Lecture 9: Overview of APR1400 Primary and Secondary Systems PDF

NUCE 402: Introduction to Nuclear System and Operation Overview of APR1400 Primary and Secondary Systems Dr. Ahmed Alkaabi Introduction 2/50  BNPP 1&2 BNPP 3&4 3/50  Plant Layout Twin units, s...

NUCE 402: Introduction to Nuclear System and Operation Overview of APR1400 Primary and Secondary Systems Dr. Ahmed Alkaabi Introduction 2/50  BNPP 1&2 BNPP 3&4 3/50  Plant Layout Twin units, slide-along arrangement Nuclear Island (NI) – Reactor Containment Building (RCB) Located at the center of NI Placed on a common basemat with AB – Auxiliary Building (AB) 4 quadrants surrounding the RCB – Compound Building (CB) Shared between two units Turbine Island (TI) – Turbine Building (TB) – Switchgear Building (SB) 4/50  APR1400 Cut-away View 5/50 Nuclear Steam Supply & Power Conversion Nuclear Steam Supply System Power Conversion System LP Steam Extract Deaerator Storage Tank Level Control Valve CTMT Spray Moisture Seperator / Reheaters (2) Deaerator MSR Drain Tank Main Steam Header MSR Drain Tank MSR Drain Tank Deaerator Intercept Valve Storage Tank (2) Atm. Dump Intermediate Stop Valve Valves (4) MSSVs (20) HP Heater 7 HP Heater 5 HP Heater 5 M M MSIVs (4) Stop Valve Control Valve LP Steam Extract POSRV (4) IRWST Steam RCGVS Steam Generator Generator 1 2 Pressurizer Downcomer Filter Feedwater High Pressure Turbine Low Pressure Turbines (3) Generator Control Valve Heaters Control Rods Letdown Ion Orifice CEDM HP Steam Extract Exchaners Economizer Feedwater Control Valve DVI (4) Letdown Heat Turbine Bypass Valves (8) Exchanger Condenser Volume Core Control Tank Aux. Reactor Reactor Power Reactor Charging Coolant Vessel Pump Pump Regenerative In-core Safety Condensate Pumps (4) Sea Water Sea Water Heat Instrumentation Injection Exchanger Tank (4) Charging Charging Control Pump Valve Boric Acid Holdup Makeup Pump IRWST Volume Tank RDT To DVI LP Heaters 1 (3) LP Heaters 2 (3) LP Heaters 3 (3) Shutdown Cooling Pump (2) HP Steam Extract HP Steam Extract MSR Drain Tank Startup Feedwater Pumps (1) Safety Injection To Hot Leg Pump (4) Feedwater Pumps (3) HP Heaters 7 (2) HP Heaters 6 (2) HP Heaters 5 (2) CTMT Spray CTMT Spray Pump (2) Booster Pumps (3) 6/50  Performance Thermal power – NSSS : 4000 MWt – Reactor core : 3983 MWt (Licensed Power) Steam pressure : 6.89 MPa (1000 psia) Net electric output : 1400 MWe Primary Side Core SG Secondary Side 7/50  Key Design Goals Design lifetime : 60 years Seismic design basis : 0.3g (SSE) Thermal margin : > 10% Plant availability : > 90% Unplanned trip : < 0.8/RY Refueling cycle : 18 months Core damage frequency (CDF) : < 10-5/RY LP Steam Extract Deaerator Storage Tank Level Control Valve CTMT Spray Containment failure frequency (CFF) : < 10-6/RY Main MSR Drain Tank Moisture Seperator / Reheaters (2) Deaerator Steam Header MSR Drain Tank MSR Drain Tank Deaerator Intercept Valve Storage Tank (2) Atm. Dump Intermediate Stop Valve Valves (4) MSSVs (20) HP Heater 7 HP Heater 5 HP Heater 5 M M MSIVs (4) Stop Valve Control Valve LP Steam Extract POSRV (4) IRWST Steam RCGVS Steam Generator Generator 1 2 Pressurizer Downcomer Filter Feedwater High Pressure Turbine Low Pressure Turbines (3) Generator Control Valve Heaters Control Rods Letdown Ion Orifice CEDM HP Steam Extract Exchaners Economizer Feedwater Control Valve DVI (4) Letdown Heat Turbine Bypass Valves (8) Exchanger Condenser Volume Core Control Tank Aux. Reactor Reactor Power Reactor Charging Coolant Vessel Pump Pump Regenerative In-core Safety Condensate Pumps (4) Sea Water Sea Water Heat Instrumentation Injection Exchanger Tank (4) Charging Charging Control Pump Valve Boric Acid Holdup Makeup Pump IRWST Volume Tank RDT To DVI LP Heaters 1 (3) LP Heaters 2 (3) LP Heaters 3 (3) Shutdown Cooling Pump (2) HP Steam Extract HP Steam Extract MSR Drain Tank Startup Feedwater Pumps (1) Safety Injection To Hot Leg Pump (4) Feedwater Pumps (3) HP Heaters 7 (2) HP Heaters 6 (2) HP Heaters 5 (2) CTMT Spray CTMT Spray Pump (2) Booster Pumps (3) 8/50  Classification for Design Safety Class 1 2 3 NNS (ANSI 51.1) Seismic Category I I I None (Reg.1.29) Mechanical Sec. III Sec. III Sec. III B31.1 (ASME) Class 1 Class 2 Class 3 Electrical 1E 1E 1E None (IEEE Std. 603) Design criteria are assigned to systems, structures, components according to their importance to the safety: for instance, … – Safety Class 1 : RCS pressure boundary equipment & supports whose failure could cause a LOCA LP Steam Extract Deaerator Storage Tank Level Control Valve CTMT Spray Moisture Seperator / Reheaters (2) Deaerator MSR Drain Tank Main Steam Header MSR Drain Tank MSR Drain Tank Deaerator Intercept Valve Storage Tank (2) Atm. Dump Intermediate Stop Valve Valves (4) MSSVs (20) HP Heater 7 HP Heater 5 HP Heater 5 M M MSIVs (4) Stop Valve Control Valve LP Steam Extract POSRV (4) IRWST Steam RCGVS Steam Generator Generator 1 2 -ASME Sec. III : Boiler & Pressure Vessel Pressurizer Downcomer Filter Feedwater High Pressure Turbine Low Pressure Turbines (3) Generator Control Valve Heaters Control Rods Letdown Ion Orifice CEDM HP Steam Extract Exchaners Economizer Feedwater Control Valve DVI (4) -ASME B31.1 : Power piping Letdown Heat Turbine Bypass Valves (8) Exchanger Condenser Volume Core Control Tank Aux. Reactor Reactor Power Reactor Charging Coolant Vessel Pump Pump Regenerative In-core Safety Sea Water -IEEE : Institute of Electrical and Electronics Engineers Instrumentation Condensate Pumps (4) Sea Water Heat Injection Exchanger Tank (4) Charging Charging Control Pump Valve Boric Acid Holdup Makeup Pump IRWST Volume Tank RDT To DVI LP Heaters 1 (3) LP Heaters 2 (3) LP Heaters 3 (3) Shutdown Cooling Pump (2) HP Steam Extract HP Steam Extract MSR Drain Tank Startup Feedwater Pumps (1) Safety Injection To Hot Leg Pump (4) Feedwater Pumps (3) HP Heaters 7 (2) HP Heaters 6 (2) HP Heaters 5 (2) CTMT Spray CTMT Spray Pump (2) Booster Pumps (3) 9/50 Reactor Coolant System 10/50  Functions Transfer of thermal energy from the Reactor Core to the Power Conversion System through steam generators Containment of any fission products that may escape the fuel … 11/50  2-Loop System Steam Generators : 2 Reactor Coolant Pumps : 4 Pressurizer : 1 Main piping – Hot leg pipes : 2 – Cold leg pipes : 4 – Suction pipes : 4 – Surge line : 1 12/50  System Design Design pressure : 17.2 MPa (2500 psia) Design temperature : 343.3 oC (650 oF) – Except for Pressurizer, whose design T is 371.1 oC (700 oF) Safety Class 1 13/50  Reactor 6 1 Reactor Vessel 5 Total Flow Reactor Internals – Upper Guide Structure Assembly 4 5 – Core Support Barrel 1 Ou 2 In – Lower Support Structure 3 Co 4 Ce 4 5 3 Reactor Core 5 Ou 6 Al CEDM (Control Element Drive Mechanism) 2 14/50  Reactor Vessel Base metal – Low carbon steel : RTNDT of “-23.3oC (-10 oF)” – Clad with austenitic stainless steel CEDM & ICI nozzles – Alloy 690 TT Inlet nozzles : 4 Outlet nozzles : 2 DVI (Direct Vessel Injection) nozzles : 4 15/50 Reactor Core Parameters Values Core thermal power 3983 MWt No. of fuel assemblies 241 Maximum burn-up (MWD/MTU) 60,000 Refueling cycle 18 months No. of reloaded fuel assemblies 100 at equilibrium cycle Fuel assembly PLUS7TM Thermal Margin >10% 16/50  Fuel Seven (7) Improvements – Enhanced thermal margin – Higher burn-up – Improved neutron economy – Improved seismic resistance – Reduced grid-to-rod fretting wear susceptibility – Increased debris filter efficiency – Improved fuel productivity 17/50  Reactor Internals (1/2) Stainless steel Integrity against vibratory loads – Verified through CVAP (Comprehensive Vibration Assessment Program) 18/50  Reactor Internals (2/2) Hydraulic design – Verified by Reactor Flow Model Test Reactor flow model – 1/5-scaled in length with geometric & hydrodynamic similitude 19/50 Integrated Head Assembly Integration & simplification of complex and heavy RV head structures to reduce : – Overhaul duration – Occupational radiation exposure – Component storage area – Loads on CEDM* & cables * CEDM : Control Element Drive Mechanism 20/50  Reactor Coolant Pump (1/3) Motor driven, single-stage centrifugal – Bottom suction & radial discharge Flexible coupling of shaft to the motor – Low vibration & noise Design changes required : 60 Hz → 50 Hz – Rotational speed: 1200 rpm → 1500 rpm – Impeller/diffuser: 6/11→ 5/(TBD) – Motor, etc. 21/50 Reactor Coolant Pump (2/3) Optimal hydraulic design to maintain the RCS flow within the allowable band over the life time – Best estimate RCS hydraulic resistance – Allowance for the changes; such as new fuels, SG tube plugging, etc. in the future RCP performance RCP Curve System Curve RCS resistance Head Head Flow Low B.E. High Min. Design Max. Design LowerFlowlimit Upper Flow limit 22/50 Reactor Coolant Pump (3/3) Seal leakage collected in Reactor Drain Tank Controlled bleed-off to CVCS RCP Shaft Seal system – Three (3) stage mechanical seal Even with one seal failure, continuous operation is allowable – Seal water injected by CVCS charging pump – CBO (controlled bleed-off) returns to CVCS Seal water Reactor injected Coolant Flow from CVCS 23/50  Pressurizer 1 RCS Pressure & Volume Control – Sufficient capacity to accommodate pressure & volume changes due to operational transients without opening the safety valves Four (4) POSRVs (Pilot Operated Safety Relief Valves) – Overpressure protection of RCS – Manual rapid depressurization of RCS to initiate “Feed & Bleed” operation in the “Total Loss of Feedwater” accident 24/50  Steam Generator Vertical, U-tube, Recirculation type Alloy 690 TT U-tubes – Resistant to PWSCC* – 10% plugging margin Integral economizer – Thermal performance increased by ~ 5% Steam pressure : 1000 psia – Moisture content ≤ 0.25% * PWSCC: primary water stress corrosion cracking < More details will be discussed in the “Overview of APR1400 Secondary Systems”> 25/50 Chemical & Volume Control System 26/50 Functions RCS inventory control by charging and letdown flow RCS chemistry control by purification, hydrogen degassing & chemical addition operations Reactivity control by boration and dilution operations And … – Seal injection to the RCPs – Auxiliary spray to the Pressurizer – Water supply to the Reactor Cavity and IRWST 27/50  System Design “Non-Nuclear Safety” – With some exceptions, partly upgraded to Safety Class 2 or 3 for reliability enhancement Many functions and many interfaces … HH H PI-220 A L Letdown CCW CH-202 S CH-200 P CH-423 CH-522 CH-523 PURIFICATION RHX PURIFICATION DEBORATING ION M FILTERS CH-520 ION EXCHANGER CH-392 EXCHANGER LETDOWN F CH-515 CH-516 CH-110X CH-201P CH-204 CH-374 LHX F-202 CH-369 CH-383 CH-404 M Charging CH-110Y CH-201Q F EDT CH-521 CH-381 CH-394 RDT CH-385 M LETDOWN CH-354 PRM CHARGING CONTROL CH-433 CH-240 VALVE CH-302 CH-110Z BRM CH-435 S SDCHX AUX. CH-363 CH-362 CH-398 SPRAY CH-378 CH-389 CH-431 CH-203 CH-199 RDT CH-500 RCPs PREHOLDUP CH-382 CH-395 (4) CH-866 CH-787 CH-241 ION S F-241 CH-507 CH-505 EXCHANGER CH-747 CH-835 CH-867 CH-802 CH-242 CH-415 F-242 FROM CH-868 CH-807 CH-243 F-243 RCP GAS CH-869 CH-812 CH-244 HYDROGEN F-244 CBO(4) STRIPPER REACTOR Containment CONTAINMENT CH-506 CH-508 CH-502 CH-511 MAKEUP WATER AUXILIARY NITROGEN REACTOR MAKEUP TANK Aux. Building BUILDING CH-255 CH-524 VOLUME CONTROL CH-503 F WATER PUMPS (2) TANK CH-512 CH-210X F-210X REACTOR MAKEUP OUTSIDE(YARD) SEAL WATER CONTAINMENT INJECTION F F FILTER FILTERS CHEMICAL REACTOR ADDITION CAVITY M CH-501 BABT M CH-189 SYSTEM IRWST CH-509 SEAL M MFHX CH-504 INJECTION OUTSIDE(YARD) HEAT CH-527 EXCHANGER BORIC CCW ACID CH-659 CH-649 EDUCTOR CH-126 CH-124 STORAGE CH-212Q TANK M M CH-210Y CH-510 CH-174 PCPS CH-212P CH-577 CH-576 F-212B BORIC F-211 CHARGING ACID CH-575 CH-753 CH-144 CONTROL CCP(2) M FILTER VALVE CH-532 F H CH-514 CHARGING CHARGING A FROM RESTRICTING RESTRICTING BORIC ACID ORIFICE 2 ORIFICE 1 P CH-191 MAKEUP PUMPS(2) IRWST PI-211 M CH-536 CH-335 CH-334 ACP CH-190 M CH-534 28/50  Flows In & Out (1/2) HH H PI-220 A L CH-202 CH-200 P S Letdown CCW CH-522 CH-523 PURIFICATION RHX FILTERS M LETDOWN F CH-515 CH-516 CH-110X CH-201P LHX F-202 M F Charging CH-110Y CH-201Q EDT RDT M LETDOWN CH-354 CHARGING CONTROL CH-433 CH-240 VALVE CH-302 CH-110Z CH-435 Aux. Spray S SDCHX AUX. CH-363 CH-362 SPRAY CH-431 CH-203 RCP Seal Injection CH-199 CH RDT RCPs PREHOLDUP (4) CH-866 CH-787 CH-241 RCP CBO ION F-241 CH-507 CH-505 EXCHANGER CH-747 CH-835 CH-867 CH-802 CH-242 F-242 CH-868 CH-807 CH-243 F-243 RCP CH-869 CH-812 CH-244 F-244 CBO(4) CH-506 Containment CONTAINMENT CH-508 AUXILIARY Aux. Building BUILDING CH-255 CH-524 VOLUME CONTROL TANK SEAL INJECTION F F FILTERS CHEMICAL ADDITION M CH SYSTEM SEAL M MFHX CH INJECTION 29/50 Flows In & Out (2/2) Outside (Yard) Reactor Cavity IRWST Outside (Yard) Aux. Building 30/50 Safety Injection System 31/50  Functions Emergency core cooling DVI – In a LOCA (loss of coolant accident) Inventory and Reactivity control – In an RCS depressurizing accident such as steam line break, SG tube rupture, etc. Feed & Bleed operation SIT – In a “Total Loss of Feedwater” accident IRWST HVT Safety Injection - IRWST: In-containment Refueling Water Storage Tank Pump (4) - HVT: Holdup Volume Tank - SIT: Safety Injection Tank 32/50  System Design Safety Class 2 Redundant active & passive injection sub systems Sufficient Capacity – In a LOCA Two (2) SI pumps with SITs : 100% for LBLOCA One (1) SI pump with SITs : 100% for SBLOCA – For Feed & Bleed operation in a “Total Loss of Feedwater” accident – Borated water inventory in IRWST for SIS SIP SIP RWST SIT SIT LPSIP RCP RCP IRWST HPSIP S/ G RV S/ G CONTAINMENT RCP RCP HPSIP SIT SIT LPSIP SIP SIP 33/50  Advanced Features (1/2) Four (4) Trains DVI (Direct Vessel Injection) – Emergency water injected directly into Reactor Vessel : Reduced spillage of injected water IRWST (In-containment Refueling Water Storage Tank) – “Injected water” returns to IRWST : No need to re-align the SI pump suction for “Recirculation” mode SIP SIP SIT SIT RCP RCP IRWST S/ G RV S/ G CONTAINMENT RCP RCP IRWST IRWST SIT SIT SIP SIP 34/50  Advanced Features (2/2) SIT (Safety Injection Tank) equipped with the Fluidic Device – Passive regulation of injection flow: High flow in early phase of a LOCA … Steady flow extended over the reflood phase Conventional SIT SEISMIC LUGS AT 90 0 X4 EA SUPPORT SUPPORT 2 EA 1 EA SIT with Fluidic Device 35/50 Shutdown Cooling System 36/50  Functions DVI Residual heat removal – Cooldown RCS from Hot Shutdown condition to the refueling temperature & maintain it for an extended period of time (cooling by S/G is ineffective) – Cooldown RCS to Cold Safe Shutdown condition following SBLOCA, SLB, FWLB in conjunction with ADV and AFWS IRWST cooling during Feed & Bleed operation Shutdown Cooling Pump (2) - SBLOCA: Small Break LOCA Shutdown Cooling HX - SLB: Steam Line Break - FWLB: Feedwater Line Break - ADV: Atmospheric Dump Valve - AFWS: Auxiliary Feedwater System 37/50  System Design Safety Class 2 Two (2) Trains “Inter-connected” with Containment Spray System – SC pumps are inter-changeable in type and capacity with CSPs (containment spray pumps) SC Pump (2) CTMT Spray Pump (2) 38/50  Operation Modes RCS residual heat removal – Plant heatup & shutdown – Reduced RCS inventory operation (Mid-Loop) – Post-accident operation (manual operation, long term cooling) IRWST cooling during post-accident operation Abnormal operation – Containment spray in case of Containment Spray pumps inoperable RCS residual Post-accident heat removal IRWST Cooling 39/50 Containment Spray System 40/50  Functions Containment Spray – Reduction of containment pressure & temperature in LOCA or MSLB* accident (inside the containment) – Removal of radioactive fission products – Mixing and cleanup of containment air to prevent local accumulation of combustible gas * MSLB : Main Steam Line Break CTMT Spray Pump (2) 41/50  System Design Safety Class 2 Two (2) Trains “Inter-connected” with Shutdown Cooling System – CS Pumps are inter-changeable in type and capacity with SCPs (shutdown cooling pumps) SC Pump (2) CTMT Spray Pump (2) 42/50  Operation Modes Accident Operation – Actuated by SIAS (SI Actuation Signal) or CSAS (CS Actuation Signal) Severe Accident Operation – Emergency Containment Spray Backup System(ECSBS) – Water from external sources delivered by fire engine truck to ECSBS spray header 43/50 Component Cooling Water & Essential Service Water Systems 44/50  Waste Heat Removal Component Cooling Water System (CCWS) ESSENTIAL SERVICE Essential Service Water System (ESWS) WATER SYSTEM (ESWS) ESW PUMP COMPONENT COOLING CCW WATER SYSTEM (CCWS) PUMP SC HX SC PUMP SHUTDOWN COOLING SYSTEM (SCS) 45/50  CCWS (1/3) Functions – Heat removal from the safety-related components to ESWS Emergency shutdown of plant Mitigation of Design Basis Events: core decay heat and containment heat – Intermediate barrier for radioactivity release to the environment