ML19347B595
| ML19347B595 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 10/08/1980 |
| From: | TENNESSEE VALLEY AUTHORITY |
| To: | |
| Shared Package | |
| ML19347B594 | List: |
| References | |
| NUDOCS 8010150398 | |
| Download: ML19347B595 (3) | |
Text
{{#Wiki_filter:. l l_ \\ LCO VIOLATION REPORT Browns Ferry Nuclear Plant-BFR0 5'0-259-8073 Report No. Report Date October 8, 1980 Occurrence Date September 28 and 29, 1980 Facility Browns Ferry Nuclear Plant Conditions Prior to Occurrence On September 28, 1980, unit I was operating at 1,070 MWe; unit 2 was shut down for refueling; and unit 3 was operating at 1,082 MWe. On September 29, 1980, unit 1 was operating at 905 MWe; unit 2 was shut down for refueling; and unit 3 was operating at 1,087 MWe. Descriptien 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 2000 through 2115 CDT and from 0615 through 0645 CDT on September 28 and 29, 1980, respectively. The maximum te=perature rise which occurred during these violations was 5.1 degrees Fahrer.heit. The maximum downstream temperatures during these periods were 78.2 and 77.5 degrees Fahrenheit, respectively. Cause of Violation Extensive rainfall throughout the Tennessee Valley combined with lower than normal ambient temperatures may have contributed to errors in predicted computer values. The predictive computer program estimated the maximum temperature rise during the periods of violation to be 2.8 degrees Fahrenheit on September 28 and 4.9 degrees Fahrenheit on September 29, 1980. As a result of these underestimations by the computer program and the rapid increases in the temperature rise, plant personnel could not react quickly enough to prevent the violation. i sc10150 %
i i 2-I i j Corrective Action i On September 28, 1980, when predictive temperature data indicated a postible thermal limit violation, no mitigative actions were taken i because it was originally believed that the thermal monitors were in error and no real problem existed. After the violation had occurred, additional river ficw was requested to previude further violation. On i September 29, 1980, at 0415 CDT when a rapid increase in the temperature i rise was noted, Unit No. 3 was placed on the cooling towers. However, j the thermal limit was again violated. i Analysis of Violation An analysis of all river water temperature data available before and after the violations indicate that the Environmental Technical Specf fication 4 limit regarding the maximum tamperature rise was exceeded. The predicted and actual temperature rises are shown on the attached graph. L~nce the violations only lasted for 1.25 hours en September 28 and 0.50 hoars on September 29, and the limit was only exceeded by 0.1 degrees Fahrenheit I in both cases, no significant adverse environmental impact was experienced in Wheeler Reservoir due to plant-induced heating. 1 l Recommendations to Avoid Future Violations l Hydrologic and thermal studies of the river near the plant have been done, and a proposal to revise the thermal monitoring system to provide more accurate thermal data has been submitted to EPA. Design change requests are being prepared as the first step in the installation of the revised system. i i 1 I e i 1
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