Text

Application for Amend to License NPF-85,consisting of Change Request 95-07-2,extending AOT to Allow Adequate Time to Install Isolation Valves & cross-ties on ESW & RHRSW Sys to Facilitate Future Insps or Maint
	ML20086A163
Person / Time
Site:	Limerick
Issue date:	06/23/1995
From:	Hunger G; PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	; NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20086A171	List: ML20086A163; ML20086A174;
References
	NUDOCS 9507030089
	Download: ML20086A163 (36)
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Ctation Support Department

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PECO ENERGY eccoc"eov c -o v Nuclear Group Headquarters .

965 Chesterbrook Boulevard Wayne, PA 19087-5691 10CFR50.90 t

June 23,1995 s

Docket No. 50-353 License No. NPF-85 -

U. S. Nuclear Regulatory Commission ,

ATTN: Document Control Desk !

Washington, DC 20555 l

SUBJECT:

Limerick Generating Station, Unit 2 Technical Specifications Change Request No. 95-07-2 i Gentlemen:

PECO Energy Company is submitting Technical Specifications (TS) Change l Request No. 95-07-2, in accordance with 10CFR50.90, requesting a change to 3 the TS (i.e., Appendix A) of Operating License No. NPF-85 for Limerick !

Generating Station (LGS), Unit 2.

Tht, TS Change Request involves a one-time (i.e., temporary) change affecting -

the Allowed Outage Time (AOT) for the Emergency Service Water (ESW)

System; Residual Heat Removal Service Water _ (RHRSW) System; the .

Suppression Pool Cooling, the Suppression Pool Spray, and. Low Pressure Coolant injection modes of the Residual Heat Removal System; and Core Spray System to be extended from 3 and 7 days to 14 days during the LGS, Unit 1, sixth refueling outage scheduled to begin January,~ 1996. This proposed extended AOT will allow adequate time to install isolation valves and cross-ties j on the ESW and RHRSW Systems to facilitate future inspections or i maintenance. This AOT extension request is the last in a series of planned TS Change Requests which have supported improvements to the ESW and RHRSW raw water systems. The installation of unitization jumpers and valves on the ESW loops will allow for isolation of one loop of ESW from one unit while maintaining the operability of the remainder of that ESW loop to support 300017 '

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June 23,1995 Page 2 I

operation on the other unit. The cross-ties will provide an operational alternative whereby either the ESW or RHRSW buried supply line can provide a common path for one loop of the ESW and RHRSW system. It will also provide the ability to isolate an RHRSW return line while maintaining a return path to the spray pond. This will allow the unused, isolated line to be drained for inspections or maintenance while maintaining the operability of the affected l ESW and RHRSW loop.

t This TS Change Request is similar to the LGS Unit 1, TS Change Request No.

94-04-1, issued by the NRC on January 27,1995, as Amendment No. 86.

Information supporting this TS Change Request is contained in Attachment 1 to l this letter, and the proposed replacement pages for the LGS TS are contained in Attachment 2. The TS change information is being submitted under j

affirmation, and the required affidavit is enclosed.

l We request that, if approved, this TS Change Request for LGS, Unit 2, be approved prior to January,1996 and become effective within 30 days of issuance.

If you have any questions, please do not hesitate to contact us.

Very truly yours,

- 1-G. A. Hunger, Jr.,

Director-Ucensing Attachments 1

I Enclosure cc: T. T. Martin, Administrator, Region I, USNRC (w/ attachments and enclosure)

N. S. Perry, USNRC Senior Resident inspector, LGS (w/ attachments and enclosure)

R. R. Janati, PA Bureau of Radiological Protection (w/ attachments and enclosure) l

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.. i COMMONWEALTH OF PENNSYLVANIA : ,

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! ss.

COUNTY OF CHESTER :

W. H. Smith, III, being first' duly sworn, deposes and says: ;

That he is Vice President of PECO Energy Company, the Applicant i

herein; that he has read the enclosed Technical Specifications ,

Change Request No. 95-07-2 "One-time.(i.e., temporary) Extension l of the Allowed Outage Time (AOT) for the Emergency Service Water .

(ESW) System; Residual Heat Removal Service Water (RHRSW) System; the Suppression Pool Cooling, the Suppression Pool Spray, and Low- f Pressure Coolant Injection Modes of the Residual Heat Removal i System; and Core Spray System to 14 days," for Limerick Generating ;

Station, Unit 2, Facility Operating License No. NPF-85, and knows

1 the contents thereof; and that the statements and matters set forth !

therein are true and correct to the best of his knowledge, ;

informationhand belief.

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Vice Presi(/ dent Subscribed and sworn to before me this .M day of 1995.

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ATTACHMENT 1 j l

LIMERICK GENERATING STATION 1 UNIT 2 :

1 DOCKET NO.

50-353 1

LICENSE NO.

NPF-85 'i l

TECHNICAL SPECIFICATIONS CHANGE REQUEST i

NO. 95-07-2 :

"One-time (i.e., temporary) Extension of the. Allowed Outage Time (AOT) for the Emergency Service Water (ESW) System;- ]

Residual Heat Removal Service Water (RHRSW) System; the o Suppression Pool' Cooling, the Suppression Pool Spray, and Low Pressure Coolant Injection Modes of the Residual Heat ,

Removal System; and Core Spray System to 14 days." l Supporting Information for Changes - 32 PAGES ,

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PAGE 1 PECO Energy Company, licensee under Facility Operating License No. NPF-85 for Limerick Generating Station (LGS), Unit 2, requests that the Technical Specifications (TS) contained in Appendix A to the Operating License be amended, as proposed herein, to temporarily extend the Allowed Outage Time (AOT) for the Emergency Service Water (ESW) System; Residual Heat Removal Service Water (RHRSW) System; the Suppression Pool Cooling (SPC),

the Suppression Pool Spray (SPS), and Low Pressure Coolant Injection (LPCI) modes of the Residual Heat Removal (RHR) System; and Core Spray (CS) System to 14 days during the LGS, Unit 1, !

sixth refueling outage scheduled to begin in January of 1996.

The purpose of this TS Change Request is to allow the one-time extension of AOTs for LGS Unit 2 while modifications are performed concurrently on the 'A' loop of the Emergency Service Water (ESW) System and the 'A' loop of the Residual Heat Removal Service Water (RHRSW) System.

l Discussion and Description of the Proposed Chances i

The RHRSW System consists of two independent supply and return loops (i.e., Loops 'A' and 'B'), common to both units, with each loop providing cooling water to the tube side (i.e., RHRSW System flow) of one heat exchanger on each unit. The cooling water originates from a common spray pond (i.e., Ultimate Heat Sink),

is carried to the RHR heat exchangers through two physically separated buried RHRSW pipe lines which enter the building structure, below grade, into a common pipe tunnel, and return to the spray pond through two separated buried pipe lines. The ESW System consists of two supply loops (i.e., Loops 'A' and 'B'),

common to both units, with each loop supplying coolant to select equipment during a Loss of Coolant Accident (LOCA) or Loss of Offsite Power (LOOP) event. Like the RHRSW System, the coolant originates from the common spray pond, is carried to the equipment through two separated, buried ESW pipe lines which enter the building structure, tclow grade, into a common pipe tunnel. However, the ESW coolant is returned to the spray pond by combining with, and through the RHRSW return pipe lines.

The purpose for this TS Change Request is to support modifications similar to those performed during the LGS Unit 2, third refueling outage in January 1995, which will improve the unit separation capability and serviceability of the ESW and RHRSW Systems. Modification P-00166 will install unitization jumpers and valves on the ESW loops. This will allow for isolation of one loop of ESW from one unit while maintaining the operability of the remainder of that ESW loop to support operation on the other unit. Modification P-00167 will install cross-ties between the ESW and RHRSW supply lines. This will allow for the use of either the ESW or RHRSW supply line to provide a common supply path for one of the ESW and RHRSW loops.

The unused supply line can then be drained for inspection or maintenance while maintaining the operability of the affected ESW and RHRSW loop. The P-00167 cross-tie has been installed between the operable loop 'B' ESW and RHRSW supply lines. This provides

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PAGE 2 l additional flexibility and reliability of the supply portion of ESW and RHRSW systems during the 1R06 extended AOT but additional ,

credit was not taken for this feature during the following safety )

evaluation nor in the Probabilistic Safety Assessment Study !

performed to support this effort. Modification P-00168 will install a cross-tie between the RHRSW 'A' and 'B' loop return lines to allow for the use of a common return path that will maintain the operability of both loops of RHRSW while one RHRSW return header is isolated.

The common portions of the ESW and RHRSW loops can not be isolated, and the use of multiple freeze seals and drain systems are necessary in order to install the piping and valves. The time required to establish multiple freeze seals, drain, install piping and valves and the subsequent system restoration dictates the need for these one-time TS changes. The modifications will be installed during the sixth, Unit 1, refueling outage, which is scheduled to begin in January of 1996.

PECO Energy proposes that TS 3.7.1.1, Action a.3, be revised to allow one subsystem of RHRSW (i.e., loop 'A') to be inoperable for 14 days and TS 3.7.1.2, Action a.3, be revised to allow one subsystem of ESW (i.e., loop 'A') to be inoperable for 14 days.

PECO Energy also proposes that the TS affecting two subsystems (i.e., 'A' and 'C') of the LPCI mode of RHR (TS 3.5.1), one loop (i.e., 'A') of the SPC mode of RHR (TS 3.6.2.3), one loop (i.e.,

'A') of the SPS mode of RHR (TS 3.6.2.2), and one subsystem (i.e., 'A') of Core Spray (TS 3.5.1), be revised to allow them to :

be inoperable for the same 14 day period. In order to maintain compliance with TS 3.5.1, PECO Energy also proposes that the OPCON 3 portion of the TS 3.5.1 APPLICABILITY statement be amended to allow, during the extend AOT period, for the alignment of the 'B' LPCI subsystem of the RHR system in the RHR shutdown

-cooling mode (SDC). In addition, three standby diesel generators (SDG), D11 and D13 on Unit 1, and D23 on Unit 2, will also be inoperable for the 14 day period. However, the SDG requirements will not require a TS change. These one-time extensions will be taken concurrently to permit completion of the modifications and to allow continued operation of Unit 2. ,

These proposed TS changes involve a one-time revision to extend the allowed outage time (AOT) for the ESW System, RHRSW System, and SPC mode of the RHR system from 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months to 14 days and to extend the AOT for the LPCI mode of the RHR system, the SPS mode of the RHR system, and one CS subsystem from 7 days to 14 days.

Finally, this request contains Unit 2 administrative changes to remove note "#" from TS pages 3/4 6-15, 3/4 6-16, 3/4 7-1, and 3/4 7-3 which were in place to support work during previous refueling outages, and are no longer valid.

l Safety Assessment These one-time TS changes are requested to allow adequate time during the Unit i refuel outage for the installation of the 1

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piping and isolation valves on the common ESW and RHRSW 'A' loops ,

without a shutdown of Unit 2. Furthermore, approval of these TS 1 changes is requested in order to install the isolation and cross-tie valves and thereby increase the availability of the ESW and RHRSW systems and minimize the need to invoke AOTs or request future one-time TS changes when maintenance or modifications on the affected portions of the ESW and RHRSW systems are planned. j 1

The ESW and RHRSW systems each consist of two independent loops, i common to both units (i.e., Loops 'A' and 'B'). The 'A' loop of each system will be removed from service concurrently during the sixth, Unit 1, refueling outage. During these activities, LGS Unit 1 (i.e., refueling) will continue to comply with its applicable TS by ensuring that the operable systems and components are supported by the operable 'B' loops of ESW and RHRSW.

The following assumptions and compensatory measures have been specified as bases of our proposal. A "Special Procedure" will be written for the control of this activity. Where appropriate, these items shall be included in the "Special Procedure."

Additional details are provided in the referenced paragraph that !

l follow these assumptions.

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1. The cooling water for the D21 SDG will be realigned from the 'A' loop of ESW to the 'B' loop of ESW in order to i maintain the operability of SDG D21. Even though a SDG D21 l start will not automatically start either of the operable ESW pumps (0BP548 or ODP548), SDG D21 is considered to be operable. A SDG D21 isolated start will require a manual start of ESW loop 'B' or a manual trip of SDG D21. (For additional details, see Items b. and c. in the following review of plant impacts)

SDG D11 may also be realigned from the 'A' loop of ESW to the 'B' loop of ESW in order to allow for local loss of ,

offsite power (LOOP) testing and other maintenance l activities on SDG D11 during the extended AOT. SDG D11 may )

be considered operable when aligned to the 'A' loop of ESW, 1 but no credit will be taken in this Safety Assessment for the operation of SDG D11. (Item c.)

The Special Procedure will prohibit the use of the operable ESW 'B' loop as a backup source of cooling water to the Unit 2 Turbine Enclosure Cooling Water (TECW) system or the Unit 1 Reactor Enclosure Cooling Water (RECW) system when more than four SDG are aligned to the operable ESW 'B' loop.

(Item c.)

2. The 'B' loop of ESW will be aligned to the operable RHRSW 'B' return header only. The ESW return valve (HV 015B) to the 'B' RHRSW return header will be verified open i and blocked open prior to entering the extended AOT. The ESW return valve (HV-11-011B) to the 'A' RHRSW return header will be blocked closed. (Item b.)

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3. A design basis change has been implemented via LGS Modification P-00212 and the supporting TS changes i incorporated into the Unit 2 TS via Amendment 46, dated !

I January 20, 1995, such that the inoperable 'A' loop of ESW l will not be required to support the operability of the Unit i 2 RCIC system. (Item g.)

4. Unit 2 will be in Operational Condition (OPCON) 1, 2 or 3 during this extended AOT. All TS required components, systems and subsystems not discussed will be maintained in l accordance with TS. The systems / equipment listed in the attached Table 1 will be verified to be operable prior to implementing the extended AOT and will be maintained operable for the duration of the extension. Otherwise, the {

applicable TS will be followed. j l

PECo will minimize the number of surveillances performed on identified equipment, which may adversely affect safety-related systems or components during the extended AOT. The Special Procedure will require that, if at all practical, tests will not be performed on the identified list of components, where the test would cause the components to become inoperable. However, it is recognized that it will be necessary to temporarily enter a 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months AOT (TS 3.8.1.1 1 ACTION e.1) for SDG D11 and D21 when they are realigned to I the A loop of ESW to support modification acceptance testing. In addition, the Special Procedure will identify the components and require a verification to be performed prior to the extended AOT to ensure the operability of the components, and once every 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months during the extended AOT.

5. Unit 1 will be in OPCON 4, 5 or *.

6. It is intended that the Unit 2 suppression pool temperature should be maintained low (i.e., below 80*F) during the extended AOT. (Item f.)

7. Any equipment / systems that, if removed from service, j would place the unit outside the bounds of the UFSAR analysis described in UFSAR Section 6.2. Will be required to be operable for the duration of the proposed extended AOTs.

(Item f.) J l

8. Work on the 'A' RHRSW loop will not begin until the decay heat generation rate of Unit 1 has been reduced to a i level that will allow the removal of the Unit 1 'A' RHR Heat i

Exchanger from service per the guidance of Procedure GP-6.2.

(Item f.)

9. Draining the Unit i reactor cavity will not occur until RHRSW loop 'A' is returned to service or an alternate decay heat removal method (e.g., core spray with MSRVs dumping to suppression pool) is available. (Item f.)

10. In order to maintain the full operability of the RHRSW

PAGE 5 and ESW 'B' loops to support Unit 2 operation, the Unit 1 SDG, D12, and Unit 2 SDG, D22 and D24, must be maintained operable. (Items kl. and k2.) In order to maintain the full operability of the CREFAS and SGTS 'B' loops to support Unit 2 operation, the Unit 1 SDG, D12 and D14, must be maintained operable. (Items 1. and m.) The Unit 2 SDG D21 and the Unit 2 Division I DC battery system must be maintained operable to support the use of the Division I ADS trip system subsystem 'A' for ECCS and decay heat removal. (Item f.)

The Unit 1 SDG, D14, must be maintained operable to support ,

the fire protection non-safeguard loads. (Item v.)

11. The 'A' hydrogen recombiner primary containment isolation valve pairs (HV-57-261/FV-DO-201A and HV 262/HV-57-266) must be maintained closed (penetration isolated) in order to avoid entering the 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months ACTION ,

statement in TS 3.8.1.1 ACTION e.l. (Item q.)

12. The drywell unit coolers, 2AV212 and 2GV212, should have, if possible, their 2A1 and 2G1 fans operable (rather than the 2A2 and 2G2 fans) when the 'A' ESW loop is made inoperable. It is intended to have the 2A1 and 2G1 fans operable, but it is not a requirement. (Item s.)

13. Appropriate measures will be taken as necessary for the fire safe shutdown method equipment that may be impacted.

(Item v.)

The ESW and RHRSW systems and their supported systems are designed with sufficient independence and redundancy such that the removal from service of a component / subsystem will t not prevent the systems from performing their required safety function. Since removal of an ESW and a RHRSW loop from service is allowed by current Technical Specifications, then the main concern is the reduced margin of safety incurred by extending the affected AOTs.

Based on the support functions of the ESW and RHRSW systems, a review of the plant was performed to determine the impacts that the inoperable ESW and RHRSW 'A' loops would have on other systems. The impacts were identified for each system as discussed below and it was determined whether there were adverse affects on the systems. It was then determined how the adverse affects would impact each system's design basis and overall plant safety. This evaluation considers the fact that single active failures are not postulated to occur during TS AOTs; however, since the selected TS AOTs are being extended beyond their normal limits, the impact of single failures is discussed to provide a better understanding of the impact that the removal of the 'A' ,

loops of ESW and RHRSW have on the affected systems. As described below the consequences of any postulated accident 1 occurring on Unit 2 during this AOT extension was found to be l bonnded by the previous UFSAR analyses as described below, i

a. RHRSW -- TS 3.7.1.1 ACTION a.3. provides for an AOT of I

PAGE 6 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months with one RHRSW loop inoperable. The result of the inoperable RHRSW loop is to declare the 'A' RHR heat exchanger inoperable on each unit. This impacts the Unit 2 RHR modes of operation as described below in Item f.

The removal of the 'A' loop of RHRSW from service will also temporarily eliminate the ability of the RHRSW system from supporting a non-TS operation of the RHR ,

system. The RHRSW 'A' loop is designed to be able to provide water to the RHR system as a backup source for post-accident containment spray and core flooding. The RHRSW supply to the RHR system is used for extreme emergency conditions when the RHR system cannot perform -

its cooling function. The 'B' loop of RHR will be operable as discussed in item f. below. Since this is a '

non-TS function, and the probability of needing this function during the extended AOTs is judged to be low, the loss of this function for fourteen days is considered to be acceptable.

The removal of RHRSW loop 'A' from service will also result in the RHRSW 'A' return header to the spray pond being inoperable. This header is also used by the 'A' and 'B' loops of ESW and the impact on the ESW system is evaluated in Item b. below.

In addition, the inoperable RHRSW 'A' loop impacts the backup source of fuel pool makeup as discussed below in '

Item hl. The potential impacts on the RHRSW system due to the inoperable ESW loop 'A' and its associated SDG are evaluated in Item kl. below. ]

b. ESW -- TS 3.7.1.2 ACTION a.3. provides for an AOT of 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months with one ESW loop inoperable. TS 3.7.1.2 ACTION a.3 also requires that all equipment aligned to the inoperable ESW loop be declared inoperable. This would .

normally include four SDG (i.e., D11. D13, D21, and I J

D23), which provide standby AC power to safety-related equipment and are normally aligned and cooled by the 'A' '

loop of ESW. However, since SDG D21 will be realigned to the 'B' loop of ESW while the 'A' loop of ESW is inoperable, then SDG D21 will not be declared i inoperable. The impact of the loss of cooling by ESW l loop 'A' and the loss of standby AC power by SDG Dil, D13, D23 are described below in detail for all of the affected equipment and systems. The potential impacts 1 on ESW loop 'B' due to the inoperability of ESW loop 'A' i and its associated SDG are evaluated in Item k2. below.

With the 'A' RHRSW return header inoperable, only the j

'B' loop of ESW will be impacted since the 'A' loop of ESW will already be out-of-service. The 'B' loop of ESW j will be aligned to the operable RHRSW 'B' return header only. With only one RHRSW return header available, the

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'B' ESW loop is not single failure proof. However, valves HV-11-011B and HV-11-015B are the only single active failure components in the ESW system which would have the potential for causing the complete failure of the 'B' loop of ESW during the extended AOT. The ESW return valve (i.e., HV-11-015B) to the 'B' RHRSW return header will be verified open and blocked open prior to entering the extended AOT. To assure the operability of the 'B' ESW loop, the ESW return valve (i.e., HV 011B) to the 'A' RHRSW return header will be blocked closed. This will eliminate the possibility of a single active failure rendering 'B' ESW inoperable. The LGS Clearance and Tagging Manual is the document that provides guidance for blocking. In addition, specific guidance for this blocking evolution will be provided by the Special Procedure.

c. Standby Diesel Generators (SDG) - The D23, D11 and D13 SDG will be declared inoperable since the required ESW loop 'A' cooling to support their operation will not be available. SDG D21 will be maintained operable since its heat exchangers will be aligned to the operable ESW loop 'B'.

The Special Procedure will prohibit the use of the operable ESW 'B' loop as a backup source of cooling water to the Unit 2 Turbine Enclosure Cooling Water (TECW) system or the Unit 1 Reactor Enclosure Cooling Water (RECW) system when more than four SDG are aligned to the operable ESW 'B' loop. This is necessary to assure adequate ESW flow to the SDG and other safety-related equipment.

SDG D11 may also be aligned to the operable ESW loop 'B' to allow for local LOOP testing and other maintenance activities on SDG D11 during the extended AOT. ,

Confirmatory testing has already been successfully l completed to verify that the ESW 'B' loop can provide j adequate cooling water flow to the six SDG without adversely affecting the operability of the ESW loop or any other operable systems. SDG D11 may be considered operable when it is aligned to ESW loop 'B' but no '

credit is being taken for its operability in this Safety Assessment since it may only be operable for a portion i of the extended AOT.

TS 3.8.1.1 requires a minimum of four operable separate I and independent SDG for the operating unit (Unit 2), and TS 3.8.1.2 requires a minimum of two operable SDG for ;

the shutdown unit (Unit 1). The TS requirement for Unit l' 1 is satisfied with SDG D12 and D14 operable.

Unit 2 will have one inoperable SDG, thus Action a. of TS 3.8.1.1, with an associated 30 day AOT will be in effect during the extended AOT period of 14 days. Since I

i PAGE 8 the inoperability is due to preplanned maintenance, the plant will only demonstrate operability of the remaining Unit 2 SDG (D21, D22 and D24) by performing surveillance requirement 4.8.1.1 (a) (breaker alignment and power availability checks). This is based on the intent of the ACTION statement as described in the LGS TS Bases and in the BWR4 Standard Technical Specification Bases (NUREG 1433). Upon failure of a SDG, the concern of a possible common mode failure is addressed by the testing of the remaining operable SDGs per Surveillance Requirement 4.8.1.1.2a.4. Since the planned inoperability in this case does not introduce the possibility of common mode failures of the remaining Unit 2 SDG or the Unit 1 SDG supporting common systems, then SDG startup tests are unnecessary, not required, and therefore, will not be performed.

With SDG D21 aligned to the loop 'B' of ESW, a SDG D21 start will not automatically start either of the operable ESW pumps (OBP548 or ODP548) supplying cooling water to SDG D21. However, SDG D21 will be considered to be operable, since following an accident and/or a LOOP an auto start of SDG D21 will coincide with an auto start of SDG D22, D24, D12 or D14. The auto start of any one of these SDG will ensure that at least one ESW pump in ESW loop 'B' will be started to support the emergency operation of the aligned SDG. However, if a Division I bus failure occurs during normal operation and ESW cooling water is not provided to SDG D21, then alarms would alert operators of the Division I failure and/or the lack of SDG cooling. Operations personnel would then manually initiate the ESW loop 'B' pumps or manually trip SDG D21. This information will be noted in the Special Procedure which will provide guidance for Operations personnel during the extended AOT.

Maintaining SDG D21 operable with ESW loop 'B' will support the operation of the Unit 2 RERS as discussed below in Item n. The Unit 2 SDG, D12 and D14, must remain operable to support the operability of the 'B' loops of RHRSW, ESW, CREFAS and SGTS as discussed below in Items kl., k2., 1. and m.

TS 3.8.1.1 ACTION el. requires the verification of the operability of two train systems and their associated SDG to provide assurance that a loss of offsite power (LOOP) will not result in the complete loss of safety function when SDG are inoperable on either unit. If at least one train is fully operable (including its standby AC power sources), then the more restrictive AOT between the AOT based on the number of inoperable SDG and the system AOT (if one of the system trains is inoperable), ,

is applied. If at least one train is not fully 1 operable, then an AOT of 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months is applied along with the inoperable SDG AOT. The impact of the inoperable l

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l PAGE 9 SDG is discussed below for each system. The standby AC power operability requirements for the common systems are addressed in the appropriate system TS ACTION statements and the potential impacts on these systems are also discussed below in Items kl and k2.

d. Core Spray -- The removal of the 'A' ESW loop from service will remove the supply of cooling water to the Core Spray 'A' and 'C' pump room unit coolers; therefore, the 'A' loop of Core Spray must be declared inoperable. This impacts Emergency Core Cooling System (ECCS) capability as discussed below in Item f.

e. HPCI -- The 'B' loop of ESW will be available to supply cooling water to the HPCI pump room's redundant unit coolers. However, HPCI is now fully operable in accordance with TS 3.5.1 with or without the unit coolers based on the implementation of Modification P-00212 and the supporting TS changes incorporated into the Unit 2 TS via Amendment 46, dated January 20, 1995.

In' addition, since HPCI is DC powered and the normally open HPCI containment isolation valves (HV-55-2F003, HV-55-2F100, HV-2F002, HV-2F093 and HV-55-2F095) are powered from SDG D22 and D24, there is no impact on HPCI due to the lack of ESW 'A' loop cooling to SDG D23.

Therefore, the HPCI system will be operable in accordance with the existing TS during the entire 14 day period that ESW loop 'A' and RHRSW loop 'A' are inoperable. The operability of HFCI will help to assure that adequate core cooling will remain available as discussed below in Item f. <

f. RHR -- The removal of the 'A' ESW loop from service will remove the supply of cooling water to the RHR 'A' and

'C' pump room unit coolers and to the 'A' and 'C' RHR pump motor oil coolers. Therefore, the 'A' and 'C' RHR pumps will be declared inoperable. This, along with the inoperability of the 'A' RHR heat exchanger (due to the inoperability of the 'A' RHRSW loop), impacts the various modes of RHR operation and emergency core cooling systems (ECCS) capability as discussed below.

ECCS CAPABILITY The removal of ESW loop 'A' from service will result in the inoperability of the 'A' Core Spray loop and the 'A' and 'C' LPCI loops. The removal of the RHRSW loop 'A' from service will not affect the capability of any of the emergency core cooling system (ECCS) loops from injecting water into the reactor vessel. The Automatic Depressurization System (ADS) trip system subsystems 'A' and 'C' are powered by the Division I and III DC battery systems which are backed up after four hours by SDG D21 and D23, respectively. Since SDG D21 will be operable, then the Division I battery system and the Division I

. . . , _ _ -. . _ ..__m . .m , _ _ ,

t

~!

.PAGE 10- -

1

. ADS trip' system subsystem 'A' are fully operable. -With :

SDG D23 inoperable, the standby.AC power source for the. .l Division III DC battery system is inoperable and thel li Division III battery system'may not be-functional after '[

four hours. ,

i However, the ECCS: design basis. function of'the' ADS is to allow for a yapid depressurization of the vessel during ,

a LOCA in which HPCI is not available so that the low pressure ECCS can provide for core cooling (UFSAR i Section 7.3.1.1.1.2). This ECCS' function'will be '?

accomplished.within the four. hour design capability of 1 the DC battery subsystems. Therefore, if.a DBA occurs ;

with or without a LOOP, then the' ADS can meet the single :t failure criteria since both ADS subsystems 'A' and 'C' and both the Division I and III DC battery systems would j be functional for a long enough duration. Therefore, in ;

either case, the ability of the DC powered ADS.to serve its ECCS design functions-is unaffected by this ;

' activity. The use of the ADS valves for longer than !

four hours is discussed below under decay heat removal.. ,

l RHR and/or Core Spray can maintain adequate core cooling- .!

for all break sizes, even. assuming that HPCI were to be 1 unavailable. This leaves HPCI, . loop 'B' of Core Spray,.

~

LPCI 1 oops 'B' and.'D' and~ ADS available to provide for

~

i adequate core cooling following a non-ECCS pipe break a loss of coolant accident (LOCA). For an ECCS pipe break LOCA, the: low pressure ECCS would'not be single failure proof since a 'D' LPCI injection line break and a failure of Division 2 AC power-would' result in the loss ,

of the 'B' Core Spray. loop and LPCI-loops 'B' and 'D'. ;

With or without applying the single failure'criterlatas i described by UFSAR Section 6.3.1.1.2 to the-available j ECCS discussed above, the' minimum ECCS combinations

~

j described in UFSAR Table 6.3-3 are not met. However,: l since plant operation will be limited.by the TS Limiting ;

Conditions for Operation (LCOs), then the minimum ECCS :

requirements to be maintained are based on the General J Electric Company document, NEDO-24708A " Additional ;

Information Required for NRC Staff Generic Report on 1 Boiling Water Reactors," Revision 1, dated December l 1980. This document, which has been incorporated into UFSAR Section 6.3.1.1.2.o and 6.3.3.1 (which were unchanged by power rerate), provides the analysis which concludes that either one LPCI pump or one Core Spray loop in conjunction with' ADS, is adequate to reflood the vessel and maintain core cooling sufficient to preclude fuel damage. For a large break LOCA, following two 1 hours1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months of LPCI injection, an alternate cooling path may .)

l be necessary for long term core cooling per NEDC-30936P-A, "BWR Owner's Group Technical Specification Improvement Methodology," dated December 1988. Guidance

PAGE 11 for this additional cooling capability is provided by existing plant TRIP procedures.

Therefore, since the minimum ECCS to be maintained operable during this extended AOT exceeds the minimums postulated in NEDO-24708A and NEDC-30936P-A and since a single failure is not required to be assumed during an AOT, then adequate core cooling capability will be maintained and the ECCS will adequately limit the consequences of an accident.

The availability of adequate ECCS during OPCONs 4 and 5 and TS 3.5.2 compliance is discussed below under decay heat removal.

DECAY HEAT REMOVAL CAPABILITY The RHR heat exchangers provide methods of residual decay heat removal and suppression pool /drywell temperature control. Residual decay heat removal is a normal shutdown cooling mode of operation when a unit is shutdown. Two loops of the shutdown cooling mode of RHR (SDC) are required to be operable while in OPCON 3 (TS 3.4.9.1) with reactor vessel pressure less than the RHR cut-in permissive set point, in OPCON 4 (TS 3.4.9.2),

and in OPCON 5 (TS 3.9.11.2) with irradiated fuel in the vessel and the water level less than 22 feet above top of the reactor vessel flange, otherwise an alternate method of decay heat removal is required to be verified or demonstrated.

Unit 2 is expected to stay in OPCON 1. Therefore, the SDC mode of RHR TS would not be applicable to Unit 2.

However, since there is a probability that Unit 2 might be forced to shutdown during the extended AOT period, the shutdown sequence and compliance with TS 3.4.9.1 must be evaluated. Upon entering OPCON 3 and while depressurizing to the RHR cut-in permissive set-point, the 'B' and 'D' RHR pumps would be maintained in their normal LPCI mode alignment. This would maintain the plant's level of compliance with the TS (as required for the extended AOTs) during OPCON 3.

The LPCI alignment would maintain the two operable LPCI subsystems (i.e., 'B' and 'D') for automatic operation.

The operable 'B' loop of suppression pool spray and the operable 'B' loop of suppression pool cooling would also be maintained operable since they could be aligned from the centrol roor if an accident were to occur. Once the RHR cut-in permissive set-point is reached, then TS 3.4.9.1 ACTION a. must be entered since only the 'B' SDC loop would be operable. The 'B' loop of SDC would be operable since it would be capable of being aligned from the control room (except for system flushing) under normal shutdown conditions. The operability of I

PAGE 12

^

ialternate methods ofl decay heat removal would be verified or demonstrated to meet the requirements of TS j 3.4.9.1 ACTION.a. The. alternate methods of decay-heati i removal'that would be considered to meet TS 3.4.9.1~ l ACTION a.1are covered by Procedure GP-6.2. .However, an 'l

= alternate method would only need-to-be put into '

-operation'if theB' loop;of SDC became inoperable,and-if_the operability of the 'B' SDC loop could.not be !

reestablished by implementing Off. Normal Procedure ON- ]'

121.

The' ADS valves can be used to support decay heat' removal- .j or alternate shutdown cooling by holding two ADS valves 1 open and providing.a flow path from the-RPV to the suppression pool after the vessel has been depressurized j to less than 75 psig (UFSAR Section 15.2.9).- This

manual action requires DC power to be available to ,

energize at least one of the two solenoid valves on each ADS valve to'be opened. Since this operation is not ,

expected to be implemented until about three hours after 1 a LOOP (UFSAR Table 15.2-12) and since decay heat removal will take longer than one hour, then the SDG .j i

will be required to power the battery chargers to i

support these DC loads. With SDG D23 inoperable, the

'C' solenoid valves on'the ADS valves are_ assumed to be i inoperable after four hours.. Therefore, the?'A' solenoid valves on the ADS valves, the Division I DC ,

battery system and SDG D21 must be relied upon to :

support this decay heat removal function. This is acceptable since-during the limited duration of the ;

extended AOT, a' single active failure that would cause -i the Division I AC or DC power to be inoperable istnot postulated to occur.

In addition, if an Appendix R fire is postulated to l occur during the extended AOT in a fire area that i depends on Shutdown Method'B-or D and the postulated .

fire contributes to the loss of the Division I DC power i required to support the operation of the Division I ADS ,

control, then alternate DC power can be supplied from {

Division II in accordance with the existing procedures i SE-8-2 or SE-8-4.

When the 'B' loop of SDC is aligned, the 'B' loops of ?

SPC and SPS and the 'D' LPCI subsystem would remain i operable. However, the 'B' LPCI subsystem would be inoperable due to_the closing of the pool suction valve HV-51-1F004B. Therefore, during the extended AOT, if ;

the plant is required to shutdown'then one Core Spray i and three LPCI subsystems will be inoperable, and the !

plant would be in a condition not addressed in TS 3.5.1 ACTIONS a.1 and b.5 as a result of aligning the operable !

'B' LPCI subsystem.for shutdown cooling. Therefore, we are proposing a change to add a note to TS 3.5.1. i similar to the existing note "##" which permits !

W' x.

Vl l PAGE 13 l alignmentLto SDCT h'owever, it will specifically address I

/the proposed configuration. :Under these conditions, !

sufficient ECCS-(i.e., LPCI subsystem 'D' and core spray. .,

subsystem.'B')"and containment. cooling capabilities are

-available.should an accident occur since a single active :

failure would not have to be postulated. If an accident doesEnot occur, then the 'B' loop' of SDC is sufficient i

-for decay heat removal and achieving cold. shutdown. !

.In OPCONs 4~or 5, the ' ' B' ' and 'D' SIX: loops, which both use'the operable 'B' RHR heat exchanger, will be considered operable-in accordance with LGS procedure GP- 7 6.2. These loops will be operable with the 'A' ESW and i RHRSW loopsJinoperable and will satisfy the Unit 2 shutdown cooling requirements in OPCONs 4 and 5, if }

required. During OPCONs 4 or 5, with the 'B' SDC loop aligned, then TS 3.5.2 (2 ECCS subsystems operable) will ;

be met since both the 'B' Core Spray subsystem and the .;

'D' LPCI subsystem-will be operable. ,

t The RHRSW system is manually operated and is not i required during the first ten minutes of an event (UFSAR !

Section 6.2.2.3). Long-term actions (i.e., greater than-ten minutes) will be affected to the extent L that only i the 'B' RHR heat exchanger will be operable for long .

term decay heat removal. Long-term cooling requirements will be met by the operable Unit 2 'B' RHR heat a exchanger and the operable 'B' RHRSW loop in either the j suppression pool spray (SPS) or suppression pool cooling' 4 (SPC) modes of' operation, as discussed below.' j t

Decay heat removal for suppression pool /drywell !'

temperature control is an accident mitigation function.

The RHR system supports this function by two modes of ;

operation, SPS and SPC, both of which utilize the RHR [

heat exchangers. TS 3.6.2.2 requires that two loops of !

the SPS mode of the RHR system be operable in OPCONs 1, '

2 and 3. The'AOT for one inoperable loop'of SPS is-7 days. The AOT for this LCO is proposed to'be. extended to 14 days. TS 3.6.2.3 requires that two loops of SPC i mode of the RHR system be operable'in OPCONs 1, 2 and 3. j The AOT for.one inoperable loop cf SPC is 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . The '

AOT for this LCO is also proposed to be extended to 14 '

days. !

LGS UFSAR Section 6.2.2 states that one operable RHR heat exchanger is adequate for accident mitigation. Two ,

f, cases with only one operable RHR heat-exchanger are i L presented. In the first case, the operable RHR heat j i

. exchanger is placed in service, in containment spray, while one LPCI pump and one Core Spray loop inject water ,

into the vessel. In the other case, the RHR heat ,

exchanger is placed in service with an associated RHR pump taking suction from the suppression pool and 1 discharging to the vessel while another RHR pump (in !

PAGE 14 LPCI mode of operation) and one Core Spray loop inject directly into the vessel. Both cases assume a LOOP and that the High Pressure Coolant Injection (HPCI) system is available for the entire accident. This analysis is for a rupture of a recirculation line and is the bounding event for similar occurrences. During the extended AOT, there will be sufficient equipment available to operate in either one of these modes.

Since one loop of RHRSW with two RHRSW pumps can mitigate a Design Basis Accident (DBA) on one unit and support the safe shutdown of the other unit, then the potential heat removal demand from the operating unit and the shutdown unit, during the period that these temporary TS changes will be in effect, is within the capacity of the single operable RHRSW 'B' loop.

During the sixth, Unit 1, refueling outage, work on the

'A' RHRSW loop will not begin until the decay heat generation rate of the Unit 1 has been reduced to a level that will allow the removal of the Unit 1 'A' RHR Heat Exchanger from service per the guidance of procedure GP-6.2. RHRSW loop 'B' may be in operation to support the shutdown cooling requirements of Unit 1.

However, due to prior establishment of cold shutdown conditions, the reduction in decay heat generation and the ability to remove decay heat via the fuel pool, the heat removal demand on RHRSW for Unit 1 will be minimal.

Draining the Unit 1 reactor cavity will not occur until RHRSW loop 'A' is returned to service or an alternate decay heat removal method (e.g., Core Spray with MSRVs dumping to suppression pool) is available. The special procedure will list tht' appropriate existing procedures which establish alternate decay heat removal.

The above discussions do not account for a single active failure that could render the operable RHR heat exchanger or operable RHRSW loop inoperable. However, by limiting the time that the RHRSW loop 'A' is out-of-service (i.e., by being in an AOT), then a single active failure is not required to be postulated. Therefore, by maintaining the Unit 1 'A' RHR heat exchanger and the

'A' RHRSW loop and associated equipment / systems operable during this period, the RHR and RHRSW system will be able to provide adequate decay heat removal, and the consequences of an accident will remain unchanged.

The following components (if they were to individually i fail) would have the potential of completely preventing the Unit 2 RHR 'B' heat exchanger or the RHRSW 'B' loop from performing their safety functions (i.e., requiring l use of the heat exchanger) on Unit 2 while RHRSW loop ;

'A' is removed from service. The RHRSW pumps and the l spray pond inlet valves HV-12-032B&D are not included j because one RHRSW pump and one inlet valve would be J

I l

l 1

l PAGE 15 sufficient for accident decay heat' removal on Unit 2'and it is assumed that the minimal heat load on Unit 1 would i be removed via an alternate method (e.g., RHRSW loop 'B' l makeup to the fuel pool).

RHR heat exchanger, RHR outlet valve:

HV-51-1F003B Giormally open - safety function-open)

RHR heat exchanger, RHR bypass valve:

HV-C-51-1F048B (normally open - safety function throttled closed)

RHR heat exchanger, RHRSW inlet valve:

HV-51-1F014B (normally closed - safety function open)

RHR heat exchanger, RHRSW outlet valve:

HV-51-1F068B (normally closed - safety function open throttled open)

The active failure of any Unit 1 components in the 'B' loop of RHRSW will only have the potential of preventing the Unit 1 RHR 'B' heat exchanger from performing its safety functions on Unit 1. The Unit 1 components will not prevent the Unit 2 RHR 'B' heat exchanger or the RHRSW loop 'B' from performing their safety functions on Unit 2. .

A review of LGS maintenance records, for both the 'A' and 'B' loops of the above RHRSW components, was performed to identify any occurrences of Unit 2 or common valves failing to operate on demand. The review involved the conservatively estimated total number of LGS RHRSW va?.ve actuations and the total number of failures compared to a 1.18 % failure rate provided by LER summaries of U.S. Nuclear Power Plants (i.e.,

NUREG/CR 1363). The review concluded that the components' failure rate to operate on demand was consistent with or less than the percentage rate (i.e.,

1.18%) of expected failure for motor operated valves.

In addition, this same percentage failure rate was applied to a probabilistic safety assessment (PSA) performed for the proposed extended A0Ts where the increase in the Core Damage Frequency (CDF) was found

not to be a significant increase in risk. Therefore, the probability of a malfunction of any of these valves preventing the Unit 2 'B' RHR heat exchanger or the RHRSW 'B' loop from performing their safety functions on Unit 2 is considered to be minimal.

The potential impacts on RHRSW loop 'B' by the inoperable ESW loop 'A' and its associated SDG are evaluated below in Item kl.

g. Reactor Core Isolation Cooling (RCIC) -- The design basis requirement for ESW loop 'A' to maintain the operability of the RCIC system has been eliminated based

s PAGE 16 .

on the implementation of LGS Modification P-00212 and !

the' supporting TS changes incorporated into the Unit 2 TS via_ Amendment 46, dated January 20, 1995. Therefore, ,

the RCIC system will be' operable in accordance with TS 3.7.3.

Since RCIC is DC powered, with the exception of the normally open containment isolation valves HV-49-2FOO8, HV-49-2F076, HV-49-2F007, HV-49-2F080 and HV-49-2F084, then there is minimal impact due to the lack of ESW loop .

'A' cooling supplied to the SDG D23. The inoperability !

of the D23 SDG during a LOOP _results in the loss of the Division III battery charger which would carry the Division III DC loads after four hours. This could ;

result in the loss of power for the Division III RCIC vertical board 20C648 (UFSAR Table 8.3-25) after four hours.- However, loss of the vertical board does not affect the operability of RCIC. J In addition, in the case of RCIC, the inoperability of the D23 SDG also results in unavailability of the '

standby AC power source for the " inboard" containment ;

isolation valves (HV-49-2FOO7 and HV-49-2F084). With ;

^

standby AC power unavailable to only one valve on each penetration (X-10 and X-241) , continued operation with j the isolation valves open is allowed by TS 3.8.1.1 i ACTION e.1, as long as the " outboard" containment isolation valves (HV-49-2F008, HV-49-2F076, and HV '

2F080) remain operable and their associated SDG (D21) remains operable. If these conditions are not i i

maintained, then the affected penetration would be required to be isolated within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months and RCIC would be declared inoperable. However, if the operability of '

the outboard valves is maintained, then continued plant operation would be limited by the AOT of 30 days for one SDG inoperable (TS 3.8.1.1 ACTION a).

Therefore, the RCIC system can be maintained operable in accordance with the existing TS during the entire 14 day period that ESW loop 'A' and RHRSW loop 'A' are inoperable. This ensures that sufficient reactor water inventory is maintained following vessel isolation or loss of feedwater to permit adequate core cooling. HPCI or ADS and low pressure ECCS will provide backup to RCIC per the design basis.

h. Reactor Enclosure Cooling Water (RECW) system -- The RECW system provides cooling water for miscellaneous reactor auxiliary plant equipment and is normally cooled by service water. The Unit 2 RECW heat exchangers can be provided with backup cooling from the 'A' loop of ESW during a loss of offsite power (LOOP) . However, ,

according to UFSAR section 9.2.8.3, the RECW has no safety-related function and is not required to be operable following a LOCA.

PAGE 17 The RECW system has the capability to provide cooling to the safety-related fuel pool heat exchangers according to UFSAR Section 9.2.8.2. Accordingly, the ESW system provides backup cooling to this equipment. However, this is considered to be backup only and is not required for. safety as discussed in Item hl. below. Therefore, there is no safety impact, due to the 'A' loop of ESW not providing backup cooling to the RECW heat exchangers, on the systems or components required to mitigate accidents or to safely shutdown.

In addition, the Special Procedure will prohibit the use of the operable ESW 'B' loop as a backup source of cooling water to the Unit 1 Reactor Enclosure Cooling Water (RECW) system when more than four SDG are aligned to the operable ESW 'B' loop. This has no safety impact since no credit is being taken for the use of RECW in maintaining Unit 1 in cold shutdown.

hl. Fuel pool cooling ---The fuel pool cooling system is normally cooled by service water. Normally, in the event of a LOOP, the Unit 2 Fuel Pool Cooling and Cleanup (FPCC) system heat exchangers can be cooled by the RECW system (which in turn can be cooled by the 'A' loop of the ESW system) or the RHR 'A' heat exchanger ,

can be used to cool the Unit 2 spent fuel pool. During the extended AOTs, neither of these backups will be available. However, with a complete loss of capability

to remove heat from the Unit 2 spent fuel pool using heat exchangers (i.e., spent fuel pool or RHR heat exchangers), the pool can be allowed to boil and the ESW.

'B' loop may be used as makeup to maintain the pool water level (UFSAR Section 9.1.3.2). Since the makeup to the Unit 2 fuel pool is the 'B' loop of ESW and the ESW pumps 'B' and 'D' will be operable, then a single failure proof method-of providing makeup that is accessible from outside of the Reactor Enclosure is available.

Makeup to the Unit 1 fuel pool will be available from the 'B' loop of RHRSW which requires access to the Reactor Enclosure. This is acceptable since Unit 1 will be in cold shutdown or in refueling and not subject to a DBA LOCA that limits accessibility to the' Reactor Enclosure and since the RHRSW Makeup valve / spool in the Reactor Enclosure will be accessible while the fuel pools are at elevated temperatures. Therefore, there is no impact due to the inoperable 'A' loop of ESW and the lack of ESW 'A' loop makeup capability to the Unit 2 fuel pool, affecting the systems or components required to mitigate accidents or to safely shutdown.

h2. Reactor recirculation pumps -- According to UFSAR j Sections 9.2.2.2 and 9.2.8.2, backup cooling to the recirculation pump seals can be provided by supplying

-=

g'7 .

w , -

^

< ;i

, PAGE 18- ,

ESWidirectly.to'theLseals. However, this nonsafety- l related ESW functionLis not allowed by plant procedures. l; Therefore,-there is no impact,.due to the inoperable-'A' loop'of'ESW and theLlack of ESWA' loop backup cooling j Lto.the-Unit 2 recirculation pump seals, affecting the

e systems orfcomponents. required to mitigate accidents or- !

to. safely' shutdown.

'i. Turbine' Enclosure Cooling Water (TECW) --- The TECW .

'l system'provides cooling water for miscellaneous turbine l plant equipment and is normally cooled by. service water. l The Unit 2 TECW heat exchangers'can be provided'with !

backup cooling from the 'B' loop of ESW during a loss of offsite power (LOOP). The ESW return:line from the TECW heat exchanger to the spray pond via the RHRSW loop 'A' i return line is also unaffected. . However, the special j procedure will prohibit the use of the operable ESWB' !

loop as a backup source of cooling water to the Unit 2 ;

Turbine Enclosure Cooling Water (TECW) system when more than four SDG are aligned to the operable ESW 'B' loop.

~

According to UFSAR section 9.2.9.3, the TECW has no= l safety-related function and is not required to be operable following a LOCA. Therefore, there is no i impact, due to the inoperable 'A' loop of ESW!and the

~

l lack of ESW 'A' loop backup cooling to the Unit 1 TECW i system,~affecting the systems or components required to mitigate accidents or.to safely shutdown. 1 t

j. Main Control Room (MCR) chillers and HVAC -- The 'A' MCR 3 chiller requires cooling water from the 'A' ESW loop and ;

therefore, the 'A' chiller will not function during ;

these extended AOTs. In addition, the removal of-the 1

'A'-ESW loop from service will render SDG D13, standby AC power source "ar the 'A' MCR chiller and HVAC ,;

subsystem, inop6L ole. The MCR HVAC is a non-TS support system which is fully redundant. The inoperability of ,

only one of the redundant trains does not require,the ,

supported systems in the MCR to be declared inoperable. ;

Continued operation is allowed by TS for an unlimited ,

period of time as long as the temperature'in the main ,

control room is maintained below 85'F (TS SR 4.7.2a). l If the 'A' MCR chiller /HVAC is out-of-service and a DBA or other event occurs with or without a LOOP, then the !

probability, that the required single failure will .

disable the operable 'B' MCR chiller or HVAC train or j its operable'SDG, is assumed to be negligible. j Therefore, the MCR HVAC is assumed to fulfill its design ,

function during the DBA or other event and will support the systems that limit the consequences of the accident :

and/or support safe shutdown. i kl. Systems supporting RHRSW -- The RHRSW pumps are supported by the operation of SDG D11, D12, D21 and D22. !

The removal of the 'A' ESW loop from service requires :

I

PAGE 19 that SDG D11 be declared inoperable. There is no additional TS impact due to the RHRSW pump / diesel generator pairs that are inoperable since there are only i two (i.e. , SDG D11/ pump OAP506 and SDG D21/ pump OCP506)

! inoperable pairs. TS 3.7.1.1 ACTION a.5 requires a 30 day AOT, which is bounded by the 14 day extension.

The following RHRSW valve pairs were evaluated for the potential impact on RHRSW and ESW due to inoperability l of ESW loop 'A' and the SDG, (i.e., D11, D13 and D23)-

supported by that ESW loop.

HV-12-017A and HV-12-017B (D11 & D12)

HV-12-034A and HV-12-034B (D11 & D12)

The above valves isolate the RHRSW loop 'B' return loop from the RHRSW loop 'A' return loop. In this case, the inoperability of the D11 SDG only results in unavailability of the standby AC power source for one valve (HV-12-017A and HV-12-034A) in each line.

However, since the 'A' loops of RHRSW and ESW will be inoperable, then both valve pairs should be maintained closed to ensure that the operable RHRSW and ESW loops remain single failure proof.

Therefore, there will be no impact on safety since the operable 'B' loop and the inoperable 'A' loop of RHRSW will remain separated.

HV-12-111 and HV-12-113 (D11 & D23)

HV-12-112 and HV-12-114 (D11 & D23)

The above valves isolate the RHRSW loop 'A' lines to and from the Unit 1 cooling tower. In this case, the inoperability of the ' D11 and D23 SDG results in unavailability of the standby AC power source for both valves in each line. Therefore, the valves must be verified closed. However, since the 'A' loops of RHRSW and ESW will already be inoperable, then these valves could be maintained open or closed ,

and will have no impact on safety as long as the '

operable 'B' loop and the inoperable 'A' loop of ,

RHRSW remain separated.

HV-12-211 and HV-12-213 (D12 & D24)

HV-12-212 and HV-12-214 (D12 & D24)

The above valves isolate the RHRSW loop 'B' lines to and from the Unit 2 cooling tower. Since both SDG D12 and D24 will be operable, these valves will be capable of being operated as designed and the RHRSW {

and ESW 'B' loops will not be adversely impacted.

The RHRSW system was designed with the capacity so that one loop of RHRSW with two pumps in operation and two

PAGE 20 I

one unit while unit (UFSAR can mitigate a of DBAtheonother bility of the Unit shutdown maintain the full opera i spray networkssupporting the safeorder to 9 2.3).

In

'B' loop tomaintained operable, W 'B' loop ray s nsupport U theSDG, 1

RHRSW D12, must'B' be loop pump OBP506 and RHRSr by-pass) ,

powers RHRSW 03B ('B' pump pit slu fill its valves HV-12-031B i g theDBA and limit (wintenetwork extended AOT can fulconsequences the 'B')

Therefore, RHRSW dur ndesign function operation' of ESW during a of the accident. are supported by theThe removal of the The ESW pumps k2 ESW 23, D24, D11 and D12 requires that SDG D23 anSDG D23 and D no SDG D loop from service 'A'. only ble but ESW loop / diesel are declared inoperable pumps in the inopera impact due to the ESW e inoperable pump pump since there11/ ire OAP548) generator pairs /that additional TS umparOCP548 and SDG Da.4 and a.5 only re are inoperable.

two pairs (SDG TSD23 p 3.7.1.2 ACTIONsor four pairs inoperable.when three tion for theirf action that required evaluadue to inoperability o il, D13 and D23)

The RHRSW valve pairs potential impact on'A' ESW were loop 'B'and the SDG (i.e.,

ESW loop

'A' supported by ESW loop ten of a above. minutessufficient exception of the firstthe ESW system hase ESW pump in With the LOCA, one ESW loop, with one onunit whileunit (UFSAR a DBA on other the postulated DBAcapacity withinmitigateshutdown of the may be required duringof ESW th loops operation, to safe supporting theTwo ESW pumpsof a DBA LOCA since bosuppl However,only the 9 2.2 3).tenminutes order to RHR pumps.and since first operating in of three shutdown B' are be must be operation dy be support thesince cooled by ESW ne E loop ' SW pump two Unit 2 RHR pumps Unit 1The will alreaone'B'loop ESW of ESW operable, then entire time.f. above.

adequate for thewas discussed support Unit 2 in Itemfull operabi pumpsorder to maintain theESW pumps) 548to maintained In

'B' valve

, op In loop (including two GESW D12 must'B' be pump OBP p

), then loop SDG D14 powers ESW'B' loo operation, Unit it 1 2

B' SDsince return to RHRSW SDG loopD12 rable.

r powers Item

/

addition, since Un have to be maintained ope HV-11-015B (ESW loop15B is being blocked openvalve pe SDG D14 would normally dby AC power to this However, valve HV-11-0and therefore, stanextended A l

b. above not required during the is

~ *u

f 9

, I "

PAGE 20 spray networks can mitigate a DBA on one unit while U supporting the safe _ shutdown of the other unit (UFSAR 9.2.3).- In order to maintain the full operability of-the RHRSW 'B' loop to support Unit 2 operation, the Unit 1 SDG,.D12, must be maintained operable, since SDG D12 powers RHRSW 'B' loop pump OBP506 and RHRSW 'B'. loop valves HV-12-031B (winter by-pass),.HV-12-032B (spray network.'B') and HV-12-003B-('B' pump pit' sluice gate).

'Therefore,.RHRSW during the extended AOT can fulfill its design function during a DBA and limit the consequences-p of the accident.

1 k2. ESW -- The,ESW pumps are supported by the operation of F' SDG D23,-D24, D11 and D12. The removal of the 'A' ESW loop from service requires that SDG D23 and D11 be C declared inoperable but SDG D23 and D11 support the ESW pumps in the inoperable ESW loop 'A'. There is no additional TS impact due to the ESW pump / diesel generator pairs that-are inoperable since there are only h- two pairs (SDG D23/ pump OCP548 and SDG D11/ pump OAP548) inoperable.- TS 3.7.1.2 ACTIONS a.4 and a.5 only require action when three or four pairs are inoperable.

The RHRSW valve pairs that required evaluation for their' potential impact on ESW loop 'B' due to inoperability of ESW loop 'A' and the SDG (i.e., Dil, D13 and'D23) supported by ESW loop 'A' were addressed in Item kl.

above.

With the exception of the first ten minutes of a postulated DBA LOCA, the ESW system has sufficient l capacity within one-ESW loop, with one ESW pump in operation, to mitigate a DBA on one unit while supporting the safe shutdown of the other unit (UFSAR 9.2.2.3). Two ESW pumps may be required during the first ten minutes of a DBA LOCA since both loops of ESW must be operating in order to supply cooling water to support the operation of three RHR. pumps. However, since Unit 1 will already be shutdown and since only the two Unit 2 RHR pumps cooled by ESW loop 'B' are E operable, then one loop of ESW with one'ESW pump will be adequate for the entire time. The adequacy of two.RHR pumps was discussed in Item f. above.

In order to maintain the full operability of the 'B'.ESW loop (including two ESW pumps) to support. Unit 2 operation, Unit 2 SDG D12 must be maintained operable, since SDG D12 powers ESW loop 'B' pump OBP548. In addition, since Unit 1 SDG D14 powers ESW- loop 'B' valve HV-11-015B (ESW loop 'B' return to RHRSW loop 'B'), then SDG_D14 would normally have to be maintained operable.

However, valve HV-11-015B is being blocked open per Item

b. above and therefore, standby AC power to this valve is not required during the extended AOT.

l l

- ___ _____-____________-________________________-______-_________________a

PAGE 21 Therefore, one loop of ESW during the proposed extended AOT can fulfill its design function during a DBA and limit the consequences of the accident.

1. Control Room Emergency Fresh' Air System (CREFAS) -- The CREFAS does not require cooling water from either ESW loop and both subsystems of this two train system are operable. However, with the 'A' loop of ESW out-of-service and SDG D11 and D13 inoperable, then both of the standby AC power sources for the 'A' CREFAS subsystem (SDG D11 and D13) are inoperable. Continued operation is allowed by TS for a limited period of time (30 days).

This AOT is not based on the CREFAS TS 3.7.2 Action a.2 statement (7 days for one CREFAS subsystem inoperable)

L but is based on the 30 day AOT with the Unit 1 SDG for one CREFAS subsystem inoperable (TS 3.7.2 ACTION a.1).

In order to maintain the full operability of the 'B' CREFAS loop to support Unit 2 operation, the Unit 1 SDG D12 and SDG D14 must be maintained operable.

If during this 30 day AOT, a DBA occurs without a LOOP, then the single failure criteria can be met since both CREFAS subsystems are functional. However, should a DBA along with a LOOP occur, then we assume that the probability that a single failure will occur and disable the operable 'B' CREFAS train or its operable SDG is negligible due to the limited time of the AOT.

Therefore, in either case, the CREFAS can fulfill its design function during a DBA and limit the consequences of the accident.

m. Standby Gas Treatment System (SGTS) -- The SGTS does not require cooling water from either ESW loop and both subsystems of this two train system are operable.

However, with the 'A' loop of ESW out-of-service and SDG D11 inoperable, the standby AC power source for the 'A' SGTS subsystem is inoperable. Continued operation is normally allowed by TS for a limited period of time (30 days). This AOT is not based on the SGTS TS 3.6.5.3 ACTION a.2 statement (7 days for one SGTS subsystem inoperable) but is based on the 30 day AOT with the Unit 1 SDG for one SGTS subsystem inoperable (TS 3.6.5.3 ACTION a.1).

In order to maintain the full operability of the 'B' SGTS loop to support Unit 2 operation, the Unit 1 SDG D12 must be maintained operable.

If during this 30 day AOT, a DBA occurs without a LOOP, then the single failure criteria can be met since both SGTS subsystems are functional. However, should a DBA along with a LOOP occur, then we assume that the probability that a single failure will occur and disable the operable SGTS subsystem or its operable SDG is

~

l.

PAGE 22 negligible due to the limited time of the AOT.

Therefore, in either case, the SGTS can fulfill its design functions during a DBA and limit the consequences of the accident.

n. Reactor Enclosure Recirculation System (RERS) -- The RERS does not require cooling water from either ESW loop and both subsystems of this two train system are operable. In addition, with SDG D21 realigned to the operable 'B' loop of ESW, the standby AC power sources (SDG D21 and D22) for both Unit 2 RERS subsystems are operable. Therefore, the RERS can fulfill its design functions during a LOCA and limit the consequences of the accident.

o. Standby Liquid Control (SLC) -- The SLC system does not require cooling water from ESW, and both trains of this two train system remain operable with ESW in an extended AOT. In addition, with the 'A' loop of ESW removed from service rendering SDG D23 inoperable, the standby AC power sources (i . e . , S DG D21, D22 and D23) for two of the three SLC pumps and the standby AC power sources (i.e., SDG D21 and D22) for both non-pump SLC subsystems remain operable. One of the two standby AC power sources (i.e., SDG D23 and D24) for one of the SLC tank heaters is inoperable;'however, the heaters are non-safeguard. TS 3.1.5 ACTION a.2 does not require that the heaters remain operable. TS 3.1.5 only requires action if the tank temperature is not maintained.

Therefore, the SLC system can fulfill its design functions during a DBA and limit the consequences of the accident.

p. Hydrogen / Oxygen (H2 /0 2 ) analyzers -- The H /02 2 analyzers do not require cooling water from ESW, and both trains of this two train system remain operable with ESW in an i extended AOT. However, with the 'A' loop of ESW removed !

from service, rendering SDG D23 inoperable, the standby ;

AC power source for the suppression pool H2 /02 analyzer )

subsystem is inoperable. Continued operation is allowed by TS for a limited period of time (i.e., 30 days).

This AOT is not based on the H2 /02 analyzers TS 3.3.7.5 .

ACTION statement (i.e., 7 days) but is based on the {

limitations imposed by TS 3.8.1.1 ACTION e. and based on j TS 3.8.1.1 ACTION a. (AOT of 30 days) for one SDG inoperable.

If during this 30 day AOT, a DBA occurs without a LOOP, !

then the single failure criteria can be met since both H,/02 analyzer subsystems remain functional. However, should a DBA along with a LOOP occur, then the !

probability, that a single failure will occur and disable the operable suppression pool H 2 /02 analyzer subsystem or its operable SDG, is assumed to be negligible due to the limited time of the AOT.

i I

l PAGE 23 :

Therefore, in either case, the H2 /02 analyzer system can fulfill its design functions during a DBA and limit the consequences of the accident.

q. Primary Containment Hydrogen Recombiner System -- The i hydrogen recombiners do not require cooling water from ESW; cooling water is provided by the 'A' and 'B' loops of RHR. However, since 'A' ESW is removed from service, the 'A' RHR pump is inoperable, and the 'A' recombiner train of this two train system is inoperable. Continued operation is allowed by TS for a limited period of time (i.e., 30 days). The 30 day AOT is based on the recombiner TS 3.6.6.1 ACTION statement for one recombiner system inoperable. Stricter limitations due to the inoperable SDG D23 are not imposed by TS 3.8.1.1 ACTION e.1, since the 'B' recombiner and both of its associated SDG, D22 and D24, are operable. However, the AOT would be 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months in accordance with TS 3.8.1.1 ACTION e.1 if either SDG D22 or D24 should become inoperable.

In addition, with the 'A' loop of ESW removed from service rendering SDG D23 inoperable, the only standby AC power source for the 'A' recombiner primary containment isolation valves (i.e., HV-57-263 / FV-DO-201B and HV-57-264 / HV-57-269) is inoperable.

Therefore, if both valves in either pair of these normally closed valves are open concurrently, then the AOT would be 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months in accordance with TS 3.8.1.1 ACTION e.l. However, the valve pairs will be maintained by having at least one valve in each pair closed in order to assure primary containment isolation capability for these penetrations during the extended AOT.

If during the 30 day AOT, a LOCA occurs with or without a LOOP, then the probability, that a single failure will occur and disable the operable 'B' recombiner subsystem or either of its operable SDG, is assumed to be negligible due to the limited time of the AOT. This is supported by the fact that continued operation is allowed for 30 days (TS 3.6.6.1) with one recombiner system inoperable. Therefore, the hydrogen recombiner system can fulfill its design functions during a LOCA and limit the consequences of the accident.

r. Main Steam Isolation Valve (MSIV) Leakage Alternate Drain Pathway -- The LGS Unit 2 MSIV Leakage Control system was removed and replaced with an alternate pathway. A Unit 2 MSIV Leakage Alternate Drain Pathway system was incorporated via TS Amendment #53, dated February 16, 1995, and does not require cooling water from either ESW loop. With the 'A' loop of ESW out-of-service and SDG D23 inoperable, the standby AC power source (SDG D22) for alternate pathway valve HV-041-2F021 is operable. Although a single failure of this valve or its power supply will disable the primary

PAGE 24 alternate drain pathway, yo different pathways have been included in the boundary of the MSIV Leakage Alternate Drain Pathway which do not require the opening of any valves. Therefore, the MSIV Leakage Alternate Drain Pathway system can provide the necessary level of protection which is required for this service and limit the consequences of the accident.

s. Drywell Hydrogen mixing system -- The containment atmosphere mixing system function is accomplished by the operation of four of the eight drywell air unit coolers, j each with one operable fan. The drywell air unit coolers do not require cooling water-from ESW to perform this safety function, and all four subsystems of this system remain operable with ESW in an extended AOT.

However, with the 'A' loop of ESW removed from service rendering SDG D23 inoperable, the standby AC power sources for two of the eight fans (i.e., the 2A2 and 2G2 fans in the 'A' and 'G' coolers) are inoperable. Based on UFSAR Section 6.2.5.2.3, the mixing system only requires that, "at least one fan in each of two of the safety-related coolers (i.e., 1AV-212 or 1BV-212 and 1GV-212 or 1HV-212) continues to run after a LOCA."

Therefore, by ensuring that the 2A1 and 2G1 fans of the

'A' and 'G' coolers are operable, then the mixing system would be fully operable and capable of tolerating a single failure (including the failure of any SDG) without a loss of the mixing system's safety function.

However, if only the 2A2 and 2G2 fans of the 'A' and 'G' coolers are operable, the standby AC power source (i.e.,

SDG D23) for coolers 2AV-212 and 2GV-212 would be l

inoperable. Therefore, the mixing system would not be capable of tolerating a single failure without a loss of the mixing system's safety function. Continued operation is allowed by TS for a limited period of time (i.e., 30 days). The 30 day AOT is not based on the L

hydrogen mixing TS 3.6.6.2 ACTION statement (i.e., 30 1 days) but is based on the limitations imposed by TS 3.8.1.1 ACTION e. and based on TS 3.8.1.1 ACTION a.

(i.e., AOT of 30 days) for one SDG inoperable.

I If during this 30 day AOT, a LOCA occurs without a LOOP, then the single failure criteria can be met since both hydrogen mixing trains are functional. However, should a LOCA with a LOOP occur, then the probability that a i

single failure will occur, disabling either of the i powered coolers (i.e., 2bV-212 or 2HV-212) or their

( operable SDG (i.e., either D22 or D24), is assumed to be l negligible due to the limited time of the AOT.

j Therefore, in either case, the hydrogen mixing system can fulfill its design functions during a LOCA and limit l the consequences of the accident.

I l

t. Spray pond -- The spray pond pump house HVAC does not

.t

.' \

I l

PAGE 25. i I

require cooling water from ESW, and this system remains -l operable with the ESW in'an extended AOT.- However, with {'

the.'A' loop of ESW removed from service rendering SDG D11.and D23_ inoperable, both of;the standby AC power sources (i.e.,.SDG D11 and D23) for the 'A' and 'C' spray pond HVAC are inoperable. However, the 'A' and

'C' fan cabinets only serve.the 'A' ESW and RHRSW loops, l which are already removed from service.. The_ redundant !

'B' and 'D' fan cabinets provide 1 full capacity, and can !

fully support operation of the.'B' ESW and RHRSW loops l assuming a single-failure. These common systems are-not !

subject to the requirements of TS 3.8.1.1 ACTION e. or' '!

any other'TS. Therefore, there'is no safety impact due -

to the loss of standby AC power to the 'A' spray pond ,

HVAC fan subsystems. l

u. Safeguard Piping Fill System (SPFS) -- The SPFS does not require cooling water from ESW, and both trains of_this two train system remain operable with ESW in.an' extended i AOT. With the 'A' loop of ESW removed from service !

rendering SDG D23 inoperable, the standby AC power l sources (i.e., SDG D21 and D22) for both SPFS' subsystems remain operable. Therefore, the SPFS can fulfill its !

design function and support the systems that limit the- !

consequences of an accident. In addition,. since the SPFS pumps and valves are provided with standby AC power i by SDG D21 and D22, the SPFS can fulfill its design function to provide water to both feedwater lines ,

following a LOCA/ LOOP to. prevent bypass leakage and i limit the consequences of an accident. >

v. Fire protection -- The fire detection and the public .

address (PA) systems are non-safeguard' loads common'to j both units but are not tripped from SDG D14 on a LOCA (UFSAR Table 8.3-3). With the 'B' loop of ESW in i service, SDG D14 is operable, and the standby AC power source for these systems are operable. !

The electric fire pump does not require standby AC power from any of the SDG and is backed up by the diesel- j driven fire pump. The fire suppression deluge and il sprinkler systems are on the non-safeguard batteries i 101D112 and 102D112 (UFSAR Figure 8.3-3). The ;

I associated battery chargers (i.e., D113) are tripped from SDG D14 on a LOCA but can be manually reloaded on r to the bus. With the 'B' loop of ESW in service, SDG !

D14 is operable, the standby AC power source for these l non-safety related systems is operable. j

' . :l The components that are relied upon for post-fire safe i shutdown, and that are either inoperable or their :

standby AC power is inoperable, can be removed from j

service in accordance with current TS AOTs. In -

4 addition, a list was compiled and a fire susceptibility :

analysis will be performed for " Rooms of Concern", which i I

a

m PAGE 26 are those fire regions.that; rely on one or more safe shutdown methods which would all be unable to safely shutdown the. plant due to the inoperable loops of the ESW and RHRSW systems or the inoperable systems that ESW or RHRSW support.. This fire susceptibility analysis will be performed for plant areas that rely on safe shutdown systems that would be affected by the inoperable ESW and RHRSW11 oops'and could affect safe plant shutdown. This analysis will evaluate ignition sources; combustible loading (normal: and transient) ; the-p availability.of fire barriers'and fire detection and suppression systems; and the use of compensatory i measures. PECo will. maintain the operability of fire L

protection systems' backup power source (SDG D14).

Additional compensatory measures will'be implemented as described in the Special Procedure which will include frequent fire watches of the affected. equipment areas.

As a result of these compensatory measures, the i increased risk of a fire event occurring during the fourteen day versus.three day AOT period is compensated for by the increased surveillance in the vulnerable areas.

Therefore, the proposed extended AOTs do not significantly affect the approved level of fire protection as described in UFSAR Appendix 9A (Fire l Protection Evaluation Report).

w. Batteries and battery chargers -- By taking the 'A' loop of ESW out-of-service, cooling water will not be available from the 'A' loop of the control enclosure chilled water system for the 'A' loop of the emergency switchgear and battery room HVAC (OAV118).. However, loss of one train of this redundant, non-TS support system does not require the supported systems to be declared inoperable.

In addition, with the 'A' loop of ESW out-of-service and.

SDG D23, D11 and D13 inoperable, the standby AC power sources are inoperable for the Unit 2 and Unit 1 Division III battery chargers and the Unit 1 Division I battery chargers. Without the ability to recharge these batteries during a LOOP, these batteries must only be relied upon for the initial four hours that the battery will maintain an adequate charge (UFSAR section 8.3.2.1.1.2). Based on a review of UFSAR Table 8.3-25, the loads on Unit 2 Division III battery 2CD101 will either fulfill their safety ~ function within~four hours or will already be inoperable. The-impact of the loss of the Division III panel 20C631 (ADS) after four hours'is discussed above in Item f.

Based on UFSAR Tables 8.3-19, 20, 21 and 25, the Unit 1 batteries 1 AID 101, 1A2D101 and 1CD101 do not support the operable 'B' loops of common systems (i.e., SGTS, CREFAS, ESW or RHRSW) that would require power to i

PAGE 27 support Unit 2 during the extended AOT. The loss of SDG D11 and D13, that would normally carry the common system DC loads after four hours following a LOOP, is not significant since SDG D11 and D13 will not be supporting the AC loads required for operation of the 'A' loops of SGTS, CREFAS, ESW or RHRSW. The loss of this function following a LOOP was previously determined to be acceptable as described in Items m., n., and k. above.

The loop 'A' devices that may need to reposition to maintain the operability of 'B' loops are fail-safe on loss of power.

These Unit 1 batteries also support Unit 1 systems that will either fulfill their safety function within four hours or that are already out-of-service or inoperable.

Therefore, there is no safety impact due to the loss of standby AC power to the battery chargers. The DC power system can fulfill its design functions during a DBA and support the systems that limit the consequences of the accident.

x. Remote shutdown system (RSS) -- By taking the 'A' loop of ESW out-of-service, cooling water will not be available from the 'A' loop of the control enclosure chilled water system for the 'A' loop of the auxiliary equipment room HVAC (OAV114). However, loss of one train of this redundant non-TS support system does not require the supported system (RSS) to be declared inoperable.

In addition, with the 'A' loop of ESW out-of-service and SDG D23, D11 and D13 inoperable, the standby AC power sources for parts of this system are inoperable. SDG D11 and D13 provide standby AC power to the common systems necessary to support the remote shutdown of Unit

2. In addition, equipment such as the 'A' ESW pump will not be operable. For other areas and events, alternate means are available for remote shutdown by operating equipment locally / remotely in accordance with Station Special Event Procedure SE-6.

y. Non-safeguard SDG loads -- The non-safeguard equipment loads listed in UFSAR Table 8.3-9 can be manually loaded on to the SDG bus following a LOOP or a LOCA; however, since SDG D23 will be inoperable, we assume that these loads will not be fully functional following a LOOP or a LOCA. This is considered acceptable since the equipment is non-safeguard and are not accident mitigation systems.

The existing AOTs limit the amount of time that the plant

, can operate with certain equipment inoperable, where single failure criteria is still met. The minimum equipment required to mitigate the consequences of an accident and/or

PAGE 28 safely shutdown the plant will be operable or the plant will be shutdown. Therefore, by extending certain AOTs and extending the assumptions concerning the combinations of .

events and single failures for the longer duration of each I extended AOT, we conclude, based on the evaluations above, that at least the minimum equipment required to mitigate the consequences of an accident and/or safely shutdown the plant ,

will still be operable during the extended AOT. Therefore, l the consequences of an accident previously evaluated in the i SAR will not be increased.

l Information Succortina a Findina of No Sionificant Hazards l Consideration We have concluded that the proposed changes to the Limerick Generating Station, Unit 2, Technical Specifications, which will one-time (i.e., temporarily) extend the Allowed Outage Time (AOT) l for the Emergency Service Water (ESW) System; Residual Heat Removal Service Water (RHRSW) System; the Suppression Pool Cooling (SPC), the Suppression Pool Spray (SPS), and Low Pressure )

l Coolant Injection (LPCI) Modes of the Residual Heat Removal (RHR)

System; and Core Spray (CS) subsystem to 14 days do not involve a Significant Hazards Consideration. In support of this determination, an evaluation of each of the three (3) standards, set forth in 10 CFR 50.92 is provided below.

1. The proposed Technical Specifications chanaes do not involve a sianificant increase in the probability or conseauences of an accident previous 1v evaluated.

The proposed one-time TS changes will not increase the probability of an accident since it will only extend the time period that the 'A' ESW and RHRSW loops and the affected equipment can be out-of-service. The extension of the time duration that certain equipment is out-of-service has no direct physical impact on the plant. The proposed inoperable systems are normally in a standby mode while the unit is in OPCON 1 or 2 and are not directly supporting plant operation. Therefore, they can have no impact on the plant that would make an accident more likely to occur due to their inopernbility.

During transients or events which require these systems to be operating, there is sufficient capacity in the operable loops to support plant operation or shutdown, in-so-much that failures that are accident initiators will not occur more frequently than previously postulated.

In addition, the consequences of an accident previously evaluated in the SAR will not be increased. With the 'A' loops of ESW and RHRSW inoperable, a known quantity of equipment is either inoperable o" the equipment is not fully capable of fulfilling its design function under all design conditions due to certain support systems not being

PAGE 29 operable. Based on the support functions of the ESW and RHRSW systems, a review of the plant was performed to determine the impacts that the inoperable ESW and RHRSW 'A' loops would have on other systems. The impacts were identified for each system, as discussed in the preceding Safety Assessment, and it was determined whether there were any adverse affects on the systems. It was then determined how the adverse affects would impact each system's design basis and overall plant safety. The consequences of any postulated accidents occurring on Unit 2 during this AOT extension was found to be bounded by the previous analyses as described in the SAR.

The existing AOTs limit the amount of time that the plant can operate with certain equipment inoperable, where single failure criteria is still met. The minimum equipment required to mitigate the consequences of an accident and/or safely shutdown the plant will be operable or the plant will be shutdown. Therefore, by extending certain AOTs and )

extending the assumptions concerning the combinations of i events and single failures for the 1cnger duration of each l extended AOT, we conclude, based on the evaluations above, that at least the minimum equipment required to mitigate the consequences of an accident and/or safely shutdown the plant will still be operable during the extended AOT. Therefore, the consequences of an accident previously evaluated in the SAR will not be increased. l Therefore, these proposed one-time TS changes will not result in a significant increase in the probability or consequences of an accident previously evaluated.

2. The crocosed TS chances do not create the possibility of a i new or different kind of accident from any accident I previously evaluated.

The proposed one-time TS changes will not create the {

possibility of a different type of accident since it will ,

only extend the time period that the 'A' ESW and RHRSW loops i and the affected equipment can be out-of-service. The ;

extension of the time duration that certain equipment is out-of-service has no direct physical impact on the plant and does not create any new accident initiators. The systems involved are either accident mitigation systems, safe shutdown systems or systems that support plant operation. All of the possible impacts that the inoperable equipment may have on its supported systems were previously analyzed in the SAR and are the basis for the present TS ACTION statements and AOTs. The impact of inoperable support systems for a given time duration was previously evaluated and any accident initiators created by the inoperable systems was evaluated. The lengthening of the

PAGE 30 time duration does not create any additional accident initiators for the plant.

4 Therefore, the proposed one-time TS changes will not create the possibility of a new or different type of accident from any accident previour.y evaluated. j

3. The orocosed TS chances do not involve a sianificant reduction in a marain of safety.

The ESW and RHRSW systems and their supported systems are designed with sufficient independence and redundancy such that the removal from service of a component / subsystem will ;

l not prevent the systems from performing their required l I

safety functions. Since removal of an ESW and a RHRSW loop from service with one unit in operation and the other unit in a refueling outage is allowed by the current Technical Specifications, then the concern is the reduced margin of safety incurred by extending the affected AOTs.

The present ESW and RHRSW AOT limits were set to ensure that sufficient safety-related equipment is available for response to all accident conditions and that sufficient I decay heat removal capability is available for a LOCA/ LOOP I on one unit and simultaneous safe shutdown of the other unit. A slight reduction in the margin of safety is incurred during the proposed extended AOT due. to the increased risk that an event could occur in a fourteen day period versus a three or seven day period. This increased ;

risk is judged to be minimal due to the low probability of I an event occurring during the extended AOT and based on the )

following discuscion of minimum ECCS/ decay heat removal i requirements.

The reduction in the margin of safety is not significant i since the remaining operable ECCS equipment is adequate to mitigate the consequences of any accident. This conclusion is based on the information contained in the UFSAR reference )

documents NEDO-24708A and NEDC-30936-A. These documents describe the minimum requirements to successfully terminate a transient or LOCA initiating event (with scram), assuming multiple failures with realistic conditions were used to justify certain TS AOTs per UFSAR sections 6.3.1.1.2.o and 6.3.3.1. The minimum requirements for short term esponse to an accident would be either one LPCI pump or cr( Core Spray loop in conjunction with ADS, which would be adequate to re-flood the vessel and maintain core cooling sufficient to preclude fuel damage. For long term response, the minimum requirements would be-one loop of RHR for decay heat removal, along with another low pressure ECCS loop. These minimum requirements will be met since implementation of the l proposed TS changes will require the operability of HPCI, l

1

PAGE 31 ADS, two LPCI subsystems (or one LPCI subsystem and one RHR subsystem during decay heat removal) and one Core Spray subsystem be maintained during the 14 day period. A Special Procedure will be written to ensure the operability of specified components and that other appropriate compensatory measures are implemented.

Compensatory measures will be taken prior to or during the proposed extended AOT for those fire regions that rely on one or more safe shutdown methods which would all be unable to safely shutdown the plant with inoperable loops of the ESW and RHRSW systems or the inoperable systems that ESW or RHRSW support. These compensatory measures will offset the increased risk of a fire event occurring in the vulnerable areas, during the fourteen day versus three day AOT period.

Therefore, the proposed extended AOT does not adversely affect the approved level of fire protection as described in UFSAR Appendix 9A (Fire Protection Evaluation Report).

A Special Procedure will be written to administratively control the requirement to maintain the operability of specified components and implementation of any appropriate compensatory measures which are deemed necessary during the proposed AOT. In addition, operations personnel are fully qualified by normal periodic training to respond to and mitigate a Design Basis Accident, including the actions needed to ensure decay heat removal while LGS Unit 1 and Unit 2 are in the operational configurations described within this submittal. Accordingly, procedures are already in place that cover safe plant shutdown and decay heat removal for situations applicable to those in the proposed AOTs.

A Probabilistic Safety Assessment (PSA) Study was performed for an ESW and RHRSW loop being out-of-service for 14 days on an operating unit. 4 The Core Damage6 Frequency (CDF) increase by 3.14x10 , from 5.11x10 / reactor-year to 8.25x10 ,d/ reactor-year. In absolute terms, this is not a significant increase in risk. In addition, the modifications to be installed during this proposed extended AOT will allow for future maintenance and inspections to be performed on the ESW and RHRSW loops without removing an entire loop from service, which will reduce risk in the future. For example, if the ESW loop unavailability, due to testing or maintenance, is reduced by half, the CDF will decrease by more than four percent. It will also minimize the potential need for future AOT extensions on these systems.

Therefore, the implementation of the proposed one-time TS changes will not involve a significant reduction in the margin of safety.

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i Information SuDDortina an Environmental Assessment An Environmental Assessment is not required for the Technical Specifications changes proposed by this Change Request because '

the requested changes to the Limerick Generating Station, Unit 2, TS conform to'the criteria for " actions eligible for categorical exclusion," as specified in 10CFR51.22 (c) (9) . The requested-changes will have no. impact on the environment. The proposed TS ;

changes do not involve a Significant Hazards Consideration as discussed in the preceding safety assessment section.. The proposed changes do not involve a significant change'in the types ,

or significant increase in the amounts of any effluent that may be released.offsite. In addition, the proposed TS changes do not involve a significant increase in individual or cumulative !

occupational radiation exposure. ;

ggnplusion The Flant Operations Review Committee and the Nuclear Review Board have reviewed these proposed changes to the Limerick Generating Station, Unit 2, Technical Specifications,;and have concluded that they do involve an unreviewed safety question; i however, they do not involve a significant hazards consideration, f and will not endanger the health and safety of the public.

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