PLA-5537, Proposed Amendments, Main Turbine Bypass System Operability Requirements

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Proposed Amendments, Main Turbine Bypass System Operability Requirements
ML023100282
Person / Time
Site: Susquehanna  Talen Energy icon.png
Issue date: 10/31/2002
From: Shriver B
Susquehanna
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
PLA-5537
Download: ML023100282 (27)
v • d • e


Text

Bryce L Shriver PPL Susquehanna, LLC SI j Senior Vice President and 769 Salem Boulevard

. I Chief Nuclear Officer Berwick, PA 18603 Tel. 570.542.3120 Fax 570.542 1504 blshriver@pplweb corn I

OCT 3 12002 .. TM U. S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Station OP 1-17 Washington, DC 20555 SUSQUEHANNA STEAM ELECTRIC STATION PROPOSED AMENDMENT NO. 250 TO LICENSE NPF-14 AND PROPOSED AMENDMENT NO. 215 TO LICENSE NPF-22:

MAIN TURBINE BYPASS SYSTEM OPERABILITY REQUIREMENTS Docket Nos. 50-387 PLA-5537 and 50-388 Pursuant to 10 CFR 59.90, PPL Susquehanna, LLC hereby requests the following amendment to the Susquehanna Steam Electric Station (SSES) Unit 1 and Unit 2 Technical Specifications (TS). The proposed amendment would revise the SSES TS requirements for OPERABILITY of the Main Turbine Bypass System (MTBS) bypass valves. Specifically, Surveillance Requirement (SR) 3.7.6.1 would be revised to verify one complete cycle of only each required turbine bypass valve every 31 days. Currently this Technical Specification assumes all five (5) main turbine bypass valves are required to be operable.

Attachment I to this letter presents the Safety Assessment for the proposed change. to this letter contains the "No Significant Hazards Consideration" and "Environmental Consideration" assessments.

The proposed change provides LCO requirements for operation of the facility that are consistent with the safety analyses. The proposed change does not increase the probability of initiating an analyzed event and does not alter assumptions relative to mitigation of an accident or transient event. Thus the probability or consequence of an accident previously evaluated is not significantly increased. The proposed change does not involve a physical alteration of the plant (no new or different types of equipment will

Document Control Desk PLA-5537 be installed), or a change in methods governing plant operation, thus does not create a possibility of a new or different kind of accident from previously evaluated. The imposition of less restrictive LCO requirements does not involve a significant reduction in a margin of safety, and has been evaluated to ensure that the current safety analyses and licensing basis requirements are maintained. This change does not involve a significant reduction in a margin of safety, since the required number of main turbine bypass valves will be the number assumed in the safety analysis. Therefore, the proposed amendment presents no significant hazard consideration.

The "Environmental Consideration" assessment concludes that the revision conforms to the criteria for actions eligible for categorical exclusion as specified in 10 CFR 51.22 (c) (9), and will not impact the environment. contains marked-up pages of the Unit 1 and Unit 2 Technical Specifications. contains "Camera-Ready" versions of the revised Unit I and Unit 2 Technical Specification pages. contains, for information, mark-ups of the Associated Unit 1 and Unit 2 Technical Specification Bases.

The proposed changes have been approved by the SSES Plant Operations Review Committee and reviewed by the Susquehanna Review Committee.

SSES requests approval of the proposed amendment by April 30, 2003. Once approved, the amendment shall be implemented within 60 days.

Should you have any questions or require additional information, please contact Mr. John M. Oddo at (610) 774-7596.

Sincerely, B. L. Shriver

Document Control Desk PLA-5537 Attachments: Affidavits Attachment 1 - Safety Assessment Attachment 2 -No Significant Hazards Consideration Evaluation Environmental Consideration Assessment Attachment 3 - Technical Specification Mark-ups (Units 1 & 2)

Attachment 4 - "Camera-Ready" Technical Specification Pages (Units I & 2)

Attachment 5 - Technical Specification Bases Mark-ups (Units 1 & 2)

Copy: NRC Region I Mr. S. Hansell, NRC Sr. Resident Inspector Mr. R. Janati, DEP/BRP Mr. T. G. Colburn, NRC Sr. Project Manager

BEFORE THE UNITED STATES NUCLEAR REGULATORY COMMISSION In the Matter of PPL Susquehanna, LLC: Docket No. 50-387 PROPOSED AMENDMENT NO. 250 TO LICENSE NPF-14 AND MAIN TURBINE BYPASS SYSTEM OPERABILITY REQUIREMENTS UNIT NO. 1 Licensee, PPL Susquehanna, LLC, hereby files a revision to its Facility Operating License No. NPF-14 dated July 17, 1982.

This amendment involves a revision to the Susquehanna SES Final Safety Analysis Report Specifications.

PPL Susquehanna, LLC 1 L hriver Sr. Vice-President and Chief Nuclear Officer

-S, to and Sworn this of O*--d before day subscribed me

, 2002. Notaril Sea L Laurie Minto, Notary Public Notarial Sea]

My C~ommission Expires Salem .Twp.,L.uz July 24. 2006

.e County Membe,Pe*ylna Assodatof Notates l

Notary Public

BEFORE THE UNITED STATES NUCLEAR REGULATORY COMMISSION In the Matter of PPL Susquehanna, LLC: Docket No. 50-388 PROPOSED AMENDMENT NO. 215 TO LICENSE NPF-22 AND MAIN TURBINE BYPASS SYSTEM OPERABILITY REQUIREMENTS UNIT NO. 2 Licensee, PPL Susquehanna, LLC, hereby files a revision to its Facility Operating License No. NPF-22 dated March 23, 1984.

This amendment involves a revision to the Susquehanna SES Final Safety Analysis Report.

    • ,.- i - f PPL Susquehanna, LLC By:

BL. Sýiver Sr. Vice-President and Chief Nuclear Officer Sworn 2t Noar Publi and subscribed before me this 31 day of (3rotat_,ý, 2002.

-N,- rial Seal Launr mini. N'otawy Public Salen N M* .,Jzerne Coulty Nota - r- ubli Memtoies July 24. 206o memD~ar, rennsylvaniaAssoaatOnofNOtaIMe

Attachment I to PLA-5537 Safety Assessment

Attachment 1 to PLA-5537 Page 1 of3 Safety Assessment SECTION I

SUMMARY

OF PROPOSED CHANGE In accordance with 10 CFR 50.90, PPL Susquehanna, LLC (PPL) proposes to revise the Susquehanna Steam Electric Station Units 1 and 2 (SSES) Technical Specification (TS) requirements for OPERABILITY of the Main Turbine Bypass System (MTBS) bypass valves. Specifically, Surveillance Requirement (SR) 3.7.6.1 is revised to verify one complete cycle of only each required turbine bypass valve every 31 days.

The MTBS is designed to control steam pressure when reactor steam generation exceeds turbine requirements during unit startup, sudden load reduction, and cooldown. It allows excess steam flow from the reactor to the condenser without going through the turbine.

The full bypass capacity of the system is approximately 25% of the Nuclear Steam Supply System rated steam flow. Sudden load reductions within the capacity of the steam bypass can be accommodated without reactor scram. The MTBS consists of five valves connected to the main steam lines between the main steam isolation valves and the turbine stop valve bypass valve chest. Each of these five valves is operated by hydraulic cylinders. The bypass valves are controlled by the pressure regulation function of the Turbine Electro Hydraulic Control System.

The MTBS fast opening feature is assumed to function during the turbine generator load rejection, turbine trip, and feedwater controller failure transients. Opening the bypass valves during the pressurization event mitigates the increase in reactor vessel pressure, which affects the Minimum Critical Power Ratio (MCPR) during the event. An inoperable MTBS may result in a MCPR penalty.

The current cycle-specific safety analyses, which include those analyses defined in Chapter 15 of the Final Safety Analysis Report, assume as input that four main turbine bypass valves are OPERABLE. The proposed change takes credit for the number of main turbine bypass valves assumed to be OPERABLE in the safety analyses by requiring only that number of valves to be OPERABLE. Accordingly, the proposed change requires only the number of main turbine bypass valves assumed to be OPERABLE in the safety analyses to be cycled monthly.

Attachment 1 to PLA-5537 Page 2 of 3 The applicable TS Bases are also revised to document the proposed changes and to provide supporting information. The TS Bases are revised in accordance with TS 5.5.10, "TS Bases Control Program." TS Bases mark-ups are included in Attachment 5 for information.

The proposed change provides a potential economic benefit. Currently, if one main turbine bypass valve becomes inoperable, the entire MTBS would be declared inoperable and a unit power reduction of more than 10% could be required due to the associated MCPR penalty. However, once the proposed change is implemented, one inoperable main turbine bypass valve would not necessarily require application of a MCPR penalty and a unit power reduction would not be necessary.

SECTION II DESCRIPTION AND BASIS (BOTH LICENSING AND DESIGN)

OF THE CURRENT REQUIREMENTS The existing LCO 3.7.6 requires the MTBS to be OPERABLE when the reactor THERMAL POWER is Ž 25% of RATED THERMAL POWER. SR 3.7.6.1 verifies OPERABILITY of the MTBS by requiring that each main turbine bypass valve be operated through one complete cycle every 31 days.

Currently, there is no allowance in LCO 3.7.6 to take credit for only the number of main turbine bypass valves assumed in the safety analyses. For example, if one of the five main turbine bypass valves is inoperable, two hours are allowed to either restore the inoperable main turbine bypass valve to OPERABLE status or apply the MCPR limits for an inoperable main turbine bypass valve as specified in the COLR. This requirement applies even if the safety analysis assumes less than 5 OPERABLE main turbine bypass valves.

SECTION III EVALUATION OF PROPOSED CHANGE AND BASIS The MTBS is designed to bypass main steam directly to the condenser to control the pressure in the reactor during reactor heatup and cooldown, turbine run up and run back, during power operation when more steam is generated by the reactor than is required by the turbine, and sudden load reduction. The main turbine bypass valves have both regulation capability and a fast opening response approximately equivalent to the fast closure of the turbine stop and control valves.

Attachment 1 to PLA-5537 Page 3 of 3 The safety analyses are performed using NRC-approved methods as delineated in the COLR and listed in TS 5.6.5, "Core Operating Limits Report (COLR)." The current cycle-specific safety analyses assume that four main turbine bypass valves will be OPERABLE. Since the safety analyses do not take credit for OPERABILITY of the fifth main turbine bypass valve, the proposed change does not reduce a margin of safety.

The results of the safety analyses provide inputs to the MCPR and linear heat generation rate (LHGR) operating limits provided in the COLR, and are ultimately governed by LCO 3.7.6, LCO 3.2.2, "Minimum Critical Power Ratio (MCPR)," and LCO 3.2.3, "Linear Heat Generation Rate (LHGR)." MTBS requirements in LCO 3.7.6 require adherence to more conservative operating limits in the COLR when the MTBS is inoperable.

There are no adverse effects on safety functions as a result of the proposed change. The proposed change makes the OPERABILITY requirements for the MTBS consistent with the assumptions used in the safety analyses.

SECTION IV CONCLUSIONS The proposed change is acceptable because it continues to provide the required functional capability and performance level of equipment required for safe operation of the facility.

The proposed change ensures consistency between the requirements of LCO 3.7.6 and the number of main turbine bypass valves assumed to be OPERABLE in the safety analyses.

Similar to the current requirements, if the number of OPERABLE main turbine bypass valves becomes less than the number assumed in the safety analyses, the MCPR limits specified in the COLR for an inoperable MTBS will be made applicable.

Attachment 2 to PLA-5537 No Significant Hazards Consideration Evaluation Environmental Consideration Assessment

Attachment 2 to PLA-5537 Page 1 of 3 No Significant Hazards Consideration The Commission has provided standards in 10 CFR 50.92(c) for determining whether a significant hazards consideration exists. A proposed amendment to an operating license for a facility does not involve a significant hazards consideration if operation of the facility in accordance with the proposed amendment would not (1) involve a significant increase in the probability of occurrence or consequences of an accident previously evaluated; (2) create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) involve a significant reduction in a margin of safety.

PPL Susquehanna, LLC (PPL) proposes to revise the Susquehanna Steam Electric Station, Units 1 and 2 (SSES) Technical Specifications (TS) requirements for OPERABILITY of the Main Turbine Bypass System (MTBS). Specifically, Surveillance Requirement (SR) 3.7.6.1 is revised to verify one complete cycle of only each required turbine bypass valve every 31 days.

The proposed change reflects the Improved Standard Technical Specification approach to provide LCO requirements that specify the protective conditions that are required to meet safety analysis assumptions for required features. The proposed change maintains the protection required by the safety analysis and provides flexibility for meeting the LCO without adversely affecting plant operations. The proposed change is also consistent with the plant current licensing basis, and has been evaluated and determined to not be detrimental to plant safety.

In accordance with the criteria set forth in 10 CFR 50.92, PPL has evaluated the proposed TS change and determined that it does not involve a significant hazards consideration.

The following is provided in support of this conclusion.

1. Does the proposed change involve a significant increasein the probability of occurrence or consequences of an accidentpreviously evaluated?

The proposed change provides LCO requirements for operation of the facility that are consistent with the safety analyses. Since the safety analyses do not take credit for any margin provided by the fifth main turbine bypass valve, these LCO requirements do not result in operation that will increase the probability of initiating an analyzed event and do not alter assumptions relative to mitigation of an accident or transient event. The requirements continue to ensure process variables, structures, systems, and components are maintained consistent with the current safety analyses and licensing basis. Therefore, this change does not involve a significant increase in the probability or consequences of an accident previously evaluated.

Attachment 2 to PLA-5537 Page 2 of 3

2. Does the proposed change create the possibility of a new or different kind of accidentfrom any accidentpreviously evaluated?

The proposed change does not involve a physical alteration of the plant (no new or different type of equipment will be installed) or changes in methods governing normal plant operation. The proposed change does impose different requirements.

However, the change is consistent with the assumptions in the current safety analyses and licensing basis, and has been evaluated to ensure that no new accident initiators are introduced. Thus, this change does not create the possibility of a new or different kind of accident from any accident previously evaluated.

3. Does the proposed change involve a significantreduction in a margin of safety?

The imposition of less restrictive LCO requirements does not involve a significant reduction in a margin of safety. As provided in the justification, this change has been evaluated to ensure that the current safety analyses and licensing basis requirements are maintained. This change does not involve a significant reduction in a margin of safety since the required number of main turbine bypass valves will be the number assumed in the safety analysis.

Attachment 2 to PLA-5537 Page 3 of 3 ENVIRONMENTAL CONSIDERATION ASSESSMENT 10 CFR 51.22(c)(9) identifies certain licensing and regulatory actions which are eligible for categorical exclusion from the requirement to perform an environmental assessment.

A proposed amendment to an operating license for a facility does not require an environmental assessment if operation of the facility in accordance with the proposed amendment would not (1) involve a significant hazards consideration; (2) result in a significant change in the types or significant increase in the amounts of any effluents that may be released offsite; or (3) result in a significant increase in individual or cumulative occupational radiation exposure. PPL Susquehanna, LLC has evaluated the proposed change and has determined that the proposed change meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Accordingly, pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment needs to be prepared in connection with issuance of the amendment. The basis for this determination, using the above criteria, follows:

Basis

1. As demonstrated in the No Significant Hazards Consideration Evaluation, the proposed amendment does not involve a significant hazards consideration.
2. There is no significant change in the types or significant increase in the amounts of any effluents that may be released offsite. The proposed change does not involve any physical modification or alteration of plant equipment (no new or different type of equipment will be installed) or change in methods governing normal plant operation.
3. There is no significant increase in individual or cumulative occupational radiation exposure. The proposed change does not involve any physical modification or alteration of plant equipment (no new or different.type of equipment will be installed) or change in methods governing normal plant operation.

Attachment 3 to PLA-5537 Technical Specification Mark-Ups (Units 1 & 2)

Main Turbine Bypass System 3.7.6 3.7 PLANT SYSTEMS 3.7.6 Main Turbine Bypass System LCO 3.7.6 The Main Turbine Bypass System shall be OPERABLE.

OR LCO 3.2.2. "MINIMUM CRITICAL POWER RATIO (MCPR)." limits for an inoperable Main Turbine Bypass System, as specified in the COLR, are made applicable.

APPLICABILITY: THERMAL POWER : 25% RTP.

ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. Main Turbine Bypass A.1 Satisfy the 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> System inoperable, requirements of the LCO or restore Main AND Turbine Bypass System to OPERABLE status.

Requirements of LCO 3.2.2 not met.

B. Required Action and B.1 Reduce THERMAL POWER 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> associated Completion to < 25% RTP.

Time not met.

SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.7.6.1 Verify one complete cycle of each main 31 days turbine bypass valve.

S(continued)

SUSQUEHANNA - UNIT I 3.7-15 Amendment 178

Main Turbine Bypass System 3.7.6 3.7 PLANT SYSTEMS 3.7.6 Main Turbine Bypass System LCO 3.7.6 The Main Turbine Bypass System shall be OPERABLE.

OR LCO 3.2.2. "MINIMUM CRITICAL POWER RATIO (MCPR)," limits for an inoperable Main Turbine Bypass System, as specified in the COLR, are made applicable.

APPLICABILITY: THERMAL POWER z 25% RTP.

ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. Main Turbine Bypass A.1 Satisfy the 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> System inoperable. requirements of the LCO or restore Main AND Turbine Bypass System to OPERABLE status.

Requirements of LCO 3.2.2 not met.

B. Required Action and B.1 Reduce THERMAL POWER 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> associated Completion to < 25% RTP.

Time not met.

SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.7.6.1 Verify one complete cycle of each main 31 days turbine bypass valve.

(continued)

SUSQUEHANNA - UNIT 2 3.7-15 Amendment 151

Attachment 4 to PLA-5537 "Camera-Ready" Technical Specification Pages (Units 1 & 2)

Main Turbine Bypass System 3.7.6 3.7 PLANT SYSTEMS 3.7.6 Main Turbine Bypass System LCO 3.7.6 The Main Turbine Bypass System shall be OPERABLE.

OR LCO 3.2.2, "MINIMUM CRITICAL POWER RATIO (MCPR)," limits for an inoperable Main Turbine Bypass System, as specified in the COLR, are made applicable.

APPLICABILITY: THERMAL POWER > 25% RTP.

ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. Main Turbine Bypass System A.1 Satisfy the requirements of the 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> inoperable. LCO or restore Main Turbine Bypass System to OPERABLE status.

AND Requirements of LCO 3.2.2 not met.

B. Required Action and B.1 Reduce THERMAL POWER to 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> associated Completion Time < 25% RTP.

not met.

SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.7.6.1 Verify one complete cycle of each required main 31 days I

turbine bypass valve.

(continued)

SUSQUEHANNA - UNIT 1 TS / 3.7-15 Amendment

Main Turbine Bypass System 3.7.6 3.7 PLANT SYSTEMS 3.7.6 Main Turbine Bypass System LCO 3.7.6 The Main Turbine Bypass System shall be OPERABLE.

OR LCO 3.2.2, "MINIMUM CRITICAL POWER RATIO (MCPR)," limits for an inoperable Main Turbine Bypass System, as specified in the COLR, are made applicable.

APPLICABILITY: THERMAL POWER > 25% RTP.

ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. Main Turbine Bypass A.1 Satisfy the requirements of the 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> System inoperable. LCO or restore Main Turbine Bypass System to OPERABLE AND status.

Requirements of LCO 3.2.2 not met.

B. Required Action and B.1 Reduce THERMAL POWER to 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> associated Completion Time < 25% RTP.

not met.

SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.7.6.1 Verify one complete cycle of each required main 31 days I turbine bypass valve.

(continued)

-TS / 3.7-15._ Amendment

-SUSQUEHANNA - UNIT-2

Attachment 5 Technical Specification Bases Mark-ups (Units 1 & 2)

Main Turbine Bypass System B 3.7.6 B 3.7 PLANT SYSTEMS B 3.7.6 Main Turbine Bypass System BASES BACKGROUND The Main Turbine Bypass System is designed to control steam pressure when reactor steam generation exceeds turbine requirements during unit startup, sudden load reduction, and cooldown. It allows excess steam flow from the reactor to the condenser without going through the turbine. The ass it of thes stem is 5% of the Nuclear Steam Supply System I rated steam flow. Sudden load reductions within the capacity of the steam ypass can be accommodated without reactor scram. The Main Turbine Bypass System consists of five valves connected to the main steam lines between the main steam isolation valves and the turbine stop valve bypass valve chest. Each of these five valves is operated by hydraulic cylinders.

The bypass valves are controlled by the pressure regulation function of the Turbine Electro Hydraulic Control System, as discussed in the FSAR, Section 7.7.1.5 (Ref. 1). The bypass valves are normally closed, and the pressure regulator controls the turbine control valves that direct all steam flow to the turbine. If the speed governor or the load limiter restricts steam flow to the turbine, the pressure regulator controls the system pressure by opening the bypass valves. When the bypass valves open, the steam flows from the bypass chest, through connecting piping, to the pressure breakdown assemblies, where a series of orifices are used to further reduce the steam pressure before the steam enters the condenser.

APPLICABLE SAFETY ANALYSES The Main Turbine Bypass System fast opening feature is assumed to functioi ai uring the turbine generator load rejection and feedwater controller transients, as discussed in the FSAR, Section 15.2.2 (Ref. 2).

I

-Opening the bypass valves during the pressurization event mitigates the

,tI V6 S s"n *increase in reactor vessel pressure, which affects the MCPR during the

/e event. An inoperable Main Turbine Bypass System may result in an MCPR k*.~ ~ penalty.

v--****

c The Main Turbine Bypass System satisfies Criterion 3 of the NRC Policy Statement. (Ref. 3)

(continued)

SUSQUEHANNA- UNIT 1 TS / B 3.7-27 Revision 2

Main Turbine Bypass System B 3.7.6 I

BASES (continued)

LCO The Main Turbine Bypass System fast opening feature is required to be OPERABLE to limit peak pressure in the main steam lines and maintain reactor pressure within acceptable limits during events that cause rapid pressurization, so that the Safety Limit MCPR is not exceeded. With the Main Turbine Bypass System inoperable, modifications to the MCPR limits (LCO 3.2.2, "MINIMUM CRITICAL POWER RATIO (MCPR)") may be applied to allow this LCO to be met. The MCPR limit for the inoperable Main Turbine Bypass System is specified in the COLR. An OPERABLE Main Turbine Bypass System requires the bypass valves to open in response to increasing main steam line pressure. Licensing analysis credits an OPERABLE Main Turbine Bypass System as having the bypass valve fast opening feature in response to turbine control valve or turbine stop valve closure. This response is within the assumptions of the applicable analysis APPLICABILITY The Main Turbine Bypass System is required to be OPERABLE at

> 25% RTP to en that the fuel claddin mt afe Limit is not

,u_*'1 e Violated during "4bi -tbr,Jobns As discussed in the Bases or LCO 3.2.2, su icient margin to these limits exists at

< 25% RTP. Therefore, these requirements are only necessary when operating at or above this power level.

ACTIONS A.1

,the Main Turbine Bypass System is inoperabl I1*1ýýýnse

-asKsg6 r and the MCPR limits for an ino*'era e ainT iirnlhe Bypassýys e, as specified in the COLR, are not applied, the assumptions of the design basis transient analysis may not be met. Under such circumstances, prompt action should be taken to restore the Main Turbine Bypass System to OPERABLE status or adjust the MCPR limits accordingly.

The 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> Completion Time is reasonable, based on the time to complete the Required (continued)

SUSQUEHANNA - UNIT 1 TS / B 3.7-28 Revision 2

Main Turbine Bypass System B 3.7.6 BASES ACTIONS B.1 (continued)

Action and the low probability of an event occurring during this period requiring the Main Turbine Bypass System.

If the Main Turbine Bypass System cannot be restored to OPERABLE status or the MCPR limits for an inoperable Main Turbine Bypass System are not applied, THERMAL POWER must be reduced to < 25% RTP. As discussed in the Applicability section, operation at < 25% RTP results in sufficient margin to the required limits, and the Main-Turbine Bass System

&picOe t protect fuel integrity during ther ogd The 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> Completion Time is reasonable, based on operating experience, to reach the required unit conditions from full power conditions in an orderly manner and without challenging unit systems.

SURVEILLANCE SR 3.7.6.1 REQUIREMENTS Cycling each -ain turbine bypass valve through one complete cycle of full traI.Meemonstrates that the valves are mechanically OPERABLE and will function when required. The 31 day Frequency is based on engineering judgment, is consistent with the procedural controls governing valve operation, and ensures correct valve positions. Operating experience has shown that these components usually pass the SR when performed at the 31 day Frequency. Therefore, the Frequency is acceptable from a reliability standpoint.

SR 3.7.6.2 The Main Turbine Bypass System is required to actuate automatically to perform its design function. This SR demonstrates that, with the required system initiation signals (simulate automatic actuation), the valves will actuate to their required position. The 24 month Frequency is based on the need to perform this Surveillance under the conditions that apply during a unit outage and because of the potential for an unplanned transient if the Surveillance were performed with the reactor at power.

Operating experience has shown the 24 month Frequency, which is based on the refueling cycle, is acceptable from a reliability standpoint.

(continued)

SUSQUEHANNA - UNIT 1 TS / B 3.7-29 Revision 2

BASES INSERT 1 The cycle specific safety analyses assume a certain number of OPERABLE main turbine bypass valves as an input (i.e., one through five). Therefore, the Main Turbine Bypass System is considered OPERABLE when the number of OPERABLE bypass valves is greater than or equal to the number assumed in the safety analyses. The number of bypass valves assumed in the safety analyses is specified in the COLR.

Main Turbine Bypass System B 3.7.6 B 3.7 PLANT SYSTEMS B 3.7.6 Main Turbine Bypass System BASES BACKGROUND The Main Turbine Bypass System is designed to control steam pressure when reactor steam generation exceeds turbine requirements during unit startup, sudden load reduction, and cooldown. It allows excess steam flow from the reacto LQ._.j the condenser without going through the turbine. The bypass iGEij3 capacity of the system iA25% of the Nuclear Steam Supply System rated steam flow. Sudden load reductions within the capacity of the steam bypass can be accommodated without reactor scram. The Main Turbine Bypass System consists of five valves connected to the main steam lines between the main steam isolation valves and the turbine stop valve bypass valve chest. Each of these five valves is operated by hydraulic cylinders. The bypass valves are controlled by the pressure regulation function of the Turbine Electro Hydraulic Control System, as discussed in the FSAR, Section 7.7.1.5 (Ref. 1). The bypass valves are normally closed, and the pressure regulator controls the turbine control valves that direct all steam flow to the turbine.

If the speed governor or the load limiter restricts steam flow to the turbine, the pressure regulator controls the system pressure by opening the bypass valves. When the bypass valves open. the steam flows from the bypass chest, through connecting piping, to the pressure breakdown assemblies, where a series of orifices are used to further reduce the steam pressure before the steam enters the condenser.

APPLICABLE The Main Turbine Bypass System fast opening feature is SAFETY ANALYSES assumed to functio during the turbine generator load rejection and feedwater controller failure transients, as discussed in the FSAR, Section 15.2.2 (Ref. 2). Opening the bypass valves during the pressurization event mitigates the increase during thein event.

reactor vessel pressure, which affects the MCPR An inoperable Main Turbine Bypass System may result in an MCPR penalty.

The Main Turbine Bypass System satisfies Criterion 3 of the NRC Policy Statement. (Ref. 3)

(continued)

SUSQUEHANNA - UNIT 2 B 3.7-27 Revision 0

Main Turbine Bypass System B 3.7.6 BASES (continued)

LCO The Main Turbine Bypass System fast opening feature is required to be OPERABLE to limit peak pressure in the main steam lines and maintain reactor pressure within acceptable limits during events that cause rapid pressurization, so that the Safety Limit MCPR is not exceeded. With the Main Turbine Bypass System inoperable, modifications to the MCPR limits (LCO 3.2.2, "MINIMUM CRITICAL POWER RATIO (MCPR)")

may be applied to allow this LCO to be met. The MCPR limit for the inoperable Main Turbine Bypass System is specified in the COLR. An OPERABLE Main Turbine Bypass System requires the bypass valves to open in response to increasing main steam line pressure. Licensing analysis credits an OPERABLE Main Turbine Bypass System as having the bypass valve fast opening feature in response to turbine control valve or turbine stop valve closure. This response is within the assumptions of the appliy-ble analysis (Ref. 2).

APPLICABILITY The Main Turbine Bypass System is required to be OPERABLE at

-25% RTP to ensure that the fuel cladding integritSafety Limit is not violated during u e OAIaIC&bl~.e 1 r e As discused i~n th~aes e for GU2 3.2.2 sufficient margin to these limits exists at

< 25% RTP. Therefore, these requirements are only necessary when operating at or above this power level.

ACTIONS A.1 If the Main Turbine Bypass System is inoperable 0 yp e er e, and the MCPR limits for an Toperable Main Tur mne Bypass System, as specified in the COLR, are not applied, the assumptions of the design basis transient analysis may not be met. Under such circumstances, prompt action should be taken to restore the Main Turbine Bypass System to OPERABLE status or adjust the MCPR limits accordingly. The 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> Completion Time is reasonable, based on the time to complete the Required Action and the low probability of an event occurring during this period requiring the Main Turbine Bypass System.

(continued)

SUSQUEHANNA - UNIT 2 B 3.7-28 Revision 0

Main Turbine Bypass System B 3.7.6 BASES ACTIONS B.1 (continued) If the Main Turbine Bypass System cannot be restored to OPERABLE status or the MCPR limits for an inoperable Main Turbine Bypass System are not applied, THERMAL POWER must be reduced to < 25% RTP. As discussed in the Applicability section. operation at < 25% RTP results in sufficient margin to the required limits, and the Main Turbine Bypass System the Sis to protect fuel integrity during Completion not required "Pen *a*oo. oaen nsen The 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />

-me is reasona e. based on operating experience, to reach in the required unit conditions from full power conditions an orderly manner and without challenging unit systems.

SURVEILLANCE SR 3.7.6.1c bie REQU IREMENTS complete Cycling each main turbine bypass valve through one are cycle of full travel demonstrates that the valves (duei - cnanica y LE and will function when required. The g S-j opp-"IV 31 day Frequency is based on engineering judgment, is consistent with the procedural controls governing valve operation, and ensures correct valve positions. Operating experience has shown that these components usually pass the SR when performed at the 31 day Frequency. Therefore, the Frequency is acceptable from a reliability standpoint.

SR 3.7.6.2 The Main Turbine Bypass System is required to actuate automatically to perform its design function. This SR demonstrates that, with the required system initiation signals (simulate automatic actuation), the valves will actuate to their required position. The 24 month Frequency is based on the need to perform this Surveillance under the conditions that apply during a unit outage and because of the potential for an unplanned transient if the Surveillance were performed with the reactor at power. Operating experience has shown the 24 month Frequency, which is based on the refueling cycle, is acceptable from a reliability standpoint.

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B 3.7-29 Revision 0 SUSQUEHANNA - UNIT 2

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