ML20045B281

LER 93-004-00:on 930513,both Trains of CR Ventilation Sys Declared Inoperable Due to Equipment Failure.Exact Cause of Failure Could Not Be Determined.Train B Nuclear Svc Water Sys Flow Balance completed.W/930611 Ltr

ML20045B281
Person / Time
Site:	McGuire
Issue date:	06/11/1993
From:	Mcmeekin T, Pedersen T DUKE POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-93-004-02, LER-93-4-2, NUDOCS 9306170128
Download: ML20045B281 (5)

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a Il I Duke Pourr Company T C Alwittm AlcGuire Nudecr Generation Department Vice President 12700 uners Terry Road (AfC01A) (704)ST5-4800

' Hun: erst die, NC260iM$h5 (704)STS-4809 Ikx

. DUKEPOWER June 11, 1993 U.S. Nuclear Regulatory Commission Document Control Desk l

Washington, D.C. 20555

Subject:

McGuire Nuclear Station Unit 1 Docket No. 50-369 Licensee Event Report 369/93-04 Problem Investigation Process No.: 0-M93-0428 Gentlemen:

Pursuant to 10 CFR 50.73 Sections (a) (1) and (d), attached is Licensee Event Report 369/93-04 concerning' Control Room Ventilation.

This report is being submitted in accordance with 10 CFR 50.73 (a) _ (2)

(1). This event is considered to be of no significance with respect to the health and safety of the public.

Very truly yours, T'.C. McYee 1 TLP/bcb Attachment xc: Mr. S.D. Ebneter INPO Records Center Administrator, Region II Suite-1500 U.S. Nuclear Regulatory Commission 1100 Circle 75 Parkway 101 Marietta St., NW, Suite 2900 Atlanta, GA 30339 Atlanta, GA 30323 l

Mr. Victor Nerses Mr. P.K. Van Doorn U.S. Nuclear Regulatory Commission NRC Resident inspector Office of Nuclear Reactor Regulation McGuire Nuclear Station Washington, D.C. 20555 9306170128 930611 PDR ADOCK 05000369 S r PD_R_

em-- r- -

, LICENSEE EVENT REPORT (LER) f 9

s .-

) FACILITY NAME(1) DOC 7ET NUMBER (2) FACRf3)

' McGuire Nuclear Station, Unit 1 05000 369 1 OF 4 l TITLE (s) Both Trains Of Control Room Ventilation Were Inoperable Resulting In A Technical

. Specification Violation Attributed To Equipment Failure Due To Unknown Cause.

[ WDPP DATE(5) LPR NUMEJ'Df 6) RFPORT DATEf7) CP1HER FACILTTIES TNVOLVEDf e) l YEAR TEAR rJ VISION PONTH DAY YEAR FACT 177Y NAMES !O"7ET NtXEERf S) fMaNTs DAY SEQUENTIAL g NtxnEn NuMrEn McGuire, Unit 2 05000 370 l 05 13 93 93 04 0 06 11 93 05000 oPERATrao 6 w1s mEParer Ts stmarTrED rimscAur m wrourREMENTS or 1ocra f check cma or more or the ro12c-ing)(11)

M E(9) 20.402(b) 20.405(c) 50.73(a)(2)(iv) 73.71(b)

P0wER 0% 20.405(a)(1)(1) 50.36(c)(1) 50.73(a)(2)(v) 75.71(c)

LEVEL (10) 20.405(a)(1)(ii) 50.36(c)(2) 50.73(a)(2)(vii) OTHER (Specify in ,

20.405(a)(1)(iii) X 50.73(a)(2)(1) 50.73(a)(2)(viii)(A) Abstract below and in Text) 20.405(a)(1)[1v) 50.73(a)(2)(ii) 50.73(a)(2)(viii)(B) 20.40$(a)(1)(v) 50.73(a)(2)(iii) 50.73(mi'I;(x)

LICENSEE anrrACT mR THIS LLRf 12 )

I mAME TrmnoNe Nunnsa Terry L. Pedersen, Manager, Safety Review Group AmEA mDE 704 875-4487 CCMPLPTE ONE LINK Fold LACH COMPONDfT FAILifRE DESCRIBED IN TilS }tEloRT(13)

ODMPONTNT MANLTACTURER REPORTABLE CAUSE SYSTD4 CCEPONENT MANUFACT" JEER REPORTABLE CAUSE SYSTEM TO NPRDS TO NPRDS NO I

EXPECTED MONTH DAY YEAR )

SUPPLTFJ'NTAL REPOIfT EXPECTED { 14 )

SUBMISSION YES (If yes, cortplete DCTECTED SUBMISSION LATE) X i N3 EATE(15)

ABSTRACT (Limit to 1400 spaces, i.e. approximately fifteen single-space typewritten lines (16)

On May 13, 1993, at 1140, Operations personnel declared Train 'B' of the Control Room Ventilation (VC) system inoperable. This was done in accordance with PT/1/A/4403/08, Nuclear Service Water (RN) Train IB Flow Balance. At 1255, Train 'A' Chilled Water (YC) chiller for the VC system tripped due to a High Bearing Temperature alarm. At this time, both trains of t the VC/YC system were inoperable requiring entry into Technical Specification (TS) 3.0.3.

Immediate steps were taken to accelerate the completion of the RN Flow Balance and return the Train 'B' chiller to service. At 1314, the Train 'B' chiller was started and TS 3.0.3 was exited. Emergency Work Order 93034579 was also issued to troubleshoot the problem with the Train 'A' chiller. The investigation into the problem with the Train 'A' chiller revealed a f aulty temperature sensor cor' tact in the chiller motor module. The module was replaced and the chiller was returned to service at 2255. Unit I was in Mode 6 (Refueling) at 0% power and Unit 2 was in Mode 1 (Power Operations) at 100% power at the time of this event. This '

i event is assigned a cause of Equipment Failure / Malfunction due to an unknown cause. There are no further actions planned.

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION r

FACILITY MAME(1). DOCKrF NUMBER (2) LER NUMBER (6) PAGE(3)

• YEAR SEQUENTIAL REVISION wment Noami McGuire Nuclear Station, Unit 1 05000 369 93 04 .O 2 or 4 5

EVALUATION: i

Background

The Control Area Heating, Ventilation, and Air Conditioning (VC) system [EIIS:VI) and Chilled Water (YC) system [EIIS*KM) combine to form one system designed to maintain.the '!

environment in the Control Room [EIIS:NA), Control Room Area, and Switchgear [EIIS SWGR) ,

Rooms within acceptable temperature limits for safe occupation by personnel performing f maintenance and equipment operation. The system is also designed to maintain the Control Room in a habitable condition during and following post accident shutdown. The system is -

dasigned as an Engineered Safety Features'(ESF) system with absolute and carbon filtration in the outside air intakes and with equipment redundancies for use as conditions require. .

i Technical Specification (TS) 3.7.6 includes requirements that in Mode 1 (Power Operation),

Mode 2 (Startup), Mode 3 (Hot Standby), and Mode 4 (Hot Shutdown), with one Train of the i VC/YC system inoperable, the inoperable Train must be restored to operable status within .j seven days or be in at least Hot Standby within the next six hours, and in Cold Shutdown within the next thirty hours.

TS 3.0.3 states that when a Limiting Condition for Operation is not met, except as l provided in the associated action requirements, within one hour action shall be initiated'  !

to place the unit in a mode in which the specification does not apply by placing it, as ,

applicable, in: 'i

a. At least Hot Standby within the next six hours, i

b. At least Hot Shutdown within the following six hours, and l

c. At least Cold shutdown within the subsequent twenty-four hours. l t

JD escription of Event 7 l

On'May 13, 1993, Operations personnel prepared to perform the Unit 1, Train 'B', Nuclear Sarvice Water (RN) system flow balance in accordance with procedure PT/1/A/4403/08, RN

~

Train IB Flow Balance. Unit I was in an outage at the time and Train 'B' IU4 system was  !

was inoperable for maintenance activities. This procedure required that the Control Room Ventilation / Chilled Water system (VC/YC) chiller [EIIS:CHU) be aligned to Unit 1. -The  :

alignment of Unit 1 RN to the Train 'B' chiller, in combination with power being supplied.  ;

from Unit 2, forced the Train 'B' VC/YC chiller to be declared inoperable.

r LICENSEE EVENT REPORT (LER) TEXT CONTINUATION j TACILITY KAME (1) DOCKET NUMBER (2) LER NUMBER (5) FACE (3)

. YEAR SEQUENTIAL REVISION f

NUMBER NUMBER McGuire Nuclear Station, Unit 1 05000 369 93 04 0 3 or 4 i i

At 1255, while Train 'B' was inoperable, Train 'A' VC/YC chiller tripped due to a High  !

i Bearing Temperature alarm [EIIS:TA), thereby leaving both trains of the VC/YC system inoperable requiring entry into TS 3.0.3. Personnel performing the Unit 1 Train 'B' RN  ;

flow balance were instructed to complete their test and return the system to operations as soon as possible. Emergency Work Order 93034579 was also written to troubleshoot the ,

problem with the Train 'A' chiller. At 1308, preparations for starting the Train 'B'  !

VC/YC chiller had begun. At 1314, alignment of Train 'B' RN to Unit 2 was completed and TS 3.0.3 was exited. Temperature within the Control Room was monitored and procedure AP/0/A/5500/39, Control Room High Temperature, was referenced in the event temperature rose above 80 degrees F. Actual temperatures were not recorded; however, the Shift Supervisor stated that temperatures never exceeded 75 degrees F.

Investigation into the trouble on the Train 'A' chiller, by Instrument and Electrical personnel in conjunction with Mechanical Maintenance Ventilation personnel, revealed a set j of open contacts in the motor [EIIS:MO) run circuit. These contacts monitored bearing and l winding temperature and were normally closed. After checking the motor temperature and associated controls, it was concluded that the temperature sensor contact in the motor ,

module was bad. A replacement module was obtained from the Catawba Nuclear Station on the Duke system. The module was not available at McGuire due to the fact that it was not a o part that commonly fails. The module was replaced and Train 'A' of the VC/YC system was returned to service at 2255, on May 13, 1993.

conclusion This event is assigned a cause of Equipment Failure / Malfunction because the Motor Module f failed in service. The exact cause of the failure could not be determined. There was no indication of an electrical surge and there was no work being done in the proximity of the i equipment or related circuits. There are no further actions planned as a result of this  !

event.  !

i A review of the Operating Experience Program (OEP) for the twenty-four months prior to this event revealed no events involving failed Motor Modules.

i This event is not Nuclear Plant Reliability Data System (NPRDS) reportable.

There were no personnel injuries, radiation overexposures, or uncontrolled releases of radioactive material resulting from this event.

i 6'

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION FAC11Irr RAME(1) DOCKET NUMBER [2) LER WUMBER(6) PACE (3) 'l l

TEAR SEQUENTIAL REVISION NUMBER NUMBER ,

McGuire Nuclear Station, Unit 1 05000 369 93 04 0 4 or _4 f B

OORRECTIVE ACTIONS:

.l T==madiate: 1) Unit 1, Train 'B' RN Flow Balance was completed, and the Train 'B' VC/YC system was returned to service.

Subsequent: 1) Emergency Work Order 93034579 was generated to troubleshoot the Train  !

'A' VC/YC chiller. .

I Plenned: 1) None .;

SAFETY ANALYSIS:

i The design requirements of the VC system are to supply filtered air at a controlled  !

temperature and humidity and to pressurize the Control Room to 0.125 inches w.g. to I r

prevent in leakage of unfiltered air. A positive pressure of 0.05 inches w.g. is ,

considered sufficient to prevent in leakage in excess of 10 CFM, which is the assumed  ;

leakage value used for radiation dose calculations in chapter 15 of the FSAR.

The VC i l

system helps ensure radiation doses to the Control Room personnel remain below 10CFR50, j GDC-19 limits. Also, the Control Room is required to be maintained below 90. degrees F, j with specific action steps to be taken if temperatures exceed 80 degrees F. l

^i i

During this event, both trains of VC/YC were out of service for approximately 19 minutes. I The temperatures in the Control Room were monitored and at no time exceeded 75 degrees. j In the event the Control Room became uninhabitable, self contained breathing apparatuses  ;

(SCBA's) are provided and could be employed. At no time was there a situation'were the VC

. system would have been required to maintain the habitability;of the Control Room.

The health and safety of the public and plant personnel were not affected as a resalt of this event. j I

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