ML20038B495

Proposed Tech Spec Changes Revising Definition of Equipment Comprising RHR Containment Cooling Loop

ML20038B495
Person / Time
Site:	Quad Cities
Issue date:	12/03/1981
From:	COMMONWEALTH EDISON CO.
To:
Shared Package
ML20038B491	List: ML20038B490 ML20038B495
References
NUDOCS 8112080338
Download: ML20038B495 (10)

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. 1 ATTACHMENT A Quad Cities Unit 1 Proposed Amendment to DPR-29 Technical Specifications Revised Pages: 3.5/4.5-3 3.5/4.5-12 8112080338 811203 PDR ADOCK 05000254 P PDR

QUAD-CITIES DPR-29 i -

continued reactor operation is permis- containment cooling mode of the sible only during the succeeding 7 days RHR. and the diesel generators re, unless it is sooner made operable, pro- quired for operation of such compo-vided that during such 7 days all active nents if no external source of power components of both core spray subsys- were available shall be demonstrated

, sems, the containment cooling mode of to be operable immediately and daily the RHR (including two RHR thereafter.

pumps) and the diesel generators re-quired for operation of such compo-nents if no external source of power were available shall be operable.

6. If the requirements of Specification 3.5.A cannot be met, an orderly shut-down of the reactor shall be initiated, and the reactor shall be in the cold <

shutdown condition within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

B. Containment Cooling Mode of the RHR B. Containment Cooling Mode of the RHR System System Surveillance of the containment cooling mode of the RHR system shall be performed as follows:

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-I 1.a. Both loops of the containment cooling mode

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1. RHR service water subsystem testing:

of the RHR system, as defined in the bases for Specification 3.5.B. shall be operable whenever irradiated fuel is in the reactor Item frequency vessel and prior to reactor startup from a cold condition. a. Pump and valve Once/3 operability months 1.b. From the effective date of this amendment until June 1, 1982, the "A" loop of the b. Flow rate test - After Pump containment cooling mode of the RHR system each RHR service maintenance for each reactor may share the Unit 2 "A" water pump shall and every 3 and "B" RHR service water pucps using deliver at least months cross tie line 1/2-10124-16*-D.

Consequently, the requirements of 3500 gpm against Specifications 3.5.B.2 and 3.5.B.3 will a pressure of 198 impose the corresponding surveillance psig testing of equipment associated with botn reactors if the shared RHR service water c. A logic system Each pump or pumps, or the cross tie line, are functional test refueling made or found to oe inopersole.

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2. From and aner the date that one of the 2. When it is determined that one RHR RHR service water pumps is made or service water pump is inoperable, the found to be inoperable for any reason, remaining components of that loop continued reactor operation is permis- and the other containment' cooling sible only during the succeeding 30 loop of the RHR system shall be dem-( days unless such pump is sooner made onstrated to be operable immediately I

operable, provided that during such 30 and daily thereafter.

fi}~ days all other active components of the containment cooling mode of the RHR system are operable.

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. QUAD-GTIES DPR-29 Should the loss of one RHR pump occur, a nearly full complement of core and containment cooling equipment is available. Three RHR pumps in conjunction with the core spray subsystem will perform the core cooling function. Because of the availability of the majority of the core cooling equipment, which will be demonstrated to be operable, a 30-day repair period is justified. if the LPCI mode of the RHR system is not available, at least two RHR pumps must be available to fulfill the containment cooling function. The 7-day repair period is set on :his basis.

B. RHR Senice Water -

The containment cooling mode af the RHR systerr. is provided to remove heat energy from the containment in the event of a loss.of-coolant accident. For the flow specified, the containrent long term pressure is limited to less than 8 psig and is therefore more than ample to provide the required heat removal capability (reference SAR Section 5.2.3.2).

The Containment Cooling mode of the RHR System consists of two loops.

Each loop consists of 1 Neat Exchanger, 2 RHR Pumps, and the associated g valves, piping, electrical equipment, and instrumentation. The "3" loop on each unit contains 2 RHR Service Water Pumps. During the period from Novembe r 24, 1981, to June 1,1982, the "A" loop on each unit may utilize the "A" and "B" RHR Service Water Pumps from Unit 2 via a cross-tie line. After June 1, 1982, each "A" loop will contain 2 RH9 Service Water Pumps. Either set of equipment is capable of performing tue containment cooling function. Loss of one RHR service water purnp does not seriouslyjeopardize the containment cooling capability, as any one of the remaining three pumps can satisfy the cooling requirements. Since there is some redundancy left, a 30-day repair period is adequate. Loss of one loop of the containment h

cooling mode of the RHR system leaves one remaining system to perform the contair. ment cooling function. The operable system is demonstrated to be operable each day when the above condition occurs.

> Based on the fact that when one loop of the containment cooling mode of the RHR system becomes j inoperable, only one system remains, which is tested daily, a 7-day repair period was specified.

C. High-Pressure Coolant Injection f

The high-pressure coolant injection subsystem is provided to adequately cool the core for all pipe breaks smaller than those for which the LPCI mode of the RHR system or core spray subsystems can protect the core.

The HPCI meets this requirement without the use ofoffsite electrical power. For the pipe breaks for which the HPCIis intended to function :he core never uncovers and is continuously cooled, thus no cladding damage occurs (reference SAR Section 6.2.5.3). The repair times for the limiting conditions of operadon were set considering the use of the HPCI as part of the isolation cooling system.

D. Automatic Pressure kellef The relief valves of the automatic pressure relief subsystem are a backup to the HPCI subsystem. They enable the core spray subsystem or LPCI mode of the RHR system to provide protection against the small pipe break in the event of HPCI failure by J perssurizing the reactor vessel rapidly enough to actuate the c core spr:y subsystems or LPCI mode of the RHR system. The core spray subsystem and/or the LPCI mode of the RHR system provide sufficient flow of coolant to hmit fuelcladding temperatures toless than

2200*F, to assure that core geometry remains intact, to limit the core wide clad metal. water reaction to less than 1%, and to limit the calculated local metal-water reaction to less than 17%.

F loss of 1 of the relief valves affects the pressure relieving capability and, therefore, a 7 day repair period is l specified. Loss of more than one relief valve significantly reduces the pressure relief capability,thus a 24. hour repair period is specified based on the HPCI system availability during this period.

! E. RCIC The RCIC system is provided to supply continuous makeup water to the reactor core when the reactor is isolated from the turbine and when the feedwater system is not available. Under these conditio ts the pumping capacity of the RCIC system is sumcient to maintain the water level above the core without any other water system in operation. If the water level in the reactor vessel decreases to the RCIC initiation level, the system automatically starts. The system may also be manually initiated at any time.

3.5/4.5-12

ATTACHMENT B Quad Cities Unit 2 Proposed Amendment to DPR-30 Technical Specifications Revised Pages: 3.5/4.5-3 3.5/4.5-11

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QUAD-CITIES DPR-30 continued reactor operation is permis- containment cooling mode of the sible only during the succeeding 7 days RHR, and the diesel generators re-unless it is sooner made operable, pro- quired for operation of such compo-vided that during such 7 days all active nents if no external source of power components of both core spray subsys- were available shall be demonstrated tems, the containment cooling mode of to be operable irrmediately and daily

. the RHR (including two RHR thereaner.

pumps), and the diesel generators re-quired for operatior of such compo-nents if no external source of power were available shall be operable.

6. If the requirements of Specification 3.5.A_cannot be met, an orderly shut-down of the reactor shall be initiated, and the reactor shall be in the cold shutdown condition within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

B. Caetalaanent Cooling Mode of the RHR B. Containment Coo'ing Mode of the RHR

, Syssen System Surveillance of the containment cooling mode of the RHR system shall be performed as follows:

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4 Both loops of the Containment cooling mode

1. RHR service water subsystem testing.

l1.a. of the RHR system, as defined in the bases for Specification 3.5.0, shall be operable N#* N'9" " F whenever irradiated fuel is in the reactor a.

vessel and prior to reactor startup from a Pump and valve Once/3 cold condition. operability months 1.b. From the ef fective date of this amendment b. Flow rate test - After pump until June 1,1982, the "A" loop of the each RHR service maintenance containment cooling mode of the RHR system water pump shall and every 3 for each reactor may share the Unit 2 "A" and "B" RHR service water pumps using deliver at least months cross tie line 1/2-10124-16"-D. 3500 gpm against Consequently, the requirements of a pressure of 198 Specifications 3.5.B.2 and 3.5.B.3 will pgjg impose the corresponding surveillance testing of equipment associated witn botn c. A logic system Each reactors if the shared RHR service water pump or pumps, or the cross tie line, are functional tesi rerueling made or found to be inoperable. outage

2. From and after the date that one of the 2. When it is determined that one RHR RHR service water pumps is made or service water pump is inoperable. the found to be inoperable for any reason, remaining components of that loop continued reactor operation is permis- and the other containment cooling sible only during the succeeding 30 loop of the RHR system shall be dem-days unless such pump is sooner made onstrated to be operable immediately operable, provided that during such 30 and daily the:cafter.

days all other active components of the containment cooling mode of the RHR (s system are operable.

3.5/45-3

- QUAD-CITIES DPR-34 3.5 LJMITING CONDITIONS FOR OPERATION BASES A. Core Spray and LPCI Mode of the RHR System This specification assures that adequate emergency cooling capability is available.

- Based on the loss-of-coolant analyses included in References I and 2 and in accordance with 10 CFR 50.46 and Appendix K, core cooling systems provide sufficient cooling to the core to dissipate the energy associated with the loss-of coolant accident, to limit the calculated peak cladding temperature to less than 2200

• F, to assure that core geometry remains intact, to limit the corewide cladding metal water reaction to less than IE and to limit the calculated local metal water reaction to less than 175 l The allowable repair times are established so that the average risk rate for repair would be no greater than the basic risk rate. The method and concept are described in Reference 3. Using the results developed in this referencc, the repair period is found to be less than half the test interval. This assumes that the core spray subsystems and LPCI constitute a one-out-of-two system; however, the combined effect of the two systems to limit excessive cladding temperature must also be considered. The test interval specified

) in Specification 4.5 :.as 3 months. Therefore, an allowable repair period which maintains the basic risk i considering single failures should be less than 30 days, and this specification is within this period. For multiple failures, a shorter interval is specified; to improve the assurance that the remaining systems will 4

1 function, a daily test is called for. Although it is recogr.ized that the information given in Reference 3

[ provides a quantitative method to estimate allowable repair times, the lack of operating data to support g the analytical approach prevents complete acceptance of this method at this time. Therefore, the times y statrd in the specific items were established with due regard to judgment.

Should one core spray subsystem become inoperable, the remaining core spray subsystem and the entire g LPCI mode of the RHR system are available should the need for core cooling arise. To assure that the remaining core spray, the LPCI mode of the RHR system, and the diesel generators are available, they

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are demonstrated to be operable immediately. This demonstration includes a manualinitiation of the 5 pumps and associated valves and diesel generators. Based onjudgments of the reliability of the remaining systems, i.e., the core spray and LPCI a 7-day repair period was obtained.

Should the loss of one RHR pump occur, a nearly full complement of core and containment cooling equipment is av.tilable. Three RHR pumps in conjunction with the core spray subsystem will perform the u core cooling function. Because of the availability of the majority of the core cooling equipment, which will be demonstrated to be operable, a 30-day repair period is justified. If the LPCI mode of the RHR system is not available, at least two RHR pumps must be available to fulfill the containment cooling function. The 7-day repair period is set on this basis.

L B. RHR Smke Water The containment cooling mode of the RHR synem is provided to remove heat energy from the containment in the es ent of a loss-of coolant accident. For the flow specified, the containment long-term F

pressure is limited to le s than 8 psig and is therefore more than ample to provide the required s heat removal capability (reference SAR Section 5.2.3.2).

$ The Containment Cooling mode of the RHR System consists of two loops.

} Each loop ccmists of 1 Heat Exchanger, 2 RHR Pumps, and the associated valves, piping, electrical equipment, and instrumentation. The "B" loop b on each unit contains 2 RHR Service Water Pumps. During the period from m ember 24, 1931, to June 1,1982, the "A" loop on each unit may utilize the "A" and "B" RHR Service Water Pumps from Unit 2 via a cross-tie i me . Af ter sne 1,1982, each "A" loop will contain 2 RHR

• Service water Pumps.

} Either set of equipment is capable of performing the containment h tooling function. Loss of one RHR service water pump does not seriously jeopardize the containment

( cooling capability, as any one of the remaining three pumps can satisfy the cooling requirements. Since there is some redundanty left, a 30 day repair period is adequate. Loss of one loop of the containment cooling mode of the RHR system leaves one remaining system to perform the containment cooling function. The operable system is demonstrated to be operable each day when the above condition occurs.

3.5/45-11

1 ATT_A_CHMENT C SAFEIY ANALYSIS OP 'IEE CROSSTIED SYSTDi Pursuant to Title 10, Code of Federal Regulations, Part 50 59 a safety analysis of the crosstied sysven has been perfomed. It has been detemined that this modification does not involve an unreviewed safety question as defined in 10CFR50 59 (c) and the basis for this detemination are presented for your review.

1. The probability of occurrence or the consequences of an accident or malfunction of equipment important to safety previously evaluated in the safety analysis report will not be increased. Since the RHR Service Water system is desi;ned to mitiCate the consequences of an accident, the probability of occurrence of an accident is not increased by failure of any cor.qcnents in this system.

As described in Section 6, Amendments 16 and 17 to the PSAR, only one RHR and one RHI. Service Water pumps are required to provide containment cooling following a loss of coolant accident. A similar combination of equipment is ade<;uate on the

- remaining unit to place and maintain the reactor in the cold shutdown condition. T.is minimum

• combination of equipment is only experienced in i the degraded cond.tionc of locs of off-site power, A

I i loss of coolant accident on one unit, and failure of a diesel generator to start. Since the modification does not reduce the minimum RHR Service Water system availability as described in the FSAR, the consequences of an accident or malfunction of equipment important to safety are not increased. As will be addressed in greater detail later, redundancy of pumps remains at the v

original desig.1 basis of 100<:.

2. The possibility for an accident or malfbnction of a different type than any evaluated previously in the safety analysis report is not created.

This crosstie modification merely shares tuo RHR Service 'Jater pumps between Units 1 and 2 in the saae manner as their emergency power supply, the 1/2 diesel generator, is shared between the two units. The crosstie does not require the addition of active components, electrical interlocks, etc. The two valves being installed are for the ivrpose of heat exchanger inlet valve maintenance only.

Without there two valves, maintenance of one I

inlet valve would require a containment cooling loop out of service on each unit.

3 The margin of safety as defined in the basis for i

any technical specification is not reduced. Since one containment cooling loop per unit corgoccd of one RHR and one RHR Service Water pump has been previously analyzed as adequate and since i

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only one RHR Service Water pump can be operated on a diesel generator, the reduction from a total of eight pumps to six has no effect on the nargin of safety. This is evident when examining the riiping an'1 the electrical diagrarns. 'ihe Unit I diesel generator supplies tha Unit 1 "C" or "D" pumps. The Unit 2 diesel cererator supplies the Unit 2 "C" or "D" rum ~.

The Unit 1/2 diesel generator supplies the "4" c* "P" pumps on either Unit 1 or Unit 2 depending or wMet unit is rostulated to have the loss of coo 19-t accident. Therefore, only six of the eight tumps are truly available and only three can be operated if all diesels are available. Identien1 redundancy is present under the crosstied se ere; six pumps are available but only three car be operated if all diesels are available.

Similarly, the worst case analysed in the PSAR assumes an accident on one unit, loss of off-site power, and failure of any one of the three diesel generators to start. This set of conditions results in operability of two RHR Service Water pumps, one per unit. The same results exist in the crosstied condition.

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- It is therefore concluded that an unreviewed safety question does not exist and that the station can be operated with the "A" RHR Service Water loop of each' unit pemanently crosstied with no degradation of the oririnal marr;in of safety.

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