ML17258A357

Final Evaluation of SEP Topic VI-7.C.1, Independence of Redundant Onsite Power Sys,Re Ginna Nuclear Station.

ML17258A357
Person / Time
Site:	Ginna
Issue date:	11/30/1981
From:	Mays S, Vanderbeek R EG&G, INC.
To:
Shared Package
ML17258A356	List: ML17258A357
References
CON-FIN-A-6425, TASK-06-07.C1, TASK-6-7.C1, TASK-RR EGG-EA-5641, NUDOCS 8112030320
Download: ML17258A357 (11)

Text

0 EGG-EA-5641 NOVEMBER 1981 SYSTEMATIC EVALUATION PROGRAM, TOPIC VI-7.C.1,

.INDEPENDENCE OF REDUNDANT ONSITE POWER SYSTEMS, R. E. GINNA NUCLEAR STATION S. E. Mays Revised by R. VanderBeek Prepared for the U.S. Regulatory Commission Under DOE Contract No. DE-AC07-76ID01570 FIN Ho. A6425 8112030320 811i127 PDR ADDCK 08000244 P

f PDR

t olus r(iSG 398 (Hev 11 19)

INTERIM REPORT Accession No.

Report No. EGG-EA-5'641 Contract Program or Project

Title:

Electrical, Instrumentation, and Control Systems Support for the Systematic Evaluation Program (III)

Subject of this Document:

Systematic Evaluation Program, Topic VI-7.C.l, Independence of Redundant Onsite Power Systems, R. E. Gi nna Nuclear Station Type of Document:

Informal Report Author(s):

S. E. trays Pevised by R. VanderBeek Date of Document:

November 1981 Responsible NRC Individual and NRC Oflice or Division:

Ray P. Scholl, Jr., Oivision of Licensing This document was prepared primarily for preliminary or internal use. It has not received full review and approval. Since there may be substantive changes, this document should not be considered final.

EG8 G Idaho, Inc.

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

Under DOE Contract No. OE-AC07-761D01570 NRC FIN No. A6425 INTERIM REPORT

0094 J SYSTE(luTIC EVALUATION PROGRAH TOPIC V1-7.C.1 INDEPENDENCE OF REDUNDANT ONSITE POl~ER SYSTEMS R. E. GINNA NUCLEAR STATION Docket No. 50-244 November 1981 S. E. Hays Revised by R. Vanderbeek EGEG Idaho, Inc.

11-5-81

ABSTRACT This SEP Technical Evaluation, for the R. E. Ginna Nuclear Station, reviews the electrical independence between redundant standby (onsite) power sources and their distribution systems.

FOREWARD This report is supplied as part of the "Electrical, Instrumentation, and Control Systems Support for the Systematic Evaluation Program ( II) being conducted for the U.S. Nuclear Regulatory Commission, Office of Nuclear Reactor Regulation, Division of Licensing by EGSG Idaho, Inc.,

Reliability 8 Statistics Branch.

The U.S. Nuclear Regulatory Commission funded the work under the authorization B8R 20-10-02-05, FIN A6425-1.

I "CONTENTS

1.0 INTRODUCTION

2.0 CRITERIA ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

I 2.1 AC Suppl leS ............ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

l.

1 2' DC Suppl les ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

3.0 DISCUSSION AND EVALUATION 3.1 AC Suppl les 2 3.2 DC Suppl 1 eS ~ ~ ~ ~ ~ ~ ~ ~ 2 4 o0 SU/ 1HARY o ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

5.0 REFERENCES

YSTENATIC EVALUATION PROGRAM TOPIC V1-7.C. 1 INDEPENDENCE OF REDUNDANT ONSITE, POWER SYSTEMS FINAL DRAFT R. E. GINNA NUCLEAR STATION

1.0 INTRODUCTION

The objective of this review is to determine if the onsite electrical power systems (AC and DC) are in compliance with current licensing criteria for electrical independence between redundant standby (onsite) power sources and their distribution systems.

General Design Criterion 17 requires that the onsite electrical power supplies and their onsite distribution systems shall have sufficient inde-pendence to perform their safety function assuming a single fai lure.

Regulatory Guide 1.6, "Independence Between Redundant Standby (Onsite)

Power Sources and Between Their Distribution Systems," and IEEE Stan-dard 308-1974, "IEEE Standard Criteria for Nuclear Power Generating Sta-tions" provide a basis acceptable to the NAC staff for meeting GDC 17 in regards to electr ical independence of onsite power systems.

2.0 CRITERIA 2.1 AC Supplies. Regulatory Guide 1.6 Section D.4 states that when operating from standby sources, redundant load groups and redundant standby sources should be independent of each other at least to the following extent.

The standby source of one load group should not be automatically paralleled with the standby source of another load group under accident conditions i

2. No provisions should exist for automatically trans-ferring one load group to another load group or loads between redundant power sources

3. If means exist for manually connecting redundant load groups together, at least one interlock should be provided to prevent an operator error that would parallel their standby power sources.~

2.2 DC Supplies. As stated in Regulatory Guide 1.6, Section 0.3, each d-c load group should be energized by a battery and battery charger.

The battery-charger combination should have no automatic connection to any other redundant d-c load group.

0 3.0 DISCUSSION AND EV UATION 3.1 AC Supplies Discussion. The Ginna onsite emergency AC power system consists of .

two redundant diesel-generator power trains. Diesel generator lA (DGlA) supplies 480 V buses 14 and 18 while diesel generator 1B (DG1B) supplies buses 16 and 17.

Hanual means'xist to tie buses 17 and 18 through a tie breaker and to tie buses 14 and 16 through a tie breaker. The control circuit for each breaker provides interlocks such that the breaker cannot be shut if either DG is closed on either bus or if the normal feeders to the bus are closea.

Additionally, if the tie breakers are closed, they will trip open upon restoration of normal power, DG closing on the bus, or any safety injection signal.

f<eans exist to power safety injection pump SI-1C from either bus 14 or

16. The control circuit for the breaker from each bus is designed such that shutting of one breaker prevents shutting the other breaker so that paralleling the redundant OGs is prevented.

Instrument buses lA, 1B, 1C, and 1D are capable of being supplied by multiple sources. Each bus is supplied by a pair of mechanically inter-locked breakers such that paralleling of redundant sources is prevented.

Evaluation. The redundant onsite AC power trains have no automatic transfers of loads and/or load groups. The manual transfer of load groups or manual interconnection of emergency buses have the required interlocks to prevent inadvertent paralleling of redundant sources. Therefore, the onsite emergency AC system is in compliance with current licensing criteria for independence of onsite power systems.

3.2 OC Systems Discussion. Ginna Nuclear Station has two redundant battery and charger trains to supply 125 V DC emergency loads. Each train consists of a battery, a 75-amp charger, .and a 150-amp charger.

tleans exist to.interconnect both trains by manually shutting a tie breaker. This breaker is padlocked open and the key is maintained by the shift foreman'urrent operating procedures require removal of the feeder fuse one of the buses feeding the tie breaker prior to closing the tie breaker fromm. However, no interlocks exist to prevent closure of the tie breaker if the feeder fuse has not been removed. This would allow par-alleling of the redundant DC trains'utomatic transfer of 125 V DC load groups from train A to 8 (or vice versa) occurs in seven locations. Control power for 480 V switchgear on buses 14, 16, 17, and 18, DGlA control panel, OG1B control panel, and the rod drive MG set control panel automatically transfer to the redundant train on a loss of power from the normal source. Each load will automati-cally transfer hack to the normal supply when it is regained.

Evaluations The V DC system has one manual tie between redundant f f the other. Although administrative controls are provided to prevent par-alleling redundant trains via the tie breaker, no physical or electrical interlocks exist to prevent parallel operation of the two trains. There-fore, the 125 V DC system is not in compliance with Regulatory Guide 1.6 Section D.4.C for current licensing criteria with respect to independence of onsite power systems.

4 .0 SUN'"1AR Y The review of docketed information and plant electrical drawings indi-cate that the Ginna Nuclear Station onsite AC redundant power sources and distribution system meet the current licensing criteria for independence of onsite power systems. The 125 V OC system has seven automatically trans-ferred loads and one manual tie breaker which are not in compliance with current criteria for independence of onsite power systems.

5.0 REFERENCES

1. General Design Criterion 17, "Electrical Power System," of Appendix A, "General Design Criteria of Nuclear Powe~ Plants," to 10 CFR Part 50, "Domestic Licensing of Production and Utilization Facilities."

2. "Independence Between Redundant Standby (Onsite) Power Sources and Between Their Distribution Systems," Regulatory Guiae 1.6.

3. Rochester Gas and Electric Corp. letter (white) to NRC (niemann) dated Ap)' 1 18, 1979.

4. RGEE Corp. drawings 10905-59, 62, 63, 74, and 75.

5. RGEE Corp. drawings 21489-269, 33013-652 and 33013-756.

I