ML20046B560

LER 92-004-01:on 920730,RWCU Sys Isolated During Substation E7 de-energization Due to Personnel Error.Preparation of Project Plan for Development of Electrical Load List Using Plant Staff Resources underway.W/930730 Ltr

ML20046B560
Person / Time
Site:	Brunswick
Issue date:	07/30/1993
From:	Hinnant C, Tabor S CAROLINA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
BSEP-93-0121, BSEP-93-121, LER-92-004, LER-92-4, NUDOCS 9308050159
Download: ML20046B560 (5)

Text

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Carolina Power & Light Company ESGN#mmeilmiluuslEmmanums Brunswick Nuclear Plant P. O. Box 10429 Southport, N.C. 28461-0429 JUL 301993 FILE: B09-13510C 10CFR50.73 SERIAL: BSEP-93-0121 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk I Washington, D. C. 20555 BRUNSWICK NUCLEAR PLANT UNIT 2 DOCKET NO. 50-324 LICENSE NO. DRP-62 ..

LICENSEE EVENT REPORT 2-92-004 Surolement One Gentlemen:

In accordance with Title 10 of the Code of' Federal Regulations, the enclosed Licensee Event Report is submitted. This report fulfills the requirement for a written report within thirty (30) days of a reportable occurrence and is submitted in accordance with the format set forth in NUREG-1022, September 1983.

Very truly yours, C. S. Hinnant, Director Site Operations Brunswick Nuclear Plant SFT/

Enclosure cc: Mr. S. D. Ebneter Mr. P. D. Milano BSEP NRC Resident Office i

i 031115 9308050159 930730 j .

PDR ADOCK 05000324 @M  !-

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NRC FORM 366 U.S. NUCLEAR REGULATORV COMMISSIOM APPROVED OMB NO. 3150-0104 i (5/92)

• EXPIRES: 5/31/95

. EST IM ATED BURDEN PER RE SPONSE TD COMPLY WIT H T HIS INFORM A T ION COLLE CTfDN REQUEST: 50.0 HRS. F OP WARD LICENSEE EVENT REPORT (LER) COMMENTS REaARD,ua ,UnDtN EST, MATE TO THE ,N,ORM,1,0N AND RECORDS M ANAGEMENT BRANCH tMNEiB 7714). U.S. NUCLEAR REGULATORY COMMISSION W ASHINGTDN, DC20555 0001, AND TO THE FAPERWORK REDUCTION PROJECT (3150-0104). OFFICE OF MANAGEMENT AND BUDGET. WASHINGTON, DC 20503.

FACIUTY NAME 11) DOCKET NUMBER 12) PAGE 131 Brunswick Steam Electric Plant, Unit 2 05000324 1 of 4 i

TITLE 14!

Reactor Water Cleanup System Isolation During E7 Substation De-energization 1 EVENT DATE (5) LER NUMBER (6) REPORT DATE (7) OTHER FACILITIES INVOLVED (8) t MONTH DAY YEA 9 YEAR M ONT H DAY YE AR NUMBER N9MPER 05000 07 001 07 30 93 FACitfTY NAME DOCKET NUMBER 30 92 92 05000 +

THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR 6: (Check one or rnore of the following)(11)

OPERATING 4

MODE (M 20 402(b) 20 405tc) X 50.73faH2Hiv) 73 71(b)

POWER O

LEVF L (10) 20 405!aH1Hn) 50 36fcH2) 50.73(aH2Hvii) OTHER r

20 405(aH1 Heii) 50.73(aH2Hil 50.73(a:f 2HviiiMA) (Specify in Abstract 20 405(aH1Hevt 50 73(aH2Hnl 50 73(aH2HviiiHBI and Text)  ;

20 405taH1Hv) 50 73(aH2Hiid 50.73(aH2Hz)

LICENSEE CONTACT FOR THIS LER (12) ,

NAME TELEPHONE NUMEER Steve F. Tabor, Regulatory Compliance Specialist (919) 457-2178 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13) >

C A USE SYSTEM COMPONE N T M ANUF ACTURE R CAUSE SYSTE M COMPONENT M ANUF ACTURER SUPPLEMENTAL REPORT EXPECTED (14) M NTH DAY YEAR EXPECTED g g SUBMtSSION ve v n. comsme EXPECTED SUbMISEION DATE) DATE (15) i ABSTRACT (Umit to

• 400 spaces, i e. approwsmately fifteen single space typewritten knes) (161 On July 30, 1992, at approximately 0450 hours0.00521 days <br />0.125 hours <br />7.440476e-4 weeks <br />1.71225e-4 months <br />, both units were in Cold Shutdown and preparations were being made to de-energize the 480 volt Substation E7 to support planned ,

maintenance. The research performed to identify the loads supplied by E7 did not  ;

identify that loss of the bus would result in de-energization of the Reactor Water Cleanup (RWCU) heat exchanger outlet temperature switch, 2-G31-TS-N008. Consequently, upon de-energization of E7, 2-G31-TS-N008 de-energized which, by design, resulted in generation ot~ an isolation signal and subsequent closure of the RWCU Outboard Isolation Valve, 2-G31-F004. Following the event t he 2-G31-TS-N008 was re-energized using the designed alternate power source, the 2-G31-F004 reopened, and the RWCU system realigned for normal operation. Corrective actions to prevent recurrence include incorporation of lessons learned from a previous similar event as reported in LER 1-92-013, revision of ,

appropriate procedures to incorporate a list of currently known loads affected by emergency bus de-energization, and the development of an electrical load list including plant effects which will be incorporated into a formally approved operating procedure.

As an interim measure, appropriate management (i.e., Manager of Operations, Technical Support, or Nuclear Engineering Department) will review and approve planned emergency bus outages including the method used to determine the consequences of bus de-energization.  :

The safety significance was minimal since both units are in Cold Shutdown and the plant systems responded as designed. Similar events have been reported in LERs 1-88-01, 1 02, 1-89-04, 1-89-15, 1-90-01, 1-90-27, 1-91-12, 1-92-13, and 2-89-16. ,

Additional information is provided in the Supplemental Information and Corrective Action I sections, i i

i

NRC FORM~ 366A U. S. NUCLEAR REGULATORY COMMISSION APPROVED OMB NO. 3150-0104 I

. (5/92) EMPLAES: 5/31/95 ESTIMATED BURDEN PER DESPONSE TO COMPLY W!TH THIS INFORM ATION COLLECTION RE QUE ST: 50.n HRS, FORWARD LICENSEE EVENT REPORT (LER) COMuEm REGARo=G euRoEN tsTiMATc TO THE mrORuAT:ON ANo RECORDS MANAGEME NT BRANCH IMNBB 3714), U.S. NUCLE AR TEXT CONTINUATION REGULATORY COMMISSION, WASHINGTON, DC 20555 0001, AND TO l

THE PAPERWORK REDUCTION PROJECT (3150-0104). OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 205C3.

F ACILITY NAME {1) DOCKET NUMBER (2) LER NUMBER (6) PAGE (3)

SEQUENTIAL REVISION

, , g 2 of 4 Brunswick Steam Electric Plant 05000324 Un.i t 2 92 001 TEXT lif enore space is required, use additionalNRC form 366A's! (17)

TITLE Reactor Water Cleanup System Isolation During E7 Substation De-energization INITIAL CDNDITIONS On July 30, 1992, with both units in Cold Shutdown, Unit 2 shif t operations personnel were preparing to de-energize the 480 volt Bus Substation E7 to support replacement of the substation's feeder breaker, 2-E7-A21-52.

EVENT NARRATIVE Following review of the research package by the Operations Shift Supervisor and alignment of affected system power sources, E7 was de-energized at approximately 0450 hours0.00521 days <br />0.125 hours <br />7.440476e-4 weeks <br />1.71225e-4 months <br /> in accordance with Operations Procedure, OP-50.1. Subsequently, Operations  ;

personnel observed the unexpected closure of the RWOU Outboard Isolation Valve, 2-G31- ,

F004. Investigation into the cause of the RWCU isolation revealed that an E7 supplied distribution panel, 2-2AB-RX, had not been transferred to its alternate power source prior to de-energizing the bus. Distribution panel 2-2AB-RX circuit #5 supplies logic power to the RWCU heat exchanger outlet temperature module 2-G31-TS-N008. Per design, de-energization of 2-G31-TS-N008 results in closure of the RMCU Outboard Isolation Valve, 2-G31-F004. The research package used to support the E7 bus outage did not indicate that the transfer of the 2-2AB-RX power supply to the alternate source was a requirement prior to de-energizing E7. Consequently, following de-energization of E7, an unplanned RWCU isolation occurred. -

Following the closure of the 2-G31-F004, Operations transferred the 2-2AB-RX to its '

alternate power source, opened the valve, and realigned the RWCU system for normal operation. Following main breaker replacement, bus E7 was re-energized at approximately 0609 hours0.00705 days <br />0.169 hours <br />0.00101 weeks <br />2.317245e-4 months <br />.

CAUSE OF EVENT The personnel de-energizing the E7 bus did not perf orm an adequate review of the potential effects prior to proceeding with the activity. The following factors contributed to the l event:

The task of de-energizing an emergency bus is compler The research package >

consisted of several hundred pages of information and, although the package contained summaries of bus loads, the summaries did not identify the plant effects resulting from de-energization of those loads.  ;

Existing emergency bus de-energizing procedures do not provide specific details enabling the user to recognize the extent of the impact and the potential for component actuation resulting from bus de-energization.

A controlled comprehensive plant emergency load list does not exist as an approved procedure.

NRC FORM 366A U. S. NUCLEAR REGULATORY COMMISSION l APFHOtfED OMB No. 3150-0104

• (S/92) EXPlREE: 5/31/95 E SilM ATED BURDEN ,RR RE SPONSE TO COMPLY W:TH 1H!!

INFORMATION COLLECllON REQUEST: 50.0

• IRS. FORW ARD LICENSEE EVENT REPORT (LER) muE NTs REGAROm eURarN E n um TO THE iv0RM ATiON ,.:e TEXT CONTINUATION RE CORDS M ANAGEME NT PRANCH (MNBB 7714L U S. NUCLEAR REGULATORY COMMISCfCN, W ASHINGTON, DC 20555-0001. AND TO THE PAPERWORK REDUL7 TON PROJECT (3150-0104). OFFICE OF MANAGEMENT AND BUDGIT, W ASHINGTON, DC 20503, FACluTY NAME 0) DOCKET NUMBER (21 LER NUMDER (G) PAGE 131 SE QUE NnAL RE V?SION

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Brunswick Steam Electric Plant """*'" """

05000324 Unit 2 92 001 TEXT Uf more space is required, use addir;onalNRC form 366A's) 0 7)

CORRECTIVE ACTIONS The following completed and planned corrective actions are considered adequate for preventing recurrence:

Statements (notes, cautions, etc.) have been incorporated intc OP-50.1 to capture the lessons learned from a previous similar event reported in LER 1-92-013.

Special procedures were developed to incorporate lists of currently known loads affected by emergency bus de-energization.

Operations will develop an electrical load list reference procedure to identify 4KV bus loads including the 1 cads supplied by each breaker on the associated 120 VAC panels. This procedure will identify the plant effects resulting from de- '

energization of individual components including the affected Technical Specifications.

FAFETY ASSESSMENT The safety significance was minimal since both units are in Cold Shutdown and the plant systems responded as designed.

FREVIOUS SIMILAR EVENTS Similar events have been reported in LERs 1-88-01, 1-88-02, 1-89-04, 1-89-15, 1-90-01, 1-90-27, 1 91-12, 1-92-13, and 2-89-16.

EIIS COMPONENT IDENTIFICATION System /Cemnonent EIIS Code RWCU CE 2-G31-TS-NCDB CE/TS 2-G31-F004 CE/ISV Bus EU Bus, Substation SSBU

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NRC FORM 366A U. S. NUCLEAR REGULATORY COMMISSION APPROVED OMB NO. 3150-0104

• EX.PIRES: 5/31/95 (5]S2).

E STIM ATED BURDEN PER RE SPONSE TO COMPLY WITH T Hl$

, g gn g INFORM ATtON COLLECTION RE QUEST: 50.0 HRS. FORW ARD Lob i i COMMENTS REGARDING BURDEN ESTIMATE TO THE INFORMATION AND TEXT CONTINUATION RE CORDS MANAGEMENT BRANCH (MNisB 7714), U.S. NUCLE AR REGUL ATORY COMMIS$10N, WASHINGTON. DC 20556-0001. AND TO T HE PAPERWORK REDUCTION PROJE CT (3150-0104L OFFICE OF MANAGEMENT AND BUDGET. WASHINGTON, DC 20503.

FACILITY NAME (O DOCKET NUMBER (2) LER NUMBER 16) PAGE (3I SEQUENTIAL REVISf0N g Brunswick Steam Electric Plant * * '" ""*'"

05000324 Unit 2 92 001

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TEKT tif more space is requerd, use additionalNRC Form 366A's) (17)

SUPPLEMENTAL INFORMATION SECTION Revision 0 of this LER committed to the development of an electrical load list including plant effects. On October 1, 1992, the Euclear Engineering Department (NED) presented a plan to management to control scope and provide the methodology for the implementation of an electrical load list. Management elected to complete the list development using plant .

staff resources because of the benefits of retaining the expertise and knowledge gained '

during list develcpment.

Preparation of the project plan for the development of the load list using a project team is underway. Project team management will be provided by Operations Staff management.

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