ML20079C820

Proposed Tech Specs,Changing APLHGR Limits

ML20079C820
Person / Time
Site:	Oyster Creek
Issue date:	06/18/1991
From:	GENERAL PUBLIC UTILITIES CORP.
To:
Shared Package
ML20079C810	List: ML20079C809 ML20079C812 ML20079C820
References
NUDOCS 9106260155
Download: ML20079C820 (8)

Text

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3'. 4 EMER0ENCY'COOLTNG l

Acolicability: Applies to the operating status of the emergency coolant systems.

Obiectives. To assure operability of the emergency cooling systems.

Specifications:

A. Core Sorav System

1. The core spray system shall be operable at all times with irradiated fuel in the reactor vessel, except as otherwise specified in this section.

2. The absorption chamber water volume shall be at least 82,000.

ft.3 in order for the core _ spray system to be considered operable.

3. If one core spray system loop or its core spray header delta p instrumentation becomes inoperable during the run niode, the reactor may remain in operation for a' period not to exceed 7 days provided:

a. The remaining loop has no inoperable components and is demonstrated. daily to be operable and,

b. The average planar linear heat generation rate (APLHGR) of all the rods in any fuel assembly, as a function of average planar exposure, at any axial location shall not exceed 90% of the limits given in specification 3.10.A. The action to bring the core to 90% of the APLHGR Limits must be completed within two hours after the system has been determined to be inoperable, t

4. The reactor may remain.in operation for a period not to exceed 15 days if one of the redundant active loop components in the core spray system becomes inoperable during the run mode provided:

a. In the event of'an inoperable core spray booster pump, the other core spray booster pump in the loop is demonstrated daily to be operable.

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b. In the event of_an inoperable core spray main pump, the other core spray main pump in the loop is demonstrated daily to be operable and the APLHGR of all the rods in any fuel assembly, as a function of average planar exposure, at any axial l location shall not exceed 90% of the limits.given in

(= Specification 3.10.A. The action to bring the core to 90% of i the APLHGR Limits must be completed within two hours after the component has been determined to be inoperable.

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l OYSTER CREEK 3.4-1 Amendment No: 75 l- 9106260155 910619 l POR ADOCK 05000219 P PDR

If two of the redundant active loop components become inoperable, the limits of Specification 3.4.A.3 shall apply. l S. During the period when one diesel is inoperable, the core spray equipment connected to the operable diesel shall be operable.

6. If Specifications 3.4.A.3, 3.4.A.4, and 3.4.A.5 are not met, the reactor shall be placed in the cold shutdown condition. If the core spray system becomes inoperable, the reactor shall be placed in the cold shutdown condition and no work shall be performed on the reactor or its connected systems which could result in lowering the reactor water level to less than 4'8" above the top of the active fuel.

7. If necessary to accomplish maintenance or modifications to the core spray systems, their power supplies or water supplies, reduced system availability is permitted when the reactor ist (a) maintained in the cold shutdown condition or (b) in the refuel mode with the reactor coolant system maintained at less than 212 F and vented, and (c) no work is performed on the reactor vessel and connected systems that cculd result in lowering the reactor water level to less than 4'8" above the top of the active fuel. Reduced Coro Spray System Availability is minimally defined as follows:

a. At least one core spray pump, and system components necessary to deliver rated core spray to the reactor vessel, must remain operable to the extent that the pump and any necessary valves can be started or operated from the control room or from local control stations,

b. The fire protection system is operable, and

c. These systems are demonstrated to be operable on a weekly basis.

8. If necessary to accomplish maintenance or modifications to the core spray systems, their power supplies or water supplies, reduced system availability is permitted when the reactor is in the refuel mode with the reactor coolant system maintained at less than 212 0 F or in the startup mode for the purposes of low power physics testing. Reduced coro spray system availability is defined as follows:

a. At least one core spray pump in each loop, and system components necessary to deliver rated core spray to the reactor vessel, must remain operable to the extent that the pump and any necessary valves in each loop can be started or operated from the control room or from local control stations.

b. The fire protection system is operable and,

c. Each core spray pump and all components in 3.4.A.8a are demonstrated to be operable every 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

OYSTER CREEK 3.4-2 Amendment No.: 75 1

9. If Specifications 3.4.A.7 and 3.4.A.8 cannot be met, the requirements of Specification 3.4.A.6 will be met and work will be initiated to meet minimum operability requirements of 3.4.A.7 and 3.4.A.8.

10. The core spray system is not required to be operable when the following conditions are mets

a. The reactor mode switch is locked in the " refuel" or j

" shutdown" position. l

b. (1) There is an operable flow path capable of taking suction from the condensate storage tank and transferring water to the reactor vessel, and (2) The fire protection system is operable,

c. The reactor coolant system is maintained at less than 212 F and vented (except during reactor vessel pressure testing).

d. At least one core spray pump, and system components necessary to deliver rated core spray flow to the reactor vessel, must remain operable to the extent that the pump and any necessary valves can be started or operated from the control room or from local control stations, and the torus is mechanically intact.

e. (1) No work shall be performed on the reactor or its connected systems which could result in lowering the reactor water level to less than 4'8" above the top of the active fuel and the condensate storage tank level is greater than thirty (30) feet (360,000 gallons).

At least two redundant systems including core spray pumps and system components must remain operable as defined in d. above OR (2) The reactor vessel head, fuel pool gate, and sepa.rator-dryer pool gates are removed and the water level is above elevation 117 feet.

NOTE: When filling the reactor cavity from the condensate storage tank and draining the reactor cavity to the condensate storage tank, the 30 foot limit does not apply provided there is sufficient amount of water to' complete the flooding operation.

B. Automati? Deoressurization Svetem

1. Five electromatic relief valves of the automatic depressurization system shall be operable when the reactor ,

water temperature is greater than 212 F and pressurized above 110 peig, except as specified in 3.4.B.2. The automatic pressure relief function of these valves (but not the OYSTER CREEK 3.4-3 Amendment No.: 75 I

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automatic.depressurization function) may be inoperable or

. bypassed during the system hydrostatic pressure test required by ASME Code Section XI, IS-500.at or near the end of each ten year inspection interval.  ;

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2. If at any time there are only four operable electromatic relief valves, the reactor may remain in operation for a period not to exceed 3 days provided the motor operated isolation and condensate makeup valves in both isolation condensers are demonstrated daily to be operable.

3. If Specifications 3.4.B.1 and 3.4.B.2 are not met; reactor pressure shall be reduced to 110 psig or less, within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

4. The time delay set point for initiation after coincidence of low-low-low reactor water level and high drywell pressure shall be set not to exceed two minutes.

C. Containm9nt Sorav System and Emeroency Service Water System

1. The containment spray system and the emergency service water

. system shall be operable at all times with irradiated fuel in the reactor vessel, except as specified in Specifications 3.4.c.3, 3.4.c.4, 3,4.c.6 and 3.4.c.8.

2.

Theabsorgtionchamberwatervolumeshallnotbelessthan 82,000 ft in order for the containment spray and emergency service water system to be considered operable.

3. . If one emergency service water system loop becomes inoperable, its associated containment spray system loop shall be considered inoperable. If one containment spray system loop and/or-its associated emergency service water system loop becomes inoperable during the.run mode, the reactor may remain in operation for a period not to exceed 7 days provided the remaining containment spray system loop and its associated

, emergency service water system loop each have no inoperable I components and are demonstrated daily to be operable.

4. If a pump in the containment spray system or emergency service water system becomes inoperable, the reactor may remain in operation for a period not to exceed 15 days provided the other similar pump is demonstrated. daily to be operable. A maximum of two pumps may be inoperable provided the two pumps are not in the same loop. If more-than two pumps become inoperable, the limits of Specification 3.4.c.3 shall apply.

5. During the period when one diesel is inoperable, the containment spray loop and emergency service water system loop connected to the-operable diesel shall have no-inoperable components.

6. If primary containment integrity is not required (see Specification 3.5.A), the containment spray system may be made inoperable.

- OYSTER CREEK 3.4-4 Amendment No.: 75

7. I' Specifications 3.4.C.3, 3.4.C 4, 3.4 C.5 or 3.4.C.6 are not

+ met, the reactor shall be p' aced in cold shutdown condition.

If the containment spray system or the emergency service water system becomes inoperable, the reactor shall be placed in the cold shutdown condition and no work shall be performed on the reammr or its connected systems which could result in lowering the teactor water level to less than 4'8" above the top of the active fuel.

8. The containment spray system may be made inoperable during the integrated primary containment leakage rate test required by Specification 4.5, provided that the reactor is maintained in the cold shutdown condition and that no work is performed on the reactor or its connected systems which could result in lowering the reactor level to less than 4'8" above the top of the active fuel.

D. Control Pod Drive Hydraulic System

1. The control rod drive (CRD) hydraulic system shall bo operable when the reactor water temperature is above 212 F except as specified in 3.4.D.2 and 3.4.D.3 below.

2. It one CRD hydraulic pump becomes inoperable when the reactor water temperature is above 212*F, the reactor may remain in operation for a period not to exceed 7 days provided the second CRD hydraulic pump is operating and is checked at least once every 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />. If this condition cannot be met, the reacto.-

water temperature shall be reduced to less than 212*F.

3. During reactor vessel pressure testing, at least one CRD pump shall be operable.

E. Coro Sorav and Containment Sprav Pump Compartmente Doore The core spray and containment spray pump compartments doors shall be closed at all times except during passage in order to consider the core spray system and the containment spray system operable.

F. Fire Protection System

1. The fire protection system shall be operable at all times with fuel in the reactor vessel except as specified in Specification 3.4.F.2.

2. If the fire protection system becomes inoperable during the run mode, the reactor may remain in operation provided both core spray system loops are operable with no inoperable components.

Bases:

Thio specification assures operability of the emergency core cooling system to provide adequate core cooling. The Oyster Creek ECCS has two core spray loops; each containing a core spray sparger, two main pumps and two booster pumps. Specification 3.4.A.1 insures the availability of OYSTER CREEK 3.4-5 Amendment No.: 75 l

c,oro cooling to meet the ECCS acceptance criteria in 10CFR50.46 utilizing theMAPLHCRljmitsprovidedinSection3.10. These limits are from calculations ( I that include models and procedures which are specified in st/R50 Appendix K. -A core spray flow of at least 3400 gpm (1 main and 1 booster pump) from 1 loop plus 2200 gpm (1 main pump) from the otner loop at a vessel pressure of 110 psig is used in the calculation. Core spray loop 2 would be required to deliver 3640 gpa if loop 2 is relied upon as the two pump contributor and 2360 gpm if loop 2 is the single pump contributor, since loop 2 has flow losses through cracks in the core spray i sparger. l 1

Specification 3.4.A.3 allows continued operation with one core spray loop inoperable for a limited period of time. An evaluation of data presented in Reference 5 shows that flow from a single core spray sparger, main and booster pumps delivering 3400 ?pm (3640 gpm for loop 2) at a vessel pressure of 110 poig, will meet 10 CFR 50.46 criteria with a 10% reduction in MAPLHGR Limits specified in Section 3.10. At 90% of the APLHOR, each core spray system is capable of supplying the regaired minimum bundle flow rate to ensure core cooling (References 6 and 7). Two houra is allowed for

a. reduction in the APLHGR limit which is consistent with two hours provided ,

by Specification 3.10.A.3 to return an exceeded APLHGR to within the prescribed-limit.

Under the operational constraints of Specification 3.4.A.3 the operable core spray loop meets all Appendix K requirements except for the case of a core spray line break inside che drywell in the operable loop. As a result, reactor operation is permitted for a period not to exceed seven days. The allowed time out of service for the redundant core-spray loop is justified based on the low probability of the event, the direct operator ,

indication of a Core Spray-System pipe break, and emergency procedures which provide tut additional cooling water through the fire system.

The probabi ty of a pipe break between the reactor vessel at' the core spray choc. valve in the operable core spray loop (approx. l3 feet of 6 inch pipe) compared to the total pipe in the reactor coolant pressure boundary is very small. The probability of a core spray line break in conjunction with the other core spray loop out of service, which in itself is a-low probability, is so small that it does not constitute an unacceptaole risk. In the extremely unlikely event that this-LOCA scenario were to occur, the_ operators are provided with a specific visual and audible alarm alerting them of a " Core Spray System I (II) Pipe Dreak" (one for each core spray loop). These alarms are initiated by differential pressure detectors on each core spray loop. In nuch a case the core spray line break would occur above the top of the r.ctive fuel allowing the core to be re-flooded from the fire protection system through the intact core

) spray _ loop.

In addition, a_small break LOJA in the operable core spray. loop prior to a larger break will be detected by the drywell unidentified leakage syctem (drywell sump) even before-it'ie detected by the core spray-alarm system.

This will provide the operators with additional time to respond.

Therefore, the out-of-service time for one of the two core spray loops, as evaluated as per the guidelines in Reference 8, has been conservatively selected to be 7 days.

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. OYSTER CREEK 3.4-6 Amendment No.: 75

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specification 3.4.A.4 allows continued operation with one component inoperable for a limited period of time. Each core spray loop contains redundant. active components based upon Reference 1 or 5, as appropriate.

• Therefore, with the loss of one of these components, the system as a whole (both loops) can tolerate an additional single failure of one of its active components and still perform the inte1ded function and meet 10CFR50.46 criteria.- If a redundant active component fails, a fifteon day period is allowed for repairs, based on 1 out of 4 components being required.

3.4. A.4.b insures that the 1 out of 4 requirement is maintained.

Spt.cification 3.4. A.5 et sures that if one diesel is out of service for repair,_the core spray components fed by the other diesel must be operable. Since each diesel will provide power to components for both core ,

spray loops, the required flow specified in the bases for Specification 3.1.A.1 will be met.

When the reactor im in the shutdown or refueling mode and the reactor coolant-system is leau than 212*F and vented and no work is being performed that could result in lowering the water level to less than 4i8" above the core, the likelihood of a leak or rupture leading to uncovering of the core is.very low. The only source of-energy that must be removed is decay heat and one day after shutdown this heat generation rate is conservatively calculated to be not more than 0.6% of rated power. Sufficient core spray flow to cool the core can be supplied by one core spray pump or one of the two fire protection system pumps under these conditions. When it is necessary to perform repairs on the core spray system componente, power supplies or water sources, Specification 3.4.A.7 permits reduced cooling system capability to that which could provide sufficient core spray flow from two independent sources. Manual initiation of these systems is adequate since it-can be easily accomplished within 15 minutes during which time the temperature rise in the reactor will not reach 2200*F.

In order to allow for certain primary system maintenance, which will' include control rod _ drive repair, LPRM removal / installation, reactor leak test, etc., (all performed according to approved procedure), specification 3.4.A.0 requires the availability of an additional core spray pump in an independent loop, while this maintenance is being performed the likelihood of the core being uncovered is still considered to be very low, however, +

the requirement of a second core spray pump capable of full rated flow and the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> operability demonstration of both core spray pumps is specified.

Specification 3.4.A.10 allows the core spray system to be inoperable in the cold shutdown or refuel modes if the reactor cavity is flooded and the spent fuel pool gates are removed and a source of water supply to the reactor vessel is available. Water would then be available to keep the core flooded.

The relief valves of the automatic depressurization system enable the core.

spray system to provide protection against the small break in the event the feedwater system is not active.

OYSTER CREEK 3.4-7 Amendment 10.1 75

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. The. containment spray system is provided to remove heat energy from the containment in the event of a loss-of-coolant accident. The flow from one pump in eithne loop is more than ample to provide the required heat removal capability (2). The emergency service water system providec 'oling to the i containment spray heat exchangers and, therefore, is requirt .o provide the ultimate heat sink for the energy release in the event v. a loss-of-coolant accident. The emerge.'cy service water pumping requirements are those which correspond to containmsnt cooling heat exchanger performance implicit in the containment cooling description. Since the loss-of-coolant accident while in the co.d shutdown condition would not require containment spray, the system may be deactivated to permit integrated leak rate testing of the primary containment while the reactor i is in the cold shutdown condition.

Thecontrolroddrivehydraulicsystemcanprovidehighpreosurecoolant  ;

injection capability. For break sites up to 0.002 ft , a single control _

rod drJve-pump with a flow of 110 gpm is adequate for maintaining the water level nearly five feet above the core, thus alleviating the necessity for auto-relief actuation (3).

r The core spray main pump compartments and containment rpray pump compartments were provided with water-tight doors (4). Specification 3.4.E ensures that the doors are in place to perform their intended function.  !

s Sieilarly, since a loss-of-coolant accident when primary containment-integrity is not being maintained would not result in pressure build-up in the drywell or torus, the system may be made inoperable under these conditions. This prevents possible personnel injury asnociated with contact with chromated torus water.

Egferences

1. NEDC-31462P, " Oyster Creek Nuclear Generating Station SAFER /CORECOOL/GESTR-LOCA Loss-of-Coolant Accident Analysis," August 1987.

2. Licensing Application, Amendment 32, Question 3

3. Licensing Application, Amendment 18, Question 1

4. Licensing Application, Amendment 18, Question 4-

5. GPUN Topical Report 053, " Thermal Limite with One core Spray Sparger"

-December 1988.

6. -NEDE-30010A, " Performance Evaluation of the Oyster. Creek Core Spray Spargor", January 1984.

7. Letter and enclosed Safety Evaluation, Walter A. Paulson (NRC) to P. B.

F1edler (GPUN), July 20, 1984.

8. APED-5736, " Guidelines for Determining Safe Test Intervals and Repair Times for Engineered Safeguards", April 1969.

I OYSTER CREEK 3.4-8 Amendment No.: 75 L_...__. _ _ _ . _ _ _ . _____.___;_:___._._____._________. .- _ . _ _ , . . _ _

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