ML18283A852
| ML18283A852 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 02/14/1977 |
| From: | Gilleland J Tennessee Valley Authority |
| To: | Moseley N NRC/RGN-II |
| References | |
| Download: ML18283A852 (13) | |
Text
NRC FORM 195 (2-7B) C U.S. NUCLEAR REGULATORY Co ION DOCKET NUMBER o-re(
FI E NUMBER NRC DISTRIBUTION FoR PART 50 DOCKET MATERIAL
@LETTER QORIGINAL 3ICOP Y DESCRIPTION CINOTORIZED IRUNCLASSIFIE0 TO:
Mr N C Moseley PROP INPUT FORM ENCLOSURE FROM: Tennessee Valley Authority Chattanooga, Tn J
E Gilleland DATE OF DOCUMENT 2-14-77 DATE RECEIVED 2-23-77 NUMBER OF COPIES RECEIVED lcc Ltr trans the following:
lp Licensee Event Report (RO/II 771) on 2-3-77 which concerni Appendix B violation with regard to reservoir water temperature exceedin tech specs limitations.......
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FOR ACTION/INFORMATION 7
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SYSTEMS SAFETY HEINEMAN SCHROEDER ENGXNEERING MACARR BOSNAK SIHWEIL PAWL CK REACTOR SAFE ROSS NOVAK ROSZTOCZY CHECK AT & I SALTZMAN RUTBERG EXTERNALDISTRIBUTION NAT LAB REG V IE LA PDR CONSULTANTS! I PLANT SYSTEMS TEDESCO IPPOLITO OPERATING REACTORS STELLO OPERATING TECH EXSENHUT B
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S SA ERNST BALLARD SPANGLER SITE TECH GAMMILL STEPP HULMAN SITE ANALYSIS VOLLMER J
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830 P<FFFF.r Building TENNESSEE VALLEYAUTHORlTY CHATTANOOGA, TENNESSEE 37401 February 14, 1977 Ih. Norman C. HoseleyDirector
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Nuclear Regulatory Commission Region II 230 Peachtree Street, Rf., Suite 1217 Atlanta,, Georgia 30303
Dear Nr; Moseley:
TENNESSEE V~ AUTHORITY BROWS FERRY NtJCLEAR PLQF2 UNXT 1-DOCKET NO. 50-259 - FACILXTY OPERATING LICENSE DPR-33 ENVIRON-MENTAL REPORTABLE OCCUREKNCE BFERO-50-259/773, The enclosed. report is to provide details concerning the reservoir vater temperature
.exceeding the maximum temperature rise of 5 degrees F on February 3, 1977.
This report supplements our telecopy to you on February 3, 1977, from H. J. Green, This report is submitted i.n accordance vith Brovns Ferry Technical Specgfication 5.6.3b.
This event occurred on Brovns Ferry Nuclear Plant unit 1.
Very truly yours',
J. E. GilloFland Assistant Ravager of'over
~if I gA,'y Enclosure (3)
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Office of Management Information and. Program Control U.S. Nuclear Regulatory Commission Washington, DC 20555 Director (40)
Office of Xnspection and, Enforcement U.S, Nuclear Regulatory Commission Uashington, DC 20555 An Equal Opportunity Employer CP~+~oO
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7 09 14 15 REPORT LICENSE TYPE EVENT TYPE 0
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25 26 30 31 32 (PLEASE PRINT ALLREOUIREO INFORMATION)
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A'A'TCOORY TYPE SOUIICE OOCSE'T NUMOER EVCNT DATE
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50 59 60 61 68 69 74 EVENT OESCR!PTION I002".~l Attachment 75 REPORT DATE 0 elI 7
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[cC 0 9 toOGI 'L 0 9 SYSTEM CAUSE COOL CODE COMPONENT CODE
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~TH l PAME COMPONENT SUPPUEA 17 43 COMPOI4FN7 MANUFACTURER 9
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48 eo 80 8 9 FACILITY STATUS PDWEA OTHER STATUS 3Qi
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9 10 12 13 FOAM OF ACTIVAY CON TENT ALLFASEO OF RELEASE AMOUNT OF ACTIVITY A
NA 0
s 10 11 PERSONNEL EXPOSURES 89 11 12 10 PERSONNEL INJUR!ES 89
'l1 12 OFFSITE CONSEQUENCES 1+5 LN AA 0 9 LOSS OR DAMAGE TO FACILITY TgPE OCSCAIPTION K~l L~J LN A 09 1G PUBLICliY ig)L NA 09 ADDITIONAL FACTORS i
I Atteolvaent 89 METHOD OF DISCOVEAY A
44 45 46 44 45 DISCOVERY DESCRIPTION LOCATION OF RELEASE 6G ec 80 80 85 00 00
Report No.:
BFHRO-50-259/771 Report Date:
February 14, 1977 Occurrence Date:
February 3, 1977 Facility:
Browns Ferry Nuclear Plant EVENT DESCRIPTION On February 3, 1977, from 0929 to 1129 hours0.0131 days <br />0.314 hours <br />0.00187 weeks <br />4.295845e-4 months <br />, the reservoir water temp'erature exceeded the maximum temperature rise of 5 degrees F.
The maximum value was 6.2 degrees F occurring at 1029 hours0.0119 days <br />0.286 hours <br />0.0017 weeks <br />3.915345e-4 months <br />.
The maximum downstream temperature was 43 degrees F.
(BFHRO-50-259/771)
CAUSE DHSCRIPTION A computer program, which is run daily, calculates for the next 24-hour period hourly values of maximum temperature and temperature rise in the reservoir as a function of scheduled nuclear and hydro plant generation levels and recommends to the Browns Ferry plant operator the most economical combination of condenser cooling at the plant.
Releases from Guntersville and Wheeler Hydro Plants had'een fairly steady from 1800 hours0.0208 days <br />0.5 hours <br />0.00298 weeks <br />6.849e-4 months <br /> until 2300 hours0.0266 days <br />0.639 hours <br />0.0038 weeks <br />8.7515e-4 months <br /> on February 2 at rates that produced river flows in excess of 20,000 cfs.
The hydro discharges were then reduced at 2400 hours0.0278 days <br />0.667 hours <br />0.00397 weeks <br />9.132e-4 months <br /> and held at very low flows until 0500 hours0.00579 days <br />0.139 hours <br />8.267196e-4 weeks <br />1.9025e-4 months <br /> on February 3.
The computer program was not updated to reflect a change in hydro plant generation or the plant notified of this change.
As a result, the river temperature rise exceeded 5 degrees F before appropriate action at Browns Ferry could be taken to avoid it.
Water temperature at the time of the streamflow reduction was 40.5 degrees F downstream with an indicated Delta T of 3.3 degrees F.
The Browne Ferry plant condenser cooling operating mode is scheduled in advance by the computer calculation.
When the February 3 schedule was developed on February 2, river flows were predicted to be "adequate for condenser cooling at Browns Ferry.
- However, the Guntersville and Wheeler Hydro Plants were shut down during the night of February 2, resulting in greatly reduced river flows.
Browns Ferry personnel were not notified of this situation, so Browns Ferry continued to operate at the predicted load.
The temperature increase was detected by'he downstream monitors after'he river flow was reestablished.
DHSIGNATION OF APPARHNT CAUSH OF OCCURRHNCH River flow was not maintained according to the predicted schedule.
When the change was made, Browne Ferry personnel were not notified.
CORRHCTIVH ACTION When the plant superintendent noticed the rapid increase in the river temper-ature rise, he called the assistant chief load dispatcher in Chattanooga to xequest more river flow.
He was then informed of the decreased river flow that had occurred a few hours earlier and was advised that river flow had already been increased to a level that should assist in maintaining temperatures less than the 5 degrees F limit.
Therefore, plant load was not reduced.
In order to prevent future occurrences of this type, the plant operator will be notified immediately by the load coordinator of significant deviations from the predicted river flow as required by existing procedures.
Using this information, the plant operating personnel will select the optimum
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condenser cooling modes to ensure compliance with the technical speci-fications.
The importance of following this procedure has been reemphasized to the plant operators and the Power System Load Coordinator.
Table 1
ANALYSIS Ol'IVER VATER TE".PERATURE DATA BEFORE AND POLLOllPilG OCCURRENCE Date and Time CST Temperature Dovnstream Delta T OP Guntersville Dischar e
Wheeler Discharge
'100 CPS 2/2/77, 1900 Hrs.
2000
'2100 2200 2300 2400 443 332 322 212 175 112 419 303 300 272 233ill 2/3/77, 0100 0200 0300 0400 0500 0600 0700 0800 0829 0900 0914 0929 0944 0959 1014 1029 1044 1059 1114 1129 1144 1159 40.5 40.3 40.3 40.2 40.3 40.7 41.0 40.8 41.0.
41.4 41.7 41.9 42.. 1 42.4 42.8 43,0 42.9 42.7 42o3 41.8 41.3
- 40. 9 3.3 3.0 2.9 3.0 3.5 4.2 4.6 4 '
4,4 4.8 5,0 5.2 5.4 5,7 6.0 6.2 6.1 5.9 5.4 4.9 4, lt 4.0 26 0
0 90 214 214 442 491
- 488, 512 507 14 0
0 83 178 178 461
,586 592 583 536 1214 1229
- 40. 5 40.0 3 '
3.0