ML20199F650
| ML20199F650 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 11/14/1997 |
| From: | Abney T TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9711240287 | |
| Download: ML20199F650 (3) | |
Text
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nn w usavc., e.a, wno m eo m n.ar., eu m m 3 November 14, 1997 U.
S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C.
20555
Dear Sir:
In the Matter ot
)
Docket No. 50-260 Tennessee Valley Authority
)
BROWNS FERRY NUCLEAR PLANT (BFN) - SPECIAL REPORT ON INOPERABLE HIGH RANGE PRIMARY CONTAINMEN4 RADIATION MONITOR This Special Report is being submitted in accordance with Technical Specification (TS)
- 3. 2. F, Table 3.2.F, Note (7) and TS 6.9.2.
This report informs NRC that a Unit 2 High Range Primary Containment Radiation Monitor (HRPCRM) has been inopetable for more than seven (7) days. The containment high-range radiation monitors were installed in response to NUREG-0737, Clarification of TMI Action Plan Requirements, Item II. F.1. 3.
The purpose of these monitors is to detect gross fuel failures after an accident.
There are two HRPCRMs (2-90-272C and 2-90-273C) in the drywell on elevation 582.
On October 31, 1997, one of the HRPCRMs
!. 2-90-27 2 C ) was declared inoperable due to a downscale indication.
A downscale indication is the rcsult of a failed monitor or the monitor is not sensitive enough. At this time, HRPCRM (2-90-273C) is operable and capable of detecting gross fuel failures after an accident.
The Post-Accident Sampling System (PASS) also provides a redundant method for detecting gross fuel failures, through both the sampling of primary 3/'
system coolant and the containment atmosphere.
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U.S. Nuclear Regulatory Commission Page 2 November 14,1997 The'immediate corrective actions taken for HRPCRM 2-90-272C
-include:
(1) changed out the monitcr chassis,- (2) : tested -
coaxial cable from the monitor chassis to-the detector using a Time Domain Reflectometer, (3) repaired. rear connector of the monitor chassis, and (4) took continuity measurements-of the cable from its shielding to ground an'd-from the center
~
conductor to shield / ground using an electrometer and a digita]
multimeter.
Based on these corrective actions, the root cause of the inoperable HRPCRM continues to be indeterminate.-
However, the most probable cause is a component / cable' failure inside the drywell.
During power operations, the.drywell atmosphere is required to be inerted.
Hence, additional troubleshooting within the drywell is not possible at this time.
TVA plans to repair / replace the detector or its associated cable the next time BFN has a forced Unit 2 outcge of sufficient duration in which ti.e drywell is entered, or the l
next Unit 2 refueling outage, whichever comes first.
If you have any questions regarding this report, please contact me at (205) 729-2635, 4
Spacelely, O W
T. E.
ey Manager Lic sing and Ind stry Affairs
P
.+
5 l
U.S. Nuclear-Regulatory Commission Page 3 November 14, 1997 cc:' Mr. Mark S.-Lesser, Branch Chief ~
- U.S. Nuclear Regulatory Commission
- Region II 61 Forsyth Street S.W.
Suite 23T05 Atlanta, Georgia 30303 NRC Resident Inspector Browns Ferry Nuclear Plant-10833 Shaw Road Athens, Alabama 35611 Mr. Luis A. Reyes Regional Administrator U.S. Nuclear Regulatory Commission Atlanta Federal Center 61 Forsyth Street S.W.
Suite 23T85 Atlanta,-Georgia 30303 Mr.
J.
F. Williams, Project Manager U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852 a
e
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