ML20041D644

Adequacy of Station Electrical Distribution Sys Voltages, Quad Cities Station,Units 1 & 2, Informal Rept,Revision 1

ML20041D644
Person / Time
Site:	Quad Cities
Issue date:	02/28/1982
From:	Udy A EG&G, INC.
To:	Prevatte R Office of Nuclear Reactor Regulation
References
CON-FIN-A-6429 EGG-EA-5323, NUDOCS 8203080266
Download: ML20041D644 (12)

Text

. .... .._ _ _ .

v.i:. w ,, aer. i i h r< t j A R V ! 9 di' PM ADFQUAU Qi UAINAlifURR ;): ' :P :fM n , .F tY igg 68 voi ' Au s, ouAi; < t t :s s s: A- c, us; . ^% '

pud 7

ans -

Me (ese L a d lse 'jec),,ieaf /ss%ce Quf -

^ ( ""' ^

3Se n~

'q9 4 g A

U.S. Department of Energy >.,O ,

Idaho Operations Of fice + idaho National Engineenng Laboratory I 4g -

I g m

\ -

ed%$I' d _

.r g

b , % % 4 fe-~ ~=%

= "s

_ _ _ _ _ _ L>{l=4, .ge

, }"

tsag s~

1 y,gNq (w .' g w .m_ :.-

Je a: + ,~ n.

-me m.  % t~ .

, 4.

Ni 6M ~

[-- [

-~ y g,4e w

This is an informal report intended for use as a preliminary or working document -

Prepared for the J.S. Nuclear Requlatory Commission -

Under D01 Lont ract No. Dl-AC07-/6:0015/0 FIN No. A6429 h EGnG,a.nc  ;

93080266 820220 .

) RES -

93080266 PDR -

l

l h EScG .. . ,-

FORM EG4G 396

• ~ " "

INTERIM REPORT Accession No.

Report No. EGG-EA-5323, Rev.1 Contract Program or Project

Title:

Selected Operating Reactors Issues Program (III) l5 Subject of this Document Adequacy of Station Electric Distribution System Voltages, Quad Cities Station, Unit Nos. I and 2 Type of Document:

Informal Report Author (s):

A. C. Udy Date of Document:

February 1982 Responsible NRCIDOE Individual and NRCIDOE Office or Division:

R. L. Prevatte, Division of Systems Integration, NRC This document was prepared primarily for preliminary orinternat use. it has not received full review and approval. Since there may be substantive changes, this document should not be considered final.

EG&G Idaho, Inc.

Idaho Falls, Idaho 83415 l

i ,

Prepared for the .

, U.S. Nuclear Regulatory Commission '

t Washington, D.C.

Under DOE Contract No. DE-AC07-761001570 NRC FIN No. A6429 l

INTERIM REPORT l

0196J ADEQUACY OF STATION ELECTRIC DISTRIBUTION SYSTEM VOLTAGES QUAD CITIES STATION, UNIT N05.1 AND 2 Docket Nos. 50-254 and 50-265 February 1982 A. C. Udy Reliability and Statistics Branch Engineering Analysis Division EG&G Idaho, Inc.

9 TAC Nos. 12808 and 12809

ABSTRACT This EG&G Idaho, Inc. report reviews the capacity and the capability of the onsite distribution system at the Quad Cities Station, in conjunction with the offsite power sources, to automatically start and continuously operate all required safety loads.

FOREWORD This report is supplied as part of the Selected Operating Reactors Issues Program (III) being conducted for the U.S. Nuclear Regulatory Commission, Office of Nuclear Reactor Regulation, Division of Operating Reactors, by EG&G Idaho, Inc., Reliability and Statistics Branch.

The U.S. Nuclear Regulatory Commission funded the work under the auth-orization B&R 2019 0106, FIN A6429.

t 1

ii

2

, CONTENTS 1

1.0 INTRODUCTION

.................................................... 1

]

1 2

2.0 DESIGN BASIS CRITERIA ........................................... 1 3.0 S YS TEM DES CR I PT IO N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 4.0 ANALYSIS DESCRIPTION ............................................ 2 4.1 Analysis Conditions ....................................... 2 4.2 An al ys i s R e s ul t s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

, 4.3 An alys is Ver i fi ca ti on . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 i

5.0 EVALUATION ...................................................... 5 1

6.0 CONCLUSION

S ..................................................... 7 7.0 R E F ER EN C E S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 FIGURE

1. Quad Cities Station, Unit One Line Diagram ...................... 3 TABLE

1. Class 1E Equipment Voltage Ratings and i

Wors t Case Load Te rminal Vol tages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

?

iii

, yw ,._ ,-_<y. - -- -_--2 - ----.-e 9

- - - - - + _ - - - -

l ADEQUACY OF STATION ELECTRIC DISTRIBUTION SYSTEM VOLTAGES QUAD CITIES STATION, UNIT NOS. 1 AND 2

1.0 INTRODUCTION

An event at the Arkansas Nuclear One station on September 16, 1978 is described in NRC IE Information Notice No. 79-04. As a result of this event, station conformance to General Design Criteria (GDC) 17 is being questioned at all nuclear power stations. The NRC, in the generic letter of Augujt 8,1979, " Adequacy of Station Electric Distribution Systems Volt-ages,"

required each licensee to confirm, by analysis, the adequacy of the voltage supplied each Class lE load. The letter included 13 specific guidelines to be followed in determining if the voltage is adequate to start and continuously operate the Class lE loads.

I Commonwealth Edison Company (CECO) responded to the N}C letter , for the Quad Cities Station, with letters of November 1, 1979 (which included a report on this subject, written by Sar 3 The Final Safety Analysis Report (FSAR), gent test results submitted on June 11, ,

& Lundy) and December 14, 1979 4

1980 , additional analyses submitted on June 30, 19805 on the original analysis, and a letter of September 14, 1976toan9werconcerns

, complete the information reviewed for this report. Telephone conversations in September 19808 also provided information.

unit inter-tie was submitted Analgsisontheuseofthe 9" ' * * " # " *#

supplemented on April 24, 1981 30 and June 22, 1981.

Based on the information supplied by CECO, this report addresses the capacity and capability of the onsite distribution system of the Quad Cities Station, in conjunction with the offsite power system, to maintain the voltage for the required Class lE equipment within acceptable limits for the worst-case starting and steady-state load conditions.

2. 0 DESIGN BASIS CRITERIA The positions applied in determining the acceptability of the offsite voltage conditions in supplying power to equipment are derived from the following:

1. General Design Criterion 17 (GDC 17), " Electrical Power Systems," of Appendix A, " General Design Criteria for Nuclear Power Plants," of 10 CFR 50

' 2. General Design Criterion 5 (GDC 5), " Sharing of Struc-tures, Systems, and Components," of Appendix A " General Design Criteria for Nuclear Power Plants," of 10 CFR 50

3. General Design Criterion 13 (GDC 13), " Instrumentation and Control," of Appendix A, " General Design Criteria for Nuclear Power Plants," of 10 CFR 50 1 l

4. IEEE Standard 308-1974, " Class 1E Power Systems for Nuclear Power Generating Stations"

5. Staff positions as detailed in a letter sent to the licensee, dated August 8, 1979

6. ANSI C84.1-1977, " Voltage Ratings for Electric Power Systems and Equipment (60 Hz).

jix review positions have been established from the NRC analysis guide-lines and the above-listed documents. These positions are stated in Section 5.

A 3.0 SYSTEM DESCRIPTION Figure 1ofthisreportisasimplifiedgketchoftheunitone-line diagram taken from the Sargent & Lundy report . Figure 1 shows that, for Unit 1, the Class lE 4160V buses 13-1 and 14-1 are normally supplied power from auxiliary buses 13 and 14, respectively. With loss of the unit gener-ator,the from 345kV switchyard.these buses are supplied by the station auxiliary transformer (

Class lE 4160V gus 14-1 can be supplied power from the other unit via a manual connection to Class lE bus 24-1 of Unit 2. This inter-tie can also be used in the other direction to energize bus 24-1 of Unit 2 from the Unit 1 SAT. The Unit 2 distribution system is identified as similar in the FSAR, except for different bus and transformer numbers.

Each 4160V Class lE bus supplies power for one 480V Class lE bus via independent transformers (4055/480V tap). These 480V buses can be connected together without technical specification res Class lE 480V bus has an undervoltage alarm.gictions; however, each CECO supplied the equipment operating ranges identified in Table 1.

Station 125V DC buses supply power for all Class 1E switchgear, except for 480V MCC circuits which use individual control power transformers and contactors.

4.0 ANALYSIS DESCRIPTION 4.1 Analysis Conditions. CECO has determined by load-flow studies that the maximum expected offsite grid voltage is 354kV and the minimum is 333kV. The station auxiliary transformer was used for the analyses supplied.

CECO has analyzed each offsite source to the onsite distribution system '

under extremes of load and offsite voltage conditions to determine the terminal voltages to lE equipment. The worst case Class lE equipment ter-minal voltages occur with the SAT supplying power and under the following

• conditions:

a. CECO also refers to this as a reserve auxiliary transformer (RAT).

b. This connection between Units 1 and 2 is hereafter referred to as an inter-tie in this report.

2

1 l Unit Generator and 345KV Main Transformer Switchyard

/\

ww Unit Auxiliary Station Auxiliary Transformer Transformer qq ,,

TPTT 11(21) ,

12(22) j {'~'A mm g4160V d l 4160V E

l 11(21) 12(22)

~~

' ~~

NC NO NO -

NC T 4160v {F T 4160v r 13(23) 14(24)

]NC

~

To Other

{ NC Unit DG A DG 12j I(2)

[] NC [] NO {] NO []NC 4160V 4160V 13-1(23-1) 14-1(24-1)

[]NC [] N0 []NC 480V Trans. ' d'#

480V Trans.

m m 18(28) U m m 19(29)

] ])

i

~~

~~

[~

~~

NC N0 N0 NC I q_

~

480V 480V l j 18(28) T9Tf9) ___

NOTE: This diagram is for unit 1. The unit 2 class 1E distribution system l

is identical, with bus and equipment numbers shown in parenthesis.

, Figure 1. Quad Cities Station, Unit One Line Diagram.

l 3

TABLE 1 CLASS lE EQUIPMENT VOLTAGE RATINGS AND ANALYZED WORST CASE TERMINAL V0LTAGES

(% of nominal voltage)

Maximum Minimum Rated Anal yzed Rated Analyzed c Nominal Vol tage Steady Equipment (100%) state Transient Motors 4kV Start -- --

75 --

89.9a Operate 110 109.4 90 95.5 b __

460V Start -- --

75 --

83.6c Operate 110 112.6 90 90. 5a ,c __

Starters 480V Pickup -- --

85 --

84.7 Dropout -- --

70 --

84.7 Operate 110 107.9 85 89.8a,c __

Other Equipmentd

a. Load terminal voltage supplied by CECO.

b. This value includes the typical (0.5%) feeder cable voltage drop.

c. This is the lowest voltage that occurs in either unit in the CECO analysis. The inter-tie is used for these voltages. When in addition the intra-unit 480V bus-tie is used, the resultant steady-state voltage at the starters is 86.3%; at the 460V motors-87.0%.

d. Self-regulated motor-genarator sets presently supply power for 120V AC c essential buses. These are scheduled to be replaced with inverter sets that have their own voltage regulation.

e l

l t

4 l

CECO has shown that, by using the inter-tie between the two Quad Cities units, adequate starting and operating voltages are supplied to the Class lE equipment for an accident in one unit and an orderly shutdown and cooldown in the remaining unit (Table 1).

6.0 CONCLUSION

S The voltage analyses submitted by CECO for the Quad Cities station were evaluated in Section 5.0 of this report. It was found that:

1. Voltages within the operating limits of the Class 1E

. equipment are supplied for all projected combinations

i. of plant load and normal offsite power grid conditions; including an accident in one unit and the safe shutdown of the other unit.

2. The test used to verify the analyses shows the analysis to be an accurate representation of the worst case conditions analyzed.

3. CECO has determined that no potential for either a simultanous or consequential loss of both offsite power sources exists.

EG&G Idaho, Inc., is performing a separate review of the undervoltage relay protection at the Quad Cities station. This will evaluate the relay setpoints and time delays to determine that spurious tripping of the Class lE buses will not occur with normal offsite source voltages.

7.0 REFERENCES

1.

NRC letter, William Gammill, to All Power Reactor Licensees (Except Humboldt Bay), " Adequacy of Station Electric Distribution Systems Voltages," August 8,1979.

2. ' CEC'o letter, Robert F. Janecek, to William Gammill, "Adequancy of Station Electric Distribution System Voltages", November 1,1979.

3.-

CECO letter, Robert F. Janecek, to William Gammill, " Adequacy of Sta-tion Electric Distribution System Voltages", December 14, 1979.

4.

CECO letter, Robert F. Janecek, to William Gammill, U.S. NRC, " Adequacy of Station Electric Distribution System Voltages," June _11, 1980.

}

5.. CECO letter, Robert F. Janecek, to T. A. 1ppolito, U. S. NRC, " Adequacy of Station Electric Distribution System Voltages," June 30, 1980.

c 6. CECO letter, Robert F. Janecek, to Darrell G. Eisenhut, U.S. NRC,

, i "Second Level of Undervoltage Protection for 4kV Ons'te Emergency Power Systems," June 26, 1980.

7. CECO letter, G. A. Abrell, to Karl R. Goller, U.S. NRC, "Information Concerning System Voltage Conditions," September 14, 1976.

~

7 i

8. Telecon, A. C. Udy, EG&G Idaho, Inc., to H. Stolt, CECO, September 11, 1980.

9. CECO letter, Robert F. Janecek, to U.S. NRC, Darrell G. Eisenhut,

" Additional Response concerning Adequacy of _ Station Electric Distribu-tion System Voltages," August 18, 1980.

10. CECO letter, Robert F. Janecek to T. A. Ippolito, NRC, " Adequacy of Station Electric Distribution System Voltages," April 24, 1981.

4 11. CECO letter, T. J. Rausch to T. A. Ippolito, NRC, " Response to Request for Additional Information Concerning Adequacy of Station Electric Distribution System Voltages," June 22, 1981. /

t'

12. Telecon, R. Bevan & R. Prevatte, NRC, T. J. Rausch, CECO, and A. Udy, EG&G Idaho, Inc., January 21, 1982.

'l I

i i

L '

8