ML20099G613

Forwards Response to NRC 920713 Request for Addl Info Re Dc Sys Design Function in Event of Accident

ML20099G613
Person / Time
Site:	Grand Gulf
Issue date:	08/13/1992
From:	Cottle W ENTERGY OPERATIONS, INC.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GNRO-92-000107, GNRO-92-107, NUDOCS 9208170130
Download: ML20099G613 (11)

Text

4 I;ntergy Operations,Inc.

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W. T. Cottle August 13, 1992 i

U.S. Nuclent Regulatoi, Commi<.* ton finil Stat ion PI-137 Washitigton, D.C.

20555 Attentjon:

Document Cont rol Desk Subject 1 Grnml Gulf Nuclear Stat lon (In i t 1 Docket No. 50-416 1.icetmo No. NPP-29 Additional luformntion Concerning the DC System Design

Reference:

1,et t er Paul W. O'Connor (NRC) to William T. Pottln. " Request for Additional infornint Jon (RA1)" Grand Gulf Nuclenr Stat f on, Unit No. 1 (M82545), dnt ed,luly 13, 1992 GNRO-92/00107 Gont lemen Entergy Operations. Inc. by this let ter is submit ting nddit ionni infornation to support your review of 1ha Grnml Gulf Nuclonr Stat.bn (GGNS)

Safet3 Enlat ed DC Syst em.

Thin letter is in rosponsn t o your let ter dnt ed

.luly 13, 1992.

This letter and its attachments providn informnLion supporting Entergy Operntion9' conclusion that thn safety relat ed DC system will perform it s dn91gn funct ion in the event of an nccident.

You:ts truly, 42PW WTC/WEL/mtc attachment:

Response t o NRC Questions ec:

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August 13. 1992 GNRO-92/00107 l'ago 2 of 3 cc Mr. D. C. Illntz (w/a) lir. J. L. Mathis (w/a)

Mr. R. B. McGehoe-(w/a)

Mr. N. S. Reynolds (w/a)

Hr.11. L. Thomas. (w/o)

' l Mr. Stewart D. Ebnetor (w/a)

Regional Administrator 4

U.S. Nuclear Regulatory Commission j

Region 11 101 Marietta St., N.W., Suite 2900.

Atlant.a. Georgia 30323 Mr. P. W. O'Connor, Project Manager (w/2)

Offico of Nuclear Reactor Regulation i

U.S. Nuclent Regulatory Commissit.n

Hall.Stop 13113 Washington, D.C.

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. to GNRO 92/00107 Page 1 of 9 NRC Question 1 The licensee is requested to provide a list of the components that may not be receiving adequate voltage and their purpose and safety significance.

ftGNS Resoonse to Question 1 The Grand Gulf Nuclear Station (GGNS) safety related 125 Vdc system is designed to ensure compliance with General Design Criterion (GDC) 17. To ensure the requirements of GDC 17 are mot, the system's design is based on the criteria described in IEEE Standard 3081974 (IEEE 308) and IEEE Standard 4851975 (IEEE 485) with testing as recommended in IEEE Standard 450 1975 (IEEE 450) and supplemented by Regulatory Guide 1.128. As discussed in the Final Safety Analysis Report (FSAR), the safety related 125 Vdc system has ample capacity available to serve essential loads for the timo that alternating current will not be available at the station site.

The GGNS design basis accident for the safety related 125 Vdc system is a Loss of Coolant

- Accident (LOCA) concurrent with a Loss of Offsite Powe, ROP) and the failure of both battery chargers (for Divisions I and II) while maintaining the diviwn operable. To support this system design basis accident, the GGNS safety related 125 Vdc system is designed such that the Division 1

- and 11 batteries have sufficient stored energy to supply their essentialloads for 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> (2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> for Division 111). This design feature of the safety related 12B Vdc system bounds the GDC 17 requirements for battery capacity, since the de systom's iuad will be assumed by the redundant (for Divisions I and 11) safety related battery chargers following the starting of the diesel generators instead of being supplied by the battorios.

Table 1 below is a list of the essential components which have the potential to receive less than the manufacturer's minimum operating voltage when they are called upon to operate. Proper operation of these components is verified by the engineering evaluation and testing performed as described in the response to Question 3. All essential components receive adequate voltage to perform their safety functions during the 125 Vdc system's design basis accident.

I M_kf_1 COMPONENTS WHICH POTENTIALLY RECEIVE LESS THAN THE MANUFACTURER'S MINIMUM VOLTAGE WHEN THEY ARE REQUIRED TO OPERATE DURING THE SYSTEM DESIGN BASIS PROFILE Component Function olVistoN I Breaker 152 1508 Close Coil Diesel Generator Feeder Breaker to 416o V switchgear Bus 15AA

' Breaker 152 1509 Close Coit Residual Heat Removal Pump Motor A Feeder Breaker Breaker 15215o5 Close cost Drywell Purge Compressor A Feeder Breaker MoV 1E51Fo45 72F Contactor Contactor energizes the RCic steam to Turbine MoV Actuator to open the 1E51Fo45 valve MoV 1E51Fo13 72F Contactor Contactor energues the RCIC injection Shutoff MoV Actuator to open valve 1E51Fo13 when valve 1E51Fo45 opens MoV 1E51Fo13 72R Contactor Contactor energites the RCIC injection Shutoff MoV Actuator to close valve 1E51FC13 when valve 1E51Fo45 or the trip valve closes Division 11 Breaker 152 1608 Close Coil oiesel Generator Feeder Breaker to 416o V switchgear Bus 16 AB r-

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! to GNRO-92/00107 Page 2 of 9 l

In addition to the components identified above, certain indicating lights may receive less than the manufacturer's nominal voltage for intermittent periods. During subsequent time periods, however, most recover and receive adequate voltage. Although the GGNS calculations conservatively assumed that all indicating lights were incandescent, most circuits in the control room use neon lamps. The nominal voitage for neon lamps is less than half of the nominal voltage for incandescent lamps. Circuits which utilize incandescent lamps and experience voltage levels below the manufacturer's nominal voltage may exhibit lights which momentarily become dim. It is not l

expected that the lights would actually extinguish as a result of the fluctuations in the voltage levels. The most severe voltage drops occur for only a fraction of a second. The lights potentially receiving less than the manufacturer's nominal voltage are indicating lights (e.g., logic initiation lights) and are located both in the control room and various locations in the plant on local panels.

The affected lights do not include the control room annunciators. During a LOP LOCA event, all of t

these lights should receive adequate voltage when the battery chargers assume the de load after the diet,el generators start.

Some indicating lights have the potential to operate at levels below the manufacturer's nominal voltage for extended periods during the evaluated profile. The following are the incandescent lights located in the control room which are expected to receive the lower voltage levels for an extended period of time.

Division 1 One indicating light in the control room was identified to receive up to 3 volts less than the manufacturer's nominal voltage after the first 105 seconds and before the last minute of the profile. This indicating light was the Low Pressure Core Spray (LPCS) Logic initiation light.

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Division ll The following indicating lights in the control room were identified to potentially receive up to 5 volts less than the manufacturer's nominal voltage after the first 30 seconds and before the last minute of the profile.:

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- Control Room Isolation Initiation (2 lights)

- Control Room isolation Logic in Auto

- Drywell/Containmer6 Purge Control Initiation (2 lights)

- Containment isolatica initiation (2 lights)

- Suppression Pool Makeup initiation (2 lights)

- Standby Gas Treatmbnt System initiation (2 lights)

- Standby Gas Treatment System in Auto Standby Service Water System initiation (2 lights) i U

Division 111 Two lights in the control' room were identified to potentially receive up to 9 volts less l.

than the manufacturer's nominal voltage during the profile. These lights are the High Pressure Core Spray initiation / Reset and the Reactor Pressure Vessel High Water Level indication lights.

Although these lights are only postulated to dim due to the lower voltages at their terminals, if the lights are assumed not to work at all, sufficient information would be available to the operator from other devices to indicato the affected systems' status. The operation of the indicating lights noted does not affect the operation of the associated equipment.

l' Other than indicating lights, Division lil of the GGNS safety related de system contains no equipment which has been identified to potentially receive less than the manufacturer's minimum voltage.

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. to GNRO 92/00107 Page 3 of 9 NRC Ouestion 2 The licensee is requested to justify (hv class where appropriate) the acceptability of below minimum operating voltage for the components identified by the voltage drop study in Division 1, il and til 125 Vdc systems, and demonstrate that the components will function during the plant's design basis event (loss of-coolant accident with loss of battery chargers for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />). The justification should include discussion of 1) possible effects of low voltage upon the components, 2) damage to the related components and systems, and 3) operator actions during the scenario.

GGNS Resoonse to Question 2 For the equipment verified to be operable via testing, the testing and its associated engineering evaluation provide.;surance that there are no possible adverse effects of the lower voltage on the components. This testing and engineering evaluation assure that there will be no damage to related components and systems and that no additional operator actions are required as a result of the operation at voltage levels below the manufacturer's minimum rated voltage. Th9 testing and engineering evaluation are described in the response to question 3.

i l

The voltage drop calculations also identify components which may receive less than the manufacturer's rated minimum voltage during some period but receive adequate voltage when they are postulated to operate, or the components are not required to operate. Table 2 is a list of those components which may receive less than the manufacturer's minimum voltage during some period but will receive the manufacturer's minimum voltage during the times they are postulated to operate. Table 3 is a list of those components which may receive less than the manufacturer's minimum voltage but are not required to operate to mitigate the accident. Since the items in Tables 2 and 3 receive the manufacturer's minimum voltage required to perform their safety functions, these Tables were not included in the response to Question 1. The periods in which these components do not receive their manufacturer's minimum rated voltages do not have any detrimental effects since the components are not required to operato during these times. No operator actions are required to mitigate the effects of the potential degraded voltages to those components.

TABLE 2 COMPONENTS WHICH RECEIVE THE MANUFACTURER'S MINIMUM VOLTAGE WHEN THEY ARE REQUIRED TO OPERATE BUT WERE IDENTIFIED TO POTENTIALLY RECEIVE LESS DURING SOME PORTION OF THE DESIGN BASIS PROFILE Component Function Justification Division 1 Relay R39 standby service Water This relay has the required minimum pickup voltage at its terminals at the time it is (sSW) Pump Feodor postulated to pick up and the voltage at its terminals never drops below ne maximum Breaker Control drop out voltage for the romswier of the time that it is energized. Therefore, this device will perform its design funcRn.

Relay Rs2 orywell Purge

.This relay has the rt,q('d m;nimum pickue ytritar a11ts terminals at the time it is Compressor Manuel and postulated to pick ut* and the voltage et its terr % alt never drops below its maximum Compressor Protective drop out voltage for tH temeinder of the 'ime that at is energized. Therefore, this Tnp Relay device will perform 6. tee gn]nction.

Relay 62-1 Enclosure Buildirsg This relay has the required r.are e > r4L up voltage et its terminals at the time it is Recirculation Fan Feeder postulated to pick up arvi the veitese et its terminals never drops below its maximum Breaker Control drop out voltage. Therefore..he dwice will perform its design function.

4 Attachm.

'o GNRO 92/00M Page 4 of 9 TABLE 2 COMPONENTS WHICH RECEIVE THE MANUFACTURER'S MINIMUM VOLTAGE WHEN THEY ARE

- REQUIRED TO OPERATE BUT WERE IDENTIFIED TO POTENTIALLY RECEIVE LESS DURING SOME PORTION OF THE DESIGN BASIS PROFILE (Continued)

Component Function Justification Relay 74 6 Load Center 15BA5 TNs relay functions to provide er onciation onloss of control power. It is (R20) 480 V Feeder Breaker continuously energised and would remain picked up on initiat;on of the postulated

• Loss of Control Power event since voltage at its terminale never drops below its maximum drop out voltage.

Indecation if control power is lost to the logic, the relay would perform its function when it de-energized. Therefore. this device will perform its design function.

Relay R41 SSW Cooling Tower This relay provides a permissive to energire the close coil for its re oective breaker.

Fan A Feeder Breaker The relay has the required rninimum pick up voltage et its terminala when it receives Alarm and Control its permissive to pick up until the close coil energizes. Therefore, this device performs its design function.

Rele *.42 SSW Cooling Tower This relay provides a permissive to energiro the close coil for its respective breaker.

Fan B Feeder Breaker The relay has the required tunimum pick up voltage at its temiinals when it receives Alarm and Control its permissive to pick up untii the close coil energizes. Therefore, this device performs its design function.

DIVISION 11 Relay R43 SSW Cooling Tower This relay provides a perrassive to energite the close coil for its respective breaker.

Fan C Feeder Breaker The relay has the required miniran pick up voltage at its terminals whenit receives Alarm and Control its permissive to pick Lp until the close coil energites. Therefore, this device performs its design function.

Relay R44 SSW Cooling Tower -

This relay provides a permissive to energiro the close coil for its respective breaker.

Fan D Feeder Bresker The relay has the required rninimum pick up voltage at its terminals when it receives Alarm and Control its permissive to pick up until the close coil energizes. Therefore, this device performs its design function.

Relay 74-5 SSW Cooling Tower This relay functions to provide annunciation on loss of control power. It is Fan C Feeder Breaker continuously energized and would remain picked up on initiation of the postulated Loss of Control Power event sir.co voltage et its terminale never drops below its maximum drop out voltage, if control power le lost to the topc, the relay would perform its function when it de-energized; therefore, this device will perform its design function.

Relay 74-6 SSW Cooling Tower This relay functions to provide annunciation on loss of control power. It is (P41)

Fan D Feeder Breaker continuously energized and would temmin picked up on initiation of the postulated Loss of Control Power event since voltage at its terminals never drops below its maxirrum drop out voltage, if control power is lost to the tc gic, the relay would perform its function when it de-energized; therefore, the device will performits design function.

Relay 74 6 Load Center 16885 This relay functions to provide annunciation on loss of control power. It is (R20) 4160 V Feodor Dreaker continuously energized and wculd remain picked up on initiation of the postulated Loss of Control Power event since voltage at its terrrenals never drops below its maximum drop out voltage. y indication if control power is lost to the logic, the relay would perform its function when it de-energized; therefore, this dev'ce will perform its design function.

Relay 74 22 Load Center 16BB5 This relay functions to provide annunciation on loss of control power. It is 4160 V Feeder Breaker continuously energized and would remain picked up on initiation of the postulated Undervoltage Circuit event since v'ottage at its trirminals never drops below its maximum drop out voltage.

Loss of Control Power if control power is lost to the logic, the relay would perform its function when it de-Indication energized; therefore, this device will perform its design function.

Roley 7412 Load Center 16BB4 480.

This relay functions to provide annunciation on loss of control power, it is

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V Feeder Breaker to continuously energized and would remain picked up on initiation of the postulated Motor Control Center event since voltage at its terminals never drops below its maximum drop out voltage.

(MCC) 16842 Loss of -

If control power is lost to the logic, the relay would perform its function when it de-Control Power indication energized; therefore, this device will perform its design function.

. to GNRO 92/00107 Pago 5 of 9 TABLE 3 COMPONENTS WHICH POTENTIALLY RECEIVE LESS THE MANUFACTURER'S MINIMUM VOLTAGE BUT ARE NOT REQUIRED TO OPERATE Compenent Function Justification DIVISION I Roley R6 Diesel Generstor (ESF TNs relay provides a permissive for annuncistion of en automatic trip of its nus 1S A A) Breaker:

respective breaker. Sinoa the diesel generator breaker is not postulated to tnp

tuvides Annunciation and tNs relay performs no other controllindication function, tNo relay is not of EDG Breaker required to coerste.

Automatic Trip Relay K47 A Permissive for transfer TNs relev brovides a permanive for annunciation of a trip of the recirculation of Recirculation Pump to pump and a porrass;ve to transfer the recirculation pump to low speed. The Low Speed recirculatior. purop is not evadable during a LOP Therefore, tNo relay is not required to opero e.

Brooker 152-1S03 SSW Pump A feeder The spring chargir g motor provides the energy requieed to compress the Spring Charging Breaker respective breaker o close spring and inp spring. The opnng charging motor is Motor energized when the breaker's close springe are discharged (i.e., right after the breaker closes), T he breaker is not postulated to trip after it closes; therefore, the close opnngs are not required to be recharged for the brooker to performits design function.

This component was tested as desenbod in the response to question 3.

Breaker 1S2-SSW Cooling Tower Fan The spring charging motor provices the energy required to compress the 15S05 Spring A Feeder Brooker respective brooker's close spring and trip spring. The spring charging motor is Charging Motor energized when the breaker's close springs are discharged (i.e., rigot after the breaker closes). TNs breaker is not postulated to trip after it closes; therefore, the close springs are not required to be techarged for the breaker to perform its design function.

TNs component was tested as described in the response to question 3.

Relay 62-S Perruissive for Th e teley provides a permissive for annunciation of an automatic trip of its Annunciation of SSW respectivo breaker. Since the SSW Coohng Tower Fan brookeris not postulated Cooling Tower Fan A to trip and this reley performs no other control / indication function. this relay is Feeder Breaker Trip not required to operate.

Relay R86 SSW Cooling Tower Fan TNs relay provides e permissive for annunciation when its respective breaker is A Feeder Breaker Test in the test position. Since the SSW Cooling Tower Fan breaker is not postulated Indication to be in the tesi position and tNs relay performs no other controlAndication function, this relayis not required to operate.

Breaker 152-SSW Cooling Tower Fan The spring charging motor provides the energy required to compress the 15506 Spring B Feeder Breaker respective breaker's close spring and trip spring. The spring charging motor is Charging Motor energized when the breaker's close springs are discharged (i.e., right af ter the breaker closes). The breaker is not postulated to trip after it closes; therefore, the close spnnga are not required to be recharged for the breaker to perform its design function.

TNs component was tested as described in the response to question 3.

Relay 62 6 Permissive for This relay provides a permissive for annunciation of an outomatic trip of its Annunciation of SSW respective breaker. Since the SSW Cooling Tower Fan breaker is not postulated Cooling Tower Fan B to trip ard this relay performs no other controtAndication function, tNs relayis Feeder Breaker Trip not required to operate.

Relay R87 SSW Cool;ng Tower Fan TNs relay provides a permissive for annunciation when its respective breaker is B Feeder Breaker Test in the test position. Since the SSW Cooling Tower Fan breaker is not postulated 1:4cetion to be in thir test position and this relay performs no other control / indication function this relay is not required to operate.

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( to GNRO-93/00107 Page 6 of 9 TABLE 3 i

COMPONENTS WHICH RECEIVE LESS THE MANUFACTURER'S MINIMUM VOLTAGE BUT ARE

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NOT REQUIRED TO OPERATE (Continued) l Component Function Justification Breaker 1621$09 Residual Heat Removal The spring charging motor provides the energy required to compress the Spring Charging (RHR) Pump A Feeder respectne breaker's close spring end trip spnng. The sprang charging motor is Motor Breaker energized when the breaker's close springs are discharged (l.a., right efter the breaker closes). The breaker is not postulated to trip after it closes; therefore, the close springs are not required to be recharged for the breaker to perform its design function.

This component was tested es described in n rasponse to question 3.

Breaker 152 Drywell Purge The spring charging motor provides the energy re:raired to compress the 15105 Spring Compressor A Feeder respective breaker's close spring and trip spring, 'ihe spriaC che J ng motor is i

Charging Motor Breaker energsred when the breaker's close springs are discharged (i.e., right efter the breaker closes). The breaker is not postulated to trip after it closes; therefore, the close springs are not required to be recharged for the breaker to perform its design function.

TNs component was tested as described in the rispense to question 3.

Solenold RCIC Trip and Throttle This solenoid operates to allow the RCIC Turbine Trip and Throttle Valve to TB1ES11C002 Valve Trip Coit close. During the accident conditions postulated, the low preseure isolation signal will close the isolation valves in the steam eupply line to RCIC and closure of tNs valve will not be required.

Breaker 152-Diesel Generator Room The spring charging motor provides the energy required to compress the 15106 Spring Outside Air Fan A respective breaker's close spring and trip spring. The spring charging motor lo Charging Motor Feeder Breaker energized when the breaker's close spings are discharged (i.e., right after the breaker closes). The breaker is not postulated to trip after it closes; therefore, the close springs are not required to be recharged for the breaker to perform its design function.

This component was tested as desenbed in the response to question 3.

Breaker 152-Enclosure Building Fan A The spring charging motor provides the energy required to compress the 15304 Spring Feeder Breaker respective breaker'r 4'ose spring and trip spring. The spring charging motor is Cha*ging Motor energized when the Dreaker's close springs are discharged (i.e., right efter the breaker closes). The breaker le not postulated to trip af ter it closes; therefore, the close springs are not required to be recharged for the breaker to perform its design function.

This component was tested as described in the response to question 3.

DIVISION 11 i

Relay R6 -

Diesel Generator (ESF TNs relay provides a permisoive for annunciation of an automatio trip of its Bus 16AB) Breaker:

respective breaker, Since the diesel generator breaker is not postulated to trip Provides Anrdmciation and this relay performs no other function, tNo relay le not required to operate, of EDG Break Autometti '..

n Relay K478 Permisst i ir transfer This relay provides a permissive for annunciation of a trip of the recirculation of Recirculatir n Pump to pump and a permissive to transfer the recirculation pump to low speed. The Low Speed recirculation pump is not available during a LOP. Therefore, this relay is not required to operate.

Rs'ay 63X N025 Component Cooling This relay provides a start signal to Component Cooling Water Pump B on a low Water (CCW) control discharge pressure signal and annunciation of a low discharge pressure and logic low system pump emergency trip. Since this pump is locked out on a LOCA and performs no pressure signal

< afety related function, this relay is not required to operate.

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6'41 I to GNRO 92/00107 age 7 of 9 TABLE 3 COMPONENTS WHICH RECEIVE LESS THE MANUFACTURER'S MINIMUM VOLTAGE BUT ARE NOT REQUIRED TO OPERATE (continued)

Cornponent Function Justification Breaker 5216505 SsW cooling Tower The spring charging motor provides th( energy required to compress the l'

sprir$ Charging Fan C respective breaker's close spring and trip spring, spring charging moto*s are Motor enerphed when their breaker's close springs are discharged 0.e., right Aat the bror - ' closes). The breaker is not postutated to trip c'ter it closes; therefore, the cio a spring is not required to be recharged for the breaker to perform its safety function. Circuit protection is provided for the control power circuit to preclude adverse effects in the event of a failure of the component.

Relay 62-7 Permissive for This relay provides a permissive for annunciation of en automatic trip of its Annunciation of ssW respective breaker, since the ssW cooling Tower f an is not postulated to trip Cooling Tower Fan C and this relay performs no other control / indication function, this relay is not i

Feeder Breuker Trip required to operate.

Breaker 5216506 ssW Cooling Tower The spring chargir2 motor provides the energy required to compress the l

spring Charging Fan D tespective breaker's close spring and trip spring. Spring charging motors are M uor surgized when their breaker's close springs are discharged (i.e., right after the breaker closes), The breaker is not postulated to trip after it closes; therefore, the close spnng is not required to be recharged for the breaker to perform its design function. Circuit protection is piovided for the c^ntrol power circuit to preclude adverse effects in the event of a failure,0f the component.

Relay 62 8 Perrnissive for This relay provides a permissive for annunci. tion of an automatic trip of its Annunciation of ssW respective breaker, since the Ssw Jooling Tower fan is act postulated to trip Coohng Tower Fan D and this relay performs no other controllindicatiort function, this relay is not Feeder Breaker Trip required to operate.

Brooker 5216104 Diesel Generator Room The spring charging motor provides the energy required to compress the spring Charging ortside Air Fan D respective breaker's close spring and trip spring. The spring charging motor is Motor Feeder Breaker energized when the breaker's close springe are disef %f

• u.e., right after the breaker closesh The breaker is not postulated to ?

• it closes; therefore, l

the close springs are not required to be rechargeo for r s brooker to perform its

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design funution. Circuit protection is provided twr the control power circuit to preclude adverse effects in the event of a failur1 of the component.

Breaker 52-163o4 Enclosure Building Fan B The spring charging motor provides the energy required to compress the Spring Charging respective breaker's close spring and trip spring. The spring charging motor is Motor energized when the breaker's close springs are dischstged U.e., right after the breaker closes). Tho breaker is not postulated to trip after it closes; therefore, the close springs are not required to be recharged for the breaker to perform its design function. Circuit protsetion is provided for the control power circuit t+

preclude adverse effects in the event of a failure of the component.

NRC Question 1 i

The licensee is requested to documert the adequacy of its dedication programs to ensure that these components will perform their required functions.

GGNS Respont to Ouriqal.

The evaluation of the Division I and 11 safety related 125 Vdc systems identified components that have the potential to receive less than the manufacturer's rated minimum voltage during'the system's design basis accident (Table 1). GGNS established a program to demonstrate the adequacy of these components. This program requbs periodic testing of the actualinstalled devices to demonstrate that the components are capable of performing their safety functions. The devices identified are all electromechanical devices including switchgear clom coils and de

. to GNRO 92/00107 Page 8 of 9 contactors, in addition, testing has been performed on switchgear spring charging motors and de solenoids. The components are installed in safety related Class 1E equipment. The qualification of Class 1E equipment provides assurance that the equipment will meet or exceed its perforrnance requirements throughout its installed life.

I In accordance with the guidance provided in IEEE 323 for qualifying Class 't 'quipment, any change to the equipment specification must be evaluated e determine its W on the equipment's cualification. This evaluation is to indicate whether or not re-qualificatior, e assary. Re-qualification is not necessary if the modification is fully justified and dncumad as having no bearing on the validity of the tests or equipment qualification. The evaluation of the offects of the operation of these devices at lower than manufacturer's rated voltage determined that device qualification is not invalidated or the design lifetimes reduced for the following reasons:

i A.

All of the tested devices are intermittently energized for very brief petiods to perform their design function, and the operation of these devices during normal plant operation is only for testing purposes. Therefore, effects such as mechanical wear or thermal aging associated with device energization are insignificant.

B.

All of the tested devices were procured in accordance with IEEE 323. Therefe o, the devices are qualified for the service conditions to which the devices could be exposed. The only electrically induced failure mode for these electromechanical devices is insulation failure.

(Coil winding conductors and device cores are metallic and, as a result, not susceptible to radiation or thermal aging. Therefore, the device cualification needs specific review only to ensure that reduced voltage does not increase the degradation rate for which the device was qualified.)

C.

As discussed in IEEE 323, routine maintenance and housekeeping practices reduce the possibility of degradation of the components due to external contamination.

D.

Device performance varit in due to conductor temperature effects for the tested devices is not significant. This is due to the relatively low resistance temperature coefficient for copper in conjunction with the tested devices being located in areas where temperature swings are accounted for by the available margins (e.g., Switchgear Rooms). Only the contactors associated with the RCIC valves are located in an area where accident conditions for temperature exist.

The test program was performed using a variable DC voltage source to demonstrate the operation of the tested component at a voltage level below the postulated minimum voltage available. This testing was performed by:

1.

connecting a variable de power supply and a multimeter to the circuit.

2.

increasing the output voltage of the variable de power supply until the device operates, 3.

recording the multimeter indicated operating voltage, 4.

repeating steps 2 and 3, and 5.

verifying that the recorded operating voltage was at least 10% below the calculated minimum available voltage.

. to GNRO 92/C0107 Page 9 of 9 The testinD was specified to be performed every 18 months to verify that component degradation has not occurred, although the evaluation of the components' qualification indicates that degradation should not be expected. The method of testing ensures that conservative results are obtained. The test is intended to demonstrate that the component will function at voltage levels i

below the calculated minimum voltage level. The results may not indicate a tretid since the voltage gradient applied during the testing could affect the point of operation due to respunse of the test power supply (a slow rate of increase in test voltage would produce the most accurate response, a fast rate of increase in test voltage would result in a higher voltage level measurement upon completion of the test due to response of the test power supply). The test results, howover, are conservative by demonstrating operation of the component in successive testing below the calculated voltage level.

This testing has been performe 'wice (during RFO4 and RF05) since this condition was identified.

All of the installed components passed both of these tests.

TABLE 4 COMPONENT TESTING l Test Acc ptance Component Manuf acturer's Rated Calculated Minimum Minimum Voltage (vdc) ' Cnteria voltage (Vde) during Design Basis Proble olVisioN I Breaker 152 1508 Close Coit 100 70.1 78 solenoid T81E51 coo 2

108 79.5 88.3 MoV 1E51F045 72F Contactor 88.8 72.5 80.6 MoV 1E51F013 72F Contactor 88.8 78.5 87.3 MoV 1E51F013 72R Contactor 88 8 78.9 87.7 Breaker 152-1503 spring Charging Motor

100 82.1 91.3 Breaker 52-15304 spring Charging Mo*9r *

300 75.8 84.3 Breaker 1 E 215505 spring Charging Motor

100 54.2 60.2

~

Breaker 152-15506 spnng Charomo Moto'

100 54.2 60.2 Breaker 152-1509 spring Charging Motor

100 75.8 84.3 Breaker 152-1509 Close Coit 100 88.4 98.2 Breaker 152-15105 Close Coil 100 87.7 97.5 Breaker 152 15105 Spnng Chargmg Motor

100 75.6 84.1 Break er 152 15106 spring Charging Motor 100 77.7 86.4 Division 11 Breaker 152-1608 Close Coil 100 81.5 90.6 Due to the natu.e of the devices affected (all electromechanical and procured in accordance to IEEE 323) and the margin between the actual minimum device operation voltage and the calculated minimum voltage, this testing provides adequate assurance of the proper operation of this equipment during a Design Basis Accident.

These devices were tested although they are not required to operate at voltages below their manufacturer's minimum voltage.

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