ML20006A867

LER 89-042-01:on 891209,inadvertent Actuation of Control Room Emergency Ventilation Sys Occurred.Caused by Keying of Hand Held Radio in Vicinity of Chlorine Monitors by Technician.Technician counseled.W/900122 Ltr

ML20006A867
Person / Time
Site:	Arkansas Nuclear
Issue date:	01/22/1990
From:	Ewing E, Millar D ARKANSAS POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
1CAN019015, 1CAN19015, LER-89-042, LER-89-42, NUDOCS 9001300378
Download: ML20006A867 (4)

Text

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1 Arknaas q3 Fow r & Light C;mpany .

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. *tle nock Arkansas 72203 tl 601377 3525 T. G. Campbell VN.e Preswlent Nuclear January 22, 1990 ICAN#19515 U.S. Nuclear Regulatory Commission Document Control Desk Mail Station PI-137 Washington, D.C. 20555 4

SUBJECT:

Arkansas Nuclear One - Unit 1 Docket No. 50-313 License No. DPR-51 Licensee Event Report 50-313/89-042-01 Gentlemen:

Attached is the supplemental report lerning an inadvertent actuation of

. the Control Room Emergency Ventil System initiated by a trip of the.

chlorine monitors caused by a per , error.

Very truly yours, 1

i.

l E. C. Ewing

! General Manager, j Technical Support j and Assessment l ECE/DM/abw l- attachment I cc: Regional Administrator -

l Region IV l U.S. Nuclear Regulatory Commission Gil Ryan Plaza Drive, Suite 1000 Arlington,-TX 76011 INPO Records. Center 1500 circle-75 Parkway Atlanta, GA 30339-3064 9001300378 900122 An Entergy Company L PDR ADOCK 05000313 j

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firm 1D62.01 A NRC Form 366 U.S. Nuclear Regulatory Comeission (9-83) Approved DMB No. 3150-0104 Expires 8/31/85 LICENSEE EVENT REP 0RT (L E R)

FACILITY NAME (1) Arkansas Nuclear One, Unit One IDOCKET MJMfdR (2) lPAGE (3) 10151010101 3I Il 311t0FID13 llTLE (4) Inadvertent Actuation of the Control Room Emergency Ventilation System Initiated by a Trip of the Chlorine Monitors Caused by a Personnel Error

_ EVENT OATE (5) I LER NUMBER (6) i REPORT DATE (7) l OTHER FACILITIES INVOLVED (8) i i i i 15equentiali IRevisioni i l l l Monthi Day lYear lYear I i Number 1 l Number IMonth! Day l Year 1 Facility Names 100cket Number (s)

{ i l l l l l l l l l ANO. Unit 2 10151010101 31 61 8 11 21 01 91 81 91 81 91--I 0 1 41 2 I--I O l 1 1 01 Il 21 21 91 0! 10151010101 1 I OPERATING l lTH15 REPORT 15 $UBMITTED PUR5UANT TO THE REQUIREMENTS OF 10 CFR 6:

MODE (9) 1 Ni (Check one or more of the followino) (11)

POWER l 1,_,1 20.402(b) l__l 20.405(c) l_El 50.73(a)(2)(iv) l__l 73.71(b)

LEVEll l__l 20.405(a)(1)(1) l__l 50.36(c)(1) l__l 50.73(a)(2)(v) l__l 73.71(c)

(10) 10f0f01 1 20.405(a)(1)(11) l__l 50.36(c)(2) 1 _l 50.73(a)(2)(vii) l__l Other (Specify in I._.1 20.405(a)(1)(iii) l__l 50.73(a)(2)(1) l__l 50.73(a)(2)(v111)(A)) Abstract below and l__t 20.405(a)(1)(iv) l__l 50.73(a)(2)(ii) l__l 50.73(a)(2)(v111)(B)! in Text, NRC Form l l 20.405(a)(1)(v) 1 I 50.73(a)(2)(iii) I I 50.73(a)(2)(x) l 366A)

LICENSEE CONTACT FOR THIS LER (12)

Name l Telephone Number l Area l Dana Miller Nuclear Safety and Licensing Specialist (Code i 1510111916l41-13111010 COMPLETE ONE LINE FOR EACH CDMPONENT FAILURE DESCRIBED IN THIS REPORT (13) i l i IReportablel i 1 l 1 lReportablel CauselSysteel Component lManufacturerl to NPRD$ 1 lCauselSysteel Component IManufacturert to NPROS l l 1 l l l l l l l l l l 1 I I I I l l l t l l l t l 1 1 1 I I l t i i l i l i I l i i l l l l i I I I I I 1 l l l 1 I I l 1 I I I i l i l i l l SUPPLEMENT REPORT EXPECTED (14) l EXPECTE0 l Month! Day lYear

~

, 1 SUBMISSION l l l l l Yes (If yes. complete Expected Submission Date) lKl No l DATE (15) l I I I I 1 ABSTRACT (Limit to 1400 spaces, i.e'.. approximately fifteen single-space typewritten lines) (16) s On December 9,1989 at approximately 2004 hours0.0232 days <br />0.557 hours <br />0.00331 weeks <br />7.62522e-4 months <br />, an inadvertent actuation of the Control Room Emergency ventilation System (CREVS) occurred. The CREVS actuation was caused by the Arkansas Nuclear One. Unit Two chlorine monitors tripoing. A hand held radio was keyed in the vicinity of the monitors causing the monitors to trip and initiate the actuation of the CREVS. The system actuated as designed. After determination that the actuation was spurious, the chlorine monitors were reset and the ventilation I

system was returned to normal. Since no actual high chlorine concentration existed, and because the CREVS actuated as designed, there was no safety' significance related to this event. The individual who keyed the hand held radio in the vicinity of the chlorine monitors has been counselled regarding the use of radios in the restricted area. As a result of previous inadvertent CREVS actuations, several system enhancements have been completed. Additionally, an engineering evaluation of the system design was previously initiated to determine if additional corrective actions are necessary. This event is being reported pursuant to 10CFR50.73(a)(P)(iv), as an event that resulted in an automatic actuation of an Engineered Safety Features system.

~ ~ -

Farm 1062.013 NRC Form 3,66A U.S. Nuclear Regulatory Commission (9-83) ' -

Approved OMB No. 3150-0104 Expires: 8/31/85 LICENSEE EVENT REPORT (LER) TEXT CONTINUATION FACILITY NAME (1) l DOCKET NUMBER (2) l LER NUMBER (6) l PAGE (3)

I 1 1 15equentiell lRevisioni Arkansas Nuclear One, Unit One l l_Yearl I Number l l Number l 10151010101 31 11 31 81 91--I O 1 41 2 l -I O I 1 101210Fl013 TExl (1f more space is required, use additional NRC Form 366A's) (17)

A. Plant Status At the time of occurrence of this event, Arkansas Nuclear One, Unit One (ANO-1) was in Cold Shutdown.

A mid-cycle outage was in progress. Arkansas Nuclear One, Unit Two (ANO-2) was at one hundred percent of rated thermal power, Mode 1 (Power Operation).

B. Event Description On December 9,1989 at appusimetely 2004 hours0.0232 days <br />0.557 hours <br />0.00331 weeks <br />7.62522e-4 months <br />, an inadvertent actuation of the Control Room Emergency Ventilation System (CREb) (VI) occurred.

The CREVS is designed to maintain habitability of the ANO-1 and ANO-2 Control Room by automatically isolating the normal Control Room ventilation system and starting upon receipt of an indication of high radiation or high chlorine concentration. The system cunsists of two redundant filter trains, both of which are located outside the ANO-1 section of the Control Room. Each filter train includes a centrifugal fan, roughing filter, an absolute filter and charcoal adsorbant. The CREVS trains are normally isolated from the Control Room by isolation dampers. System actuation instrumentation consists of two quick acting chlorine detectors located in the normal ventilation supply duct for ANO-1 and two additional detectors at the ANO-2 supply air duct. Also, there is an area radiation monitor located in the ANO-1 Control Room area and a process radiation monitor located in the ANO-2 normal ventilation system outside air intake ductwork. An actuation signal from any of these instruments will initiate operation of the CREVS.

The CREVS actuation which occurred on December 9, 1989, was caused by the ANO 2 chlorine monitors 2CLS-8762-2 and 2CLS-8763-1 tripping. The system actuated as designed. After determination that the actuation was spurious, the chlorine monitors were reset and the ventilation system configuration was returned to normal.

C. Safety Significance Since no actual high chlorine concentration existed, and because the CREVS actuated as designed, there was no safety significance related to this event.

D. Root Cause The chlorine monitor trips which initiated the actuation were caused by the keying of a hand held I radio in the vicinity of the chlorine monitors by a Health Physics Technician. The area in the

vicinity of the chlorine monitors is posted to prohibit the use of hand held radios since testing i and previous actuations have proven them to be sensitive to radio frequency interference. Therefore, l

this event was the result of personnel error. The root cause of this event, however, is directly related to system design. The extreme sensitivity of the chlorine monitors coupled with the actuation logic which requires only one monitor to trip to initiate the CREVS makes the system highly susceptible to inadvertent actuations.

E. Basis for Reportability This event is being reported pursuant to 10CFR50.73(a)(2)(iv), as an event that resulted in an automatic actuation of an Engineered Safety Features system. The non-emergency event was also reported pursuant to 10CFR50.72(b)(2)(11) on December 9, 1989 at 2050 hours0.0237 days <br />0.569 hours <br />0.00339 weeks <br />7.80025e-4 months <br />.

F. Corrective Actions The Health Physics Technician who keyed the hand held radio in the vicinity of the chlorine monitors has been counselled regarding the use of radios in the restricted area. Additionally, a memorandum has been issued to Health Physics personnel to emphasize the importance of not using radios in the vicinity of the chlorine monitors. A memorandum has been previously issued to inform plant personnel of the events involving thu effects of radio frequencies on the chlorine monitors and to ensure personnel are cognizant of the restriction on the use of hand held radios in this area.

Shielding which will decrease the sensitivity of the chlorine monitors to radio frequencies will 9

be installed. The expected completion date for installation is March 1, 1990.

~ Farm 1062.013 CRC Form 366A U.S. Nuclear Regulatory Commission (9.83) '

Approved DMB No. 3150-0104 Expirest 8/31/85 LICENSEE EVENT REPORT (LER) TEKT CONTINVATION F ACILITY hAME (1) (DOCKET NUMBER (2) l LER NUMBER (6) l PAGE (3) l l l l$equentiell l Revision!

Arkansas Nuclear One, Unit One l l Yearl l Number I i Number l 10151010101 31 11 31 61 91--! O i 41 2 t--I O I 1 101310rl013 TEXT (If more space is required, use additional NRC Form 366A's) (17)

As a result of previous inadvertent actuations, several system enhancements have been completed (see LER 50-313/89-009-01). Additionally, an engineering evaluation of the system design was initiated to determine if additional corrective actions are necessary. This evaluation is planned to be completed by March 31, 1990.

G. Additional Information Previous inadvertent CREv5 actuations were reported in LERs 50 313/89-009-01, 50-313/89-011-00, 50 313/89-014-00, 50-313/89-025-00, 50-313/89-035-00, 50-313/89-036-00 and 50-313/89-D42-00.

Energy Industry Identification System (EII5) codes are designated in the text as (XX).