ML20062K302

RO 50-259/8085:on 801123 Reservoir Water Temp Exceeded Max Allowable Temp.Caused by Influence of Colder Water Upstream.Load on Unit 3 Reduced in Four Stages to Shutdown & Water Flows Increased

ML20062K302
Person / Time
Site:	Browns Ferry
Issue date:	12/03/1980
From:	Mills L TENNESSEE VALLEY AUTHORITY
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
RO-50-259-8085, NUDOCS 8012090410
Download: ML20062K302 (2)

Text

..

TENNESSEE VALLEY AUTHORITY CH ATTANOOG A. TENNESSEE 37401 400 Chestnut Stt eet Tower II December 3, 1980 Mr. Jues P. O'Reilly, Director U.S. !!uclea- Regulate 7 Cem ission Pegio7 IT - Sui te 3100 101 Marietta St reet, Ti Atlanta, Georgi i 30303 k

1 Cese Mr. O'*te!D 7-

• FIJFSSE VALL?! ALEH08:IT - BROWN 3 FER!IY NUCLEAR PLAh!, UNIT 1 -

DOCKET NO.10-259 - FACILITT OPEPATING LIC llEE - LPR ENVIRCNMENTAL 3EPOR74 ELE C000RRENCE - 3F30-$0-259/8085 The er. closed report is cubmitted in accordance with Browns Ferry's t e crmen '. spe:ct n es tion ; .t..l o. This report supplechents our report by telecopy te fou cr. !'cymoer 24, 1980, from H. L. Aberereshie, Power Plant Superintendent, Browns Ferry Nuclear Plant, and providea details concerning the reservoir vnter tempereture c:xceer.ir.g the na:::: cur ter.perature rice of i degroes Fahrenhett on hoveder 23,19d0.

Very truly yours, TENICSOEE VALLCl AUTiiOEITY L. N. ;Illis, k.anagesr Nuclear Regulation and Jafety Encionuro ec Enclosure):

Di: cetor

tit: ten of Licen-ter, THIS DOCUMENT CONTAINS 0..s. suelcar e.asulatcry cc::a:iss "

,sashington, DC 20555 POOR QUAllTY PAGES DLeector (3)

Office of ;tnagasent and Program Analysis 9.3. :luelkar Regulator'; Comnission Wasqington, DC 20555 bO S

Director (40)

Office of Inspection and Enformoesent /f U.3. Fuc!ena Reirulatory Cormaission 4anhington, DC 20555 8012090 N An Ecua; ococcune :moicyer

, 's' LCO Vle.ATION Report Date: December 3, 1980 Report Number: BFR0 50-259/8085 Occurrence Date: November 23, 1980 Facility: Browns Ferry Nuclear Plant Description of Violation The temperature rise of Wheeler Reservoir measured between upstream and downstream thermal monitors exceeded the maximum allowable temperature rise limitation of 5.0 degrees Fahrenheit from 2030 through 2230 CST on November 23, 1980. The maximum temperature rise during this period was 5.6 degrees Fahrenheit at 2115 CST. The maximum downstream temperature during this period was 58 degrees Fahrenheit.

Cause of Violation Extensive rainfall in the area rapidly lowered the temperature in the tributary streams that discharge into Wheeler Reservoir. A thermal monitor at the mouth of Flint Creek, upstream of the plant at TRM 308.5 indicated 50.2 degrees Fahrenheit while the upstream control thermal monitor at TRM 297.6 indicated greater than 54 degrees Fahrenheit. When the colder water reached the upstream control monitor the noncompliance occurred. The violation was caused by the influence of colder water upstream, not by an increase in temperature of the condenser cooling water.

Analysis of Violation An analysis of all river water temperature data available before and after the violation indicates that th.. Environmental Technical Specification limit regarding the maximum temperature rise was exceeded. Since the violation only lasted for 2.00 hours0 days <br />0 hours <br />0 weeks <br />0 months <br />, and the limit was only exceeded by 0.6 degrees Fahrenheit, we believe that no significant adverse environ-mental impact was experienced in Wheeler Reservoir due to plant-induced heating.

Corrective Action The load on unit 3 was reduced in 4 stages from 862 MW at 2009 hours0.0233 days <br />0.558 hours <br />0.00332 weeks <br />7.644245e-4 months <br /> to 460 MW at 2107 hours0.0244 days <br />0.585 hours <br />0.00348 weeks <br />8.017135e-4 months <br /> and shutdown completely at 2144 hours0.0248 days <br />0.596 hours <br />0.00354 weeks <br />8.15792e-4 months <br /> in an attempt to prevent a continuation of the noncompliance. Also, the flows at Guntersville Dam and Wheeler Dam were increased at 2004 hours0.0232 days <br />0.557 hours <br />0.00331 weeks <br />7.62522e-4 months <br />.

Recommendations to Avoid Future Violations --Since this violation was primarily because of a sudden decrease in the upstream temperature caused by localized rainfall and not because of plant-induced heating, no further action is recommended at this time.

_ _ _ _ _ - _ _ _ _ _ _ _ _ _ _ _ _ _ _