ML18038B655
| ML18038B655 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 03/26/1996 |
| From: | Machon R TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9604010255 | |
| Download: ML18038B655 (16) | |
Text
CATEGORY j.
REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)
~ 1 QCC
. CION "NBR::9604010255 DOC.DATE: 96/03/26 NOTARIZED:
NO ACYL:50.;.259 Browns Ferry Nuclear Power Station, Unit 1, Tennessee 50-",60 Browns.Ferry Nuclear Power, Station, Unit 2, Tennessee 50-296 'Browns Ferry Nuclear Power Station, Unit 3, Tennessee
'AUTH.NAME AUTHGR AFFILIATION MACHON,R.D.
Tennessee Valley Authority RECIP.NAME Pc:CIP'I'ENT
.QFFILIIATION Documen'5 control Branch (Document Control Desk)
DOCKET I 05000259 05000260 05000296
SUBJECT:
Re~~ponds to NRC 960229 ltr re violation noted in insp repts 50'-.259/96;01,50-260/96-01 6 50-296/96-01.C/As:reduced reactor power 'a deleted FW temp point from processi.ng.TVA plans to troubleshoot resistance temp, detector loop.
DISTRIBUTION CODE'EOID COPIES RECEIVED'LTRj ENCL i
SIZE' TITLE: General (50 Dkt)-Insp Rept/Notice of Violation Response NOTES:
RECIPIENT ID CODE/NAME PD2-3-PD INTERNAL: ACRS AEOD/SPD/RAB DEDRO NRR/DISP/PIPB NRR/DRPM/PECB NUDOCS-ABSTRACT OGC/HDS3 EXTERNAL: LITCO BRYCEIJ H
NRC PDR COPIES LTTR ENCL 1
1 2
2 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 RECIPIENT ID CODE/NAME WILLIAMS,J.
AEOD/DEIB AEOD/TTC FILE CENTER NRR/DRCH/HHFB NRR/DRPM/PERB 8E B&R-RGN2 EL+~0 4
NOAC COPIES LTTR ENCL
- l 1
1 1
1 1
1 1
1 l.
1 1
1 1
1 1
1 D
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t NOTE TO ALL "RIDS" RECIPIENTS:
PLEASE HELP US TO REDUCE WASTEI CONTACT THE DOCUMENT CONTROL DESK, ROOM OWFN SD-5 (EXT. 415-2083)
TO ELIMINATE YOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!
TOTAL NUMBER OF COPIES REQUIRED:
LTTR 20 ENCL 20
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Tennessee Valley Authority, Post Office Box 2000. Decatur. Alabama 35609.2000 R. D. (Rick) Machon Vice President, Browns Feny Nuclear Plant March 26, 1996 U.S. Nuclear Regulatory Commission ATTN:
Document Control Desk Washington, D.C.
20555 10 CFR 2 Appendix C
Gentlemen:
In the Matter of Tennessee Valley Authority Docket Nos.
50-259 50-260 50-296 BROWNS FERRY NUCLEAR PLANT (BFN) - NRC INSPECTION REPORT 50 259'0 260I 50 296/96 01 REPLY TO NOTICE OF VIOLATION (NOV)
This letter provides our reply to the subject NOV transmitted by letter from Mark S. Lesser, NRC, to Oliver D. Kingsley, Jr.,
TVA, dated February 29, 1996.
This NOV involved a failure to maintain Unit 3 core thermal power less than or equal to the maximum thermal power authorized by the operating license.
TVA admits the violation.
The enclosure provides our response to the NOV.
No commitments are made in this letter. If you have any questions regarding this reply, please contact Pedro Salas at (205) 729-2636.
Sincerely, R.
D.
chon e
Enclosure cc:
See page 2
9604010255 960326 PDR ADQCK 05000296 8
0
U.S. Nuclear Regulatory Commission Page 2
March '26, 1996 Enclosure cc (Enclosure):
Mr. Mark S. Lesser, Branch Ch'i.'ef U.S'. Nuclear Regulatory Commission Region II 101 Marietta Street,.
NW, Suite 2900 Atlanta, Georgia 30323'RC Resident Inspector Browns Ferry Nuclear Plant 10833 Shaw Road
- Athens, Alabama 35611 Mr. J.
F. Williams, Project Manager U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852
ENCLOSURE'ENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNITS 3.g 2p AND 3 INSPECTION REPORT NUMBER 50-259~
50-260~
50-296/96-01 REPLY TO NOTICE OF VIOLAT10N (NOV)'During an NRC inspection conducted'n December 31, 1995 to February 3,
- 1996, a violation of NRC requirements was identified.
In accordance with the "General Statement.
of Policy and Procedure for NRC Enforcement Actions,"
NUREG 1600, the violation is listed below:
Browns Ferry Unit 3 Facility Operating License Condition 2.C.(1) states that the licensee is authorized to operate the facility at steady state reactor core power levels not in, excess of 3293 megawatts thermal.
Contrary to the above, on December 27 and 28, 1995, Unit 3 steady state reactor core power level, as averaged over an 8
hour period, exceeded 3293 megawatts thermal.
This is a Severity Level IV violation (Supplement 1)."
0 e
o o
e
his event was caused by the gradual failure of a feedwater temperature instrument.
This provided inaccurate input to the nuclear heat balance resulting in an inaccurate indication of reactor power.
As a result, the operator responded to the observed plant indication (i.e.,
decrease in power level) and proceeded to adjust recirculation flow.
On December 27, 1995, at approximately 1455 hours0.0168 days <br />0.404 hours <br />0.00241 weeks <br />5.536275e-4 months <br />, reactor feedwater inlet A1 temperature transmitter 3-TT-3-48A, which had previously been deleted from computer processing due to its wide swings in readings, was recalibrated by maintenance personnel and reentered into the plant computer for feedwater temperature point 3-48A.
At approximately 1600
- hours, feedwater temperature point 3-48A started to gradually increase until it reached 391 degrees F at approximately 1852 hours0.0214 days <br />0.514 hours <br />0.00306 weeks <br />7.04686e-4 months <br />.
il
During this time period, the Integrated Computer System (ICS) heat balance display indicated a slight reduction in core thermal power.
To compensate for the slight power reduction and to maintain an indication of near full power on the ICS display, the Unit Operator (UO) adjusted reactor recirculation pump speed to maintain indicated average core thermal power between 3289 and 3293 MWt.
Feedwater temperature point 3-48A remained at about 391 degrees F until approximately 0045 hours5.208333e-4 days <br />0.0125 hours <br />7.440476e-5 weeks <br />1.71225e-5 months <br /> on December 28, 1995 when it suddenly increased to 402 degrees F.
This also resulted in a sudden decrease in core thermal power on the ICS heat balance display.
The UO noticed this sudden decrease in indicated core thermal power (approximately 20 MWt) with no corresponding change in generator output (MWe).
The operator investigated this change and noted that the indicated feedwater temperature point was abnormally high.
As a conservative action, reactor power was reduced approximately 15 MWt.
Subsequent troubleshooting on feedwater temperature point 3-48A determined that transmitter 3-TT-3-48A had drifted high resulting in the increase in temperature readings.
Following discovery of the drifting transmitter, at approximately 0112 hours0.0013 days <br />0.0311 hours <br />1.851852e-4 weeks <br />4.2616e-5 months <br /> on December 28,
- 1995, temperature point 3-48A was deleted from processing and indicated thermal power immediately increased above 3293 MWt.
Power was again reduced to less than 3293 MWt.
2.
C e
es c 'e The immediate corrective actions were to reduce reactor power and delete the feedwater temperature point from processing.
TVA plans to troubleshoot the resistance temperature detector loop of the failed transmitter to identify the root cause of the failure.
Although the operator responded as trained and in accordance with procedures, TVA has taken this event as an opportunity to improve future performance.
As a result, TVA has clearly communicated management expectations to operations personnel for,the review of reactor heat balance, plant parameters during and after power adjustments.
TVA also plans to revise the operator training program to review these expectations.
Additionally, TVA will brief operations shift personnel on the lessons learned from this event.
- Finally, TVA plans to review the recirculation system operating instruction and revise this instruction as necessary to ensure it includes appropriate guidance for review of heat balance inputs.'
These actions are voluntary enhancements and are not regulatory commitments.
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one.
TVA is in full compliance.
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During this time period, the Integrated Computer System (ICS) heat balance display indicated a slight reduction in core thermal power.
To compensate for the slight power reduction and to maintain an indication of near full power on the ICS display, the Unit Operator (UO) adjusted reactor recirculation pump speed to maintain indicated average core thermal power between 3289 and 3293 MWt.
Feedwater temperature point 3-48A remained at about, 391 degrees F until approximately 0045 hours5.208333e-4 days <br />0.0125 hours <br />7.440476e-5 weeks <br />1.71225e-5 months <br /> on December 28, 1995 when it suddenly increased to 402 degrees F.
This also resulted in a sudden decrease in core thermal power on the ICS heat balance display.
The UO noticed this sudden decrease in indicated, core thermal power (approximately 20 MWt) with no corresponding change in generator output (MWe).
The operator investigated this change and noted that the indicated feedwater temperature point was abnormally high.
As a conservative action, reactor power was reduced approximately 15 MWt.
Subsequent troubleshooting on feedwater temperature point 3-48A determined that transmitter 3-TT-3-48A had drifted high resulting in the increase in temperature readings.
Following discovery of the drifting transmitter, at approximately 0112 hours0.0013 days <br />0.0311 hours <br />1.851852e-4 weeks <br />4.2616e-5 months <br /> on December 28,
- 1995, temperature point 3-48A was deleted from processing and indicated thermal power immediately increased above 3293 MWt.
Power was again reduced to less than 3293 MWt.
2 ~
Corrective Actions Taken And Results Achieved The immediate corrective actions were to reduce reactor power and delete the feedwater temperature point from processing.,
TVA plans to troubleshoot the resistance temperature detector loop of the failed transmitter to identify the root cause of the failure.
Although the operator responded as trained and in accordance
.with procedures, TVA has taken this event as an opportunity to improve future performance.
As a result, TVA has clearly communicated management expectations to operations
.personnel for the review of reactor heat balance plant parameters during and after power adjustments.
TVA also plans to revise the operator training program to review these expectations.
Additionally, TVA will brief operations shift personnel on the lessons learned from this event.
- Finally, TVA plans to review the recirculation, system operating instruction and revise this instruction as necessary to ensure it includes appropriate guidance for review of heat balance inputs.'hese actions are voluntary enhancements and are not regulatory commitments.
E-2
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Corrective Ste s That Have Been Or Wi.ll Be Taken 'To Avoid Further Violations None.
Date When Full Com liance Will Be Achieved TVA is in full compliance.
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