ML20094H384

Proposed One Time TS Change Request 92-04-2 to Extend Allowed Outage Time for ECCS Sys Supported by B Loop of ESW

ML20094H384
Person / Time
Site:	Limerick
Issue date:	03/03/1992
From:	PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:
Shared Package
ML20094H382	List: ML20094H379 ML20094H384
References
NUDOCS 9203100101
Download: ML20094H384 (14)

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ATTACHMENT 1 LIMERICK GENERATING STATION UNIT'2

' Docket No. 50-353 License No. NPF-85 TECHNICAL SPECIFICATIONS CHANGE REQUEST No. 92-04-2 "One-Time Technical Specifications Change to Extend. the-Allowed Outage Time f or Emergency Core-Cooling Systems Supported by the "B"

Loop of Emergency Service Water" Supporting Information for Changes --12 pages

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Page 1 Philadelphia Electric Company (PECo), 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 of Operating License NPF-85 be amended as proposed herein to allow for a-one-time (i.e., temporary) extension in the allowed-outage time (AOT) for Emergency Core Cooling Systems (ECCS) supported by the "B" loop of the Emergency Service Water (ESW) system while repairs are made to the piping for the "B"

loop of ESW.

This proposed change would involve adding a one-time provision to TS Section 3.7.1.2, " Emergency Service Water System-Common System."

We propose that TS Section 3.7.1.2, Action a.3, be changed such that a'72-hour period be authorized for continued operation of Unit 2 although the equipment supported by.the "B" loop of ESW will be considered inoperable during this 72-hour period.

This one-time TS change is

-requested to avoid a Unit 2 shutdown, since TS Section 3.0.3'would normally require that the unit be in at least startup within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> when the "B" loop of ESW is determined to be inoperable.

The proposed change to the_ LGS Unit 2 TS is indicated'by a vertical bar in the margin of the proposed TS page 3/4 7-3.

The proposed TS change page

'is contained in Attachment.2.

This-Change Request for LGS Unit 2 provides a discussion and description of the proposed TS change, a safety assessment of the iproposed TS change, information supporting a finding of No Significant Hazards Consideration, and information supporting an Environmental Assessment.

We request that, if approved, the Amendment to the LGS Unit 2 TS be effective upon issuance.

Discussion and Description of the Proposed Change The ESW system. is a - se.fety-related system and-is common to Units 1 and

2.. The system is designed to supply cooling water to selected equipment during a Loss of Offsite Power-(LOOP) condition or Loss of Coolant Accident (LOCA).

.The system consists of two (2) independent 100% capacity loops (i.e.,. "A" and "B") which supply the necessary cooling water to heat exchangers and coolers associated with various safety-related and nonsafety-related equipment specified below.

Residual Heat Removal (RHR) pump motor oil and seal coolers RHR pump compartment unit coolers Core Spray (CS) pump compartment unit coolers Main Control Room.(MCR) chillers Emergency Diesel Generator (EDG) heat exchangers Reactor Core Isolation Cooling (RCIC) pump compartment unit coolers

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Page 2 liigh Pressure Coolant Injection (HPCI) pump compartment unit coolers Spent fuel pools (i.e., makeup water)

Heactor Enclosure Cooling Water (RECW) system heat exchangers Turbine Enclosure Cooling Water (TECW) system heat exchangers Dy letter dated December 19,, 1991, we requested relief from the American Society of Mechanical Engineers (ASME) Code repair

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3equirements for Code Class 3 piping as a result of the discovery of a flawed section of ESW system piping.

This rollef request was submitted in accordance with the guidance specified in NRC Generic Letter 90-05, " Guidance for Performing Temporary Non-Code Repair of ASME CoJo class 1, 2,

and 3 Piping."

A condition of the rollef regt.e s t is that permanent repairs will be completed at the next outage of more than 30 days duration.

Since the flaw exists on the "B"

loop of ESW piping from the Unit 1 IIPCI room unit coolers, the next such outago will be the Unit 1 fourth refueling outage scheduled to begin on March 21, 1992.

The NRC approved this relief request by letter dated February 26, 1992 on the basis that the flawed ESW piping will be repaired or replaced in accordance with the ASME Code no later than the next (i.e.,

fourth) refueling outage.

This proposed TS change requests a one-time change to the LGS Unit 2 TS ta allow continued operation of Unit 2 while repaira are made to the "D" loop of the ESW system.

The proposed TS change would involve a one-time (i.e., temporary) change to TS Section J.7.1.2.

We propose that TS Section 3.7.1.2, Action a.3, be temporarily amended such that a 72-hour period is authorized for continued operation of Unit 2 although the equipment supported by the "B" loop of ESW will be considered inoperable during this 72-hour period.

This one-time TS TS Section 3.0.3 change is requested to avoid a Unit 2 shutdown.

w.'uld normally require that the unit be in at least startup within 6 hvars when the "B" loop of ESW is determined to be inoperable.

This proposed change is necessary in order to complete the repair to the ESW pipe section without being required to shut down Unit 2 since it cannot be isolated from the remainder of the "B" loop of ESW common piping.

The strategy for the ESW pipe repair is to establish freeze seals at the appropriate locations in the "B" loop of ESW piping such that work can be accomplished while the "B" loop remains available for use (i.e., after the freeze seals are established).

Although freeze seals do not provide an ASME Code approved pressure boundary such that the "B" loop of ESW can be considered operable, a level of confidence exists from experience that the loop would be available if required to support ECCS or EDG operation since the "B" lor >p of ESW pumps will remain in standby after the freeze seals are established.

If thic proposed change is approved, the "B" loop of ESW will be declared inoperable once the freeze seal process is initiated.

f Pago 3 n

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• systems rollod upon for accident mitigation during the proposed AOT shall be operable at the start of and during the 72-hour period.

If any of the operablo Unit 2 ECCS or EDGs are rendon ed inoperable i

during the proposed 72-hour AOT, then the action statomot.t in TS Section 3.0. 3 shall be implemented, i.e., immediato plant shutdown will bo started.

i Safety Assessuont This proposed TS change requests a one-timo (i.e., ' to-9orary) chango to the LGS Unit 2 TS to allow continued operation of valt 2 whilo repairs are mado on the "B" loop of the ESW system.

This one-timo TS chango is requestod to avoid a Unit 2 shutdown.

TS Section 3.0.3 would normally require the unit to bo in at least startup within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> when the "B" loop of ESW in determined to be inoperable.

During the proposed 72-hour A0T, Unit I will be shut down for its fourth refueling outage.

Two (2) Unit 1 EDGs and other Unit 1

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equipment. cooled by the "B" loop of ESW will be rendered inoperable.

Although this does not present a problem with respect to system operabil.ity requirements during an outage period, inopornbility of addJtional TS equipment would require that the applicablo Unit 1 TS rostrictions are adhered to during the proposed 72-hour A0T.

During the proposed 72-hour ACT, at least two (2) Unit 2 EDGs that are normally aligned to the "A"' loop of ESW will remain operable. However, the capability to align a third Unit 2 EDG to the "A" loop of ESW instead of its ncrmal alignment to thc "B" loop of ESW, may be accomplished according to approved proceduros.

If this action is taken, a third Unit 1 EDG will be required to be aligned to the "B" loop of ESW.

Should this alignment be mado, applicablo Unit i TS requirements for throo inoperable EDGs will be mot.

Thorotore, the following discussion provides the necessary justification to ensure safe operation of LGS Unit 2 during tho proposed 72-hour AOT needed to re-establish an ASME Code boundary repair on the "B"

loop of ESW.

The minimum requirements for long-term accident responso arcs ono ECCS pump (CS or Low Pressuro Coolant Injection (LPCI)) for reactor vessel level control and one decay heat removal loop, consisting of an -

RHR pump, an RHR Servico Water (RHRSW) pump and ono RHR heat

-exchanger.

These requirements are mot by equipment serviced by the operable "A" loop of ESW.

The ESW system does have other functions which support ECOS and post accident responso systems such as indirectly cooling omergency switchgear rooms via the-room chillors.

One loop of ESW is sufficient to provide-onough room cooling for half of the ECCS, by design..The availability of the RHR "B" and "D" and CS pumps is still' maintained short term. (i.e.,. sovoral hours) without ESW cooling.

The rooms have temperaturo instrumentation that will givo operations personnel indication of a room cooling problem.

Actions specified in approved Wd 4w mu

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Pago 4 procedures would then be taken to lossen the temperaturo in the rooms in which cooling capabiltty was lost.

In the event of a LOCA on Unit 2 with a temporarily degraded ECCS (i.e., a reduction in the redundancy of operablo ECCS due to the inoperability of the "B" loop of ESW), the conclusion that the unit can be safoly shutdown, the vessel reflooded, and adequato coro cooling provided is obtained from NEDO-24708A, " Additional Information Required for NRC Staff Generic Report on Boiling Water Reactors" -

August 1979, Reviulon No.

1, December 1980 and NEDC-30936P-A, "BWH Owner's Group Technical Specification Improvement Methodology (with Demonstration for DWR ECCS Activation Instrumentation - Part 1),"

December 1988.

NEDO-24708A states that for postulated recirculation suction line breaks, one low-pressure ECCS (and Automatic Depressurization Systom-(ADS) to depressurize, if necessary) is sufficient to reflood the reactor vessel and provide adequate coro cooling.

NEDCO-30936P-A was written to support revising TS to minimi:o unnecessary and excessively restrictive out-of-service times.

It concludes, through the use of realistic analyses, that one low pressuro ECCS injecting is sufficient to provido adequate core cooling for all break sizes up to and including the double-ended guillotine break of the recirculation suction piping.

Provided the "A" loop of ESW and all equipment aligned to it remain operable, one (1) loop of CS and two-(2) LPCI pumps are operable to provido more than adequato core cooling.

Furthermore, our calculations show that the Unit 2 HPCI pump can operate for 15 minutos with a HPCI barometric condenser failure occurring simultaneously with loss of HPCI pump room cooling.

Therefore, HPCI system injection would occur for a short initial period of a LOCA on Unit 2.

Bowever, the remaining systems relied upon for accident mitigation during the proposed'72-hour A0T shall be operable at the start of and during the 72-hour period.

If any of the operablo Unit 2 ECCS or EDGs are rendered inoperable during the proposed 72-hour A0T, then the

-action-statement in-TS Section-3.0.3 shall-bo implemented.-

In addition, based on our review, during the repair activity the unavailability of any system that is affected by the ESW repair will result in less risk of an accident for a 72-hour period than that associated with a plant shutdown and startup transient.

Although the current Probabilistic Risk Assessment (PRA) model has not explicitly calculated the cumulative ' risk caused by shutdown and startup, this

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-cumulative risk is estimated to be higher than the cumulative risk during the A0T for the ESW system repair.

The primary reason for this is the small cumulative risk that any transient or accident would occur during the period of the A0T.

ff Informa, tion Supporting a Finding of'No Significant Hazards Consideration s

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The proposed change does not involve a significant hazards consideration because the margin of safety is not significantly

Attachmont 1 pago 5 t

reduced by the inoperability of the "B" loop of ESW during the A single activo failure occurring in one of proposed 72-hour perioo.

the remaining operablo ECCS subar atoms does not increase the consequences of a previously evaluated accident.

Since ono CS and two RHR pumps will remain operable and only one low pressuro injection pump and one decay heat removal pump are necessary to safely shutdown and maintain Unit 2 in saf o shutdown.

In support of this determination, an ovaluation of each of the_ throo (3) standards set forth in 10 CFR-50.92 is provided below.

The proppsed chango does not_ involve a significant increaso___in 1) the probability or consequences of an accident previously evaluated.

The-proposed one-timo TS change does not increase the consequences of an accident from any previously evaluated.

The 4

4,'donts that woro considered are the full range of LOCAs with enc tithout a concurrent LOOP.

Unit 2 will romain in operation curing-the repair on the "B" loop of ESW.

Unit 1 will not be operating at this timo but will be in a refueling outago and will be maintained in compliance with appropriate TS requirements.

The inoperability of HPC1 and half of the ECCS for Unit 2 does not causo an increase in the probability of an accident sinco all the systems affected are not accident initiators as defined in Chapter 15 of the LGS Updated Final Safety Analysis Hoport (UFSAR).

However, based on the probability of occurronco of a soismic-event of any soverity, and assuming this would cause f ailure of the froozo seals and the comploto loss of the "D" loop of ESW, a small increase of approximately 4X10"* (i.e., 0.1%) in the annual Coro Damage Frequency (CDP) would result.

This increase is judged not to:be significant, since the cumulativo risk caused by shutdown and startup'is estimated to be higher

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than the cumulativo risk duriag the A0T for the ESW system repair.

Maintaining the remaining ECCS equipment operablo during

-the 72-hour period ensures that the consequences of the accidents previously evaluated will remain bounded by the UFSAR-safoty analysis.

Thorofore, thoro is no increano in the consequences of an accident.

This conclusion is based on the following considerations.

All ECCS will_be available for short term mitigation of the

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consequences of an accident.

For long term accident responso (i.e., greator than 10 minutos), sufficient ECCS and components will remain available to mitigato the consequences of an accident, even considering a single active failure, For long term response to an accident occurring during the b.

proposed 72-hour AOT, suf ficient= timo exists so that plant 1 9 operators. could take appropriate actian to realign equipment and establish cooling flow to ECCS. Operator actions beyond those assumed in the UFSAR are not required for the short term response to an accident for the consequences to be

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maintained within those evaluated in the UFSAR.

ECCS equipment has been analyzed for a variety of conditions involving loss of room cooling, and we have cetermined that several hours are available for operators to take corrective action to maintain certain ECCS equipment operable before environmental qualification temperaturo limits are exceeded, c.

-Unit I will be shutdown during this 72-hour period.

This reducesEthe demand on the remaining operable ESW loop and other common safety-related equipment such that additional margin exists in the "A" loop of ESW for heat removal from Unit 2 should an accident occur.

d.

The "B" loop of ESW could still be considered to be functionally available to support equipment cooling needs even though it will be considered inoperable.

The pressure boundary of the "B" ESW piping will be maintained through the use-of freeze seals in the areas where repair and maintenanco activities are in progrent.

pECO experience with freeze seals indicates that they are a reliable method of maintaining a pressure boundary intacu, and therefere, the "B" loop of ESW is expected to be capabic of supporting loop operations should the nood arise.

Novertheless, a freeze seal is not " qualified" as a presouro boundary in accordance with ASME Code requirements and the "B" loop of ESW will be considered inoperable.

Sinco loss of the Unit 2 ECCS room unit coolers, RHR pump seal cooling, and RHR pump motor oil cooling cooled by the "B" loop of ESW will not cause an immediate failure of these components upon initiaion of the RHR pumps, operability for short term automatic response (i.e., less than-10. minutes) under the postulated accident conditions will be maintained.

Beyond this 10 rinute period, there would be two (2) RHR pumps and one (1) loop of CS operable to provide the necessary long term accident mitigation.

The availability of the ADS, which itself is single _ failure proof and is unaffected by this activity, assures that the remaining RHR and/or CS pumps can maintain adequate core cooling.

NEDO-24708A, provides the analysis that_ supports the conclusion-that either one (1) RHR pump (operating in the LPCI mode) or one (1) CS loop in conjunction with ADS, will provido adequate core cooling.

Therefore, even if a single failure were to occur, adequate core cooling capability would be maintained-since two (2) RHR pumps and one-(1) loop of CS will be operable during the proposed 72-hour AoT.

Based on the accident mitigating capabilities of the ECCS equipment that remains operable-with the "B" loop of ESW inoperable, tho' consequences of accidents previously evaluated will not be increased by this activity.

Additional system

' specific details are provided below to support this conclusion.

RHR System - Even with a single failure of additional low-a.

pressure ECCS equipment that will not be-rendered inoperable

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due to the loss of the "B" loop of ESW, the RHR system has enough redundancy that this system in conjunction ' tith ADS could operate properly and mitigate an accident.

Therefore, the consequences of accidents previously evaluated are not 1

increased.

b.

CS System - One of the two (2) loops of the CS system will be rendered inoperable due to the loss of the "B" loop of ESW.

The analysis in NEDO-24708A has shown that one (1) CS loop is adequate to provide the required core cooling.

Therefore, the consequences of an accidont previously evaluated are not increased by the impact of this change on the CS system.

c.

EDGs - The EDGs (i.e., D12 and D14 for Unit 1, and D22 and D24 for Unit 2) will be rendered inoperable. The EDGs that will remain-operable provide the necessary emergency electrical power to assure that Unit 2 (assumed to be in power operation) and Unit 1 (assumed to be shutdown) have the equipmont and systems operable to mitigate the accidents

.l proviounly analyrod. The number of EDGs operable meets or exceede the minimum required by TS without requiring an I' mediate Unit 2 shutdown.

TS requirements for emergency m

power for primary containment isolation valves will be verified as part of the Surveillance Tests which are j

I performed when EDGs become or are made inoperable.

Also, the inoperable EDGs will still remain functionally available assuming that the freeze seals maintain an adequate pressure boundary.

Approved procedures exist which provide the ability to assess the applicable TS requirements relative to the specific inoperable EDGs.

Therefore, the consequences of an accident previously evaluated are not increased by the inoperability of the EDGs cooled by the "B" loop of ESW.

d.

HPCI System - This proposed change does remove room cooling capability f rom the Unit 2 HPCI compartment.

This will eliminate the long term response of the HPCI pump for water injection capability in response to a small break LOCA, but the capability to use HPCI to inject into the reactor vessel for at least 15 minutes still exists.

Despite this impact on HPCI, the remaining operable subsystems of RHR and CS in conjunction with-ADS assures that adequate core cooling will remain available long term and that the consequences of an accident previously evaluated are not increased.

RCIC System - This proposed change, which renders the "B" e.

loop of ESW inoperable for 72-hours, -does not remove room cooling capability from the RCIC compartment.

This is due to the-fact that the "A" loop of ESW supplies the room unit coolers for this-pump.

This change has r.o effect on-the alignment, configuration, or operation of the RCIC system.

Therefore, with respect to the RCIC system,.the consequences of an accident previously evaluated are not increased.

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Attachmont 1 pago 8 j

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RECW System:- The "A" loop of ESW provides backup cooling to the RECW heat exchangers.

Thoroforo, the-loss of the "D" loop o'f ESW cooling water to the RECW heat exchango does not increase the consequences of an accident previously evaluated.

g.

TECW System - TECW is provided with a backup cooling water supply from the "B" loop of ESW.

The TECW heat exchangers are not safety-related and do not require ESW as a cooling water supply.

Therefore, there is no increaso in the consequences of an accident previously evaluated because of the temporary loss ofothe back-up cooling water to the TECW heat exchangers from the "B" loop of ESW.

h.

Reactor Recirculation (RR) Pumps - ESW provides a backup sourco of cooling water to the RR pumps should normal cooling be unavailable.

The RR pumps form a portion of the primary coolant' pressuro boundary, and are thereforo, safety-related in the passivo sense.

However, even if normal and backup cooling were lost to the pump seals, the t

potential leakage is within the makeup capability of the operable ECCS equipment.

Therefore, with respect to the RR pumps, the consequences of an accident previously~ evaluated are not increased.

i.

Fuel Pool Cooling System - The fuci pool cooling system does not perform a safety function to mitigate the consequences of an accident.

Therefore, the loss of the ESW as a potential ~ backup cooling (i.e., make-up) source to the Unit 2 fuel pool does not increase the consequences of an accident previously evaluated.

j.

RHRSW System - The RHRSW system TS Section 3.7.1.1 provides a 30-day AOT with two (2) RHRSW pump /EDG pairs inoperable.

Therefore, the impact of the one-time TS change on RHRSW-system capability does not increase the consequences of an accident previously evaluated.

k.

Spray Pond - The proposed TS chango does not impact the spray pond operation as the ultimate heat sink.

The Spray pond was sized to be able to handle both units' decay heat removal requirements from 100% power operating conditions.

Since_ Unit I will not be in operation, minimal decay heat removal will be required for that unit.

Also, the motor

. operated valves needed to align the operable ESW and RHRSW loops to the spray networks are still operable.

Therefore, with respect to.the Spray Pond, this one-time TS change does not increase the consequences of an accioont previously_

evaluated, i

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Control Room Emergency Fresh Air Supply (CREFAS) system -

The TS change does impact the CREFAS system since only one

-of the EDGs which supplies emergency power to the CREFAS j

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system is affected.

The emergency power supply to the "A"

CREFAS subsystem is provided by Unit ) D11 and D13 EDGs, whereas the "D" subsystem is powered av the Unit 1 D12 and

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D14 EDGs.

The Unit 2 TS allow the CRE/AS to be considered operable when the "D" loop of ESW is out-of-service for a period not to exceed 30 days.

This envelopes the ADT that this TS change is requesting.

Therefore, with respect to the CREFAS system this one-time TS chango does not increase the cor.acquences of an accident previously evaluated.

MCR Chillers - These are safety-related components and are f

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The required to be available in the event of an accident.

chillers are common plant equipment; however, only ono (1) j a

of the two (2) chillors is required to be available to support the design heat loads.

Therefore, by taking the "D" loop of ESW out of service, only ono of the chillers will be a

unavailable.

If the available chiller would subsequently be lost and the MCR temperature exceeds the TS limit, oppropriate action would be taken in accordance with TS.

Therefore, with respect to the MCR chillors, the l

consequences of an accident previously evaluated are not increased, Standby Gas Treatment System (SGTS) - This proposed change n.

makes the emergency power supply for one of the SGTS subsystems inoperablo, but does not make either subsystem inoperable.

TS Section 3.8.1.1.0 imposes the appropriate actions when loss than the full complement of emergency power supplies are operable.

In no case will the A0T for the affected SGTS_emorgency power supply bo less than 72-hours, which is conristent with the requested A0T for this activity.

Therefore, with respect to the SGTS, this one-time TS chango does not increase the consequences of an accident previously evaluated.

Reactor Enclosure Recirculation System (RERS) - This change

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makes the emergency power supply _for one (1) of two (2) RERS subsystems inoperable, but does not make either subsystem Inoperable.

TS_Section 3.8.1.1.o imposas the appropriate actions when-less than the full complement of emergency power supplies are operable.- In no case will the A0T for the affected power supply be loss than 72-hours.

Therefore, the 72-hour A0T requested for_this activity falls within the bounds of the TS AOT for the RERS,' and does not increase'the consequences of an' accident previously evaluated with respect to the RERS.

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Standby: Liquid. Control'(SLC) System - This chango makes the emergency.-power supply to_ono (1) of the three-(3) SLC pumps and-one (1) of the two (2) SLC subsystems inoperable,-but does not make any pump or either subsystem inoperable.

TS Section 3.8.1.1.e imposes the appropriate actions when less than the full complement of_ emergency power supplies are' operable.

In no case will the A0T for the affected SLC T97hw

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Pago 10 Sinco system emergency power supply be less than 72-hours.

the proposed 72-hour A0T is bounded by the SLC system A0T, the consequences of an accident previously ovaluated are not increased with respect to the SLC system.

Post LOCA Hydrogen Recombiner - This change makes the q.

emergency power supply for ono (1) of two (2) subsystems of 3'

the Post-LOCA'Hydrogon Recombiner inoperable, but does not make either subsystem inoperable.

TS Section 3.8.1.1.0 imposes the appropriate actions when less than the full complement of emergency power supplies are operable.

In no case will the A0T for the affected Post-LOCA Hydrogen Recombiner omergency power supply bo loss than 72-hours.

Since the proposed 72-hour AOT requested for this activity is bounded by the Post-LOCA Hydrogen Recombinor TS A0T, this activity does not increase the consequences of an accident previously evaluated with respect to the Post-LOCA !!ydrogen Recombiner, Main Steam Isolation Valve (MSIV) Leakage Control System -

r.

This change makes the emergency power supply to one (1) of the two (2) MSIV leakage control subsystems inoperable, but does not mako either subsystem inoperable.

TS Section 3.8.1.1.0 imposes the appropriate actions when less than the full complement of emergency power supplies are operable.

-In no caso-will the A0T for the affected MSIV Leakago Control System omorgency power supply be less than 72-hours.

The 72-hour A0T requested for this activity falls within the bounds of the TS AOT for the MSIV Leakago Control System.

Thorofore, the consequences of an accident previously ovaluated are not increased with respect to the MSIV Leakage Control System.

Drywell Hydrogen Mixing System - As a result of this s.-

activity, the emergency power supply for two (2) of the four (4) subsystems associated with the Drywell Hydrogen Mixing system will be Inoperable,.but-nono of the hydrogen nixing subsystems are made' inoperable.

TS Section 3.8.1.1.0 imposes-the appropriate actions when loss than the full complement of emergency power supplies are operable.

In no case will the A0T for the affected Drywell Hydrogen Mixing system emergency power supply be lesu than 72-hours.

Therefore, since the 72-hour A0T requested for this activity isLbounded by the Drywell' Hydrogen Mixing-system TS-A0T, thoro-is-no increase in the consequences of an accident previously evaluated with respect to the Drywell Hydrogen Mixing systera.

- For the-proposed 72-hour period in which the "B" loop ~of ESW will-be inoperable, two (2) RHR pumps, one (1) CS subsystem, ADS, and RCIC remain operable for accident mitigation.

Because thia configuration remains single-failure-proof, a malfunction of any of these systems will not remove the ability tv provide adequato core cooling.

'All other affected components, taken individually,

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I are currently evaluated for allowable out-of-service times of at i

Icast 72-hours.

i mplementation of the proposed 72-hour A0T will not i

Thereforo, result in an increase in the probability or consequences-of an l

accident previously evaluated.

The proposed change does not creato the possibility of a nuw or l

2 )1 different kind-of accident from any accident _previously evaluated.

- Since there are no chances in the configuration, alignment, or operationni procedures, the possibility of a new or different kind of accident is.not created.

Tne systems affected are not

= accident initiators.

The systems that will remain operable are capable of mitigating an accident.

The following compensatory measures will be taken to offset the fact that the "B" loop of ESW will be inoperable but available due to this planned activity. Proper position of ESW system flow-path valves will be verified prior to (i.e., within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of) initiation of this activity to reduce the possibility of valve 1 misalignments.

The proposed change will not cause the components important-to safety that have been discussed above to be challenged by a different type of malfunction, since no now type of malfunction will be created by any operation associated with this activity.

Therefore, this proposed change does not create the possibility of a new or different kind of accident from any accident previously evaluated.

The proposed chsnge does not involve a significant reduction-in a 3)

, margin of safety.

Implementation of this proposed TS change will_ result in a

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reduction in the margin of safety due to the loss of system However, this reduction in the margin is not redundancy.

significant since the remaining operable ECCS equipinent is adequate to mitigate the consequences'of an-accident, even assuming e. single failure.

This is based on the analysis in NEDO-24708A and NEDC-30936P-A. These documents describe the aj.2 mum requirements to successfully terminate a transient or i

i I CA initiating event (assuming reactor-trip), assuming. multiple failures with realistic conditions.

.The minimum requirements for 4

short term response to an accident would be one (1) low pressure ECCS in conjunction with ADS operation.

For long term response, which would include decay heat removal _through one (1) RHR loop is along with another low pressure ECCS -(0.g., CS _ or LPCI) required..

Implementation of the proposed TS change will require that operability of two (2) RHR subsystems and uno (1) CS loop be In addition, the RCIC maintained during the 72-hour period.

system will remain operable during the 72-hour period although credit is not taken for-it in the-UFSAR safety analysis.

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-Pago la The bases for TS section 3/4.5.1 for ECCS during plant operation stato that with the llPCI system inoperable, adequate core cooling is assured by the_ operability of ADS, both the CS and LPCI systems, and RCIC (although no credit is taken for RCIC in the UFSAR safety analysis),

for the duration of the ESW pipe repair activity, a period not to exceed 72-hours, two (2) RilR LPCI pumps and ono (1) Loop of CS will not be operable duo to the loss of cooling from the "B"

loop of ESW.

liowever, the ability to j

provide adequate core cooling and decay heat removal is I

maintained, even assuming a singic failure, by the remaining two (2) RHR pumps and ono (1) loop of CS.

Therefore, implementation of the proposed 72-hour ADT will not involve a significant i

reduction in a margin at safoty.

l Information Supportina an Environmental Assessment An environmental assessment is not required for the change proposed by this Chunge Request because the requestod change to the LGS Unit 2 TS 1

conf orms. to the criteria for " actions eligible for categorical exclusion" as specified in 10 CFR 51.22(c)(9).

The requested change will have no impact on the environment.

The_ proposed change does not Involvo a significant hazards consideration as discussed in the preceding section.

The proposed change does not involve a significant I

change in the-types or significant increase in the amounts of -any offluents that may be released offsite.

In addition, the proposed chango does not involve an increase in individual or cumulativo occupational radiation exposure.

Conclusion

[

h The Plant Operations Review Committee and the Nuclear Review Board have reviewed this proposed change to the LGS Unit 2 TS and have concluded that it does involve an unrevoiwed safety question,.but that it does-not involve significant hazards consideration, and will not i

endanger the health and safety of the public.-

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ATTACHMEliT 2

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LIMERICK GENERATING STATION i

i Uti1T 2 Dockot No. 50-353-1 Licenso No. NPF-85 PROPOSED TECHNICAL SPECIFICATION CHANGE t

No. 93-04,

List of Attached Page-Changea 1

Unit 2 3/4 7-3 s

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EMERGENCY SERVICE WATER SYSTEM - COMMON SYSTEM LIMITING' CONDITION FOR OPERATION 3.7.1.2' At least the following independent emergency service water system loops, with each loop comprised of:

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a. Two OPERABLE emergency service water pumps, and t

b. An OPERABLE flow path capable of taking suction from the emergency service water pumps wet pits which are supplied from the spray pond or the cooling tower basin and transferring the water to the associated Unit 2 and common safety-related equipment, j

shall be OPERABLE:

a. In OPERATIONAL CONDITIONS 1, 2, and 3, two loops.

b. In OPERATIONAL CONDITIONS 4, 5, and *, one loop.

APPLICABillTY: OPERATIONAL CONDITIONS 1, 2, 3, 4, 5, and *.

ACTION:

a. In OPERATIONAL CONDITION 1, 2, or '-

1. With one emergency service water pump inoperable, restore the inoperable pump to OPERABLE status within 45 days or be in at least HOT SHUTDOWN within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and in COLD SHUT 00WN within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

2. With one emergency service water pump in each loop inoperable, restore at least one inoperable pump to OPERABLE status within 30 days or be in at least HOT SHUTDOWN within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and in COLD SHUTOOWN within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

3. With one emeri:ency service water system loop otherwise inoperable, declare all equipment aligned to the inoperable loop inoperabic**#, restore the inoperable laop +o OPERABLE status with at least one OPEPABLE pump within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or be in at least HOT SHUTDOWN within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and in COLD SHUTDOWN within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

0When handling irradiated fuel in the secondary containment.

ooThe diesel generators may be aligned to the OPERABLE emergency service water system loop provided cor 'trmatory flow testing iis been performed. Those diesel generators not aligned to the OPERABLE emergency service water system loop shall be declared inoperable and the actions of 3.8.1.1 taken.

1. - The performance of a repair on the common ESW system during the Unit 1 Fourth Refueling Outage will require that the "B" Loop of ESW be inoperable for a period of time no longer than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to f acilitate completion of the ' repair.

During the time that the "B" Loop is inoperable, the associated equipment aligned to the

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"B" Loop will also be declared inoperable. However, the required TS ACTIONS

,' associated with the affected inoperable ECCS equipment will not be required to be taken for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

Otherwise, the TS ACTIONS associated with the affected inoperable equipeent aligned to the "B" Loop will be followed.

LIMERICK.- UNIT 2 3/4 7-3

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