, restore at least four (4)

MSSVs on each steam generator to OPERABLE status within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> or be in HOT SHUTDOWN within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

At least one (1) OPERABLE MSSV on each steam generator must have a nominal lift setpoint

~ 1050 psig. If either steam generator does not have at least one (1) OPERABLE MSSV with a nominal lift setpoint ~ 1050 psig, restore at least one (1) MSSV with a nominal setpoint ~

1050 psig on each steam generator to OPERABLE status within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> or be in HOT SHUTDOWN within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

3.4 Bases The MSSVs will be able to relieve to atmosphere the total steam flow if necessary. Below 5% power, only a minimum number of MSSVs need to be operable as stated in Specifications 3.4.1.2.1 and 3.4.1.2.2. This is to provide steam generator over pressure protection during hot functional testing and low power physics testing. Additionally, when the Reactor is between hot shutdown and 5% full power operation, the overpower trip setpoint in the RPS shall be set to less than 5% as is specified in Specification 3.4.1.2.2. The minimum number of MSSVs required to be operable allows margin for testing without jeopardiZing plant safety. Plant specific analysis shows that one MSSV is sufficient to relieve reactor coolant pump heat and stored energy when the reactor has been subcritical by 1% delta K/K for at least one hour. Other plant analyses show that two (2) MSSVs on either OTSG are more than sufficient to relieve reactor coolant pump heat and stored energy when the reactor is below 5% full power operation but had been subcritical by 1% delta K/K for at least one hour subsequent to power operation above 5% full power. According to Specification 3.1.1.2a, both steam generators shall be operable whenever the reactor coolant average temperature is above 250 degrees F. This assures that all four (4) MSSVs are available for redundancy.

During power operations at 5% full power or above, if more than two MSSVs are inoperable on a single steam generator, the power level and overpower trip setpoint must be reduced, as stated in Specification 3.4.1.2.3 such that the remaining MSSVs can prevent overpressure on a turbine trip. The turbine trip event is the limiting event in terms of peak secondary pressure. Analyses have shown that overpressure will not occur if a turbine trip occurs with two or less MSSVs out of service on each steam generator and an initial power level less than or equal to 102% of 2772 MWth. Having MSSVs out of service as allowed by Specification 3.4.1.2.3 does not adversely impact the transient progression of the remaining Safety Analysis events. The Code requires that at least one MSSV on each steam generator

A AFt.VA Document No. 86-9054640-005 TMI-1 MSSV Operability Phase 2 Results be set at or below the MS System design pressure. Therefore, Specification 3.4.1.2.3 requires that each steam generator has at least one operable MSSV with a nominal setpoint :$ 1050 psig.

Paae A-12

A ARIIVA Document No. 86-9054640-005 TMI-1 MSSV Operability Phase 2 Results APPENDIX B: RAI SUPPORT Following the submittal of the LAR for MSSV operability, the NRC produced five RAls. For several of the RAls, Exelon requested support from AREVA to provide part or all of the information needed to address the RAls. That support is provided in this Appendix.

A brief summary of each RAI is provided followed by the AREVA support requested for that RAI. Information provided in bold italic text provides the source reference for the information in this Appendix, but does not nessasarily need to be included in the official response to the RAls.

B.1 RAI #1 B.1.1 RAI #1 Summary RAI #1 asks why Exelon deleted the AREVA recommendation for always requiring at least one MSSV with a 1050 psig nominal setpoint to be operable.

B.1.2 Requested AREVA Support for RAI #1 AREVA was not asked to provide support for RAI #1. Exelon will prepare the response in its entirety.

B.2 RAI #2 B.2.1 RAI #2 Summary RAI #2 asks for the basis behind and assumptions used in analyzing the MSSV drift tolerance and valve accumulation.

B.2.2 Requested AREVA Support for RAI #2 The analyses model a setpoint tolerance of +3%. an accumulation of +3%. and a blowdown of

-4%. (Reference [5] Table 7-1, Reference [6] Table 7-1, Reference [1] Table 5-1, and Reference [4] Section 7.4.2).

Consistent with AREVA NP Inc. methodology [BAW-10193PA-00. Section A.3.2.3]. the MSSVs are modeled to lift to 70% open (Le. 70% of the full open area) at the nominal setpoint plus the 3% maximum lift tolerance. As the inlet pressure increases. the valve flow area is linearly increased until the valve is 100% open at 106% of the nominal lift setpoint (+3% lift tolerance plus +3% accumulation). Once the MSSV is full open. the valve will blow down at the full open area until the valve reseats at the blowdown pressure. Should the inlet pressure decrease before the valve reaches full open, the valve flow area will linearly decrease as a function of inlet pressure until the valve reseats at the blowdown pressure. The MSSV model is illustrated in Figure B-1.

Page B-1

A AREVA Document No. 86-9054640-005 TMI-1 MSSV Operability Phase 2 Results Figure B*1: Normalized MSSV Area vs. Steam Pressure Logic Diagram 1.0 --Path 1

-'-'Path 2 0.8 t1I

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z 0.2 0.0 P blowdown P lift P full Steam Pressure B.3 RAI#3 B.3.1 RAI #3 Summary RAI #3 compares a plot of peak steam line pressure (Figure 4-13) to the nominal MSSV setpoints and determined that Figure 4-13 appears to contradict Figures 4-16 through 4-19 in regards to the time in which the MSSVs actuate during the transient. The particular information requested by the NRC includes:

a. The licensee clarify whether MSSVs MS-V19A, MS-V20B, and MS-V20C open in response to the maximum steam line pressures exceeding the safety valves' setpoints during a turbine trip transient.

b. The licensee clarify the times in which the other MSSVs as described above lift open in comparison to the pressure in each steam line during the turbine trip transient.

c. For the limiting case, steam generator exit pressure is provided in Figure 4-13. The NRC staff requests a plot showing the pressure in the control volume for each steam line representing the pressure at the safety valves, and the parameters used to derive these values.

d. Please provide a nodalization diagram of the main steam system, indicating the location of each safety valve.

Page B-2

A A FUEVA Document No. 86-9054640-005 TMI-1 MSSV Operability Phase 2 Results 8.3.2 Requested AREVA Support for RAt #3 There are two reasons why the nominal MSSV setpoints and the peak steam line pressure in Figure 4-13 can not be used to predict the times at which the MSSVs would open (shown in Figures 4-16 through 4-19).

1) The first reason is that the analysis does not model the MSSVs as opening at the nominal setpoint. As explained in the response to RAI #2, the analysis conservatively models the MSSVs opening to 70% of the full open area at the nominal setpoint plus 3% lift tolerance. The pressure must rise to 106% of the nominal lift setpoint (3% lift tolerance plus 3% accumulation) before the MSSV is modeled to be fully open.

Table B-1 (Reference [5J Table 7.3) shows the correspondence between the nominal lift setpoint, the analyzed lift setpoint, and the analyzed pressure at which the valves become fully open.

Table B*1: Correspondence between Nominal Lift Setpoint and Analyzed Setpoints Nominal Setpoint 103% of Nominal Setpoint 106% of Nominal Setpoint (psig) (psia) (psia) 1040 1085.90 1117.10 1050 1096.20 1127.70 1060 1106.50 1138.30 1080 1127.10 1159.50 1092.5 1139.98 1172.75

2) The second reason that Figure 4-13 can not be used to predict the times that the MSSVs would open is that Figure 4-13 is a plot of the maximum steam line pressure. The maximum steam line pressure occurs at the steam generator exit, not at the inlet of the MSSVs.

Figure B-2 is a nodalization diagram of the TMI-1 main steam lines (Reference [5] Figure E-4). Figure B-2 shows that the control volumes (CV) plotted in Figure 4-13 (CV 650, CV 651, CV 750, and CV 751) are at the exit of the steam generator. Figure B-2 also shows that the MSSVs are attached to CV 660, CV 661, CV 760, and CV 761. Due to form losses in the steam lines, inclUding a conservative form loss added to account for diverting steam from the steam lines to the MSSVs, the pressure at the inlet to the MSSVs will be lower than the pressure at the steam generator exit. The magnitude of the pressure drop through the steam lines is dependent on the flow through the steam lines and therefore will vary for each steam line over the course of the transient.

Figures B-3 and B-4 are provided to aid in validation of the MSSV open times. Figure B-3 plots the pressure in CV 660 and CV 661. Figure B-4 plots the pressure in CV 760 and 761. (The Information for Figures B*3 and B-4 was extracted from Reference [5] computer output file TTtrans5.out (CALM)). The pressures in Figures B-3 and B-4 were compared to the analyzed lift setpoint in Table B-1 for each steam line to predict the times at which the MSSVs would open. The nominal setpoint for the MSSVs on each steam line is provided in Table 1-1.

Steam Line #1 From Table 1-1, the valves on steam line #1 and the nominal setpoints are MS-V21A (1040 psig), MS-V17A (1050 psig), MS-V20A (1050 psig), MS-V18A (1060 psig), and MS-V19A (1080 psig). Figure B-2 shows that the MSSVs on steam line 1 are connected to CV 660.

Figure B-3 shows that the pressure in CV 660 reaches the analyzed lift setpoint for MS-V21A (1085.9 psia) at - 2 seconds. MS-V21A opens but the pressure continues to rise.

Between 2.25 and 2.50 seconds, the pressure in CV 660 reaches the analyzed lift setpoint for MS-V17A and MS-V20A (1096.20 psia). As soon as these valves open, the pressure decreases slightly before beginning to rise again.

A AREVA Document No. 86-9054640-005 TMI-1 MSSV Operability Phase 2 Results The pressure in CV 660 reaches the analyzed lift setpoint for MS-V18A (1106.5 psia) at - 4 seconds. As soon as MS-V18A opens, the pressure decreases slightly before beginning to rise again.

The analyzed lift setpoint for MSN19A (1127.10 psia) is never reached by CV 660. Therefore, although MS-V19A is operable, this valve does not open.

The times listed above are consistent with Figure 4-16.

Steam Line #2 From Table 1-1, the valves on steam line #2 and the nominal setpoints are MS-V17B (1050 psig), MS-V18B (1060 psig), MS-V19B (1080 psig), and MS-V20B (1092.5 psig). Figure B-2 shows that the MSSVs on steam line 2 are connected to CV 661.

Between 2.25 and 2.50 seconds, Figure B-3 shows that the pressure in CV 661 reaches the analyzed lift setpoint for MS-V17B (1096.20 psia). When MS-V17B first opens the pressure stops increasing for about 1 second. After this time, the pressure begins to rise again.

The pressure in CV 661 reaches the analyzed lift setpoint for MS-V18B (1106.5 psia) between 3.5 and 3.75 seconds. Once MS-V18B opens, the pressure stops increasing for about 0.5 seconds before beginning to rise again.

The analyzed lift setpoint for MS-V19B (1127.10 psia) is reached by CV 661 between 6 and 6.25 seconds. As soon as MS-V19B opens, the pressure decreases slightly before beginning to rise again.

The analyzed lift setpoint for MS-V20B (1139.98 psia) is never reached by CV 661. Therefore, although MSN20B is operable, this valve does not open.

The times listed above are consistent with Figure 4-17.

Steam Une #3 From Table 1-1, the valves on steam line #3 and the nominal setpoints are MS-V21B (1040 psig), MS-V17C (1050 psig), MS-V18C (1060 psig), and MS-V19C (1080 psig), and MS-V20C (1092.5 psig). Figure B-2 shows that the MSSVs on steam line 3 are connected to CV 760.

Figure B-4 shows that the pressure in CV 760 reaches the analyzed lift setpoint for MS-V21B (1085.9 psia) between 2 and 2.25 seconds. MS-V21 B opens but the pressure continues to rise.

Between 2.25 and 2.50 seconds, the pressure in CV 760 reaches the analyzed lift setpoint for MS-V17C (1096.20 psia). As soon as this valves opens, the pressure decreases slightly before beginning to rise again.

The pressure in CV 760 reaches the analyzed lift setpoint for MS-V18C (1106.5 psia) at - 3 seconds. As soon as MSN18C opens, the pressure decreases slightly before beginning to rise again.

The analyzed lift setpoint for MS-V19C (1127.10 psia) is reached by CV 760 at -5 seconds. As soon as MS-V19C opens, the pressure decreases slightly before beginning to rise again.

The analyzed lift setpoint for MS-V20C (1139.98 psia) is never reached by CV 760. Therefore, although MS-V20C is operable, this valve does not open.

The times listed above are consistent with Figure 4-18.

A AAEVA Document No. 86-9054640-005 TMI-1 MSSV Operability Phase 2 Results From Table 1-1. the valves on steam line #4 and the nominal setpoints are MS-V17D (1050 psig), MS-20D (1050 psig), MS-V18D (1060 psig), and MSN19D (1080 psig). However, for the case analyzed, the two lowest setpoint valves (MSN17D and MS-V20D) are assumed to be Inoperable. Figure B-2 shows that the MSSVs on steam line 4 are connected to CV 761.

Figure B-4 shows that between 2.25 and 2.50 seconds, the pressure in CV 761 reaches the analyzed lift setpoint for MS-V17D and MS-V20D (1096.20 psia). Since these valves are inoperable, they do not open and the pressure continues to rise without interruption.

At -3 seconds, the pressure in CV 761 reaches the analyzed lift setpoint for MSN18D (1106.50 psia). As soon as MS-V18D opens, the pressure decreases slightly before beginning to rise again.

The analyzed 11ft setpeint for MS-V19D (1127.10 psia) is reached by CV 761 between 4.25 and 4.50 seconds.

Figure B-4 shows that once MS-V19D opens, the pressure stops increasing for - 0.5 seconds before starting to rise again.

The times listed above are consistent with Figure 4-19.

8.4 RAI #4 8.4.1 RAI #4 Summary RAI #4 refers to the discussion in Section 4.1 that Indicates that the limiting case for two MSSVs out of service is when MSN17D and MS-V20D are inoperable. The NRC staff postulates that the condition with MS-V17B and MV-V18B being Inoperable may be a more limiting case. The NRC staff requests the results of the sensitiVity study as well as the inputs and assumptions used to determine how the case with MS-V17D and MS-V20D was selected as the most limiting case.

8.4.2 Requested AREVA Support for RAI #4 As explained in Section 4.1, the MSSV setpoints and size on each steam line were used to narrow down the cases analyzed with two MSSVs out of service. The limiting case will not occur If the MSSVs out of service are on steam line #1 or steam line #3 because these steam lines each have 5 MSSVs compared to the 4 MSSVs on steam line #2 and steam line #4. For example, if the two MSSVs out of service on steam line #1 are the lowest setpolnt valves with the larger size (6 by 10 inches), steam line #1 would be left with MS-V21A (1040 psig),

MS-V18A (1060 psig), and MS-V19A (1080 psig). This condition is less limiting than taking the two lowest setpolnt valves out of service on steam line #4 because steam line #4 would be left with MS-V18D (1060 psig) and MS-V19D (1080 psig). Similany, if the two MSSVs out of service on steam line #3 are the lowest setpoint valves with the larger size (6 by 10 inches), steam line #3 would be left with MS-V21B (1040 psig), MS-V19C (1080 psig), and MS-V20C (1092.5 psig). This condition is less limiting than taking the two lowest setpoint valves out of service on steam line #2 because steam line #2 would be left with MS-V19B (1080 psig) and MS-V20B (1092.5 psig).

Although the setpoints and valve size can be used to justify not evaluating steam lines 1 and 3, the difference between steam lines 2 and 4 is more difficult to predetermine. Therefore, two cases were explicitly run. The first case (Reference [5J computer output file TTtrans4.out I CJIV) considers MS-V17B and MS-V18B (I.e. the two lowest setpoint valves on steam line #2) being out of service. The second case (Reference [5J computer output file TTtrans5.out I CALM) considers MS-V17D and MS-V20D (I.e. the two lowest setpoint valves on steam line

1. 4) being out of service. Table B-2 compares the key results from these two cases.

A A FUEVA Document No. 86-9054640-005 TMI-1 MSSV Operability Phase 2 Results Table B-2: Comparison of Cases at 102% of 2772 MWt with Two MSSVs Out of Service Valves Out of Service MS-V17B, MS-V17D, MS-V18B MS-V20D Maximum ReS Pressure (psia) 2580.47 2581.11 Maximum SG Pressure (psia) l166.59 1170.97 Maximum Steam Line Pressure (psia) 1154.79 l159.06 As Table B-2 shows, the case with MS-V17D and MS-V20D out of service resulted in a higher SG and steam line pressure. Therefore, Section 4.1 used the case with MS-V17D and MS-V20D out of service for Table 4-1 and Figures 4-1 through 4-25. Figures B-5 through B-31 are plots of the key results from the case with MS-V17B and MSV-18B out of service (the plots were generated using Reference [5J computer output file TTtrans4.out /

CJIV).

8.5 RAI #5 8.5.1 RAI #5 Summary RAI #5 requests the analysis of four MSSVs inoperable per steam generator at 77% power for confirmation that the analysis supports the requested TS changes.

8.5.2 Requested AREVA Support for RAI #5 As explained in Section 5.5, Reference [1} used a linear relationship between the power and peak SG pressure to demonstrate that 77%FP is conservative for allowing four MSSVs out of service per SG with the E-OTSGs.

Consequently, an explicit analysis at 77%FP was not performed.

Exelon has requested that AREVA document an analysis at 77%FP with four MSSVs out of service. Reference

[1} Appendix H documents the requested information.

A steady-state initialization was created at 77% of 2772 MWt (2134.44 MWt) plus 5.6 MW of net pump heat per reactor coolant pump (2156.84 MWt of heat removed by the steam generators). The initialization used a targeted RCS average temperature of 579 OF and a targeted turbine header pressure of 900 psia. The initialization achieved the targeted Tave at a slightly higher secondary side pressure (905.4 psia), which is a conservative starting point for the turbine trip transient. A heat balance versus power level for the TMI-1 plant was used to estimate the MFW enthalpy to be -420 BTUllbm when removing 2156.84 MWt by the steam generators. The MFW flow was adjusted during the steady-state to achieve the targeted conditions.

The initialized model was then used to evaluate the turbine trip transient with 4 MSSVs out of service. As explained in Section 5.2, the limiting combination occurs when the 4 MSSVs on steam line #4 (MS-V17D, MS-V18D, MS-V19D, and MS-V20D) are out of service. This combination removes all of the safety valves from a single steam line while also removing two full-sized MSSVs with the lowest nominal setpoint of 1050 psig. Since the peak pressure in the steam lines is closer to the analyzed limit than the pressure in the E-OTSGs, removing all of the MSSVs from a single steam line is the most limiting combination of 4 MSSVs out of service. Note that the turbine trip transient models MS-V21A and MS-V21 B at an increased nominal setpoint of 1050 psig.

Plots of the turbine trip transient with 4 MSSVs out of service are included in Figures B-32 to B-58. The results are summarized in Table B-3. The RCS pressure is below the maximum RCS pressure from the Startup accident (2707.69 psia). The maximum SG pressure is less than the 1279.7 psia Code requirement for the E-OTSGs.

Finally, the steam line pressure is less than the analyzed limit of 1169.7 psia.

A A FUEVA Document No. 86-9054640-005 TMI-1 MSSV Operability Phase 2 Results Table B-3: Turbine Trip at 77% of 2772 MWt, Four MSSVs Out of Service, E..QTSG Valves Out of Service MS-VI7D, MS-VI8D, MS-VI9D, MS-V20D Maximum ReS Pressure (psia) 2583.72 Maximum sa Pressure (psia) 1169.80 Maximum Steam Line Pressure (psia) 1164.12

A

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Page 6-6

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Figure B-18 TlVlI Turbine Trip at 102 % of 2772 IVI\Vt  ::tl t'11 with I7B and I8B Out of Service

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Figure 8-19 Tl\tU Turbine Trip at 102% of27721VIWt  :;:.;,

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Figure B-20 T~lI Turbine Trip at 102% of 2772 ~IWt with 17B and 18B Out of Service 300. =:'0'::;.=':", I 250 or.:

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Figure B-22 TlVH Turbine Trip at 102% of 2772lVIWt with 17B and 18B Out of Service 300 I - 'C';;:: * =::,,-, I 250 a rJl

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Figure B-23 TMI Turbine Trip at 102 % of 2772 ~lWt with 17B and 18B Out of Service 300 i-=;~' I 250 crJ

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Figure B-24 TlVlI Turbine Trip at 102% of 2772lVIWt ~

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Figure B-25 TMI Turbine Trip at 102 % of 2772 l\lWt with 17B and 18B Out of Service 18000 'r--------------------------------r'''""";;"'* UIAZ!AZ!!lAx _ IA*!AZZ""""~*---- I 15000 S

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Figure B-26 TMI Turbine Trip at 102% of 2772l\lWt 17B and 18B Out of Service 6000 i F'""':~==-. . -"'- _."",~.. '~-C' . I 5000

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Figure B-27 Tl\;U Turbine Trip at 102% of 2772l\;IWt  :::<:::

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I;'igure B-28 TMI Turbine Trip at 102% of 2772 ~1'Vt with lOut 6000 I  :=.- .- ;.z;;. ._, ;~ - - ;':':':'=" I 5000 8

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Figure 8-29 TMI Turbine Trip at 102% of 2772 ~1'Vt  ::::0 t't:1 with 17B and 18B Out of Service )2 6000 i ~-_ . _:;.-_ . _. ;-;. '",,:;,''". I 5000 8

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Figure B-30 TMI Turbine Trip at 102% of 2772 ~lWt ~

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Figure B-31 Tl\t1I Turbine Trip at 102 % of 2772 l\tI\Vt 1175 f' -----------------~~~~~:~:~~~~~~~--"F"'~'g':~:'7"""""="'~'!'''''''''''''''''''''''"----

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Figure B-32 TlVII Turbine Trip at 77% of 27721VI\Vt  ::tr

~

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Figure B-33 TMI Turbine Trip at 77% of 2772l\I\Vt With 170, 180, 190, 200 Out of Service 3200 I r~"tjFlu)( r;;'"dicii;rR;;'acfor PowerTCVAR~37d 2800 2400

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Figure B-34 T~lI Turbine Trip at 77% of 2772l\IWt With 170, 180, 190, 200 Out of Service 630 i --:.. _. -"':".";". __"'2': I 620 610 J:,I.. 600 u5

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l

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Figure B-35 TlVII Turbine Trip at 77% of 27721VIWt

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Figure B-36 TlVlI Turbine Trip at 77 % of 2772 IVIWt  ::::e t1'l With 170, 180, 190, 200 Out of Service 270

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Figure B-37 1'1\:11 Turbine Trip at 77% of 2772lVIWt  ::z:::,

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= Flux weighted (cvIiJ:j" 58) I 600 u..

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Figure B-38 Tl\H Turbine Trip at 77 % of 2772 l\ilWt With 17D, 18D, 19D, 20D Out of Service 1600 I i -~J Flux weightedTCVAR-59) l 1500 1400 1300 u...

~ 1200

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Figure B-39 TMI Turbine Trip at 77% of 27721\'1\\1t With 170, 180, 190, 200 Out of Service 16 i .~- __ ._... __ . n I 12 4::

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Figure B-40 T}\;U Turbine Trip at 77% of 2772 }\;lWt With 17D, 18D, 19D, 20D Out of Service 60000 55000 50000 45000 S

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Figure B-41 TIVII Turbine Trip at 77% of 2772l\IWt With 17D, 18D, 19D, 20D Out of Service 0.40 I r-f:'Ri{REKQ!ti2C9 I

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30 Time (s) ttl 1.-

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Figure B-42 TlVlI Turbine Trip at 77% of 2772lVI\Vt With 170, 180, 190, 200 Out of Service 3300 i r==~FlCi:) Dis~Cha:g:-'::..*~***:**~* ' I RCP Dlsc:har!~e RCP D!sc:haf!~e RCP Disc:harge (CV 290-01)

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Figure B-43 Tl\U Turbine Trip at 77% of 2772lVIWt With 170, 180, 190, 200 Out of Service 1500 I r""::itSG 1 Downcomer lev 62O::-05i'"""~ ----

630-01 730-01 1400 1300 C';l Cf.l Q..

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I 15 20 25 30 Time (s) co 1-\0 12

Figure B-44 Tl\lI Turbine Trip at 77% of 2772l\I\Vt ~

~

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13

Figure B-45 Tl\t1I Turbine Trip at 77% of 2772l\tIWt With 17D, 18D, 19D,20DOutofService 1800 I I --icl SG 1 Maj;i Feedwater Flow~Tcv 615)*1 1500 en S

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Figure B-47 T}\;lI Turbine Trip at 77% of 2772 }\;I\Vt  ::tl t:r:l With 170, 180, 190,200 Out of Service

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16

Figure B-48 TlVlI Turbine Trip at 77% of 2772lVIWt With 17D, 18D, 19D, 20D Out of Service 240 i =-- ~ -: .:.-. ;- u;:';e;:'::7.-~"i t 200 en S

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Figure B-49 TlVlI Turbine Trip at 77% of 27721\t\Vt r---------------------~=:.:...:..:.::.::.:.::::.:::::~i":'=""~~~~:;;"r--------...,

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Figure B-50 Tl\lI Turbine Trip at 77 % of 2772 lVl\Vt With 17D, 18D, 19D, 20D Out of Service 240 I r----"C ccc "_ ;C;"c"::~ ", I 200

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Figure B-51 Tl\lI Turbine Trip at 77% of 27721\11\\'t With 170, 180, 190, 20D Out of Service 12000 i "_";-:": "" ";-'-=";l I 1oo a

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Figure B-52 T~U Turbine Trip at 77 % of 2772 IVIWt With 170, 180, 190,200 Out of Service 18000 i~-----':" -_. .* ~---- . ;."::. : j 15000 S

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Figure 8-53 T~lI Turbine Trip at 77 % of 2772 ~I\Vt  :::tl t'l1 With 170, 180, 190, 200 Out of Service 6000 r------------------------------.....:....:.~:....7""''''''''::'7'''''''-''-''''''''''''''''-----

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Figure 8-54 Tl\;U Turbine Trip at 77% of 2772l\;IWt With 170, 180, 190,200 Out of Service 6000 i .";;;--=:-:;.--- ,_..* ",,':: *.;", I 5000 S

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Figure B-55 T~U Turbine Trip at 77% of 2772 ~I\Vt With 170, 180, 190, 200 Out of Service 6000 i ---- --- '" - .;--;;.-- - -"';-; -~ ;,.;;-;;.-;-;;.-; i 5000 S

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Figure B-56 T.NII Turbine Trip at 77 % of 2772 .Nf\Vt With 170, 180, 190,200 Out of Service 6000 i f"- _,,,,,,Z!2!W!2_ ,,,",- ~. - -"-" I 5000 8

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Figure B-S7 Tl\tH Turbine Trip at 77 % of 2772 l\t1\Vt With 17D, 18D, 19D, 20D Out of Service 1175

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Figure B-58 Tl\iII Turbine Trip at 77% of 2772lVIWt

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_27