ENS Event | |
|---|---|
22:43 Aug 28, 2003 | |
| Title | 24-Hour Condition of License Report Involving Potential Violation of Maximum Power Level |
| Event Description | This 24-hour report is being made as required by Byron Unit 1 License Condition 2.F and Byron Unit 2 License Condition 2.G as a potential violation of the maximum power level (3586.6 MWt) as stated in Unit 1 and Unit 2 License Condition 2.C(1).
On August 28, 2003 at 17:43 CST Byron Station was notified by the ultrasonic flow measurement vendor via letter that there were discrepancies in the ultrasonic flow measurements used in the calorimetric calculation for reactor power. As part of an ongoing testing plan, ultrasonic flow measurements were being taken on the main feedwater system piping header on Byron Unit 1 and were compared to the results from the ultrasonic flow measurement devices on the four individual feedwater lines. Based on the results of the data analysis, and noted signal abnormalities, it was determined that Byron Unit 1 has potentially exceeded its licensed thermal power limit by approximately 1.5%. Based on the results of the testing on Unit 1, the ultrasonic flow measurements on Byron Unit 2 were also investigated. Similar signal abnormalities were identified on one of the four ultrasonic flow measurement devices installed on the individual feedwater lines on Unit 2. Subsequent evaluation indicates that Byron Unit 2 also has potentially exceeded its licensed thermal power limit by approximately 0.6%. The power level on both units was reduced to less than 100% power consistent with feedwater flow as measured directly by the venturis without using the correction factors from the ultrasonic flowmeters. Additional actions regarding investigation of the condition, determination of root cause and corrective action, and determination of the potential actual overpower will be included in the 30-day license event report. The licensee informed the NRC Resident Inspector. |
| Where | |
|---|---|
Byron  Illinois (NRC Region 3) | |
| Reporting | |
| Other Unspec Reqmnt | |
| Time - Person (Reporting Time:+21.2 h0.883 days <br />0.126 weeks <br />0.029 months <br />) | |
| Opened: | Scott Fruin 19:55 Aug 29, 2003 |
| NRC Officer: | Steve Sandin |
| Last Updated: | Aug 29, 2003 |
| 40117 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 476362012-02-03T06:00:0003 February 2012 06:00:00
[Table view]Other Unspec Reqmnt ENS 424572006-03-31T19:07:00031 March 2006 19:07:00 Other Unspec Reqmnt Low Tritium Concentration Levels Found Near Underground Piping ENS 414502005-02-28T08:06:00028 February 2005 08:06:00 Other Unspec Reqmnt Discovery of After-The-Fact Emergency Condition - Unusual Event ENS 401172003-08-28T22:43:00028 August 2003 22:43:00 Other Unspec Reqmnt 24-Hour Condition of License Report Involving Potential Violation of Maximum Power Level 2012-02-03T06:00:00 | |