ML20114C364

Forwards Info Re Use of Voltage Regulators.Tech Spec Change Request 88 Clarified Per NRC 831121 Request

ML20114C364
Person / Time
Site:	Oyster Creek
Issue date:	12/05/1983
From:	James Knubel GENERAL PUBLIC UTILITIES CORP.
To:	Crutchfield D Office of Nuclear Reactor Regulation
References
NUDOCS 8501300217
Download: ML20114C364 (9)

Text

.

A l

GPU Nuclear Corporation NUCIMr 100 lnterpace Parkway Parsippany, New Jersey 07054 t

201 263-6500 TELEX 136-482 Writer's Direct Dial Number:

December 5, 1983 Mr. Dennis M. Crutchfield, Chief Operating Reactors Branch #5 Division of Licensing U.S. Nuclear Regulatory Commission Washington, D. C.

20555

Subject:

Oyster Creek Nuclear Generating Station Docket No. 50-219 Technical Specification Change Request No. 88 Response to NRC Request for Information Per our conference call on November 21, 1983, this letter transmits the information requested regarding the use of voltage regulators at Oyster Creek and clarification of the Technical Saecifications. The enclosed information represents a preliminary submittal witch includes some schematics that will facilitate the review of these systems. This information must be reviewed and approved internally and will be formally submitted by the end of this inonth.

Very truly yours, 8501300217 031205 PDR ADOCK 05000219 p

PDR James Knubel

/ Manager, BWR Licensing 1r/0095e cc: Administrator Region I U. S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, Pa.

19406 NRC Resident Inspector Oyster Creek Nuclear Generating Station Forked River, N. J.

08731 g

00 1 I k-GPU Nuclear Corporation is a subsidiary of the General Public Utilities Corporation d

+

8 RESPONSE TO NRC REQUESr FOR INF0lu!ATION

[.

Conservattsm of Analysts A.

Grid Voltage Predictions The grid voltage of 2L4.8 KV was predicted by an analysts which included the following assumptions:

1.

Oyster Creek generator outage.

2.

Southern NJ generation of 553 MW out of a possible 805 MW which has been analyzed and the probability of this 1cvel of generation is 0.26.

This is independent of the other as-sumptions.

3.

The highly 'mprobable loss of a major 230 KV tle line to the west referred to as the Windsor-Lawrence 230 KV line.

The grid voltage level of 214.8 KV does not include nor take credit for the following improvements:

L., Installed voltage' regulators (Automatic'i 10% capab'llity))

2.

Increasing Southern Area generation levels.

3.

Operatton of Load Tap Changer controls on the 230 KV-34.5 KV transformers at Oyster Creek which improves the 34.5 KV voltage proftle. This operation is performed by personnel in the Oyster Creek control room.

4.

Avallability of the 34.5 KV capacitors to improve voltage levets. This action is also performed by control room operators.

5.

Ability to decrease Southern Aron loads on the distributton system. The lowest value-tpat the Oyster Creek grid voltage has evet degraded to i 2L7 V.

0/4 B.

Burns and Roe Voltage Analysis The voltage analysts performed by Burns and Roe assumed a grid voltage level of 214.8 KV as the minimum voltage,cnt the 230 KV system.

The analysts did not take any credit for the voltagel regulators, capacitors,. or load tap. changes on the 230 KV 4

34.5.KV, transformers.- In addttton, there were two other f airly conservative assumpticns utilized in their analysis.

M

j 1.

Bus loading was conservatively asstuned to include all safety loads and normal plant loads. including all Reactor Feed Pumps rt.nning.

It is highly unlikely that all of these loads would be running at the same time.

2.

Actual setting of the new second level (degraded grid) voltage relays ts 3671 volts but the analysts ' included the 1% tolerance of the device and used 3635 volts as the minimum allowabic 4160 volt bus voltage which will insure that all safety related motor starters will have enough voltage to' pick up at the 460 volt level.

C.

Outcome of Analysis UtiLtzing conservattvejassumptLons and'an~ Improbable grid?

Y voltage ^ level,'theionlylquestionab'e plant' equLpment loads wece ]6 f l

i the' fuel: poo1Lf L1ter pumps and,the CR0 feed pumps.

A11' other.

plant safety l loads;were found'to hav_e' acceptable; voltage' levels.-

The fuel foof f Liter pumps are raU at 460 volts. At (-)10% D

~

minimum of 414 volts would be required to safely run these <

pumps. The analysis computed a minimum voltage of 398 volts at the setpoint of the second level voltage relays. This voltage difference would be compensatdd for by automatic operatton of

' the voltage regulators or by manual operation of capacitors and/or load tap changers on the 230 KV-34.5 KV transformers.

~

IPkas also~ stated in' previous subetttals?that;Lthe fuel Fool, 9 Fiiteripump'ifare~noticonside re{to ;b' 1 toportant ;lto" t,eaci:or:7" (.

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~

s ishutdown or cooldown_ and are not required to be; running' con-p

((;

tinuously.1Therefore; e these pissps could be.'off (for exteriledf iperiods.oftime?and'; running'.only;yhenyottagelconditidis?permihme#

d e

A

, a Burns and Roe recommended that the overload heaters be replaced for the Fuel Pool Filter pumps in order to comply with the NEC requirements for overcurrent protection. This replacement was accomplished in 1981 and the new overload heaters protect the pumps f rom thermal damage by providing overcurrent protection as well as some measure of undervoltage protection.

The CRD feed pumps are rated at 480 volts.

At (-)10%, the mini-mum required voltage is 432 volts. The analysis computed a voittge level of 402 volts at the setpoint of the undervoltage (second level) relays.

This voltage dif ference would be com-h pensated;by-'the: automatic: operation ~of7the" voltage / regulators'orp c the]mamia lf operat_1.on of[ the LTC' of on i the; 23,0; KV-34. 5, KV l trans 3 /_

g forme es,and/or; theq34.5, KVEcapacitors.; 3 4

M h

m

Burns and Roe recominended that the motors or motor windings for the CRD feed pumps be replaced with those rated at 440 volts.

This recommendation was not followed and the motors remain rated

. gd

4:*.at 's80 volts.

- [.- --

J tm a The < CRo feed:pumpe

• arecimportanc~ for plantzoperation ' but are' not m c

'needed during!EntsccIdentiand--have not been'taken'cred(t'for'in1 '

f any t sec id ent - anaily s i s'.' Vo l tig e c o si t ii to ns"d u e16g p istEhp olar*

' tion ~hWye^Whinndlysed and no adverse effects on the CRD feed pumps were found (refer to our submittal of April 30, 198L).

The Burns and Roe analysts computed a voltage level of 402 volts at the terminals of the CRD feed pumps during an accident condition without any credit for voltage regulators, capacitors, or LTC's.

Butras'atated previously,- the -CRu feed" pumps 'are'not.

neededrduring the accident" scenario assumidsin theirlanalysis.?"

T 4

-~~.__w.

D.

Conclusion Based on the above information, it is our position that the voltage regulators provide a useful service but do not perfonn a safety funct ton and are not safety grade equipuent. They are merely an added feature which improves voltage levels in much the same manner as the capacitors and the LfC's.

They should not, in our view, have to be included in the Technical Speci-f teatIons as an L.C.O.

II. Overvoltage Conditions f_-

Under mintmum load condit tons and with the maxtmum prodleted grid voltage the computed maximuu MCC voltage is 498 volts.

Thus, even taVtng credit for some voltage drop in the feeder cables, does not guarantee that the 440 volt motors' maximum voltage llmit of 484 volts is not exceeded The difference in the computed maximum voltage level and the allowable maxtmum rating is compensated for autcmatically by the operatton of the voltage regulators. Thdre are, however, other actions that can be taken to ensure that this maximum limit is not exceeded.

First, operators could maintain sufficient load on the g

Startup transformers to prevent 'this limit f rom being exceeded. And 3

second, operators could chan8e the taps on the 230 KV-34.5 KV trans-formers by utilizing the hTC controls, f The control room operators are kept aware of any overvoltage condi-b s

q

< tions by means of overvoltage relays which alarm in the control room

['

kbutdonotperformanytripptngfunction. These relays were in-

/undervoltage relays and they alert the operators to the overvoltage stalled at the same time as the new second level (degraded grid) condttlon so that the above actions can be taken to bring the voltage down to acceptable levels.

%L._

f r.; : :

z tII. : 460 Volt Motor Starter Ratings

~

As~ stated in previous subatttals the following MCC starter voltage criterla apply:

b Normal V'oltage 460 VAC Drop out Voltage 60% of Normal (276 V)

Pickup Voltage _

85% of Normal (391 V)

~

The maxtmum voltage drop in control wiring for any safety related

' starter ctreult is' 3 volts.

Since the motor starters' control transformers;have a 4:1 ratto, 12 volts on the primary of these transformers ts required to account for this control wiring voltage drop. Thus the minimum voltage on the primary side of the control transformers whleh will guaranteo.all starters plek up is 403 volts

+

(391 volts F 12 volts).

Therefore, the Burns and Roe Analysis denonstrates that at the undervoltage relay trip setpoint (including device tolerance) at least 403 volts is available at the substation /MCC levels to guarantee all starters plek up.

^

IV.

LCO' For Safety Bus Tie Breakers Reference Technical Spectf tcation Change Request No. 38 which was submitted August 11, 1980, on page 3.7-1 para. 3. 7 A.5 Bus tie breaker ED or EC is in the open position.

Copy of this Lage is

. attached._'For some reason, this change was not includi3 in.

10sendment No. 55 dated August 13, 1981. Also, attached to thts k.

'N submittat is a simp 1Lfted one line diagram of the OCNGS electrical distributton system which shows breakers EC and ED.

This diagram is \\

actually P tgure 1 f rom the August 1981 EG&G report on the Adequacy L

ot. Station Electric Distribution System Voltages Oyster Creek Nuclear Pouer Station. -

V.

Technical Specificattons ClarificatLons Copies of the following revised ' Technical Specifications are provided to clarify the requested changes in light of other changes which have been incorporated during 'this review cycle.

. /'Jage 4.1-6a ( reference Amendment 63 October 15,-1982)

./Page 4.7-1 (reference Amendments 55 Aug. 13, 1981 and 60 Feb. 3, 1982).

M'Page 4.7-la with March 19, 1981 cover memo Page 3.7-3 (reference Amendment 60 February 3,1982)

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OysterCreek.. Nuclear Power Station ele,trical distribution e

system single-line diagr'am.

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3.1 i J.7 AljXlL I ARY di.I'CTRICAl.180WER Ayp t icob i l ity:

Appl ies h> tho opera fing stul'uc. of tiio inm ilary uluetrical power supply.

Objective:

To assure the operability of the auxillery electrical power supply.

Specification:

A.

The reactor shall not bo anode critical unluss all of the following requirements cro satisfied:

1.

The following buses or panels energized.

a.

4160 volt busen IC and 10 in tho turbino buil ding switcIngour rooni.

b.

460 volt buses I A2, 182, IA21, 1821 vital MCC lA2 and 182 in the reactor building switch ear room:

lA3 and IB3 at the intako 0

structure; l A21 A, 182 t A, I A218, and 18218 and vital NCC 1 Aa2 on 23'6" elevation in the reactor building; IA24 and 1824 at the steck.

c. 200/120 volt panol s 3, 4, 4A, 40, 4C und VACP-1 in,the ruuctor building switchgear rooit.

d.120 voit protection panol 1 and 2 in the cable ;

roO11.

e.125 volt DC distribution conters C and B, and c

panel 0, Panel DC-F, Isolation valve motor control ennter DC-1 and 12SV DC motor control center (E-2.-

f. 24 volt D.C. power panels A and B in the cable roan.

2. One 230 KV line is fully operational and switch gear and both startup tron,stormers are energized to carry power to thu station 4160 volt AC busos and carry power to or away from the plant.

3. An additiona'i source of power consisting of one of the following is in service connected to feed the appropriato plant 4164. V bus or buses a.-

A second 230 KV line fully operational.

b., One 34.5 KV lino f ully operational.

4. The station battarles B and C are available for' normal service and a battery chargor Is In service for occh battery.

5. Bus tle breaker ED and EC ls in the

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open position.

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3.7-3

-Se puebability enslysis in Appendix "L" of the PDSAR was, based on one diesel and shows that even with only one diesel t;ie probability of requiring engineered safety fessures at the same time as the second diesel fails is gutte small.

H is analysis used information on peaking diesels when synekronisation was required which is not the case est Oyster

/

Creek. Anse the daily test of the second diesel when one is temporarily out of service tends to improve the reliability as does the fact that.i c.a....ization is not required.

As indicated la he 18 th the Licensing Application.

these are numerous seurses of diesel Smet thish oss be obtained 4

within 4 to 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and the heating boiler ibel in a 75.000 len tank as the site could also be used.. Since the requirements spoustion of the required anF -_ l; safety features after as assident er ist saft, ion requirement for 14,500 gallons shutdown can be supplied by one dieset somerator the ; _- W t of diesel ibel can operate one diesel at a load of 2640 Bf for 3 days. As ladianted in Amenhent 32 of the Lissestag Appliestiam and including the Security System loads, the lead requirement for the less of offsite power would require 12,410 gallons for a three day supply. Per the case of loss of offsite power plus less-of.

etelsat plus bus esilure 9790 ss11ons would be required der a.

three day supply.

In the case of loss of offsite power plus 1ess-of-costant with both diesel generators starting the load I

requirements (all equipment operating) shown there wou'Ad not

.be three days' supply. However, not all of this load is required for three days and, after evaluation of the conditions,~

leads not required on the diesel will be curtailed. It is e

reasonable to expost that within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> conditions can,be evaluated and the following loads curtailed:

1.

One Core spray Pump 3.

One Core Spray Booster Puey 3.

One.Cantrol Red Drive Pump 4.

One Containment Spray Ptap 5.

One.Eastgency Service Water Pump With these pieces of equipment taken off as a hours after the.

lasident it would require a total eensassysten of 12.840 gallons for a three day supply.

L Raftrescel:

(1) Letter. Ivan R. Finfrock. Jr. to the Otwector of Nuclear Reactor i

j Replations dated April l'4.1978.

I W h n,t NO 80

. - - - - - - - ~ - - - *

• ~, ~

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a a

o.

Instrument Channel

. Check Calibrat7-

'fest Remarks (Applina.toIrtaCalibrtion)+(f(

19 Manual Scram Buttons '

NA

' NA.

1/3 mo,--

20.-

High Temperature Main.

NA Each Refuel-Each refuel-Using heat source' box:

Steamline Tunnel ing outage ing outage -

21.

SEM

' Using built-in calibration equipment 22.

Isolation Condenser High NA 1/3 mo.

1/3 mo.

By application of test pressure Flow 6P (Steam and Water)

23. Turbine Trip Scram NA Every-3 months 24.

Generator Load Rejection NA.

Every Every Scram 3 months 3 months

~

25.

Recirculation Loop Flow NA ~

Each Refuel-NA By application of test pressure ing. Outage 26.

Low Reactor Pressure NA Every Every By application cf test pressure Core Spray Valve 3 months 3 months Permissive 27.

Scram Discharge Volume (Rod Block) a) Water level high NA Each Refuel-Every 3 By varying levei in switch column ing Outage months b) _ Scram trip bypass NA NA' Each refuel-ing outage

28. Loss of Power a) 4.16 KV Emergency e.

Daily 1/18 mos.

1/mo.

Bus Undervoltage (Loss of voltage) b)

4.16 KV Emergency Daily 1/18 mos.

1/mo.

Bus Undervoltage (Degraded Voltage)

• Calibrate prior to startup and. normal shutdown and thereaf ter check 1/s and test 1/wk until no longer required.

Amendment No. 63 w=