ML20062G364
| ML20062G364 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 11/16/1990 |
| From: | Hairston W GEORGIA POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| HL-1370, NUDOCS 9011290142 | |
| Download: ML20062G364 (4) | |
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Georga Powet Cut parrt 333 Peomont A,enue Attarm Goorg a 30308,
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.blephonri 404 526 3195 Ma. Lng Address 40 invernon Center Panay.
Post On e Box 1295 c
B>rrninghurt Alabama 3L201 lelephcne 20$ Bf;0 5581 -
' the soahern ek: ant. system W, G. Hairston,111 -
Son-or Vce Presdent Nudear Operabons
.i HL-1370.-
1000932 November 16,.1990-I I
U.S. Nuclear Regul'atory Commission ATTN:
Document Control Desk i,
l Washington, D.C.
20555-1 PLANT HATCH - UNIT 2' NRC DOCKET 50-366-J l
OPERATING LICENSE NPF-5 SPECIAL REPORT-2-90-004 REACTOR BUILDING VENTILATION' ACCIDENT RA "t S
RADIATION MONITOR INOPERABLE FOR LONGER l
THAN SEVEN DAYS RESULTS IN SPECIAL REPORT Gentlemen:
In accordance with the requirer:nts-of the Unit 2 Technical Specifications Table 3.3.6.4-1, 'ncte (b),
Georgia.Powerf Company is submitting.the enclosed Special -Report concerning an' event where. the reactor building ventilation accident. range radiation monitor- -was inoperable for longer than seven days'. 'This' event-occurred at Plant Hatch
- Unit 2.
1 Sincerely, y)). $lYW W. G. Hairston, III' JKB/et
Enclosure:
SR 50-366/1990-004 c:
(See next paga.)
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-i l-U.S. Nuclear Regulatory Commission November 16, 1990 Page Two c:
Georaia Power Company Mr. H. L. Sumner, General Manager - Nuclear Plant
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Mr.'J. D. Heidt, Manager Engineering and Licensing. Hatch 9
NORMS H
.I U.S. Nuclear Reaulatory Commission. Washinaton. D.C.
Mr.-K. Jabbour, Licensing Project Manager - Hatch U.S. Nuclear Reaulatory Commission. Reaion II
.i Mr. S. D. Ebneter, Regional Administrator Mr. L. D.- Wert, Senior Resident Inspector.- Hatch 1
y 4
ENCLOSURE l
=
' PLANT HATCH - UNIT 2-l NRC DOCKET 50-366'
-OPERATING LICENSE NPF-5 SPECIAL REPORT 2-90-004-REACTOR BUILDING = VENTILATION ACCIDENT RANGE RADIATION MONITOR INOPERABLE FOR l
. LONGER THAN=SEVEN DAYS RESULTS IN SPECIAL REPORT' a
L_
A. REQUIREMENT FOR REPORT This report is required per Unit'2 Technical Specifications Table 3.3.6.4-1 note (b).
Item 14 of. that table requires this instrument to remain operable' l
while the Unit is in operational conditions 1, 2 or 3.
If the instrument..is inoperable for a period greater than seven days, a Special Report must-bei submitted to the NRC within 14 days of theievent outlining'the action ~taken,.
the cause of the-inoperability, and the plans and schedule for restoring.the system to operable status.
B. UNIT STATUS AT TIME OF EVENT.
l On 11/08/90, Unit 2 was in the Run mode at an approximate power level of 2436; CHWt (approximately 100% of rated thermal power).
I C. DESCRIPTION 0F EVENT On 11/08/90, at approximately-1300 CST, the reactor building accident range radiation monitor was declared' inoperable due to an erratic output.
Deficiency Card 2-90-3344 was written to. document the' condition and Limiting Condition for Operation 2-90-346 was initiated. Maintenance Work Order 2-90-3302 was initiated to implement corrective action.
In an attempt to restore the monitor to operable status, severa1Leourses-of,
action were pursued, including the replacement of several circuit boards in.
the system. On 11/11/90, following replacement of these electronic..
A components, and with the system still in an: inoperable status;1 technicians observed that an error code was-now being displayed on the! associated panel 1
in the Main Centrol Room.
The error code indicated a detector element. failed such that the monitor's signal output was zero.
Consequently, a replacement of the dete,cor would be required.
Since no replacement was in warehouse.
stock at t :at time, a detector was ordered.
The replacement detector element was received on site on.11/15/90, and work' was begun on replacing the detector element at that time. However, on 11/15/90, the accident range radiation monitor-was still inoperable and this Special Report is required.
On 11/16/90, the detector. element was replaced and. successfully functionally-tested. The monitor was declared operable and LC0 2-90-346 was terminated.
000932 l
HL-1370 E-1
d t
1 ENCLOSURE SPECIAL REPORT 2-90-004 REACTOR BUILDING VENTILATION ACCIDENT RANGE RADIATION MONITOR. INOPERABLE FOR t
LONGER THAN SEVEN DAYS RESULTS IN-SPECIAL REPORT i
l' D. CAUSE OF EVENT l
l l
The root cause of this event was component. failure., - Specifically,.a..
radiation detector element failed resulting in a complete loss of output-signal.
i i
E. ANALYSIS OF EVENT The reactor building vent stack radiation monitoringLsystem consists of two redundant sampling channels and an accident range monitor with one: sampling' channel. The purpose of = the system is.to monitor the activity of gaseous 1 effluent from'the reactor building stack and to proside an alarm in the' main-control room should activity levels exceed preset values.
In this event, the subject monitor was rendered inoperable by a-failed-(
detector element. The normal range detector-was operable and continued to-provide monitoring of reactor building' stack effluent.. Moreover, at 1300 l
CST on 11/08/90, the preplanned alternate method of monitoring the reactor l
building stack effluent was initiated. per 64CH-ADM-001-OS, " Chemistry l
Program." At no time during this event-were'. activity levels. abnormally high.
Based on the above analysis, it.is concluded that 'this event had no. adverse impact on nuclear safety. ~ The analysis is applicable to all power. levels.
F. CORRECTIVE ~ ACTIONS 1.
Declaring reactor building accident range radiation monitor inoperable and initiating LC0 2-90-346.
2.
Initiating the prepla:'ned alternate method of reacto'r building stack radiation monitoring.
3.
Initiating Maintenance Work Order 2-90-3302 to implement replacement of the failed detector element. -The monitor was replaced, successfully l
functionally tested, and returned to service on 11/16/90, i
000932 HL-1370 E-2
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