ML19331C203

Forwards Addl Info Re Grid Undervoltage Protection Mods,In Response to NRC 800616 Ltr.Includes List of Assumptions Utilized in Reanalysis.Forwards Proposed Tech Specs

ML19331C203
Person / Time
Site:	Oyster Creek
Issue date:	08/11/1980
From:	Finfrock I JERSEY CENTRAL POWER & LIGHT CO.
To:	Office of Nuclear Reactor Regulation
Shared Package
ML19331C204	List: ML19331C203 ML19331C205
References
TASK-08-01.A, TASK-RR EAGB-80-383, NUDOCS 8008140334
Download: ML19331C203 (14)

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Y Jersey Central Power & Light Company

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p-q L- (f Madison Avenue at Punch Bowl Road Mornstown, New Jersey 07960 (201)455-8200 GGB-80-383 August 11, 1980 Director Guclear Eeactor hegulation U.d. Nuclear Regulatory Comission

..asnington, D. C. 20555

Subject:

Cyster Creek Nuclear Generating Station Cocnet No. 50-219 Grid Undervoltage Protection By letters dated September 25, 1979 crd Novemcer 1, 1979 Jersey Central Power & Light subnittcd to tne IGC proposed design ::xxlifications in response to the NRC letter of June 3,1977, ard an analysis of station electric distribution system voltages in response to tne IEC letter of August 8,1979, respectively.

By letter dated June 16, 1980, it was requested tnat JCP&L supply additional information in regard to tne previous cuanittals.

The attacnments to tnis letter provide tne additional information requested. In order to facilitate review, Attacnment 1 presents tne NRC request, as per the June 16 letter, with the JCP&L response imediately fallowing. Attacnment II is a list of the assumptions utilized in tne reanalysis performcd in response to the request and Attacnment III is a copy of tne Tecnnical Specification Change Eequest, cuanitted under separate cover, in response to items 5 & 6 of the June 16 letter.

If you snould nave any further questions please contact hr. James Knucel at (201) 455-6753.

Very truly yours, 58W e .

Ivan R. Finfroc Jr.

Vice Presiden s 0 Ogl$0 Jersey Central Power & Light Company is a Member of the General Pubhc Utikties System l

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RESPONSES TO NRC RE00EST FOR ADDITIONAL INFORMATION Item 1: In Reference 2, the licensee took credit for motors of -15% voltage rating whereas there are some class IE motors of -10% voltage

. rating. The licensee will provide justification for using-15% as representative rating.

Response: We have examined our files for each of the safety related pumps at Oyster Creek to determine the allowable voltages. Table 1 is a sunnary of this investigation. As shown on this table, complete informa+3cn was not available for the Core Spray Booster, Reactor Building Closed Cooling Water, and the Service Water Pumps. Based on the data for ail the other large motors on the buses, it has been assumed that these motors are capable of continuous operation with 10% voltage, and starting with 80% of rated voltage.

Item 2: Existing gaps and discrepancies in various tables of Reference 1 shall be corrected as discussed and agreed.

Response:* The various tables presented in the JCP&L letter of November 1, 1979, were based on the existing electrical distribution system at that time. Since then several changes have been made as follows:

(1 ) New ITE solid state undervoltage relays have been installed on buses & 1D with a setpoint of 3666V. The new solid state undervoltage relays have associated time delay relays to bypass tripping of the main breakers for 10 seconds to ailow for large motors to accelerate.

(2) Solid State overvoltage relays have been installed on buses

! A & 18 alarm on an overvoltage condition.

(3 .1 The taps or. ~ne transformers for U.S.S 1 A3 and 183 have been changed from position #1 to position a2.

Due to the revised conditions as de:eribed above, new tables containing voltages for all safet) related buses and equipment have been prepared. Any blanks on these tables (2,3, and 4) have an associated note which clearly explains why no value is given.

Instead of giving all bus and equipment voltages at a particular grid voltage, as cone in the previous studies, al l values are given with the associated 416)V bus at its minimum trip point of 3635V. S;nce the solid st ate undervoltage rel ays will trip these buses at any voltage below 2335V, the values given in Table 2, 3, and 4, are the lowest voltages these buses and equipment wl'l see when the buses are f ed from the of f site sources. In addition, since this setpoint is based on the lowest voltage at which any saf ety related equiment can be

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shown to operate, these undervoltage relays ensure protection of all. safety related equipment under all conditions.

Due to dif ferent loading on each, Buses 1C and 10 will reach their setpoints at dif f erent associated grid voltages, as follows:

Start-up Transformers:

(With all safety loads & normal plant loads includirt all Reactor Feed Pumps running)-

Bus IC. 214.8KV Bus 10 216.3KV Auxiliary Transformer:

(With all normal plant loads including all Reactor Feed Pumps operating)

Bus IC 212.9KV Bus 10 218.3KV As shown on Tables 2 & 3, the minimum operating voltage for all safety related motors is at or above 90% of its rated voltage and thus acceptable. The one exception to this is the Fuel Pool Filter Pump. In addition, all motors are within their required starting voltage requirements as shown on Table 1. The only excentions to this are the CRD Feed Pumps, Core Spray Booster Pumps, Service Water Pumps and the Liquid Poison Pumps. These are all within 1% of the required starting voltage. This is considered acceptable due to. al l the conservative assumptions used in this analysis. For example, if brake horsepowers were used instead of nameplate values for all motors the terminal voltages for these particular motcrs would rise much more than 1,.

Item 3: Equipment terminal voltages shall be provided for the case of starting the largest non-lE motor when all safety loads are operating with other auxiliary loads energizoc.

Response: All the values given on Tables 2 and 3 for the Start-Up Transformers are with all normal plant loads running as well as al l LOCA loads. The only exception to this is the Reactor i Recirculating Water Pumps which have an ES trip signal on a LOCA. Although the Reactor Feed pumps will trip on low suction af ter a LOCA, our analysis has not taker. credit for this since there is no direct ES trip. The Reactor Feed Pumps, '

as shown on Table 1, require 85% of rated voltage for starting.

Thus, once the Reactor Feed Pumps are tripped following a LOCA,

1. a minimum grid voltage of 228KV would be required to start one

. of these pumps with all other normal plant loads and all LOCA loads still operating.

m At this grid voltage, and starting a Reactor Feed Pump, the lowest the 4160V buses would drop to is 3387 V or 81.3% of l nominal. This short duration voltage dip would have ao ef fect on any safety-related equipmer.t, since it is still much higher tnan any coil drop out or motor stall voltage. Once a Reactor Feed Pump accelerates, the bus and equiment voltages will be higher than those given in Tables 2, 3, & 4. This is.because the values in these Tables are at lower grid voltage and with all three Reactor Feed Pumps running.

Item 4: Statenent shall be provided about the qualification of all class

!E equipment of lower than 480 V rating for the voltages under all conditions of operations being analyzed.

Response:" Table 4 provides the values for voltages at all safety related 120V panels with the 480V MCC's at their minimum voltage.

The minimum required voltage was assumed to be 103.5V, per Attachment #11. As shown on the Table, the only panel with less than 103.5V is Panel 3. By changing the tap on the transformer (IT3) feeding Panel 3, the voltage rises from 101.7V to 104.4V which is acceptable.

Item 5

Since each startup transformer is incapable of assuming loads

' from both trains whereas, a tie is possible between the two trains, the licensee will include a Limiting Condition of Operation in the technical specifications that would prohibit closing the tie during operation.

Response: The Limiting Condition of Operation referred to above has been incorporated in Technical Specification Change Request No. 88 which has been submitted to the NRC under separate cover. A copy of this change request is attached to facilitate the review of this submittal.

Item 6: Draft technical specifications shall be subnitted for our review and will include items indicated in Reference 1 and requirements listed in various tables in our letter of June 3,1977.

Response: Technical Specification Change Request No. 88 (copy attached) has been subnitted under separate cover. This change request addresses those items referred to above.

I tem 7: Tests to assure the validity of analysis results in Reference 2 shal l be performed as discussed. Test method was explained to the licensee and the licensee agreed to subnit the results for our review.

Response: In order to verify the computer analysis, a test was conducted at the Oyster Creek plant. Using the existing grid voltage at the time of the test, a computer run was made to predict voltage levels at the 4160, 480, and 120 voi t level. These predicted values were conpared to actual readings taken at the Oyster Creek Station. Table 5 presents a comparison of the actual voltage

4 readings with the computer precicted values, and shows that the predicted values are within 1 % of the actual readings which verifier that the model accuratel y reflects existing conditions at the Oyster Creek plant.

NOTE:

• The v ltage drop for all safety relatec buses anc pumps was deiermir.?d by using an approved Burns & Roe computer program, ELO110. The voltage crop for all safety related valve feeder cables wag determined as e(plained in the October,1979 study.

( At' chec to JCP&L letter dated Novemoer 1,1979). In accition, the voltage drop for the.120Y level was detennined in a similar manner.

The assunptions made for this study are listed on Attachment #11.

Although assumptions, tney. are all firmly based on experience, testing, specification requirements, industry standards, or manuf acturer's guarantee. In addition, all assumptions were made in line with the intent of making this a worst case analysis.

A change from the previous study is that the 34.5 KV grid was not assumed to be an infinite bus, and thus the study included the 230/34.5 KV transformers. Inclucing these transformers in the study results in more accurate results.

AS a result of this change and the tap changes indicated in the . item 2 response, the minimum 41 60 bus voltage at whicn a minimum of 403V can be shown to exist at the MCO's for all buses on both Auxiliary and Start-Up Transformers has changed from 3630V to 3635V. This requires a change in .'he setpoint of the undervoltage relays from the 3666 voit setting specified in Enclosure 1 of the JCP&L letter of September 25, 1979, to a new setting of 3671 volts. Furthermore, this study also indicates tnat the tap on transformer IT3 feeding panel 3 should be changed to the 456 voit tap to assure greater than 103.5 volts at the panel .

The above changes will be accomplished as plant conditions permit; however, it should be noted that these changes are very minor (tenths of a percent in ef f ect) and censider-ing the conservatism applied in the analysis, the existing conditens are not deemed to present any saf ety concerns.

The fuel pool filter pumps are usec to circulate .ater through the fuel pool cool ing and f iltration system.

These pumps are not considered to be important to reactor shutdown or cooicown and are not requriec to be run continuously. The pumps could be off for extended periods of time and run only when voltage concitions permit.

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~Fheet 1 cf 1 TA3LE 1

- SUM *G.RY OF MOTOR VOLTAGE DATA COMPILED FROM LISTED SPEC RATED RUN START EQUIP. SPEC. #. VOLT VOLT VOLT SWGR. lA, lE Reactor Feec PP. 2299-13 4000 NA 85%

1A, 1B, 1C SWGR. 1C Core Spray 1A (1) 21A-5404 4000 NA 80%-

Core Spray 1C 21A-5404 4000 NA 80%

- Emerg. S.W.1-1 2299-43 4000 (+10 ) , (-15 ) 75-80%

Emerg. S.W.1-2 2299-43 4000 (+10 ) , (-15) 75-80%

SNGR. 1D Core Spray 1B '(1) 21A-5(14 4000 NA 80%

Core Spray 1D 21A-5404 4000 NA 80%

Emerg. S.W.1-3 2299-43 4000 (+10 ) , (-15) 75-80%

Emerg. S.W.1-4 2299-43 4000 (+10 ) , (-15) 75-80%

U . S . S . lA2 (TAP-3 ) -

Cont. Spray 1-1 2299-40 440 (+10 ) , (-15 ) 75-80%

Cont. Spray 1-2 2299-40' 440 (+10 ) , (-15 ) 75-80%

CRD Feed 8A (1) 21A-5351 NA NA 85%

C.S. BSTR. 3A C.S. BSTR. 3C R.B.CLSD.CLG.1-1 2299-24 .440 NA NA U.S.S.182(TAP-3)

Cont. Spray 1-3 2299-40 440 (+10 ) , (-15 ) 75-80%

Cont. Spray 1-4 2299-40 440 (+10 ) , (-15 ) 75-80%

CRD Feed 8B (1) 21A-5351 NA NA 85%

C.S. ESTR. 3B - - -

C.S. ESTR. 3D R.S.CLSD.CLG.1-2 2299-24 440 NA NA U.S.S. lA3(TAP-1; Service Wtr. 1-1 2299-22 440 NA NA U.S.S. lE3(TAP-1) service wtr. 2299-22 440 NA NA MCC 1A21 Liq. Poison PP. (1) 21A-5442 440 NA 85%

Fuel. Pool Fltr. (1) 21A-5430 460 +10% NA MCC 1B21 Liq. Poison PP. (11 21A-5442 440 NA 85%

Fuel Pool Fitr. (11 21A-5430 460 +10% NA (1) GE SPEC.

NA DATA NOT AVAILAELE

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BUS START-UP XFMRS. (TAP.#4) AUXILIARY XFMR. (TAP #5) {

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& k LOAD RUNNING V STARTING V RUNNING V STARTING V SWGR. 1C 3635 3559* 3636 3535*

Core Spray 1A 3632 3542 Note 3 Note 3 k Core Spray 1C 3627 3525 Note 3 Note 3 f Emerg. S.W.1-1 3631 3553 3631 3515 g Emerg. S.W.1-2 3631 3553 3631 3.515 fj SWGR. 1D ~3635 3559* 3636 3534* E Core Spray 1B 3627 3525 Note 3 Note 3 3631 3542 '

Note 3 Note 3 {;l.

r, Core Spray 1D Emerg. S.W.1-3 3630 3553 3631 3513 Emerg. S.W.1-4 3630 3553 3631 3513 . :i '

kt U . S . S . lA2 (TAP-3) 403 374* 409 379*

Cont. Spray 1-1 400 353 Note 3 Note 3 g Cont. Spray 1-2 400 353 Note 3 Note 3 CRD Feed 8A 402 370 408 372  !;

C.S. BSTR. 3A 399 350 Note 3 Note 3 '

C.S. BSTR. 3C 399 350 Note 3 Note 3 R.B.CLSD.CLG.1-1 402 372 408 375 U.S.S. 1B2(TAP-3) 403 375* 409 379*

CONT. SPRAY 1-3 397 335 Note 3 Note 3 Cont. Spray 1-4 397 335 Note 3 Note 3 CRD Fand 8B 402 369  ? 407 371 C.S. BSTR. 3B 399 345 i Note 3 Note 3 C.S. BSTR. 3D 399 345 Note 3 Note 3 i R.B.CLSD.CLG.1-2 401 365 405 368 U.S.S. lA3 (TAP-2) 407 355* 406 351 -

Service wtr. 1-1 406 351 405 347 U.S.S. 13 3 (TAP-2 ) 407 355* 406 350*

Service Wtr. 1-2 406 351 I 405 346 5

• LOWEST BUS VOLTAGE DUE TO ANY MOTOR STARTING WHEN BUS IS AT FULL LOAD

1. All values are with all other LOCA loads running as well '

as all normal plant loads including all Reactor Feed Pumps.

2. All values are with all normal plant loads including L't Reactor Feed Pumps running.

3. Values not given since these pumps are only used during LOCA, when all buses are on Start-up Transformers.

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Sheet 1 of 1 TABLE'3 BUS START-UP XFMRS. (TAP # '4 ) I AUXILIARY XFMR.-(TAP #5)

LOAD RUNNING V STARTING V RUNNING V' STARTING V' MCC-1A21 Liq.Pois.PP. 396 371 . 401 ._ 376 Fuel Pool Fltr. 398 379 i 405 384 V-20-21 -399 395 l 406 402 V-20-3 402 402 l 409 408 V-20-33 402 402

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409 408 V-20-12 399 395 j 406 402 V-21-7 402- 402 4

_409 408 V-21-9 402 402 , 409 - 408' V-21-11 403 402 i 409 . 408 V-21-17 403 -

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409 ' 409 V-21-18 403- 403  ; 409 409 V-3-88 403 402  ! 409 408 V-20-27 402 401 '

408 407 MCC 1B21 Liq. Pois.PP. 394 371 400 376 Fuel Pool Fltr.- 399 380 403 380 V-5-106 403 403 409 409 V-20-4 403 403  ! 409 408 V-20-18 & 40 399 395 -405 401 V-20-26 402 401 408 407 V-5-147 & 148 403 403 409 408 V-20-32 403 402 408 408' CoresprayFillPP. 401 397 406 402

-V-21-1 402 401 408 407 V-21-3 402 401 408 407 V-21-5 403 403 409 408 V-21-13 403 403 409 408 V-21-15 403- 403 -

409 409 V-3-87 403 402 408 '408 V-5-166 & 167 403 403 , 409 408 l

MCC 1AB2

. v-20-41 395 395 405 401 V-14-30 397 391 i 403 397 V-14-32 397 391 -

403 V-14-36 397 396 389 '

402 395 V-14-37 396 389 402 l

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Sheet 1.of 1 TABLE 4 120 VOLT POWER DISTRIUTION PANELS -

90% CONNECTED PANEL. VOLTAGE AT EQUIP. RATED-DESIGNATION 120V LEVEL VOLTAGE NOTES NO. 3 101.7(104.4) 103.5 1 VACP 106.5 103.5 .

'NO. 4 103.8 103.5 NO. 4A 103.8 103.5 NO. 4B 103.8 103.5 NO. 4C 103.8 103.5 No. 1 104.4 103.5 NO. 2 104.4 103.5. ,

NOTE:

1. Voltage in parenthesis corresponds to the recommended tap setting (Tap #5, 456V) on the IT-3 transformer primary.

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' TABLE 5 VERIFICATION OF' COMPUTER RESULTS-SYSTEM COMPUTED VALUES MEASURED VALUES  % VARIATION 230 KV Grid 0 0.C. Set 0 242 KV for Computer runs 242 KV N/A 4160 V SWGRIC 4303 V 4257 V + 1%

4160 V SWGR.lD 4163 V 4172 V -0.2%

480 V USSIA2- 483 V 487 V -0.8%

480 V USSIA3 480 V 475.2 V + 1%

480 V USSlB2 468 V 473 V - 1%

480 V USSlB3 465 V 462.9 V +0.4%

120 V IP-4 120.5 V 120.2 V '+0.25%

120 V IP-4A 120.5 V 120.3 V +0.17%

120 V IP-4B 120.5 V 120.3 V +0.17%

120 V IP-4C 120.5 V 120.0 V +0.42%

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1. According to General Electric technical-publication  :

No. GET-3101C, which was in effect at the time of MCC j fabrication, the following starter voltage criteria i apply:

Normal Voltage 460 VAC i

. Drop Out Voltage- 60% of normal -(276 V)

Pick Up Voltage 85% of normal (391 V)

Testing of safety related starters at Oyster Creek showed that Size 1 and Size 2 starters will pick up below this value, but 85% was used for this study since this is the value guaranteed by General Electric.

2. The maximum voltage drop in control wiring for any safety-related starter circuit is 3 V. Since the motor starters' control transformers have a 4:1 ratio,-12 V on the primary of these transformers is required to accoun gt'or this control wiring voltage drop. Thus the minimum voltage on the primary side of.the control transformers which will guarantee all starters'~ pick up is '403 V (391 V (from #1 above) +12 V).

3. The longest time required for any large motor at Oyster Creek to accelerate to running speed with rated voltage at its terminals is 7 seconds.

4. Where vendor information for motors was not tvailable, the following values were used:

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Efficiency . 9 Running pf .85 Starting pf .2 Lock Rotor / Full Load Current 6.5 Brake HP Nameplate HP

5. ES signals trip the Reactor Recirculation Pumps.

6. The minimum voltage required at the 120V level is 103 . 5v . This is based on the instruments being rated at'll5V & with a +10% voltage tolerance. This is the limiting voltage since relays and solenoids have a

minimum voltage requirement of 102V based on a 120V )

rating with a -15% tolerance.

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