ML20003G156

Adequacy of Station Electric Distribution Sys Voltages, Informal Rept

ML20003G156
Person / Time
Site:	Crystal River
Issue date:	03/31/1981
From:	Udy A EG&G IDAHO, INC., EG&G, INC.
To:	Shemanski P Office of Nuclear Reactor Regulation
Shared Package
ML20003G153	List: ML20003G156
References
CON-FIN-A-6429 EGG-EA-5338, NUDOCS 8104280394
Download: ML20003G156 (8)

Text

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EGG-EA-5338 March 1981 O

ADEQUACY OF STATION ELECTRIC DISTRIBUTION SYSTEM l-VOLTAGES, CRYSTAL RIVER UNIT 3, DOCKET NO. 50-302, TAC NO. 12743

. 1 A. C. Udy l

U.S. Department of Energy ldaho Operations Office

• Idaho National Engineering Laboratory

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This is an informal report intended for use as a preliminary or working document Prepared for the U. S. Nuclear Regulatory Consnission Under DOE Contract No. DE-AC07-76ID01570 FIN No. A6429 y EGzG,a.n.

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vom nonsee imes.11 F19 INTERIM REPORT Accession No.

Report No. EGG-EA-5338 Contract Program or Project

Title:

Electrical, Instrumentation and Control System Support Subject of this Document:

Adequacy of Station Electric Distribution System Voltages, Crystal River Unit 3, Docket No. 50-302, TAC No. 12743 Type of Document:

Informal Report Author (s):

A. C. Udy D:t3 cf Document:

March 1981 Responsible NRC Individual and NRC Office or Division:

Paul C. Shemanski, Division of Licensing This document was prepared primarily for prelim:sary or internal 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 Prepared for the U.S. Nuclear Regulatory Commission Washington, D.C.

Under DOE Contract No. DE-AC07 76tD01570 NRC FIN No. A6420 INTERIM REPORT

o 0032J ADEQUACY OF STATION ELECTRIC DISTRIBUTION SYSTEM VOLTAGES CRYSTAL RIVER UNIT 3 Docket No. 50-302 March 198r-A. C. Udy Reliability and Statistics Branch Engineering Analysis Division EG&G Idaho, Inc.

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TAC No. 12743

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CONTENTS 1,9 INIRODUCTION ...................................................... 1 2.0 DES IGN B AS IS CRITE RIA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 3.0 SYSTEM DESCRIPTION ................. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 4.0 ANALYS IS DES CRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 4.1 Design / Operation Changes ..................................... 2 4.2 Analysis Conditions .......................................... 2 4.3 Analysis Results ............................................. 5 4.4 Analysis Verification ........................................ 5 5.0 EVALUATION ........................................................ 5

6.0 CONCLUSION

S ....................................................... 6

7.0 REFERENCES

........................................................ 6 FIGURE

1. Crystal River Unit 3 one-line diagram ............................. 3 TABLE

1. Class 1E Equipment Voltage Ratings and Analyzed Worst Case Load Terminal Voltages ........................ 4 e

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ADEQUACY OF STATION ELECTRIC DISTRIBUTION SYSTEM VOLTAGES CRYSTAL RIVER UNIT 3

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 August 8,1979, " Adequacy of Station Electric Distribution Systems Volt-ages,"1 required eacn licensee to confirm, by analysis, the adequacy of the voltage at the class lE loads. This letter included 13 specific guide-lines to be followed in determining if the load terminal voltage is adequate to start and continuously operate the class 1E loads.

Florida Power Corporation (FPC) responded to the NRC letter 1 with a letter of April 3, 1980.2 The Final Safety Analysis Report and the FPC response to questions regarding Reference 2, dated December 22, 1980,3 were also reviewed for this report. A telephone call on January 5, 198I,4 clarified portions of the Reference 3 response.

Based on the information supplied by FPC, this report addresses the capacity and capability of the onsite distribution system of Crystal River Unit 3, in conjuaction with the offsite power system, to maintain the volt-age for the required class IE equipment within acceptable limits for the worst-case starting and load conditions.

2.0 DESIGN BASIS CRITERIA The positions applied in determining the acceptability of the offsite voltage conditions in supplying power to the class lE 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.

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

l 5. Staff positions as detailed in a letter sent to the licensee, dated August 8, 1979.1 i

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3A 4160V 4160V DG WW UNIT !/2 DG 38 SUT T y BUSES 1B & 23 d 3A

> BUSES 1A & 2A N0 NC h 3B NO 3A 4160V 4160V NC CLASS lE N CLASS lE

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3B 3A 480V 480V CLASS 1E CLASS 1E CRYSTAL RIVER d THESE 4160V BUSES ARE IN UNIT 3 FOSSIL FUELED UNITS 1 AND 2.

ONE LINE DIAGRAM 2. UNITS 1 AND 2 OUTPUT FICURE 1 CONNECTED TO 230 KV

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l 4.3 Analysis Result. Table 1 shows the projected worst case class lE

equipment terminal voltages.

4.4 Analysis Verification. FPC has proposed to record bus voltages on the plant auxiliary and class lE buses while Crystal River Unit 3 is operating.

i l These recorded voltages would be compared to calculated voltages.

5.0 EVALUATION Six review positions have been established from the NRC analysis guide-linesl and the documents listed in Section 2.0 of this report. Each review position is stated below followed by an evaluation of the, licensee submittals. Tne evaluations are based on completion of the design change described in Section 4.1.

Position 1-With the minimum expected offsite grid voltage and maximum load condition, each offsite source and distribution system connection combination must be capable of starting and of continuously operating all class IE equipment within the equipment voltage ratings.  ;

, FPC has shown, by analysis, that Crystal River Unit 3 has sufficient capability and capacity for starting and continuously operating the class lE loads within the equipment voltage ratings (Table 1). ,

Position 2-With the maximum expected offsite grid voltage and minimum load condition, each offsite source and distribution system connection combination must be capable of continuously operating the required class lE

! equipment without exceeding the equipment voltage ratings.

FPC has shown, by analysis, that the voltage ratings of the class 1E equipment will not be exceeded.

Position 3-Loss of offsite power to either of the redundant class lE distribution systems due to operation of voltage protection relays, must not occur when the offsite power source is within expected voltage limits.

EG&G Idaho, Inc., will verify, in a separate report, that the require-ments of this position are satisfied (TAC No.10017).

Position 4-The NRC letterl requires that test results verify the j

accuracy of the voltage analyses supplied.

FPC has proposed a test 3 to verify tne accuracy of the submitted analysis. This proposed test is acceptable if the test values can be shown to accurately show feeder and transformer voltage drops. Further, this test should verify that the feeder cable voltage drops are negligible as assumed (see footnote a of Table 1).

Position 5--No event or condition should result in the simultaneous or consequential loss of both required circuits from the offsite power network to the onsite distribution system (GDC 17).

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4. Telecon, A. C. Udy, EG&G Idaho,'Inc., and K. Baker, FPC, January 5, 1981.

5. Allen-Bradley letter, van Smith & Co., Tampa District Office, to ."C, Att: Gary Castleberry, " Crystal River Unit #3," December 3, 1980 J-I i

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