ML20054M242

Adequacy of Station Electric Distribution Sys Voltages,Big Rock Point Plant, Informal Rept

ML20054M242
Person / Time
Site:	Big Rock Point File:Consumers Energy icon.png
Issue date:	06/30/1982
From:	Udy A EG&G, INC.
To:	NRC
Shared Package
ML20054M240	List: ML20054M239 ML20054M242
References
CON-FIN-A-6429 0207J, 207J, EGG-EA-5891, EGG-EA-5891-DRF, NUDOCS 8207120157
Download: ML20054M242 (8)

Text

EGG-EA-5891 June 1982 ADEQUACY OF STATION ELECTRIC DISTRIBUTION SYSTEM VOLTAGES, BIG ROCK POINT PLANT

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e A. C. Udy U.S. Department of Energy loano Onorat6cos Of fice. Ioano Natie.ines Engineering Let' oratory Z.

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I This is an informal report intended for use as a preliminary or working document J-Prepared for the U.S. Nuclear Regulatory Comission m

Under DOE Contract No. DE-AC07-76ID01570

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FIN No. A6429 E

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1. daho. ent FORM EG&G 398 t.te, 03 til INTERIM REPORT Accession No.

Report No. EGG-EA-5891 Contract Program or Project

Title:

Selected Operating Reactors Issues Program (III)

Subject of this Document:

Adequacy of Station Electric Distribution System Voltages, Big Rock Point Plant Type of Document:

Informal Report Author (s): -

A. C. tidy Date of Document:

June 1982

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t Responsible NRC Individual and NRC Office or Division:

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

l EG&G Idaho. Inc.

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Idaho Falls, Idaho 83415 Prepared for the U.S. Nuclear Regulatory Commission Washington, D.C.

Under DOE Contract No. DE-AC07 761D01570 NRC FIN No.

A6429 INTERIM REPORT M

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ADEQUACY OF STATION ELECTRIC DISTRIBUTION SYSTEM VOLTAGES BIG ROCK POINT PLANT i

June 1982 s

A. C. Udy Reliability and Statistics Branch Engineering Analysis Division EG&G Idaho, Inc.

e Oraft 6-01-82 TAC No.

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CONTENTS 1.0 I N TR O D U CT I O N....................................................

1 2.0 D ES I GN B AS I S CR I T ER I A...........................................

I 3.0 S Y S TE M D ES CR I PT I O N..............................................

2

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4.0 ANALYSIS DESCRIPTION............................................

2 4.1 D e s i gn C h an g e s............................................

2 4.2 An a l ys i s C on d i t i on s.......................................

2 4.3 An a l ys i s Re s u l ts..........................................

4 4.4 An alys i s V eri f i ca t ion.....................................

4 5.0 E VAL U AT I O N......................................................

5 6.0 CO N C L US I O N S.....................................................

6' 7.0 REFERENCES......................................................

6 FIGURE 1.

Bi g Rock Point electrical single-line diagram...................

3 TABLES '

1.

Class lE Equipment Voltage Ratings and Anal yzed Wor st Case Load Terminal Vol tages......................

4 2.

Comparison of Analyzed Voltages and Un de rv ol tage Rel ay Se t po i n ts....................................

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ADEQUACY OF STATION ELECTRIC DISTRIBUTION SYSTEM VOLTAGES BIG ROCK POINT PLANT

1.0 INTRODUCTION

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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 ofAuggst8,1979,"AdequacyofStationElectricDistributionSystemsVolt-ages,"

required each 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 lE loads.

Consumers Power Company (CPCo) responded with letters dated February 19, 1980,2 and August 29, 1980.3 CPCosuppljedfurtherinformation June 14,1978,ghisreviewonMargh 12,1980,9spondenceof requested for 23, 1981.

CPCo corr August 21, 1980, and December were also reviewedfogthisreport. Additignalclarificationsweresubmittedon EG&GIdaho,Inc., report.g1981.

May 4, 1981 and August 2 This information culminated in an CPCo provided additional analysis, and 1982.giedtransformertapsettingchangesinasubmittaldatedMay18, ident

. Based on-the.inf.ormation supplied by CPCo, this report addresses the

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capacity and cap' ability of'the'onsite disttibution system of the 6ig Rock Point Plant, in conjunction with the offsite power system, to maintain the voltage within acceptable limits for required Class lE equipment, for tne 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,"

l of 10 CFR 50.

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2.

General Design Criterion 5 (GDC 5), " Sharing of Structures, Sys-l tems, 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 Con-trol," of Appendix A, " General Design Criteria for Nuclear Power Plants," of 10 CFR 50.

=6 4.

IEEE Standard 308-1974, " Class lE Power Systems for Nuclear Power Generating Stations."

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l 5.0 EVALUATION jix review positions have been established from the NRC analysis guide-and the documents. listed in Section 2.0 of this report. Each lines review position is stated below followed by an evaluation of the licensee submi ttals.

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l 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 lE equipment within the equipment voltage ratings.

CPCo has shown, by analysis, that the Big Rock Point Plant has sufficient capability and capacity for 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.

CPCo has shown, by analysis, that the voltage ratings of the Class lE equipment will not be exceeded.

Position 3--Loss of offsite power to either of the redundant Clas' lE s

distribution systens due to operation of voltage protection relays, must not occur when the offsite power source is within expected voltage limits.

As shown in Table ~ 2, ' voltage relays d111 not cause the loss of the Class lE distribution system when the offsite grid voltage is within expected voltage limits.

Big Rock Point does not have a redundant Class IE distribution system.

TABLE 2.

COMPARIS0N OF ANALYZED V0LTAGES AND UNDERV0L7 AGE RELAY SETP0INTS

(% of nominal voltage) a Minimum Analyzed Relay Setpoint Location / Relays Voltage Time Voltage (Tolerance)

Tinje _ ~~

2400V bus Degraded grid 96.3 continuous 90.1 (+0.5) 10.55s l

(+0.55s)9 480V bus Loss of grid 84.6 5s less than or equal instantan-3 or less to 50 eous a.

Licensee has determined by analysis the minimum bus voltages with the offsite grid at the minimum expected voltage and the worst case plant and Class lE loads.

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2.

CPCo letter, David P. Hoffman, to Director, Nuclear Reactor Regula-tion, NRC, " Adequacy of Station' Electric Distribution Systems Volt-ages," February 9,1980.

3.

CPCo letter, Dav.id P.'Hoffman, to Director, Nuclear Reactor Regula-tion, NRC, " Adequacy of Station Electric Distribution Systems Volt-ages," Augus t 29, 1980.

4 4.

CPCo letter, David P. Hoffman, to Director, Nuclear Reactor Regula-tion, NRC, " Adequacy of Station Electric Distribution Systems Volt-ages," March 23, 1981.

5.

CPCo letter, William S. Skibitsky, to Director, Nuclear Reactor Regulation, NRC, "On-site Emergency Power Sources," June 14, 1978.

6.

CPCo letter, David P. Hoffman, to Director, Nuclear Reactor Regula-tion, NRC, " Degraded Grid Voltage," August 21, 1980.

7.

CPCo letter, David P. Hoffman, to Director, Nuclear Reactor Regula-tion, NRC, " Response to Request for Additional Information Related to the Generic Issue on Onsite Power Systems," December 12, 1980.

8.

CPCo letter, Gregory C. Withrow to Director, Nuclear Rea-tor Regulation, NRC, " Generic Issue--Adequacy of Station Electric Distribution Voltages," May 4,1981.

9.

CPCo letter, David P. Hoffman to Director of Nuclear Reactor Regulation, NRC, ~ " Station. Electric _ Distribution System Voltages, and Degraded Grid Pro'tection," August"26,1981.

10. EG&G Idaho, Inc. Informal Report, " Adequacy of Station Electric Distribution System Voltages, Big Rock Point Plant, Docket No. 50-155, TAC No.12781," A. C. Udy, September 1981, EGG-EA-5433.

11. CPCo Letter, T. C. Bordine to D. M. Crutchfield, NRC, " Station Electric Distribution System Voltages," May 18, 1982.

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