ML20006B914

Special Rept 2-90-01:on 891206-900110,containment Radiation Level high-range Monitors Inoperable.Caused by Bad Preamplifier Circuit Board Which Caused Spurious Alarms. Preamplifier Circuit Board Replaced

ML20006B914
Person / Time
Site:	Vogtle
Issue date:	01/29/1990
From:	Hairston W GEORGIA POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
2-90-01, 2-90-1, ELV-01276, ELV-1276, NUDOCS 9002060088
Download: ML20006B914 (5)

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- Georg a Power company - :if

- 333 Pedmont Avenuo #

Nfanta. Georgia 30308 ~i

.*,~ Telephone 404 526 3195 l i. . j --

l Maltog Address L; - 40 invemess center Parkway i Post Off.ce Box 1295 Dirmingham; Nubama 35201 .

Telephone 205 868 5581 ,

January 29, 1990. . ,.c, ,,, ., ,, g n.c ,,,,,

W. G. Hairston,111 l Sernor Vcc ProSdent ,

Nuclear operaans .

L ELV-01276 .. ,

.0217 1 1

Docket No. 50-425

.U. S. Nuclear. Regulatory Commission '

ATTN: Document Control Desk Washington, D. C.. 20555 ,

Gentlemen:

V0GTLE ELECTRIC: GENERATING PLANT' SPECIAL REPORT' CONTAINMENT RADIATION. LEVEL HIGH .

RANGE MONITORS IN0PERABLE

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In accordance with the Vogtle Ele Generating' Plant Technical >

Specifications,-Section 3.3.3.6, t .a Power Company hereby submits the enclosed Special Report concernir' Containment . Radiation Level High: Range Monitors.

. Sincerely, et) ' b

! W..G. Hairston, III J l

WGH,III/NJS/gm 3 1

Enclosure:

Special Report 2-90-01 1

l xc: Georaia Power Company L Mr. C. K. McCoy L Mr. G. Bockhold,_Jr.

l' Mr. R. M. Odom a L Mr. P. D.-Rushton-  !

NORMS

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-U. S. Nuclear Reaulatory Commissio'n .

Mr. S. D. Ebneter, Regional Administrator  !

Mr. D.'B. Matthews, Director, Project. Directorate 11-3 Mr. R. F. Aiello, Senior Resident Inspector,.~Vogtle I4 9002060088 900129  ? 9 PDR ADOCK 05000425 S PDC g .- 'J'

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ENCLOSURE j x

V0GTLE ELECTRIC GENERATING' PLANT - UNIT 2. j

. TECHNICAL SPECIFICATION SPECIAL REPORT 2-90-01 l CONTAINMENT RADIATION LEVEL HIGH RANGE MONITORS INOPERABLE j A; REQUIREMENT FOR REPORT P

In accordance with Technical Specification 3.3.3.6, " Accident' Monitoring

• Instrumentation," and Item 14 of. Technical- Specification Table 3.3-8, at least-r one Containment Radiation Level- (High Range) channel is required'to be operable in Modes 1, 2, and 3. If this requirement is not met,' thenlable 3.3-8  ;

indicates that the action requirements. contained in Action Statement 33 apply."  !

These eetion requirements are as follows: 9

'"With .the . number of OPERABLE channels less than the Minimum Channels OPERABLE requirement, initiate' the alternate method of monitoring the.

parameter within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> 'and either, restore the inoperable channel (s) .to

. q OPERABLE status' within 7 days or prepare and submit a Special Report to the s Commission, pursutnt to Specification 6.8.2, within 14 days that provides.

actions-_taken, cause of the inoperabi.lity, and the plans and schedule for. t restoring the channels to OPERABLE status. The provisions of Specification. ,

3.0.4 are not applicable."  !

Recent problems have been experienced with containment high range radiation ,

monitors 2RE-0005 and 2RE-0006 resulting in entry of the above action requirements on several occasions (see attached Table 1). During each of these 1 occasions, the containment low range radiation-monitors 2RE-0002 and 2RE-0003  ;

were operable and the alternate method of monitoring the containment high range radiation level was initiated when required. On the last entry of these action requirements (on 1/10/90), it was decided to notLrestore 2RE-0006 to OPERABLE o status until a vendor representative could be consulted to diagnose the cause'of the recurring problem. Since radiation monitor 2RE-0005 has been inope'rable since 12/6/89 (Table 1), this action resulted in both containment high range radiation monitoring channels being inoperable in excess of 7' days and therefore a Special Report is required per the above action statement.

B. .CAUSE OF IN0PERABILITY b The cause for 2RE-0005 being removed from service was a' ground fault condition-

-i i which was traced to the AC low power supply cable for this monitor. The location of the ground required a design change to allow splicing ~ of the cable-within a cable tray. Initiation of the design change package and procurement of a qualified splicing kit has resulted in this problem taking. additional time to 'r resolve. Also, a replacement preamplifier circuit board for. this monitor must be obtained since the circuit board for 2RE-0005 was installed in the 2RE-0006-monitor in order to correct the problem that 2RE-0006 was experiencing.

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-1 ENCLOSURE (CONT'D) .

TECHNICAL SPECIFICATION SPECIAL REPORT 2-90-01 .

j CONTAINMENT RADIATION LEVEL HIGH RANGE MONITORS INOPERABLE I

The cause-for 2RE-0006 being removed from service was determined to be a bad' preamplifier circuit board which caused spurious: alarms. This' determination was  ;

made by' the vendor representative who 'was consulted to . help. troubleshoot-the -i cause of the recurring problem involving spurious: alarms.

C. CORRECTIVE ACTION PLAN Radiation monitor 2RE-0006 was returned to OPERABLE status on 1/19/90.following l replacement of the preamplifier circuit board with a board removed from -  ;.

2RE-0005. No further corrective action is expected to be: required,for this-monitor. ,

' Radiation monitor 2RE-0005 is expected to be returned to service by 2/15/90.-

Completion'of this action is dependent upon receipt of qualified . splice' kits for correcting the ground problem and -obtaining a replacement preamplifier circuit- ,

board.  !

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ENCLOSURE (CONT'D) i

.SPECIAL REPORT-2-90-01 TABLE 1

SUMMARY

OF PROBLEMS INVOLVING 2RE-0005 AND 2RE-0006 DAlf DESCRIPTION ACTION ~TAKEN:

-12/6/89 Ground on 120VAC Panel' Ground problem discovered in ,

2AY2A traced to circuit . AC.' low power supply cable to-for 2RE-0005.- 2RE-0005 2RX-0005.

deenergized to allow

. troubleshooting / repair Design change initiated to '

of ground.. allow splice of cable. - q 12/17/89- 2RE-0006 deenergized .. ' Analog-to-Digital Circuit i after failing off-scale Board replacedLin Data Processing - ';

high. . Module (DPM).

Analog Channel Operational Test .. ,

(ACOT) and Channel Check completed satisfactorily.

Returned to service on 12/18/89. .

12/22/89 2RE-0006 deenergized Signal cable and high voltage for troubleshooting connections at preamplifier assembly after experiencing cleaned, and. cables reconnected, spurious " Low Fail" and "High" alarms.

Channel monitored for approximate 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> period with-no recurrence of spurious alarms =. <

i Returned to service on 12/23/89.

4 12/23/89 2RE-0006 declared Alternate method of_monit'oring inoperable after Containment High Range Radiation experiencing further Level initiated per~ Procedure.43017-C.

spurious " Low Fail" 2 and "High" alarms. Front' Panel Input /0utput Board E replaced in'DPM.

l Channel monitored for approximate 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period with no recurrence of-l spurious alarms.

l ACOT and Channel Check completed  ;

! satisfactorily.

Returned to service on 12/27/89. -$

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ENCLOSURE (CONT'D)-

SPECIAL REPORT 2-90-01 TABLE 1-

SUMMARY

OF PROBLEMS' INVOLVING 2RE-0005 AND 2RE-0006 j i

.QalE DESCRIPTION ACTION TAKEN ,

1/1/90- 2RE-0006 declared. Alternate method' of monitoring; [

inoperable after. Containment High Range Radiation  ;

again experiencing Level initiated. -l spurious " Low Fail" -- i al arms. Signal cable' and high voltage i connections at preamplifier assembly ,

cleaned and cables reconnected. -  !

Channel monitored for approximate 24- -i hour- period with no recurrence of i spurious' alarms.

Channel check completed satisfactorily,-  :

Returned to service on_1/4/90;  ;

4 1/10/90 2RE-0006 declared Alternate method of monitoring inoperable after Containment-High Range Radiati.on' experiencing spurious Level initiated.

"High" and " Trouble" q al arms. - . Vendor-(Westinghouse) Representative-consulted.

Preamplifier- Board removed from 2RE-0005 and installed':in 2RE-0006. .

l Returned to service on 1/19/90.

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