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ACADs (08-006) Covered Keywords Description Supporting Material

Extraction Steam. ACADs (08-006) Covered Keywords Description Supporting Material. 7. 7. HP. LP A. LP B. LP C. 3. 3. 5. 5. 12. 11. 9. 9. 11. 12. 12. 11. 9. 9. 11. 12. 12. 11. 9. 9. 11. 12. 6A. 6B. 3A. 3B. 3C. 5A. 5B. 2A. 2B. 2C. 4A. 4B. 1A. 1B. 1C.

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ACADs (08-006) Covered Keywords Description Supporting Material

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  1. Extraction Steam ACADs (08-006) Covered Keywords Description Supporting Material

  2. 7 7 HP LP A LP B LP C 3 3 5 5 12 11 9 9 11 12 12 11 9 9 11 12 12 11 9 9 11 12 6A 6B 3A 3B 3C 5A 5B 2A 2B 2C 4A 4B 1A 1B 1C HDT HDT COND “A” COND “B” COND “C” B HDP B A A STEAM FLOW HDP A B FEEDWATER FLOW TO FEEDWATER LINE DRAIN FLOW C CONDENSATE PUMPS EXTRACTION STEAM HEATER, VENT, AND DRAINS

  3. OBJECTIVES • State the function of the Extraction Steam System. • Describe how Reactor Power will respond to the following: • Loss of feed water heating • Trip of a Heater Drain Pump • Describe why extraction steam stop valves and non-return check valves are used in extraction lines.

  4. OBJECTIVES • Describe the function of the “Heater Drain Pumps” • Explain why water induction into the main turbine is undesirable.

  5. Extraction Steam Purpose Provides steam to ALL 15 Feedwater heaters to heat the Condensate and Feedwater prior to entering the Steam Generators thus increasing plant efficiency.

  6. 120°F 442°F 401ºF 362ºF 442ºF 288ºF 223ºF 184ºF 120ºF

  7. 7 7 HP LP A LP B LP C 3 3 5 5 12 11 9 9 11 12 12 11 9 9 11 12 12 11 9 9 11 12 6A 6B 3A 3B 3C 5A 5B 2A 2B 2C 4A 4B 1A 1B 1C HDT HDT COND “A” COND “B” COND “C” B HDP B A A STEAM FLOW HDP A B FEEDWATER FLOW TO FEEDWATER LINE DRAIN FLOW C CONDENSATE PUMPS EXTRACTION STEAM – FEEDWATER FLOW – DRAIN FLOW Rev 1

  8. LOW PRESSURE TURBINE EXTRACTION STEAM LP HEATERS 1A, 2A, 3A 11 12 9 TO GLAND SEALING STEAM SYSTEM 1A M TO CONDENSER 2A 3A CONDENSER A Rev 1

  9. EXTRACTION STEAM INLET CONDENSATE OUTLET DRAIN INLET HIGH LEVEL DUMP CONDENSATE INLET DRAIN OUTLET Sub-cooled Zone Shell Side 6 5 4 HDT FEEDWATER HEATERS TYPICAL Of HEATERS 1, 2, 3, and 5 3 2 1 CONDENSER Condensate Condensate Condensate Condensate Flow Flow

  10. Extraction Steam Drains Inlet Subcooled Zone Drain to 5th Stage Feedwater Heater Feedwater Inlet Feedwater Outlet 6th Stage Feedwater Heater

  11. STOP CHECK VALVE Stop Valve Stop Check Valve EXTRACTION STEAM STOP VALVE HP/LP TURBINE MOV 3,4,5,6 REPRESENTIVE OF ALL FEEDWATER HEATER EXTRACTION STEAM LINES FOR HEATERS 3, 4, 5, 6

  12. Extraction Steam Stop Valves and Non-return valves are used to protect the main turbine from: • Overspeed • Water entering turbine

  13. Water entering the main turbine is undesirable due to: • Erosion of the turbine blades • Vibration of turbine • Breakage of blades

  14. TEST SWITCH COUNTER-WEIGHT CYLINDER AND PISTON EXTRACTION STEAM STOP CHECK VALVE

  15. EXTRACTION STEAM STOP CHECK VALVE

  16. 3rd I I 9th 9th LP TURBINE TT TT Stop Valve Stop Check Valve MOV High-High LT LT 9th Stage Extraction Steam From LP Turbine to 3rd Heater

  17. TT 4th High I I I LT Hi-Hi LT 7th 7th LP TURBINE Stop Valve Stop Check Valve MOV LT 7th Stage Extraction Steam From HP Turbine to 4th Heater (HP Turbine Exhaust Steam) Heater Drain Tank LT

  18. Stop Valve MOV 3RD DRAIN POT LSH I I I ORIFICE LOW POINT DRAINS Drain Manifold Condenser Drain Manifold Condenser Drain Manifold Condenser 9th 9th LP TURBINE EXTRACTION STEAM LINE DRAIN VALVE LOCATION TT Stop Check Valve High LSH

  19. TT < 25% Open 3RD High Level LSH I I I TT Steam Line Drain Valves: - Open on High HTR Level - Open on Turbine Trip - Open Stop Valve < 25% Open High Drain Pot Level Only opens Associative Drain Valve 9th 9th LP TURBINE Stop Valve TT Stop Check Valve MOV DRAIN POT LSH ORIFICE TT LOW POINT DRAINS Drain Manifold Condenser Drain Manifold Condenser Drain Manifold Condenser

  20. LP TURBINE B LP TURBINE C LP TURBINE A HTR 3B HTR 3A HTR 3C LV-4239 LV-4238 LV-4256 LV-4246 FO FO FO FO FO FO FO FO FO FO FO FO FO LV-4257 LV-4247 HTR 2C HTR 2B HTR 2A LV-4236 LV-4237 LV-4235 LV-4243 FO FO FO LV-4245 LV-4244 HTR 1C HTR 1B HTR 1A LV-4233 LV-4234 LV- 4232 LV-4240 FO FO FO LV-4241 LV-4242 CONDENSER "A" CONDENSER “B" CONDENSER “C" LP HEATER DRAINS

  21. Heater Drains The drainage from the various heat-exchanges (tube-side) after it transfers part of its heat energy to the Condensate & Feedwater flow stream is still at a relatively high energy so the water is pumped back into the Condensate & Feedwater System to also increase efficiency.

  22. Reheater Drain Tank (RHDT) • The Normal Level Control Valve modulates controlling drain flow to the 6th stage heater based on Reheater Drain Tank Level. • If the level in the Reheater Drain Tank reaches the high level setpoint it will cause the “high level dump” valve to modulate open to dump the contents of the Reheater Drain Tank to the associated 4th stage heater.

  23. Moisture Separator Drain Tank (MSDT) • The Normal Level Control Valve modulates controlling drain flow to the Heater Drain Tank based on the MSDT level. • If the level in the MSDT reaches the high level setpoint it will cause the High Level Dump Valve to modulate open to dump the contents of the “MSDT” to the Condenser.

  24. Moisture Separator Reheater • Rising level will cause a Main Turbine Trip on HIGH Level (2/3 Level Switches) on 1/4 Moisture Separator Reheaters.

  25. RHDT normal drain • Valves into 6A (C) • Scavenging Steam will • align to Main Condenser • Extraction Steam: • Isolation Valve (C) • Non-Return Valve (C) • Drain Valves (O) 6A I/P Main Condenser “A” LT B LT A LT A LT C LT C LT B LV4288 FO I/P Feedwater Heater 5A LV4284 FO

  26. Normal drain from • 6A (C) • Extraction Steam: • Isolation Valve (C) • Non-Return Valve (C) • Drain Valves (C) 5A LT B LT A LT C LT B LT A LT C I/P I/P Main Condenser “B” Feedwater Heater 4A LV4282 FO LV4286 FO

  27. 4A LT B LT A LT C LT C • Normal drain valve from • 5A (C) • MSDR normal drain • valves (C) • Extraction Steam: • Isolation Valve • Non-Return Valve • Drain Valves High HDT Level Between 4A and 5A Feedwater Heater HDT “A” LT B LT A LT C I/P I/P Main Condenser “A” LV4333 FO LV4331 FC

  28. 4A LT B LT A LT C LT C • Extraction Steam: • Isolation Valve • Non-Return Valve • Drain Valves Low HDT Level Between 4A and 5A Feedwater Heater HDT “A” LT B LT A LT C I/P I/P Main Condenser “A” LV4333 FO LV4331 FC

  29. Heater Drain Tank

  30. Heater Drain Pumps Why do we need the Heater Drain Pumps? During normal operation, the heater drain tank pump provides 1/3 of the flow requirements for NPSH to the main feedwater pumps and assists in preheating feedwater.

  31. Heater Drain Pump

  32. How would Reactor Power respond to the trip of a Heater Drain Pump with the Reactor at 100% power ? A. Stay the same. B. Increase. C. Decrease. √

  33. Heater Drain System Malfunction • Malfunction of feedwater heater drain system could have a significant impact on plant operation. • Plant efficiency would be reduced because • Loss of feedwater heating capability • May exceed reactor core limits: • Reactor Power • RCS Delta Temperature Limits • RCS Pressure limits

  34. SUMMARY • Extraction Steam, Feedwater Heaters and Heater Drain systems are important to the preheating of feedwater prior to flowing into steam generator and for improving secondary efficiency. • A loss of any feedwater heating causes reactor power to increase due to the decrease in RCS temperature. • Not maintaining proper feedwater heater level also causes a decrease in secondary efficiency which affects reactor power.

  35. Objectives Review • State the function of the Extraction Steam System. • Describe how Reactor Power will respond to the following: • Loss of feed water heating • Trip of a Heater Drain Pump • Describe why extraction steam stop valves and non-return check valves are used in extraction lines.

  36. Objectives Review • Describe the function of the “Heater Drain Pumps” • Explain why water induction into the main turbine is undesirable.

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