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Tracking and Trending of Steam Generator Leak Rate (SGLR) Monitor Backgrounds and Source Checks

Tracking and Trending of Steam Generator Leak Rate (SGLR) Monitor Backgrounds and Source Checks. Anthony T Lonnett FENOC - BVPS Units 1 & 2 PO Box 4 ( Mail Stop A-BV-RAD ) Shippingport, PA 15077-0004 Phone: 724-682-7523 e-mail: lonnetta@firstenergycorp.com.

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Tracking and Trending of Steam Generator Leak Rate (SGLR) Monitor Backgrounds and Source Checks

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  1. Tracking and Trending of Steam Generator Leak Rate (SGLR) Monitor Backgrounds and Source Checks Anthony T Lonnett FENOC - BVPS Units 1 & 2 PO Box 4 ( Mail Stop A-BV-RAD ) Shippingport, PA 15077-0004 Phone: 724-682-7523 e-mail: lonnetta@firstenergycorp.com

  2. Is there an Alternate Title to this Presentation? Maybe…just ask yourself the following: Question: How easy is it to get a repeat AFI? Answer: Simple….just have more than one person assigned to implement a trending program.

  3. Problem (INPO AFI CY.3-1) • Performance of rad monitors used to identify pri-to-sec tube leakage is not adequately trended to promptly identify and evaluate loss of sensitivity between monitor calibrations • This does not meet the guidance of Rec No. 3 to SOER 93-1, “Diagnosis and Mitigation of Reactor Coolant System Leakage Including Steam Generator Tube Ruptures”

  4. Causes and Contributors - Part 1 • A previous misconception that source checks could not be quantitative • Ownership of the program was assigned to more than one individual • Acceptance Criteria was not displayed on the plots (graphs) • There was no continuity between the two areas that needed trended (see next page for details)

  5. Causes and Contributors - Part 2 • Monitor bkgds were plotted monthly, but source checks were plotted every 18 months. Neither of these were adequate • Effect of bkgd subtract was not evaluated • Data was plotted on a log scale rather than a linear scale. • Data was plotted in terms of count rate rather than Percent Variance of the Acceptance Criteria.

  6. Corrective Actions Related To:Obtaining Raw Data • Ownership of the trending program was assigned to one individual • Changed station Logs to (1) require weekly source checks, and (2) provide instructions on how to perform the source checks • Initiated routine (weekly) trending of the background & source check data • Added "background subtract value"

  7. Corrective Actions Related To -Acceptance Criteria • Developed the 1st Acceptance Criteria to require the current background or source check data point to be within a 3-sigma band of the historical average

  8. Corrective Actions Related To -Acceptance Criteria • Developed the 2nd Acceptance Criteria to require the current background or source check data point to be within +10% of the total average

  9. Corrective Actions Related To -Acceptance Criteria • Implemented electronic comparison to the two Acceptance Criteria described above • Data outside the Acceptance Criteria must be documented in a Corrective Action to ensure an adequate investigation and resolution process is performed

  10. Corrective Action Status • In total, fourteen Corrective Actions were implemented to enhance the program for prompt detection of detector degradation • All Corrective Actions have been implemented • All SGLR program enhancements were implemented into a single station procedure

  11. Evaluate Effectiveness of Corrective Actions • The Corrective Actions implemented were evaluated using four separate methods

  12. 1st Method of Corrective Action Evaluation • The 1st method involved use of an internal Effectiveness Review • Results: A total of 4 additional comments were generated. They were evaluated and Corrective Actions were implemented

  13. 2nd Method of Corrective Action Evaluation • The 2nd method involved an independent review from a Chemistry peer at INPO • Results: A total of 4 comments were generated. They were evaluated and Corrective Actions were implemented

  14. 3rd Method of Corrective Action Evaluation • The 3rd method involved an independent review from a Chemistry peer at another FENOC site • Results: A total of 1 additional comment was generated. It was evaluated and Corrective Action was implemented

  15. 4th Method of Corrective Action Evaluation • The 4th method involved a final internal critical evaluation of background and source-check trends to determine if the revised SGLR monitoring program identifies appropriate failures • Results: No additional comments generated

  16. Results • The revised trending program now provides meaningful results • Results are reported to station management • Since implementation of the revised program, there have been several instances where the program identified a degrading trend in detector performance

  17. Unit 1 SGLR Monitor Backgrounds

  18. Unit 1 SGLR Monitor Source Checks

  19. Unit 2 SGLR Monitor Backgrounds

  20. Unit 2 SGLR Monitor Source Checks

  21. Conclusions • The Corrective Actions implemented for trending SGLR radiation monitor backgrounds and source checks are effective to satisfy SOER 93-1 • Summary: Weekly trending is considered “routine”. Monthly trending is a bad practice, and 18 month trending is a really bad practice.

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