Flow-Accelerated Corrosion at Low Temperatures R. Doremus February 20, 2009
Overview <ul><li>Summary of EPRI TR-1015170 </li></ul><ul><ul><li>Definition of Low-Temperature FAC </li></ul></ul><ul><ul...
Definition <ul><li>Typically, Flow-Accelerated Corrosion (FAC) occurs between 200ºF and 450ºF. </li></ul><ul><li>Low-Tempe...
Cause <ul><li>“poor water chemistry” </li></ul><ul><li>NOT  Low Temperature </li></ul><ul><li>Low oxygen content </li></ul...
Operating Experience in PWRs <ul><li>South Texas Project </li></ul><ul><li>Palo Verde </li></ul><ul><li>Surry </li></ul><u...
South Texas Project <ul><li>Wear in piping downstream of Condensate Polishers </li></ul><ul><li>Operating Temp. = 90-130ºF...
Palo Verde <ul><li>Wear in Resin Traps downstream of Condensate Polishers </li></ul><ul><li>Operating Temp = 135ºF </li></...
Surry <ul><li>Wear downstream of Condensate Polishers </li></ul><ul><li>Operating Temp = 135ºF </li></ul><ul><li>Carbon St...
Vogtle <ul><li>Wear downstream of Steam Generator Blowdown Demineralizers </li></ul><ul><li>Operating Temp = 130ºF </li></...
Operating Experience in BWRs <ul><li>Fukushima Daini </li></ul><ul><li>Nine Mile Point </li></ul>
Fukushima Daini <ul><li>Wear downstream of orifice in Control Rod Drive line. </li></ul><ul><li>Operating Temp. = 95ºF </l...
Nine Mile Point <ul><li>Wear in Reactor Building Closed Loop Cooling System (RBCLC) </li></ul><ul><li>Operating Temp. = 12...
EPRI Findings <ul><li>Susceptible areas in PWRs </li></ul><ul><ul><li>Downstream of Condensate Polishers before amine inje...
EPRI Findings <ul><li>According to EPRI, CHECWORKS SFA can be applied to BWRs, CANDUs, and PWRs effectively for Low-Temper...
EPRI Recommendations <ul><li>PWRs </li></ul><ul><ul><li>Perform susceptibility analyses and, if necessary, inspections on ...
EPRI Recommendations <ul><li>BWRs </li></ul><ul><ul><li>Include all low-oxygen areas (< 20 ppb) of condensate, feedwater, ...
Impact on CSI Projects <ul><li>PWRs </li></ul><ul><ul><li>Piping downstream of Condensate Polishers and Steam Generator Bl...
Impact on CSI Projects <ul><li>BWRs </li></ul><ul><ul><li>Use Water Chemistry Analysis in SFA to determine low-oxygen area...
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Low Temperature FAC

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This is an introduction to Low-Temperature FAC based on EPRI Technical Report

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Low Temperature FAC

  1. 1. Flow-Accelerated Corrosion at Low Temperatures R. Doremus February 20, 2009
  2. 2. Overview <ul><li>Summary of EPRI TR-1015170 </li></ul><ul><ul><li>Definition of Low-Temperature FAC </li></ul></ul><ul><ul><li>Cause </li></ul></ul><ul><ul><li>Operating Experience </li></ul></ul><ul><ul><ul><li>PWR </li></ul></ul></ul><ul><ul><ul><li>BWR </li></ul></ul></ul><ul><ul><li>EPRI Findings </li></ul></ul><ul><ul><li>EPRI Recommendations </li></ul></ul><ul><li>Impact on CSI Procedures </li></ul>
  3. 3. Definition <ul><li>Typically, Flow-Accelerated Corrosion (FAC) occurs between 200ºF and 450ºF. </li></ul><ul><li>Low-Temperature FAC is FAC occurring below 200ºF. </li></ul>
  4. 4. Cause <ul><li>“poor water chemistry” </li></ul><ul><li>NOT Low Temperature </li></ul><ul><li>Low oxygen content </li></ul><ul><ul><li>< 20 ppb </li></ul></ul><ul><li>Neutral water </li></ul><ul><ul><li>pH ~ 7.0 </li></ul></ul>
  5. 5. Operating Experience in PWRs <ul><li>South Texas Project </li></ul><ul><li>Palo Verde </li></ul><ul><li>Surry </li></ul><ul><li>Vogtle </li></ul>
  6. 6. South Texas Project <ul><li>Wear in piping downstream of Condensate Polishers </li></ul><ul><li>Operating Temp. = 90-130ºF </li></ul><ul><li>Carbon Steel (A106 B) </li></ul><ul><li>pH @ 77ºF = 7.0 </li></ul><ul><li>Dissolved O 2 ~ 5 ppb </li></ul><ul><li>Measured Avg. Max. Wear Rate ~ 11.9 mils/year </li></ul>
  7. 7. Palo Verde <ul><li>Wear in Resin Traps downstream of Condensate Polishers </li></ul><ul><li>Operating Temp = 135ºF </li></ul><ul><li>Carbon Steel (A106 B) </li></ul><ul><li>pH @ 77ºF = 7.0 </li></ul><ul><li>Dissolved O 2 ~ 1-3 ppb </li></ul><ul><li>Measured Avg. Max. Wear Rate ~ 6.6 mils/year </li></ul>
  8. 8. Surry <ul><li>Wear downstream of Condensate Polishers </li></ul><ul><li>Operating Temp = 135ºF </li></ul><ul><li>Carbon Steel (A106 B/A234 WPB) </li></ul><ul><li>pH of slightly less than 7.0 </li></ul><ul><li>Measured Avg. Max. Wear Rate ~ 10 mils/year </li></ul>
  9. 9. Vogtle <ul><li>Wear downstream of Steam Generator Blowdown Demineralizers </li></ul><ul><li>Operating Temp = 130ºF </li></ul><ul><li>Carbon Steel </li></ul><ul><li>pH = 7.0 </li></ul><ul><li>Measured Avg. Max. Wear Rate ~ 4.6 mils/year </li></ul>
  10. 10. Operating Experience in BWRs <ul><li>Fukushima Daini </li></ul><ul><li>Nine Mile Point </li></ul>
  11. 11. Fukushima Daini <ul><li>Wear downstream of orifice in Control Rod Drive line. </li></ul><ul><li>Operating Temp. = 95ºF </li></ul><ul><li>Carbon Steel (JIS STPT38) </li></ul><ul><li>Dissolved O 2 < 10 ppb </li></ul><ul><li>Measured Avg. Max. Wear Rate ~ 8.1 mils/year </li></ul>
  12. 12. Nine Mile Point <ul><li>Wear in Reactor Building Closed Loop Cooling System (RBCLC) </li></ul><ul><li>Operating Temp. = 120ºF </li></ul><ul><li>Carbon Steel (A53 A,B / A234 WPA,B) </li></ul><ul><li>Avg. pH = 6.5 </li></ul><ul><li>Dissolved O 2 ~ 0 ppb (“below measurable amounts”) </li></ul><ul><li>Worked in conjunction with other wear mechanisms (crevice, galvanic, and general corrosion) </li></ul>
  13. 13. EPRI Findings <ul><li>Susceptible areas in PWRs </li></ul><ul><ul><li>Downstream of Condensate Polishers before amine injection point </li></ul></ul><ul><ul><li>Downstream of Steam Generator Blowdown Demineralizers </li></ul></ul><ul><li>Susceptible areas in BWRs </li></ul><ul><ul><li>Condensate upstream of oxygen injection point </li></ul></ul><ul><ul><li>Anywhere with oxygen content < 20 ppb </li></ul></ul>
  14. 14. EPRI Findings <ul><li>According to EPRI, CHECWORKS SFA can be applied to BWRs, CANDUs, and PWRs effectively for Low-Temperature FAC. </li></ul>
  15. 15. EPRI Recommendations <ul><li>PWRs </li></ul><ul><ul><li>Perform susceptibility analyses and, if necessary, inspections on Resin Traps and piping between polishers and amine injection points. </li></ul></ul><ul><ul><li>Perform susceptibility analyses and, if necessary, inspections on piping downstream of Steam Generator Blowdown Demineralizers. </li></ul></ul>
  16. 16. EPRI Recommendations <ul><li>BWRs </li></ul><ul><ul><li>Include all low-oxygen areas (< 20 ppb) of condensate, feedwater, and auxiliary systems in the FAC program. </li></ul></ul><ul><ul><li>Be aware of possible damage upstream of oxygen injection location. Analysis and inspection may be required. </li></ul></ul>
  17. 17. Impact on CSI Projects <ul><li>PWRs </li></ul><ul><ul><li>Piping downstream of Condensate Polishers and Steam Generator Blowdown Demineralizers should not be excluded in a System Susceptibility Evaluation (SSE) analysis due to low temperature. </li></ul></ul><ul><ul><li>These lines should be modeled, if possible. </li></ul></ul><ul><ul><li>Otherwise, include in the Susceptible Non-Modeled (SNM) Program. </li></ul></ul><ul><ul><li>Will need input from client on amine injection point if not obvious from P&IDs or isometrics. </li></ul></ul>
  18. 18. Impact on CSI Projects <ul><li>BWRs </li></ul><ul><ul><li>Use Water Chemistry Analysis in SFA to determine low-oxygen areas of the plant. </li></ul></ul><ul><ul><ul><li>May require entering plant global data in CHECWORKS prior to completion of an SSE. </li></ul></ul></ul><ul><ul><li>Be aware piping upstream of oxygen injection points. </li></ul></ul><ul><ul><li>Categorize all low-oxygen areas as susceptible, regardless of temperature. </li></ul></ul><ul><ul><li>Model susceptible lines if possible. </li></ul></ul><ul><ul><li>Otherwise, include in SNM. </li></ul></ul>

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