ML13133A033

License Amendment Request for Changes to Technical Specification 3/4.7.11, Ultimate Heat Sink

ML13133A033
Person / Time
Site:	Millstone
Issue date:	05/03/2013
From:	Grecheck E Dominion, Dominion Nuclear Connecticut
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
13-227
Download: ML13133A033 (48)

Text

4t Dominion Nuclear Connecticut, Inc.

0 5000 Dominion Boulevard, Glen Allen, VA 23060 o minio Web Address: www.dom.com May 3, 2013 U. S. Nuclear Regulatory Commission Serial No.13-227 Attention: Document Control Desk NSSL/MAE RO Washington, DC 20555 Docket No.

50-336 License No.

DPR-65 DOMINION NUCLEAR CONNECTICUT, INC.

MILLSTONE POWER STATION UNIT 2 LICENSE AMENDMENT REQUEST FOR CHANGES TO TECHNICAL SPECIFICATION 3/4.7.11, "ULTIMATE HEAT SINK" Pursuant to 10 CFR 50.90, Dominion Nuclear Connecticut, Inc. (DNC) requests an amendment, in the form of changes to the Technical Specifications (TS) for Facility Operating License DPR-65 for Millstone Power Station Unit 2 (MPS2). The proposed amendment would modify TS 3/4.7.11, "Ultimate Heat Sink", to increase the current ultimate heat sink (UHS) water temperature limit from 75 0F to 80°F and change the TS Action to state, "With the ultimate heat sink water temperature greater than 80°F, be in HOT STANDBY within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />." provides a description and evaluation of the proposed changes to TS 3/4.7.11.

Attachments 2 and 3 contain the marked-up TS and TS Bases pages, respectively. The marked-up TS Bases pages are provided for information only. The changes to the affected TS Bases pages will be incorporated in accordance with the TS Bases Control Program when this amendment is approved.

A list of regulatory commitments is provided in Attachment 4.

The proposed amendment does not involve a Significant Hazards Consideration pursuant to the provisions of 10 CFR 50.92. The Facility Safety Review Committee has reviewed and concurred with the determinations herein.

Issuance of this amendment is requested no later than May 5, 2014, with the amendment to be implemented within 60 days of issuance.

In accordance with 10 CFR 50.91(b), a copy of this license amendment request is being provided to the State of Connecticut.

ADOo

Serial No.13-227 Docket No. 50-336 Page 2 of 3 If you have any questions or require additional information, please contact Wanda Craft at (804) 273-4687.

Sincerely, Eugene S. Grecheck Vice President - Nuclear Engineering and Development COMMONWEALTH OF VIRGINIA

)

COUNTY OF HENRICO The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by Eugene S. Grecheck, who is Vice President - Nuclear Engineering and Development of Dominion Nuclear Connecticut, Inc. He has affirmed before me that he is duly authorized to execute and file the foregoing document in behalf of that Company, and that the statements in the document are true to the best of his knowledge and belief.

Acknowledged before me this 32ro day of V

,2013.

My Commission Expires:

• 1A' I3 11

"*P'*'

• It D SLY 4

~Notary Public i

Commonwealth of Virginia I

J My Reg. # 7518653 My Commission Expires December 31, 20 ].*

Attachments:

1. Description and Evaluation of The Proposed License Amendment

2. Marked-Up Technical Specification Page

3. Marked-Up Technical Specification Bases Pages (For Information Only)

4. List of Regulatory Commitments

Serial No.13-227 Docket No. 50-336 Page 3 of 3 cc:

U.S. Nuclear Regulatory Commission Region I 2100 Renaissance Blvd Suite 100 King of Prussia, PA 19406-2713 Nadiyah S. Morgan Project Manager U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 08 C2A 11555 Rockville Pike Rockville, MD 20852-2738 NRC Senior Resident Inspector Millstone Power Station Director, Radiation Division Department of Energy and Environmental Protection 79 Elm Street Hartford, CT 06106-5127

Serial No 13-227 Docket No. 50-336 ATTACHMENT 1 DESCRIPTION AND EVALUATION OF THE PROPOSED LICENSE AMENDMENT Dominion Nuclear Connecticut, Inc.

Millstone Power Station Unit 2

Serial No 13-227 Docket No. 50-336, Page 2 of 33 TABLE OF CONTENTS

2.0 DESCRIPTION

OF PROPOSED AMENDMENT

3.0 BACKGROUND

4.0 REGULATORY REQUIREMENTS AND GUIDANCE

6.0 REGULATORY ANALYSIS

7.0 NO SIGNIFICANT HAZARDS CONSIDERATION EVALUATION

8.0 ENVIRONMENTAL CONSIDERATION

9.0 PRECEDENTS

10.0 REFERENCES

Serial No 13-227 Docket No. 50-336, Page 3 of 33

1.0 INTRODUCTION

Pursuant to 10 CFR 50.90, Dominion Nuclear Connecticut, Inc. (DNC) requests an amendment, in the form of changes to the Technical Specifications (TS) for Facility Operating License DPR-65 for Millstone Power Station Unit 2 (MPS2). The proposed amendment would modify TS 3/4.7.11, "Ultimate Heat Sink," to increase the current ultimate heat sink (UHS) water temperature limit from 75 0F to 80°F and change the TS Action to state, "With the ultimate heat sink water temperature greater than 80'F, be in HOT STANDBY within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />."

In recent years, the UHS temperatures have approached the current TS limit during the hotter summer months, typically starting in late July. This is a result of an increase in the temperature of Long Island Sound, the UHS for MPS2. This proposed license amendment to increase the UHS limit has been proposed to prevent an unnecessary plant shutdown during severe hot weather periods.

As part of evaluating the acceptability of the proposed increase in the UHS temperature limits, DNC has analyzed the impacts of the increased temperatures on both essential (safety related) and non-essential (non-safety related) equipment and plant events.

2.0 DESCRIPTION

OF PROPOSED AMENDMENT Currently, TS 3/4.7.11, "Ultimate Heat Sink," requires the average UHS water temperature to be less than or equal to 75 0F. The proposed amendment would modify TS 3/4.7.11 to allow an increase of the limit on UHS water temperature from 750F to 80°F and change the TS Action to state, "With the ultimate heat sink water temperature greater than 800F, be in HOT STANDBY within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />."

The bases for TS 3/4.7.11 are also being modified to address the proposed changes and are provided for information only. Changes to the TS Bases are controlled in accordance with the TS Bases Control program (TS 6.23).

3.0 BACKGROUND

The Long Island Sound is the UHS for MPS2. The service water (SW) system takes suction from the Long Island Sound, provides cooling water for various heat loads within the plant, and returns the water to the Long Island Sound after it has absorbed the heat from the various loads.

The UHS consists of the SW cooling system serving the components identified in MPS2 FSAR Section 9.7.2.1.1. The UHS supports heat removal from both safety and non-safety related heat exchangers using the SW system and circulating water (CW) system. The UHS provides sufficient cooling for more than 30 days to:

a) Permit normal full power operation, safe shutdown and cooldown of the reactor, and maintain a safe shutdown condition for MPS2 and other units at the site; b) To allow control of an accident in the event one occurs.

Serial No 13-227 Docket No. 50-336, Page 4 of 33 The design basis maximum temperature of the UHS for MPS2, Long Island Sound, is 750F per the MPS2 FSAR. The MPS2 operating license, TS 3.7.11, requires UHS temperature <

750F in order to assure operability. Action (a) of TS 3.7.11 allows continued operation of the plant with a UHS temperature up to 770F provided the water temperature averaged over the previous 24-hour period is verified < 750F at least once per hour. The UHS temperature exceeded a rolling average of 75°F during August 2012 which required a plant shutdown and associated loss of generation for a period exceeding 11 days.

Beginning on July 14, 2012, there were sixteen unplanned entries into the UHS TS 3.7.11 during July and August of 2012. The entries occurred because the UHS temperature exceeded 750F after accounting for instrument error. July 1 4 th was the earliest known unplanned entry into TS 3.7.11 in any summer season in which Millstone has operated.

Based on water temperature at the intake structure, the UHS temperature exceeded 770 F for a total of five hours, during two excursions, on the afternoons of August 1 2th and August 13 th. The UHS temperature remained above 750F for 71.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> of the 93 hours0.00108 days <br />0.0258 hours <br />1.537698e-4 weeks <br />3.53865e-5 months <br /> between August 11 th at 0430 and August 1 5 th at 0130.

In accordance with surveillance procedure, MPS2 operators use local indications rather than intake temperature above 70°F to comply with TS surveillance requirement (SR) 4.7.11. The SW temperatures measured for TS compliance showed no readings above 770F in August 2012.

In 2011, there were nine unplanned entries into TS 3.7.11 for water temperatures above 750F. In 2010, there were four unplanned entries into TS 3.7.11 for water temperatures above 750F. From 2003 - 2009, there were a total of ten unplanned entries into TS 3.7.11 and a maximum of three entries occurred per year. Before August 2012, there were no instances when the water temperature rolling average of the last 24-hours exceeded 75°F or when the intake water temperature exceeded 77°F. Collectively, this is indicative of a gradual increase in the UHS temperature over the last decade.

TS SR 4.7.11 requires the average UHS water temperature be verified to be less than or equal to the limit of 750F on a 24-hour frequency. In addition, the TS SR requires increasing the frequency of monitoring to once per 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> when average water temperature exceeds 700F. If this limit (750F) is exceeded, the TS Action is to place the plant in Mode 3 (Hot Standby) within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in Mode 5 (Cold Shutdown) within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

To address the increase in UHS temperature, Section 5.0 summarizes the analyses which support an increase in the allowable UHS temperature to 80 0F.

Serial No 13-227 Docket No. 50-336, Page 5 of 33 4.0 REGULATORY REQUIREMENTS AND GUIDANCE The applicable requirements and guidance are discussed in Sections 4.1 through 4.3. A discussion of how these requirements are addressed is presented in Sections 6.1 and 6.2.

4.1 NUREG-1432, Standard Technical Specifications - Combustion Engineering Plants Section 3.7.9, "Ultimate Heat Sink (UHS)," of NUREG-1432, Revision 4, requires the UHS be operable. Required Action B for this condition is to verify the UHS water temperature is less than or equal to the plant-specific limit averaged over the previous 24-hour period.

(This provision of averaging the UHS temperature is based on Technical Specification Task Force (TSTF)-330, Revision 3). SR 3.7.9.2 in NUREG-1432 requires verifying that the average water temperature of the UHS is less than or equal to the maximum allowed temperature on a 24-hour frequency.

4.2 Technical Specification Task Force (TSTF) -330, Revision 3 TSTF-330, "Allowed Outage Time - Ultimate Heat Sink," provides a Condition and Required Action that allow the UHS water temperature to be averaged over the previous 24-hour period. The temperature is to be monitored once per hour. The TSTF specifies four conditions that form the basis for acceptance of the UHS temperature averaging approach and requires that licensees, wishing to adopt this change to the Standard Technical Specifications (STS), confirm that these four conditions are satisfied. The NRC approved Revision 3 of TSTF-330 for use by licensees.

4.3 MPS2 Licensing Bases The proposed change is related to:

General Design Criteria (GDC) 2 - Design Bases for Protection Against Natural Phenomena

" GDC 4 - Environmental and Missile Design Bases GDC 5 - Sharing of Structures, Systems and Components

" GDC 44 - Cooling Water

" GDC 45 - Inspection of Cooling Water Systems GDC 46 - Testing of Cooling Water Systems Generic Letter (GL) 89 Service Water System Problems Affecting Safety Related Equipment

" GL 96-06, Assurance of Equipment Operability and Containment Integrity During DBA Conditions

5.0 TECHNICAL ANALYSIS

The UHS for MPS2 is Long Island Sound. Sensible and decay heat is removed from both the safety related and non-safety related cooling systems during normal operation,

Serial No 13-227 Docket No. 50-336, Page 6 of 33 shutdown, and accident conditions using the safety related SW system and the non-safety related CW system.

Plant systems were evaluated based upon the impact, directly and indirectly, of an increase in the MPS2 UHS temperature from 750F to 800F. The following systems were identified as directly impacted:

" SW System

" CW System Due to interface with directly impacted systems, the following systems were identified as being indirectly impacted:

" Emergency Diesel Generator (EDG)

" Vital Switchgear Ventilation Systems

" Reactor Building Component Cooling Water (RBCCW) System

" Turbine Building Component Cooling Water (TBCCW) System The SW thermal-hydraulic analysis was updated to demonstrate that adequate flow, under normal operation and limiting design basis scenarios, could be delivered to support cooling requirements with an 80'F UHS. The thermal-hydraulic analyses of those systems cooled by SW were revised to reflect an 80°F SW intake temperature while constrained to maintain their respective system supply side temperature design limits. Calculations associated with heat exchangers cooled by SW were revised to reflect an 80°F UHS and the impacts on those heat exchanger pressure drop surveillance limits were subsequently identified.

High accuracy resistance temperature detector transmitters at the SW inlets to the RBCCW heat exchangers are being installed to ensure compliance with the analysis assumption of an 80°F UHS temperature. These instruments have an uncertainty of 0.15 0F or less and are required to be within this limit. This instrument uncertainty is insignificant and therefore is not factored into the TS surveillance acceptance criteria. If these instruments are out of service, the alternative instruments' uncertainty is subtracted from the surveillance acceptance criteria.

Design basis information was evaluated to determine:

" which design basis calculations were impacted,

" which systems were affected and the associated impacts to pipe stress calculations, system calculations, and mechanical components,

" which instrumentation and controls process loops were affected,

" changes to equipment environmental qualification (EEQ) profiles and post-accident operating time (PAOT) for electrical equipment in containment, and

" changes to impacted Equipment Qualification Records (EQRs).

Design basis information was revised, as necessary, to support plant operation for UHS temperatures up to, and including, 80)F. These revisions were used to assess engineering programs for impact.

Serial No 13-227 Docket No. 50-336, Page 7 of 33 Mechanical components (e.g., piping, valves, heat exchangers, expansion joints, pumps, and strainers), and pipe stress and supports, were evaluated for impact as appropriate.

Water hammer analyses associated with the SW and RBCCW systems, were evaluated for impact.

Instrumentation and control process loops, associated with the affected SW and RBCCW systems, EEQ profiles, and PAOT for electrical equipment in containment, were evaluated and incorporated into the EQRs.

The impact of the change in UHS temperature on the analyses associated with the large break Loss of Coolant Accident (LOCA) and Main Steam Line Break (MSLB) was evaluated for the following:

" EEQ profile

" Containment sump temperature

" Containment heat-up on isolation valves The impact of the change in UHS temperature on containment transient temperature and pressure profiles and containment sump temperature calculations were evaluated, including:

• GSI-191 Issues

> Sump pH

> Minimum sump level

> Emergency Core Cooling System (ECCS)/ Containment Spray (CS) pump net positive suction head (NPSH)

Radiological dose calculations (LOCA doses using the Alternate Source Term)

The following MPS2 Engineering programs were evaluated for impact due to the change in UHS temperature:

0 Fire Protection/Appendix R 0 In-Service Inspection

• In-Service Testing

• Post-Accident Monitoring (Regulatory Guide 1.97) 0 Maintenance Rule 0 Coatings 0 License Renewal SW Heat Exchanger Monitoring (Generic Letter 89-13) 0 Station Blackout (SBO) 10 CFR 50 Appendix J Margin Management 0 Flow Accelerated Corrosion e Air Operated Valves 0 Motor Operated Valves

Serial No 13-227 Docket No. 50-336, Page 8 of 33 Other topics that were evaluated for impact due to the increase in UHS temperature include:

" Generic Letter 96-06

" Condenser Performance

" Systems interfacing with the SW system (e.g., SFP cooling)

" Environmental Impact Nuclear Material Control Seismic and Dynamic Qualification of Mechanical and Electrical Equipment

" Time Critical Operator Actions Failure Modes and Effects Analysis

" Licensing and Design Documents The impact of the change in UHS temperature on the CW system and main condenser was evaluated. Historical operating data was used to evaluate the impact on condenser performance.

A regulatory review was also performed to determine the impact on regulatory requirements and open, working or active commitments in the station's Regulatory Commitment Database.

Changes to licensing basis documents including; the Final Safety Analysis Report (FSAR),

Technical Requirements Manual (TRM) and the TSs and TS Bases, were evaluated for impact.

5.1 Service Water The MPS2 SW system consists of three pumps, 50 percent capacity (12,000 gallons per minute (gpm) each), which take suction from the UHS (Long Island Sound), via the intake structure, to supply cooling water to safety related and non-safety related components.

The MPS2 SW system removes heat from the following:

" RBCCW heat exchangers (X-1 8A/B/C)

" EDG heat exchangers

" Vital AC switchgear room ventilation coolers (X-1 81 A/B, X-1 82, and X-1 83)

" Vital DC switchgear room ventilation chillers (X-169A/B)

" Turbine Building Closed Cooling Water (TBCCW) heat exchangers (X-17AIB/C)

During normal operation, two of the three SW pumps are operating and provide water to the RBCCW and TBCCW heat exchangers and vital switchgear ventilation system cooling coils. On a loss-of-normal power (LNP) or a safety injection actuation signal (SIAS), SW flow to the non-safety related TBCCW system is automatically isolated (by closure of 2-SW-3.2A/B). The SW system provides cooling water to the EDG heat exchangers when those are in operation, such as in the case of a LNP or a SIAS. For unit shutdown, one SW pump and one SW header are required to provide cooling to one train of RBCCW and EDG heat exchangers, as well as switchgear coolers.

Serial No 13-227 Docket No. 50-336, Page 9 of 33 The SW system thermal-hydraulic flow analysis was evaluated to quantify the minimum available SW flow to the SW-cooled heat exchangers following an increase in SW inlet temperature from 750F to 80'F. The SW-cooled heat exchangers were also evaluated for required flow at 80'F.

This analysis demonstrated acceptable results with the following restrictions:

" The maximum allowable differential pressure (DP) for the 'A' RBCCW heat exchanger has been reduced from 10-psid to 8-psid.

" RBCCW heat exchangers must be cleaned at a 3-month interval.

" Switchgear room coolers, X1 81 A/B, must be cleaned at an 18-month interval.

" For service water temperatures above 750F, it may be necessary to also open the RBCCW winter temperature control valves (2-SW-245, 2-SW-246, and 2-SW-247) to maximize flow to the RBCCW heat exchangers to support normal operation.

SW Pumps and Strainers The SW pumps (P-5A/B/C), and their associated strainers (L-1A/B/C), were procured for inlet design temperatures of 850F and 1000F, respectively. As such, the SW pumps, strainers, and supply piping will not be affected by an increase in UHS temperature from 750F to 800F.

By calculation, the minimum Net Positive Suction Head Available (NPSHA) to the SW pumps remains greater than the Net Positive Suction Head Required (NPSHR) in the bounding cases analyzed and the minimum pump submergence criterion is met.

Structural Integrity of Piping and Components All SW system supply piping to interfacing heat exchangers and coolers is qualified to a minimum design rating of 100 psig at 100°F. The increase in the supply piping operating temperature to 80°F is fully bounded by the existing design temperature ratings of the service water supply piping.

All SW system return piping from the heat exchangers and coolers is qualified to a minimum design rating of 100 psig at 100°F with the exception of return piping from the RBCCW and EDG heat exchangers. SW return piping from the RBCCW and EDG heat exchangers are qualified to 100 psig at 150°F and 100 psig at 1250F, respectively.

A review of predicted operating conditions indicates that all SW return pressures and temperatures are bounded by the existing design ratings of the SW piping.

A piping code structural assessment for SW piping in support of an increase in the UHS temperature from 750F to 80°F validates that SW pipe stress levels, pipe supports, and equipment nozzles are acceptable for an increased UHS temperature.

Serial No 13-227 Docket No. 50-336, Page 10 of 33 5.2 Reactor Building Closed Cooling Water The function of the RBCCW system is to transfer heat from safety related structures, systems, and components to the SW system via RBCCW heat exchangers (X18A/B/C).

During normal operation, RBCCW system supply temperature is maintained below 850 F.

During shutdown and accident operations, RBCCW supply temperatures rise to 950F and 1500F, respectively.

The RBCCW system consists of two independent headers, each including one motor-driven RBCCW pump, one RBCCW heat exchanger and associated piping, valves, instrumentation, controls, and a downcomer from the RBCCW surge tank. A third RBCCW pump and heat exchanger is provided as a spare for the system. Redundant safety grade components, cooled by the RBCCW system, are split between the two independent RBCCW headers. The other systems and components cooled by the RBCCW system are divided between the RBCCW headers to equalize header heat loads. The following are cooled by the RBCCW system:

" Containment air recirculation and cooling units

" Reactor vessel support cooling coils

" Containment spray pump seal coolers

" Safety injection (SI) pump seal coolers

" Shutdown cooling heat exchangers

" Engineered Safety Features (ESF) room air recirculation and cooling units

" Reactor coolant pump thermal barrier and oil coolers

" Primary drain and quench tank heat exchanger

" Control element/rod drive mechanism coolers

" Letdown heat exchangers

" Degasifier effluent cooler and vent condenser

" Sample coolers

" Spent fuel pool heat exchangers

" Steam generator blowdown quench tank heat exchanger

" Waste gas compressor aftercoolers During normal operation, RBCCW is supplied to the above listed components with the exception of the shutdown cooling (SDC) heat exchangers, and the ESF room air recirculation and cooling units.

The design heat loads and system flow requirements for essential and non-essential equipment supplied by RBCCW during normal, shutdown, and emergency operations were evaluated against the thermal-hydraulic performance of the RBCCW system during normal, shutdown, and emergency operations with an UHS temperature of 800F.

An RBCCW supply temperature of 850F in Modes 1, 2 and 3 will be included in the FSAR and operating procedures as a design requirement of the RBCCW system. MPS2 operating procedures will be modified to maximize SW flow to the RBCCW heat exchangers and minimize RBCCW heat loads, as appropriate, whenever SW inlet

Serial No 13-227 Docket No. 50-336, Page 11 of 33 temperature exceeds 750F. Hence, the RBCCW system will be able to perform its intended function with an UHS temperature of 80 0F.

RBCCW System Operability Following LOCA A valve cavitation analysis was performed for each case at an 80°F SW inlet temperature.

Based on that analysis, the cavitation potential is consistent with the previous analysis and is considered acceptable. It was also determined that the RBCCW system provides sufficient NPSHA to operate the RBCCW pumps for all operating cases.

RBCCW Piping and Components Following LOCA RBCCW piping temperature changes have been evaluated for the effects on pipe stress and support loads and found to be acceptable.

In response to GL 96-06, the RBCCW system was evaluated to determine susceptibility for piping failures associated with water hammer events. Under this scenario, a 26-second RBCCW pump restart delay is assumed based on the EDG start and sequence times per MPS2 TRM Table 3.3-5. A void forms in the CAR cooler outlet piping during this delay and collapses following pump restart, thus creating a potential water hammer. The pressure spike induced loads on CAR cooler tubes and RBCCW piping were found to be acceptable.

Since no cooling water flow is assumed during this delay, the increase in the UHS temperature limit does not impact the evaluation for the operating train.

This potential for water hammer during a late RBCCW pump restart following a LOCA, with a single failure and loss of normal power, was evaluated. For the RBCCW pump that fails to automatically sequence on an EDG, the void formed would grow to a maximum size and then begin to shrink as containment temperatures drop. To ensure that the potential water hammer loads are bounded, the emergency operating procedure directs the operator to not attempt to manually start a RBCCW pump, unless containment pressure is less than 20 psig.

This procedural action ensures acceptable void shrinkage such that the potential water hammer loading is bound by the loading described above for the 26 second RBCCW pump restart delay based on the EDG start and sequence times per MPS2 TRM Table 3.3-5 discussed above.

It should also be noted that, subsequent to the original GL 96-06 analysis, orifices were installed in the surge tank lines. This significantly reduces the effect of a pump start water hammer.

5.3 Spent Fuel Pool The SFP cooling system is designed to remove decay heat generated by stored spent fuel assemblies by circulating borated pool water through the SFP heat exchangers. Cooling water for the SFP heat exchangers is supplied by RBCCW. During normal operation, the SFP is typically maintained at 80°F to 85°F which is well below the administrative limit of 120°F with the operation of one SFP cooling heat exchanger and one SFP cooling pump in

Serial No 13-227 Docket No. 50-336, Page 12 of 33 service. The RBCCW has sufficient capacity during normal operation to mitigate the SFP's heat load; therefore, an increase in the UHS temperature from 750F to 80°F will not impact the ability of the SFP cooling system to maintain pool temperatures below administrative limits.

Following a SIAS, RBCCW flow to the SFP cooling system is isolated by the automatic closing of valves in the cooling water discharge piping. A minimum of 4-hours post-LOCA, after RBCCW heat loads are substantially reduced, cooling water is re-established to the SFP cooling system by operator action.

It was determined that 4-hours post-LOCA, with service water at 80°F and a SFP heat load of 10.16 MBtu/hr, the maximum RBCCW supply temperature would be 1270F; this results in a peak RBCCW outlet temperature from the SFP of 141.4 0F and a peak SFP temperature of 198.4°F. Note that this is conservative as the assumed heat load is that which is present at the end of a refueling outage. This condition would not occur when UHS temperatures are elevated since refueling outages are conducted in the spring and fall.

The SFP heat exchangers and associated piping have been evaluated at this temperature and determined to be acceptable.

5.4 Emergency Diesel Generators To provide a reliable onsite source of auxiliary power if the preferred source is lost, MPS2 has two physically and electrically separate, quick starting, skid-mounted EDGs. Each EDG has the capability to power the ESF in rapid succession, and to supply continuously the sum of the loads needed to be powered at any one time for any design basis accident (DBA).

Cooling for the EDGs is provided by shell and tube type heat exchangers. Each EDG heat exchanger assembly consists of a jacket coolant heat exchanger (X-45A/B), air cooler (X-83A/B), and lube oil cooler (X-53A/B) arranged in series. Cooling water is circulated in a closed loop through the diesel engine cooling water passages and the shell-side of the cooler by an engine-driven jacket coolant pump. The cooling medium flowing through the tube-side of the jacket water cooler is supplied by the SW system. The EDGs are capable of operating for approximately three minutes at full load without cooling water supply. This provides sufficient time for the initiation of flow in the SW system by pumps connected to the emergency bus.

The heat exchanger assemblies are designed for a tube-side flow of 700 gpm at inlet and outlet temperatures of 750F and 101.5 0F, respectively. SW flow through the heat exchangers is adequate for accident conditions and will not cause excessive tube velocities during non-accident conditions due to the throttle positions of valves 2-SW-89A/B. This calculation forms the original basis for the throttle positions in the current lineup of the SW system.

It was determined that, with 5-percent tube plugging, the minimum required SW flow, at an 80°F inlet temperature is 637 gpm. As determined by calculation, the minimum available

Serial No 13-227 Docket No. 50-336, Page 13 of 33 SW flow to the EDGs is 672 gpm. As such, there is sufficient margin in the SW flow to the EDG engine cooler to support their operation at an 80°F UHS temperature.

5.5 Vital AC Switchgear Ventilation System With the exception of the east 480V load center, the vital AC switchgear rooms containing the west 480 volt unit load center and the 4160V and 6900V electrical equipment are each cooled by separate closed cycle air subsystems sized for 100 percent of the room cooling requirements under normal plant operation and emergency conditions such as LOCA and high energy line break (HELB). Each of the above subsystems consist of fan-coil units (X-181, X-1 82, and X-1 83) utilizing SW as the cooling medium. The east 480V load center is located in the auxiliary building and is cooled during normal and emergency operations by 100 percent outside air supply systems unaffected by the proposed changes.

West 480 Volt Load Center Room The west 480V load center room cooler X-1 81 uses SW as a cooling medium through cooling coils X-1 81 A/B, which is an assembly of three cooling coils in parallel (X-1 81 A has two coils and X-181B has one coil). Each coil has four banks with sixteen tubes per bank.

Air circulates over the finned tube coils to remove the heat gain from the electrical equipment in the room. During normal operations, SW from the 'A' train is aligned to these cooling coils.

SW flow of 90 gpm at 80°F provides the cooler with sufficient capacity to mitigate the generated heat load within the room.

By analysis, the SW system is capable of providing a minimum of 145 gpm to cooler X-181; as such, an increase in the UHS from 75°F to 80°F will not impact the ability of west 480V load center room cooler to meet its design requirements.

East 480 Volt Load Center Room The east 480V load center room is cooled by clean air supplied from the auxiliary building's non-radioactive ventilation system using fan unit F-17. As such, an increase in the UHS from 75OF to 80°F will have no impact on the cooling of the east 480V load center room.

Lower 4160/6190 Volt Switchgear Room The lower 4160V/6190V switchgear room cooler uses SW as a cooling medium through cooling coil X-182, which has four (4) banks with twenty-two (22) tubes per bank. Air circulates over the finned tube coils to remove the heat gain from the electrical equipment in the lower switchgear room. During normal operations, SW from the 'A' train is aligned to this cooler.

The thermal performance of cooler X-182, with a SW inlet temperature of 800F, was evaluated at the design SW flow rate of 22.9 gpm. Maximum fouling and tube plugging was conservatively assumed for the analysis.

Serial No 13-227 Docket No. 50-336, Page 14 of 33 Per that calculation, cooler X-1 82 has sufficient capacity with a SW inlet temperature of 80°F at a flow rate of 22.9 gpm. As determined by calculation, the SW system is capable of delivering a minimum of 28 gpm to cooler X-1 82 and, therefore, an increase in the UHS from 750F to 80°F will not impact the ability of lower 4160V/6190V switchgear room to meet its design requirements.

Upper 4160/6190 Volt Switchgear Room The upper 4160V/6190V switchgear room cooler uses SW as a cooling medium through cooling coil X-183, which has four (4) banks with twenty-two (22) tubes per bank. Air circulates over the finned tube coils to remove the heat gain from the electrical equipment in the upper switchgear room. During normal operations, SW from the 'B' train is aligned to this cooler.

The thermal performance of cooler X-1 83, with a SW inlet temperature of 800 F, was evaluated at the design SW flow rate of 19.1 gpm. Maximum fouling and tube plugging was conservatively assumed for the analysis.

Per that calculation, cooler X-1 83 has sufficient capacity with 80°F SW at a flow rate of 17 gpm. As determined by calculation, the SW system is capable of delivering a minimum of 23 gpm to cooler X-1 81 and, therefore, an increase in the UHS from 750F to 80'F will not impact the ability of upper 4160V/6190V switchgear room to meet its design requirements.

5.6 Vital DC Switchgear Ventilation System The east and west vital DC switchgear rooms are provided with closed cycle air subsystems utilizing mechanical refrigeration to maintain the ambient conditions within these areas. Cooling is normally provided by non-vital chilled water via the non-vital chillers (X-196A/B). During LNP and post-accident conditions, the vital chilled water system functions to provide a source of chilled water to maintain a suitable environment for the east and west vital DC switchgear rooms. Those vital chillers (X-1 69A/B) are cooled by SW. The condensing conditions (i.e., temperature and pressure) were evaluated for the vital chillers (X-169A/B) with a SW inlet temperature of 80°F at the minimum design flow rate (26.9 gpm) with maximum fouling and tube plugging. Predicted SW flow to these chillers is 30 gpm.

Based on the above conditions, the resulting condensing temperature is 1 14.5 0F with corresponding condensing and evaporating pressures of 255.9 psia (241.2 psig) and 82 psia (67.3 psig), respectively. Both condensing and evaporating pressures are within their normal operating ranges of 170 psig to 260 psig (condensing pressure) and 55 psig to 75 psig (evaporating pressure). Vital chillers X-169A/B have sufficient capacity to perform their intended function of removing heat from the east and west vital DC switchgear rooms during LNP and post-accident conditions. As such, an increase in the UHS from 750F to 80°F is acceptable.

5.7 Turbine Building Closed Cooling Water

Serial No 13-227 Docket No. 50-336, Page 15 of 33 The non-safety related TBCCW system uses treated water to remove heat from the turbine components and sample coolers. The heat is transferred to the SW system via the three, 50-percent capacity, single pass, shell and tube TBCCW heat exchangers (X17A/B/C). SW flows through the tube side of the heat exchanger to cool the TBCCW system. Valves regulate SW flow through their respective heat exchangers to maintain a TBCCW system supply temperature of 95 0F. SW flow to the heat exchangers from the main headers passes through Category I inlet isolation valves 2-SW-3.2A/B. Both valves will close automatically to isolate the TBCCW heat exchangers on receipt of a SIAS or LNP. During normal operation in the summer alignment, SW from the 'A' and 'B' trains flow through two of the three TBCCW heat exchangers.

During normal operation, in the summer alignment, SW from the 'A' and 'B' trains flow through two of the three TBCCW heat exchangers. At an inlet temperature of 800 F, the minimum required SW flow through one TBCCW heat exchanger, necessary to provide a TBCCW supply temperature of 95 0F, is calculated as 4,316 gpm.

The SW thermal-hydraulic analysis ensures this minimum flow is met by setting flow through each of the TBCCW heat exchangers as a balancing parameter in the thermal-hydraulic model. Additionally, since SW flow is modulated to ensure TBCCW supply temperatures remain at their design requirements, TBCCW system piping and components are unaffected by an increase in the UHS temperature from 750F to 80 0F.

5.8 Circulating Water The CW system uses four, one-fourth capacity pumps (137,000 gpm) to provide a continuous supply of cooling water to the main condensers (X-8A/B). Cooling water is taken from Long Island Sound, through an intake trash rack and four traveling screens located inside the intake structure, through the main condenser, and discharged into the quarry. Approximately 6.059 x 109 Btu/Hr of waste heat from the power conversion cycle is transferred to the CW as it flows through the condenser at a condenser design flow rate of 522,500 gpm.

A qualitative evaluation of the effect of an increase in UHS temperature from 750F to 80°F on condenser performance was performed to demonstrate that the condenser backpressure, at an 80°F UHS temperature, does not challenge any low condenser vacuum alarm/trip points. Evaluations have concluded that an increase in the UHS from 750F to 80°F will have a negligible effect on condenser backpressure and will not impact turbine or steam dump operation.

Additionally, the CW system supply and return piping is qualified to a design temperature of 100°F; as such, the CW system piping will not be affected by an increase in UHS temperature from 750F to 800F.

5.9 Intake Structure The intake structure, located west of the main plant, is a reinforced concrete structure founded on bedrock. It houses the four CW pumps which supply water from the UHS to the

Serial No 13-227 Docket No. 50-336, Page 16 of 33 main condensers (X-8A/B) positioned under the turbine-generator. Also located in the structure, are the three SW pumps.

The ventilation requirements for the intake structure are based on ambient air temperatures and no credit was taken for cooler fluid-filled piping within the applicable areas. As such, the temperature of the UHS has no impact on the ventilation requirements of the intake structure.

5.10 Containment Pressure-Temperature Analysis In the event of a LOCA or MSLB, the CAR cooling units, in conjunction with the MPS2 ECCS and CS system, provide the means to remove heat from containment thereby reducing containment pressure so as to minimize the leakage of airborne and gaseous radioactivity. The CAR cooling system is independent of the ECCS and it is sized such that, assuming the most adverse containment heat-removal single failure following a LOCA or MSLB accident, two of the four CAR units, in conjunction with one train of the CS system, limits the containment pressure and structural temperature to less than the containment design values (54 psig, 289°F).

An analysis of the MPS2 LOCA and MSLB accident containment response was previously performed using revised mass and energy release information provided by Westinghouse.

The analysis used the NRC-approved Dominion GOTHIC Methodology identified in topical report DOM-NAF-3-0.0-P-A and an 80°F UHS temperature. The engineering technical evaluation which implemented this analysis under the provisions of 10 CFR 50.59 also resulted in corresponding changes to the MPS2 FSAR Section 14.8.2.

The revised LOCA and MSLB accident containment analysis using the Dominion GOTHIC methodology and an 80°F UHS temperature demonstrated that the containment design pressure of 54 psig would not be exceeded.

It should be noted that, while peak containment pressures do not exceed the design accident pressure (Pa) of 54 psig, the peak containment vapor temperature (361 OF) following a MSLB exceeds the containment structure design temperature value (2890 F) for a short duration; however, as the temperature of the containment structure remains less than its design temperature, this is considered acceptable. Short duration containment vapor temperature excursions above the containment structure design temperature following a MSLB have been previously reviewed and approved in the supplemental safety evaluation attached to NRC correspondence dated January 24, 1994 associated with the MPS2 revised response to IE Bulletin 80-04.

Emergency Core Cooling Systems The MPS2 ECCS is designed to remove decay heat from the core for the necessary period of time following a LOCA. The ECCS consists of three subsystems: the high-pressure safety injection (HPSI) system, low-pressure safety injection (LPSI) system, and the passive injection system which maintains a reservoir of borated water under pressure in the

Serial No 13-227 Docket No. 50-336, Page 17 of 33 safety injection tanks (SITs). SI is initiated either when pressurizer pressure drops below 1,714 psia, or when the containment pressure rises above 4.42 psig.

Upon receipt of a SIAS, two HPSI and two LPSI pumps start and eight normally open HPSI valves and four normally closed LPSI isolation valves receive signals to open, allowing water to be pumped from the refueling water storage tank (RWST) into the reactor coolant system (RCS). Both the HPSI and LPSI pumps take suction from independent suction headers which are initially supplied with borated water from the RWST. When the RWST level drops to the sump recirculation actuation signal (SRAS) setpoint, the HPSI pumps automatically take suction directly from the containment sump, thereby providing a continuous source of borated water.

The two CS pumps also initially take borated water from the RWST upon receipt of a containment spray actuation signal (CSAS) and discharge the borated water through the three concentric spray headers located within containment. Upon receipt of SRAS, the CS pump suction is automatically transferred to the containment sump. The recirculated water from the sump is cooled by the SDC heat exchangers prior to discharge into the CS headers.

The maximum sump water temperature versus time, as previously calculated using the Dominion GOTHIC methodology as part of the10 CFR 50.59 implementation of the MPS2 LOCA containment analysis, identified an increase in sump water temperature. To assure adequate design margins, the minimum NPSHA for the ECCS and CS pumps are conservatively calculated during the recirculation mode in accordance with Safety Guide 1 and using the latest containment analysis results. Using these latest sump temperature results the NPSHA for the ECCS and CS pumps continues to exceed the NPSHR for the ECCS and CS pumps. The ECCS and CS pump flow delivery results were not adversely impacted by the increase in sump water temperature.

The maximum containment vapor and sump water temperatures versus time, as previously calculated using the Dominion GOTHIC methodology as part of the 10 CFR 50.59 implementation of the MPS2 LOCA containment analysis discussed above impacts the calculated maximum containment sump aluminum mass resulting from corrosion of aluminum inside containment by containment spray and submergence. The calculated sump aluminum loading remains below the maximum sump strainer aluminum loading used in the MPS2 GSI-191 chemical effects testing program. Therefore, there is no adverse impact on sump strainer performance.

LOCA 10 CFR 50.46 Analysis FSAR Section 14.6.5 presents the LOCA analysis demonstrating compliance with 10 CFR 50.46. The large break LOCA analysis results are sensitive to containment pressure.

Minimizing containment pressure results in more adverse large break LOCA results with respect to the 10 CFR 50.46 acceptance criteria. To minimize the containment pressure response following a large break LOCA, the analysis maximizes containment heat removal by the CAR cooling units by using a RBCCW water temperature of 35 0F. Therefore, increasing the UHS temperature from 75 0F to 80°F has no effect on this analysis.

Serial No 13-227 Docket No. 50-336, Page 18 of 33 Equipment Environmental Qualification 10 CFR 50 requires that certain categories of SSCs be designed to accommodate the effects of both normal and accident environmental conditions and that design control measures be employed to ensure the adequacy of these designs. Specific requirements pertaining to the environmental qualification of these categories of electrical equipment are embodied within 10 CFR 50.49. The categories include safety related (Class 1 E) electrical equipment, non-safety-related electrical equipment whose failure could prevent the satisfactory accomplishment of a safety function by safety-related equipment, and certain post-accident monitoring equipment.

The analysis of the MPS2 LOCA and MSLB accident containment response that was previously performed using the NRC-approved Dominion GOTHIC Methodology discussed above and implemented under the provisions of 10 CFR 50.59 assessed the impact of the analysis on the environmental qualification of safety related equipment inside containment and the ESF room. Using an 80'F UHS temperature, revised inside containment temperature and pressure profiles were developed. Additionally, a revised ESF room ambient temperature profile was calculated based on the post-LOCA RBCCW inlet temperature to the ESF room cooling units and the heat loads in the ESF rooms. These revised inside containment and ESF room profiles were incorporated into the EEQ program environmental specification. Using this updated environmental specification, the post accident operating time calculations and equipment qualification records were updated to ensure all required safety related equipment inside containment and in the ESF room will be capable of performing their LOCA and MSLB accident mitigation functions.

5.11 Program Reviews Fire Protection/Appendix R 10 CFR 50, Appendix R, requires that MPS2 come to cold shutdown (Mode 5) within 72-hours following a fire event. The MPS2 Appendix R Compliance Report postulates damage to all three SW pumps following a fire in the MPS2 intake structure (Fire Area R-16). This is considered the most limiting Appendix R scenario due to delays in restoring one train of SW. For an R-16 fire, the plant is stabilized in hot shutdown (Mode 4) using the turbine-driven auxiliary feedwater (TDAFW) pump, followed by plant cooldown to Mode 5 using one SW train and one RBCCW train. Either the 'B' or 'C' SW pump is postulated to be returned to service per procedure AOP 2579PP, Rev. 6, Fire Procedure for Cooldown and Cold Shutdown, Appendix R Fire Area R-16.

With 10 percent of the tubes plugged, the RBCCW heat exchanger removes approximately 77 MBtu/hr (60 MBtu/hr from SDC and 17 MBtu/hr for all other loads). The 77 MBtu/hr value is based upon a minimum SW flow of 6,288 gpm (at a temperature of 800F) through the RBCCW heat exchanger in order to limit the maximum SW discharge temperature to 1050F per the current NPDES permit.

With one RBCCW train in-service and SDC beginning 19 hours2.199074e-4 days <br />0.00528 hours <br />3.141534e-5 weeks <br />7.2295e-6 months <br /> after reactor shutdown, at a 260°F RCS temperature and no reactor coolant pumps operating, the estimated time to reach Mode 5 is 25.6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. Even with the decrease in heat transfer across the RBCCW

Serial No 13-227 Docket No. 50-336, Page 19 of 33 heat exchanger due to an increase from 750F to 80°F in the UHS, the time required (25.6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />) to reach cold shutdown (Mode 5) is still less than the 72-hours required by 10 CFR 50, Appendix R.

In-Service Inspection The In-Service Inspection (ISI) program is an existing program that was developed to comply with the requirements of the American Society of Mechanical Engineers (ASME)

Boiler and Pressure Vessel Code,Section XI. The ASME program provides the requirements for ISI, repair, and replacement for Class 1, 2 and 3 components and the associated component supports.

The change in UHS temperature does not affect the system classifications or boundaries for ASME Class 1, 2, and 3 systems. Augmented examination of high energy piping systems is not affected because the systems evaluated for impact are classified as moderate energy systems. The change in UHS temperature does not affect the inspection requirements for ASME Class 1, 2, and 3 components and their supports, as described in the MPS2 ISI Program manual.

In-Service Testing MPS2 TS 4.0.5 establishes the requirement that in-service testing (IST) of ASME Code Class 1, 2, and 3 pumps and valves shall be performed in accordance with a periodically updated version of the ASME Code for Operation and Maintenance of Nuclear Power Plants (ASME OM Code) and applicable Addenda as required by 10 CFR 50.55a(f).

The CW and TBCCW systems have no valves or pumps in the IST Program.

Valves Tested in the IST Program The change to the UHS temperature does not affect the maximum allowable stroke times of active valves.

The minimum required flow rates for check valves are included in the scope of the IST Program. The impact of the change in UHS temperature on the required accident mitigation flow rates for check valves in the SW and RBCCW systems has been evaluated.

Based on this evaluation, the change to the UHS temperature is acceptable.

Relief Valve Set Pressures The change to the UHS temperature does not affect any relief valve set points.

Containment Isolation Valve Leakage Testing The SW, CW, and TBCCW systems do not have any containment isolation valves. The RBCCW system lines (supply and return) to the CAR coolers and RCPs have containment isolation valves located outside containment.

Serial No 13-227 Docket No. 50-336, Page 20 of 33 Since containment accident pressure (Pa) remains unchanged, the increase in UHS temperature does not affect pressures used for the performance of the 10 CFR 50, Appendix J Type B and C tests.

Pumps Tested in the IST Program The SW pumps (P-5A/B/C), RBCCW pumps (P-1i1A/B/C), and chilled water pumps (P-122A/B) are included in the MPS2 IST Program Plan, U2-24-IST-PLAN.

The IST acceptance criteria for the SW pumps will be revised to reflect the updated SW maximum flow.

Since no physical changes are being made to the system operating conditions, no changes are required for IST acceptance criteria associated with the RBCCW pumps as a result of increasing the UHS temperature from 750F to 800 F.

Since no physical changes are being made to the system operating conditions, no changes are required for IST acceptance criteria associated with the vital chilled water pumps as a result of increasing the UHS temperature from 750F to 80 0F.

Regulatory Guide 1.97 - Post-Accident Monitoring In accordance with RG 1.97, indications of plant variables are required by the control room operating personnel during accident situations to:

(1) provide information required to permit the operator to take preplanned manual actions to accomplish safe plant shutdown; (2) determine whether the reactor trip, ESF systems, and manually initiated safety systems and other systems important to safety are performing their intended functions (i.e., reactivity control, core cooling, maintaining RCS integrity, and maintaining containment integrity); and (3) provide information to the operators that will enable them to determine the potential cause of a gross breach of the barriers to radioactivity release (i.e., fuel cladding, RCS pressure boundary, and containment) and to determine if a gross breach of a barrier has occurred.

In addition to the above, indications of plant variables that provide information on operation of plant safety systems and other systems important to safety are required by the control room operating personnel during an accident to:

(1) furnish data regarding the operation of plant systems in order for the operator to make appropriate decisions as to their use, and (2) provide information regarding the release of radioactive materials to allow for early indication of the need to initiate action necessary to protect the public and for an estimate of the magnitude of any impending threat.

Serial No 13-227 Docket No. 50-336, Page 21 of 33 A compliance review was performed to determine if instrumentation, credited for post-accident monitoring, will still meet the MPS2 acceptance criterion established in FSAR Table 7.5-3, following an increase in UHS temperature. This assessment concluded that the increase in UHS temperature from 75°F to 80'F has minimal to no effect on the operating temperatures of the instruments credited for RG 1.97 post-accident monitoring and are all within established acceptance criteria.

Maintenance Rule The MPS2 Maintenance Rule (MR) program sets and monitors performance criteria (PC) for the risk significant SSCs, in compliance with 10 CFR 50.65. All SSCs within the scope of the MR program are subject to an effective Preventive Maintenance (PM) program.

Methods of effective PM include periodic testing, inspections, predictive maintenance, and trending of equipment performance.

The MPS2 MR program is unaffected by an increase in the UHS temperature from 750F to 800F. This increase does not add, modify, or remove SSCs from the MR program and does not make any changes to the MPS2 PM program.

Coatings The MPS2 Protective Coatings and Linings program applies to all aspects of coating work classified as Service Level 1, 11, 111, and Balance of Plant.

" Service Level I coatings are used in areas where coating failure could adversely affect the operation of post-accident fluid systems. This applies to coatings used inside containment. These coatings are considered safety related.

" Service Level II coatings are used in areas of the plant outside containment. These coatings provide corrosion protection and improve the ability to decontaminate areas that are subject to radiation and decontamination. The proposed change in UHS temperature from 75°F to 80°F has no affect on these types of coatings.

" Service Level III coatings are used as linings on immersed surfaces located outside containment whose failure could adversely affect normal plant operation and safe shutdown. This includes coatings applied to internal surfaces of SW piping, valves, heat exchanger water boxes, tubes sheets, and channel heads. Some of these linings may be classified as QA Category 1.

The impact on the increase in UHS temperature from 750F to 80'F on Service Level I and III coatings is discussed:

Service Level I Coatings Since the analysis of record for peak containment pressure and temperature is bounding, there is no affect on the containment coatings for the change in UHS temperature. The change in UHS temperature does not affect the pH of the containment sump and does not affect the boron concentration of any injected boron (i.e. SITs). Therefore, the change in

Serial No 13-227 Docket No. 50-336, Page 22 of 33 UHS temperature does not have the potential for adversely affecting Service Level I coatings.

Service Level III Coatings Service Level III coatings are used in the SW system to prevent corrosion and erosion of piping. The materials used in the SW system have design temperature ratings above that which will be experienced during normal and accident conditions. Therefore, these coatings are not impacted due to an increase in UHS temperature from 750F to 800F.

License Renewal The License Renewal program is not impacted by the change in UHS temperature since the increase in temperature does not add any new components/structures nor introduce any new functions for existing components/structures that would change the license renewal evaluation boundaries.

An increase in UHS temperature does not add any new or previously unevaluated materials to these components/structures. The component/structure internal and external environments remain within the parameters previously evaluated. The change in UHS temperature also does not affect the aging management programs.

Generic Letter (GL) 89-13 Changes to the analyses/calculations due to the increase in UHS temperature were reviewed to determine the effect of GL 89-13 on the SW Heat Exchanger Monitoring Program. GL 89-13, "Service Water System Problems Affecting Safety-Related Equipment," was issued to ensure the general design and quality assurance requirements were being met for SW systems.

The SW system (open-cycle cooling) program corresponds to NUREG-1 801,Section XI.M20, "Open Cycle Cooling Water System." The program manages the aging effects of loss of material and buildup of deposits. The program implements the NRC guidelines in GL 89-13, which include:

(a) surveillance and control of biofouling (b) a test program to verify heat transfer capabilities (c) routine inspection and a maintenance program to ensure that corrosion (including microbiologically influenced corrosion), erosion, protective coating failure, silting, and biofouling do not degrade the performance of safety-related systems serviced by the SW system (d) a system walk down inspection to ensure compliance with the licensing basis, and (e) a review of maintenance, operating, and training practices and procedures Monitoring of the SW-cooled heat exchangers is performed in accordance with MPS2 surveillance procedures on a quarterly basis. The differential pressure (DP) surveillance

Serial No 13-227 Docket No. 50-336, Page 23 of 33 limits are established by calculation. As a result of the SW thermal-hydraulic analysis, the DP limit for the 'A' RBCCW heat exchanger (X-1 8A) is being lowered from 1 0-psid to 8-psid. This decreased DP is not expected to require more frequent cleanings then the current cleaning cycle for RBCCW heat exchangers; however, the DP surveillance frequency will be increased to weekly from July through September.

The schedule for inspecting and cleaning the RBCCW and the EDG heat exchangers will be altered such that those heat exchangers are cleaned annually prior to each summer.

Additionally, if necessary, the RBCCW cleaning frequency may increase based on observed RBCCW outlet temperatures and DP surveillance results.

The change in UHS temperature from 750F to 80'F has resulted in changes to the following design inputs for the GL 89-13 program:

Allowable SW side DP limit for the 'A' RBCCW heat exchanger (X-18A) is being lowered from 1 0-psid to 8-psid as established by calculation.

The changes in the design input to the GL 89-13 program have resulted in changes to the implementation of the GL 89-13 program:

" The DP surveillance frequency will be increased to weekly from July through September for the RBCCW heat exchangers (X-1 8A/B/C).

" Cleaning and inspection schedules for the RBCCW heat exchangers (X-1 8A/B/C) and the EDG heat exchangers (X-83A/B, X-53A/B, X-45A/B) will be altered such that those heat exchangers are cleaned annually prior to each summer.

The change in UHS temperature from 750F to 80°F has not resulted in changes to the approach of the GL 89-13 program, including the analytical tools and method of analysis, and does not affect any of the GL 89-13 commitments detailed in FSAR Section 19.2.1.20.

Station Blackout (SBO)

No adjustments to plant-specific assumptions related to station blackout or GL 96-06 were determined to be necessary during the evaluation of the plant response to an increase in the SW temperature limit to 800F.

10 CFR 50 Appendix J The Millstone 10 CFR 50 Appendix J program governs the leakage rate testing of the primary containment structure and components providing containment barriers in order to comply with MPS2 TSs and TRM. The increase in UHS temperature from 750F to 80°F does not change the MPS2 peak calculated containment internal pressure for the design basis LOCA, Pa, or system operations. Therefore, the Appendix J program is unaffected.

Serial No 13-227 Docket No. 50-336, Page 24 of 33 Margin Management The Margin Management program provides: Operations and Maintenance with an awareness of the low margin conditions during operation and maintenance activities, System Engineering with input to the health of the systems, Design Engineering with awareness of low margin conditions during the design change process, and Management with assurance that appropriate actions are applied to address areas of low margin.

Components with low margin as a result of this change will be entered into the Margin Management Program.

Flow Accelerated Corrosion Per FSAR Section 15.2.1.11, the Flow-Accelerated Corrosion (FAC) program corresponds to NUREG-1801,Section XI.M17, "Flow-Accelerated Corrosion." The program manages the aging effect of loss of material in accordance with the EPRI guidelines in NSAC-202L.

It includes procedures or administrative controls to assure that the structural integrity of carbon steel and low-alloy steel piping and components, such as valves, steam traps, and feedwater heaters, is maintained.

The MPS2 FAC program is not affected by the change in UHS temperature from 750F to 80°F because the systems evaluated herein for impact are not susceptible to wall loss by this mechanism.

Air Operated Valve Program There are 79 air-operated valves (AOVs) in the SW, RBCCW, TBCCW, and chilled water systems that are included the station's MR program. Only 11 of those valves, five SW valves (2-SW-3.2A/B and 2-SW-8.1A/B/C) and six RBCCW valves (2-RB-210, 2-RB-402, 2-RB-68.1A/B, and 2-RB-8.1A/B), are identified as Category 1 valves, in accordance with the Millstone AOV Program, and are required to have documented system level design basis reviews.

The operating conditions of the RBCCW system will remain unchanged for all modes of operation; therefore, an increase in the UHS temperature from 75 0F to 80°F does not impact the aforementioned RBCCW Category 1 AOVs and no further review is required.

The SW thermal-hydraulic analysis was updated to evaluate the change in UHS temperature from 75 0F to 80'F. This resulted in negligible changes in differential pressures across the valves.

Motor Operated Valve Program The technical requirements for implementation of the MPS2 Motor Operated Valve (MOV) program are contained in the Millstone MOV Program manual. The program implements the recommendations and requirements of NRC GLs 89-10, 96-05, and 95-07.

Serial No 13-227 Docket No. 50-336, Page 25 of 33 There are 52 MOVs that are subject to NRC GL 89-10, none of which are in the SW, TBCCW, or chilled water systems. Six of those valves are RBCCW valves (2-RB-210, 2-RB-402, 2-RB-68.1A/B, and 2-RB-8.1A/B). Per the RBCCW thermal-hydraulic analysis, the operating conditions of the RBCCW system will remain unchanged for all modes of operation; therefore, an increase in the UHS temperature from 750F to 80°F does not impact the aforementioned RBCCW MOVs.

NRC GL 96-05 requires licensees to verify, on a periodic basis, that safety related MOVs continue to be capable of performing their safety related function within the current licensing basis of the facility.

Per the RBCCW thermal-hydraulic analysis, the operating conditions of the RBCCW system will remain unchanged for all modes of operation; therefore, an increase in the UHS temperature from 750F to 80°F does not impact the aforementioned RBCCW MOVs.

GL 95-07 addresses operational configurations of safety-related, power-operated (including motor, air, and hydraulically operated) gate valves for susceptibility to pressure locking and thermal binding to ensure they are capable of performing the safety functions. Since the affected systems have no such valves (they are all butterfly valves), there is no impact from this change.

5.12 Environmental Impact The effect of the increase in UHS temperature limit to 80°F on the NPDES permit has been evaluated. NPDES permit CT0003263 governs cooling water intake flow for MPS2, MPS3, and all the wastewater discharges from MPS1, MPS2, and MPS3, including surface runoff to Long Island Sound. The NPDES permit was reviewed for the impact of an increased UHS temperature. This evaluation showed that the maximum discharge temperature for MPS2 will stay within the permit limits for MPS2 and MPS3 and the maximum temperature at the plume mixing zone will stay within the permit limits for MPS2 and MPS3. Continual temperature monitoring, and operational controls as needed, ensures that the NPDES permit requirements are met, which is no change from current practice.

5.13 Nuclear Material Control Nuclear material control is not impacted by the change in UHS temperature since the increase in temperature does not add, remove, or alter any source of nuclear material governed by station procedures.

5.14 Seismic and Dynamic Qualification of Mechanical and Electrical Equipment The seismic and dynamic qualification of mechanical and electrical equipment is not impacted by the change in UHS temperature from 750 F to 80'F. Seismic requirements remain unchanged, there are no changes to seismic loads, and the seismic qualification of equipment is unaffected.

5.15 Time Critical Operator Actions

Serial No 13-227 Docket No. 50-336, Page 26 of 33 Credited operator actions are not affected or changed and no additional operator actions are added as a result of the change in UHS temperature from 750 F to 800 F.

5.16 Failure Modes and Effects Analysis The MPS2 Failure Modes and Effects analyses for the discussed plant SSCs are unaffected by an increase in UHS temperature since the increase does not; introduce or remove any failure modes, impact the consequences of component failures, or affect the capability to meet single failure criterion.

5.17 Final Safety Analysis Report Review The MPS2 FSAR was reviewed to identify any required changes due to the increase in UHS temperature from 750F to 800F. Where specific heat loads or flow rates are identified in the MPS2 FSAR, the values were reviewed for changes. The following sections require updates to reflect the change in UHS temperature:

" Section 1.2.10.3, Reactor Building Closed Cooling Water System

" Section 9.4.3.1, Normal Operation

" Section 9.4.4.3, Shutdown

" Section 9.7.2.1.2, Design Criteria 5.18 Technical Specification Review The MPS2 TSs were reviewed to identify any required changes due to the increase in UHS temperature from 750F to 80 0F. Other than the TS that is the subject of this license amendment request, no other changes were identified.

5.19 Technical Requirements Manual Review The TRM was reviewed to identify any required changes due to the increase in UHS temperature from 750F to 800F. No updates are required to reflect the change in UHS temperature.

Serial No 13-227 Docket No. 50-336, Page 27 of 33

6.0 REGULATORY ANALYSIS

DNC has evaluated this proposed amendment with respect to the safety design basis identified for the systems and the analyses affected by the change. The evaluation indicates that the critical systems and equipment cooled by SW are capable of performing their safety related design functions at the proposed UHS temperature limit of 800 F.

Furthermore, the regulatory requirements and the safety design basis continue to be met with the increased UHS temperatures.

6.1 MPS2 Technical Specifications The MPS2 TSs are custom TSs. The TSs were submitted to the NRC for review and were issued by the NRC as part of the full power license on August 1, 1975.

6.2 NUREG-1432, Standard Technical Specifications-Combustion Engineering Plants Although this request is not based on the averaging methodology of TSTF-330-A, Rev. 3, the following information is provided to ensure this license amendment request more completely addresses possible concerns.

Consideration: The UHS is not relied upon for immediate heat removal (such as to prevent containment over-pressurization), but is relied upon for longer-term cooling such that the temperature averaging approach continues to satisfy the accident analysis assumptions for heat removal over time.

Response: DNC does not propose to use a time-weighted temperature averaging, approach for verifying TS compliance. Instead, the proposed TS limit of 80OF will be verified as an instantaneous value in the same manner as it is currently verified. The engineering analyses assume a maximum SW temperature of 80°F for the duration of the analyses. While any supply side SW temperature measurement location is adequate to ensure compliance with the analysis assumptions, precision instruments installed at the inlet to the RBCCW heat exchangers will normally be used. These instruments have an uncertainty of 0.15 0F or less. Therefore, instrument uncertainty need not be factored into the surveillance acceptance criteria. All in-service instruments must be within the limit. If all of these instruments are out of service, alternative instruments that measure SW supply side temperature will be used. In this case, an appropriate instrument uncertainty will be subtracted from the acceptance criteria. This guidance will be incorporated into the appropriate surveillance procedures.

Consideration: When the UHS is at the proposed maximum allowed value of 800F, equipment that is relied upon for accident mitigation, anticipated operational occurrences, or for safe shutdown, will not be adversely affected and are not placed in alarm condition or limited in any way at this higher temperature.

Response: Equipment and systems that interface with the SW system have been evaluated for the increase in SW temperature to 800F. The evaluation determined that the systems supported by the SW system can support plant operations at the increased

Serial No 13-227 Docket No. 50-336, Page 28 of 33 temperature. The LOCA containment analysis (previously discussed) confirmed the accident response, at an increased SW temperature, is bounded by the LOCA analysis.

There are no changes in expected alarms or limiting conditions that result from increasing the maximum SW temperature limit to 800F. Equipment supported by the RBCCW system will not be impacted due to the restrictions imposed upon the RBCCW system during the evaluation of the increase in the maximum SW temperature limit to 80 0F.

Consideration: Plant-specific assumptions, such as those that were credited in addressing SBO and GL 96-06, have been adjusted (as necessary) to be consistent with the maximum allowed UHS temperature of 80°F that is proposed.

Response: As discussed above, no adjustments to plant-specific assumptions related to SBO or GL 96-06 were determined to be necessary during the evaluation of the plant response to an increase in the SW temperature limit to 800F.

Consideration: Cooling water that is being discharged from the plant (either during normal plant operations, or during accident conditions), does not affect the UHS intake water temperature (typical of an infinite heat sink), but location of the intake and discharge connections, and characteristics of the UHS can have an impact.

Response: There are no changes in the plant discharge limits as specified in the Millstone Power Station discharge permit in response to an increase in the maximum SW temperature limit to 800F. Plant discharge limits are a function of the quantity of heat rejected into the UHS during plant operations and are not intake temperature limited.

Because the temperature of the water being discharged from the plant will remain within the current discharge temperature limit there will be no change of the effect on the UHS intake water temperature.

6.3 Technical Specification Task Force (TSTF) -330, Revision 3 DNC has reviewed TSTF-330 and has considered possible adoption of the UHS temperature averaging approach. However, DNC considers the temperature averaging approach of TSTF-330 as not suitable for use at MPS2 based on the small daily variation in the temperature of the UHS. The temperature of the Long Island Sound typically fluctuates only approximately 3°F over a day in the summer. DNC does not expect that averaging with this small variation would provide adequate relief. Furthermore the 24-hour average temperature of the Long Island Sound had exceeded the current limit of 750F during the summer of 2012.

DNC has performed sufficient analyses to confirm the long term cooling capabilities, and that the temperature limitations are met, for equipment required for accident mitigation and safe shutdown of the unit at the proposed UHS temperature of 800F.

Based on the above, DNC considers that an increase in the UHS temperature limit of TS 3/4.7.5 is the most practical solution at MPS2.

Serial No 13-227 Docket No. 50-336, Page 29 of 33 6.4 MPS2 Licensing Bases Design and construction of MPS2 was initiated and completed based upon the 1967 General Design Criteria for Nuclear Power Plants. Since final publication of the GDC on February 20, 1971, MPS2 has attempted to comply with the intent of the newer General Design Criteria to the extent possible, recognizing previous design commitments. The extent to which this has been possible is reflected in the discussions of the 1971 General Design Criteria which is contained in Attachment 1.A of the MPS2 FSAR.

7.0 NO SIGNIFICANT HAZARD CONSIDERATION EVALUATION 10 CFR 50.91 (a)(1) requires that licensee requests for operating license amendments be accompanied by an evaluation of significant hazards posed by the issuance of the amendment. DNC has evaluated this proposed amendment with respect to the criteria given in 10 CFR 50.92(c).

A necessary element of plant operation is the removal of the heat generated by the power generation process. This includes both the removal of heat during routine operation and removal of heat as part of mitigating accidents and transients that are postulated to occur.

There are numerous systems with the purpose of removing the generated heat during various phases of plant operation. Some systems have a safety function related to accident and transient mitigation. Other systems have a power generation function related to a routine power generation plant operation. Some systems have a combination of safety and power generation functions.

One system that is designed to remove heat is the SW system. This system has a safety function to remove heat from various other systems. The SW system draws water from the Long Island Sound and discharges the heated water back to the Long Island Sound after it has removed heat from the various systems that it cools. The Long Island Sound is referred to as the UHS.

This license amendment request proposes to increase the temperature limit for the SW system from its current limit of 75°F to 800F.

DNC has evaluated whether or not a significant hazards consideration (SHC) is involved with the proposed change. A discussion of these standards as they relate to this change request is provided below:

Criterion 1 Do the proposed changes involve a significant increase in the probability or consequences of an accident previously evaluated?

Response: No Previously evaluated accident consequences are not impacted because credited mitigating equipment continues to perform its design function. The proposed change does not

Serial No 13-227 Docket No. 50-336, Page 30 of 33 significantly impact the probability of an accident previously evaluated because those SSCs that can initiate an accident are not significantly impacted.

Based on the above, DNC concludes that the proposed increased temperature limits do not involve a significant increase in the probability or consequences of an accident or transient previously evaluated in the safety analysis report.

Criterion 2 Do the proposed changes create the possibility for a new or different kind of accident from any accident previously evaluated?

Response: No A new or different accident from any accident previously evaluated is not created because previously credited SSCs, are not impacted, there is no new reliance upon equipment not previously credited, there is no new equipment installed (except for monitoring equipment),

there is no impact upon the existing failure modes and effects analysis, and conformance to the single failure criterion is maintained. The increased limits do not introduce any new mode of plant operation and will not result in a change to the design function or the operation of any SSC that is used for mitigating accidents.

Based on the above, DNC concludes that the proposed changes do not create the possibility of a new or different kind of accident or transient from any previously evaluated.

Criterion 3 Do the proposed changes involve a significant reduction in the margin of safety?

Response: No This change does not involve a significant reduction in margin of safety because the containment analysis acceptance criteria continue to be met when operating with the proposed increased UHS temperature limit. Containment integrity will not be challenged and will continue to meet its design basis acceptance criteria following a large break LOCA or MSLB. The proposed change has no impact upon fuel cladding or RCS fission product barrier margin because credited SSCs continue to perform their design functions with an 80°F UHS temperature.

Based on the above, DNC concludes that the proposed changes do not involve a significant reduction in the margin of safety.

From the above discussions, DNC has concluded that the proposed amendment presents no 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.

Serial No 13-227 Docket No. 50-336, Page 31 of 33

8.0 ENVIRONMENTAL CONSIDERATION

10 CFR 51.22(c) provides criteria for, and identification of, licensing and regulatory actions eligible for categorical exclusion from performing an environmental assessment. 10 CFR 51.22 (c)(9) identifies a proposed amendment to an operating license for a facility as a categorical exclusion not requiring 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 amount of any effluents that may be released off-site, or (3) result in an increase in individual or cumulative occupational radiation exposure.

DNC has reviewed the proposed license amendment and concludes that it meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). The following is the basis for this determination.

1. The proposed license amendment does not involve a significant hazards consideration as described previously in the No Significant Hazards Consideration Evaluation.

2. This proposed change is to increase the temperature limits for the UHS. This proposed change will not result in a significant increase in radiological doses for any design basis accident. This proposed change does not result in a significant change in the types or significant increase in the amounts of effluents that may be released off-site. (There will be a slight increase in the temperature of the plant cooling water effluent, but the effect is small and manageable, has no effect on radiological releases, and the effluent is limited by the NPDES permit.) DNC has concluded that there will not be a significant increase in the types or amounts of effluents that may be released off-site and these changes do not involve irreversible environmental consequences beyond those already associated with normal operation.

3. The increased cooling water inlet temperatures that would be allowed under the proposed changes will not result in any increase in individual or cumulative occupational radiation exposure.

Therefore, pursuant to 10 CFR 51.22(c), no environmental impact statement or environmental assessment needs to be prepared in connection with issuance of the proposed license changes.

9.0 PRECEDENTS A number of licensees have requested and received amendment of their operating licensees authorizing increases in the temperature limit of their UHS. As a result of the different formats of the TSs that are part of the operating license for these various licensees, there have been wide variations in the approach proposed by the licensees and the format of the increased UHS temperature.

Serial No 13-227 Docket No. 50-336, Page 32 of 33 Based on the various factors involved in the design of a facility, some of the following licensing activities and license amendments are considered to be closer in nature to the proposed MPS2 license amendment than are others. These precedents involve increases in the UHS temperature limit.

H. B. Robinson

" Type of Plant -Pressurized Water Reactor.

" UHS - Lake Robinson (an onsite lake)

" Scope -UHS temperature limit increased from 97 0F to 99 0F. No temperature averaging. TS affected - Two new Required Actions: (1) on a 12-hour frequency, confirm required cooling capacity is maintained; (2) hourly, confirm temperature is less than or equal to 99 0F.

" Licensee Submittals dated -June 5 and August 4, 2000, and July 6, 2001 License Amendment -No. 191, issued August 9, 2001 Hope Creek

" Type of Plant - Boiling Water Reactor.

UHS -Delaware River

• Scope -UHS temperature limit increased from 870F to 890 F. No temperature averaging.

" TS affected - LCO 3.7.1.3

" Licensee Submittals dated -June 12, July 23, September 8, 1998

" License Amendment - No. 120, issued April 19, 1999 Davis-Besse

" Type of Plant - Pressurized Water Reactor.

UHS - Lake Erie

• Scope - UHS temperature limit increased from 850F to 90 0F. No temperature averaging.

" TS affected - LCO 3.7.11.1 Licensee Submittals dated -July 28, 1999, June 6, 2000

" License Amendment - No. 242, issued September 12, 2000 Palisades Type of Plant - Pressurized Water Reactor.

UHS - Lake Michigan

" Scope - UHS temperature limit increased from 81.5 0F to 850F. No temperature averaging

" TS affected - Surveillance Requirement SR 3.7.9.2

" Licensee Submittals dated - January 26, and March 13, 2001

" License Amendment - No. 202, issued June 4, 2001 Indian Point Unit 3

" Type of Plant - Pressurized Water Reactor.

UHS - Hudson River

Serial No 13-227 Docket No. 50-336, Page 33 of 33

" Scope -UHS temperature limit increased from 850 F to 95 0F. No temperature averaging.

" TS affected - LCO 3.3.F.4 and 3.3.F.5

" Licensee Submittals dated - July 13, 1989

" License Amendment - No. 149, issued March 27, 1990 Braidwood Station

" Type of Plant - Pressurized Water Reactor.

" UHS - onsite pond

" Scope - UHS temperature limit increased from 98 0F to 1000F. No temperature averaging.

" TS affected - Surveillance Requirement SR 3.7.9.2

" Licensee Submittals dated - March 15, 2000

" License Amendment - No. 107 for Unit 1 and No. 107 for Unit 3, issued June 13, 2000 Surry Power Station Units 1 and 2

" Type of Plant - Pressurized Water Reactor.

" UHS - James River Scope -UHS temperature limit increased from 950F to 100'F. No temperature averaging.

• TS affected - TS 3.8.4 Licensee Submittals dated -June 25, 2007 License Amendment -No. 259 for Units 1 and 2, issued June 17, 2008

10.0 REFERENCES

1. Technical Specification Task Force, TSTF-330-A Rev. 3, Allowed Outage Time -

Ultimate Heat Sink.

2. Standard Technical Specifications, Combustion Engineering Plants, Rev. 4.

Serial No 13-227 MPS2 Ultimate Heat Sink ATTACHMENT 2 MARKED-UP TECHNICAL SPECIFICATIONS PAGE Dominion Nuclear Connecticut, Inc.

Millstone Power Station Unit 2

Serial No 13-227 MPS2 Ultimate Heat Sink PLANT SYSTEMS 3/4.7.11 ULTIMATE HEAT SINK LIMITING CONDITION FOR OPERATION 3.7.11 The ultimate heat sink shall be OPERABLE with a water temperature of less than or equal to Wth the UHS water temperature greater than APPLICABILITY:

MODES 1. 2.3, AND4 80'F, be in HOT STANDBY within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in

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SURVEILLANCE REQUIREMENTS 4.7.11 The ultimate heat sink shall be determined OPERABLE:

a.

At least once per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> by verifying the water temperature to be within limits.

b.

At least once per 6. hours by verif},ing the water temperature to be within limits when the water temperature exceeds F

MILLSTONE - UNIT 2 3/4 7-34 Amendment No. +4-5, +6-*, 49+, 244,

Serial No 13-227 MPS2 Ultimate Heat Sink ATTACHMENT 3 MARKED-UP TECHNICAL SPECIFICATIONS BASES PAGES (For Information Only)

Dominion Nuclear Connecticut, Inc.

Millstone Power Station Unit 2

Serial No 13-227 MPS2 Ultimate Heat Sink LBC*RC 11 P

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Serial No 13-227 MPS2 Ultimate Heat Sink LBC 1MP2 0114 17, 2012 PLANT SYSTEMS BASES 3/4.7.11 ULTIMATE HEAT SINK (Continued)

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I THIS PAGE INTENTIONALLY LEFT BLANK I MILLSTONE - UNIT 2 B 3/4 7-7a Amendment No. 4-5, 4-9-, 243-, 24-7, 2-5-7,44 AeIJnzwvhdgzd by NRC letter-deatd

Serial No 13-227 MPS2 Ultimate Heat Sink Insert A BACKGROUND The ultimate heat sink (UHS) for Millstone Unit No. 2 is Long Island Sound. The Long Island Sound is connected to the Atlantic Ocean and provides the required 30 day supply of water. It serves as a heat sink for both safety and nonsafety-related cooling systems. Sensible heat is discharged to the UHS via the service water (SW) and circulating water (CW) systems.

The basic performance requirement is that a 30 day supply of water be available, and that the design basis temperatures of safety related equipment not be exceeded.

Additional information on the design and operation of the system, along with a list of components served, can be found in References 1, 2, and 3.

APPLICABLE SAFETY ANALYSES The UHS is the sink for heat removed from the reactor core following all accidents and anticipated operational occurrences in which the unit is cooled down and placed on shutdown cooling system (SDC) operation. With UHS as the normal heat sink for condenser cooling via the CW System, unit operation at full power is its maximum heat load. Its maximum post accident heat load occurs < 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> after a design basis loss of coolant accident (LOCA). Near this time, the unit switches from injection to recirculation and the containment cooling system is required to remove the core decay heat.

The operating limits are based on conservative heat transfer analyses for the worst case LOCA. References 1, 2, and 3 provide the details of the assumptions used in the analysis, which include worst expected meteorological conditions, conservative uncertainties when calculating decay heat, and worst casesingle active failure (e.g.,

single failure of a man-made structure).

The limitations on the temperature of the UHS ensure that the assumption for temperature used in the analyses for cooling of safety related components by the SW system are satisfied. These analyses ensure that under normal operation, plant cooldown, or accident conditions, all components cooled directlyor indirectly by SW will receive adequate cooling to perform their design basis functions.

The UHS satisfies Criterion 3 of 10 CFR 50.36(c)(2)(ii).

LCO The UHS is required to be OPERABLE and is considered OPERABLE if it containsa sufficient volume of water at or below the maximum temperature that would allow the SW System to operate for at least 30 days following the design basis LOCA without the

Serial No 13-227 MPS2 Ultimate Heat Sink loss of net positive suction head (NPSH), and without exceeding the maximum.design temperature of the equipment served by the SW System. To meet this condition, the

.UHS temperature should not exceed 80°F during normal unit operation.

While the. use of any supply side SW temperature indication isadequate to ensure compliance with the analysis assumptions, precision instruments installed at the inlet to the reactor building closed cooling water (RBCCW) heat exchangers will normally be.

used. Therefore, instrumentuncertainty need not be factored into the surveillance acceptance criteria. All in-service instruments must be within the limit. If all of the.

precision instruments.are out of service, alternative instruments that measure SW supply side temperature will be used. In this case, an appropriate instrument uncertainty will be subtracted from the acceptance criteria.

Since Long Island Sound temperature changes relatively slowly and in a predictable fashion according to the tides, it is acceptable to monitor this temperature daily when there is ample (.>5.°F) margin to. the. limit. When within 5°F of the limit, the temperature shall be monitored every 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> to ensure that tidal variations are appropriately captured.

APPLICABILITY In MODES 1, 2, 3, and 4, the UHS is required to support the OPERABILITY of the equipment serviced by the UHS and required to be OPERABLE in these MODES.

In MODE 5 or 6, the OPERABILITY requirements of the UHS are determined by the systems it supports.

ACTION If the UHS is inoperable, the unit must be placed in a MODE in which the LCO does not apply. To achieve this status, the unit must be placed in at least HOT STANDBY within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

The allowed outage times are 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 REQUIREMENTS This surveillance requirement verifies that the UHS is capable of providing a 30 day cooling water supply to safety related equipment without exceeding its design basis temperature. This surveillance requirement verifies that the water temperature of the UHS is s 800 F.

b Serial No 13-227 MPS2 Ultimate Heat Sink REFERENCES

1. FSAR, Sections 6.3, 6.4, 6.5, and 6.6 addressing Containment Systems.

2. FSAR, Sections 9.3, 9.4, and 9.5 addressing Water Systems.

3. FSAR, Section 14.6, Decrease in Reactor Coolant Inventory.

Serial No 13-227 MPS2 Ultimate Heat Sink ATTACHMENT 4 LIST OF REGULATORY COMMITMENTS Dominion Nuclear Connecticut, Inc.

Millstone Power Station Unit 2

Serial No 13-227 MPS2 Ultimate Heat Sink, Page 1 of 3 List of Regulatory Commitments The following table identifies those actions committed to by Dominion Nuclear Connecticut (DNC) for the Millstone Power Station Unit 2 (MPS2) as part of the license amendment request. Any other statements in this submittal are provided for information purposes and are not regulatory commitments.

One-Time Number Commitment Committed Action (Yes/No) 1 Administrative controls will be established for Upon Yes cleaning of the RBCCW heat exchangers at a 3-implementation month interval, of the NRC approved license amendment.

2 Administrative controls will be established for Upon Yes cleaning of the switchgear room coolers, implementation X181A/B, at an 18-month interval, of the NRC approved license amendment.

3 Administrative controls will be established to Upon Yes address the following:

implementation For service water temperatures above 750F, it of the NRC may be necessary to also open the RBCCW approved winter temperature control valves (2-SW-245, 2-license SW-246, and 2-SW-247) to maximize flow to the amendment.

RBCCW heat exchangers to support normal operation.

4 For the Reactor Building Component Cooling Upon Yes Water (RBCCW) system, a RBCCW supply implementation temperature of 850F in Modes 1, 2 and 3 will be of the NRC included in the MPS2 FSAR and operating approved procedures as a design requirement of the license RBCCW system. MPS2 operating procedures amendment.

will be modified to maximize RBCCW flow and minimize RBCCW heat loads, as appropriate, I

Serial No 13-227 MPS2 Ultimate Heat Sink, Page 2 of 3 One-Time Commitment Committed Action (Yes/No) whenever service water (SW) inlet temperature exceeds 750 F.

For pumps tested in the In-Service Testing (IST)

Upon Yes program, the IST acceptance criteria for the SW implementation pumps will be revised to reflect the updated SW of the NRC maximum flow.

approved license amendment.

For Generic Letter (GL) 89-13, the RBCCW heat Upon Yes exchanger (X-18A/B/C) surveillance procedures implementation will be revised to increase the differential of the NRC pressure surveillance frequency to weekly from approved July through September.

license amendment.

7 For Generic Letter (GL) 89-13, cleaning and inspection schedules for the RBCCW heat exchangers (X-1 8A/B/C) and the emergency diesel generator heat exchangers (X-83A/B, X-53A/B, X-45A/B) will be altered such that those heat exchangers are cleaned annually prior to each summer. Additionally, if necessary, the RBCCW cleaning frequency may increase based on observed RBCCW outlet temperatures and DP surveillance results.

Upon implementation of the NRC approved license amendment.

Yes 8

For the MPS2 Final Safety Analysis Report, the Upon Yes following sections will be updated to reflect the implementation change in ultimate heat sink (UHS) temperature:

of the NRC Section 1.2.10.3, RBCCW System approved license Section 9.4.3.1, Normal Operation amendment.

Section 9.4.4.3, Shutdown Section 9.7.2.1.2, Design Criteria Section 14.8.2.2.3, Input and Assumptions

Serial No 13-227 MPS2 Ultimate Heat Sink, Page 3 of 3 One-Time Number Commitment Committed Action (Yes/No) 9 For NUREG-1432, Standard Technical Specifications for Combustion Engineering Plants considerations, if all of the installed instrumentation at the inlet to the RBCCW heat exchangers are out of service; alternative instruments that measure SW supply side temperature will be used. In this case, an appropriate instrument uncertainty will be subtracted from the acceptance criteria. This guidance will be incorporated into the appropriate MPS2 surveillance procedures.

Upon implementation of the NRC approved license amendment.

Yes