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SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES
TYPE VS99 PILOT OPERATED
The design, construction and activation of the safety valves depends on the
design of the respective reactor and the corresponding specifications
GENERAL APPLICATION
Pressurizer safety relief valves protect the
pressurizer from overpressure and must
ensure the following functions:
• Pressurizer relief for normal operating
transients
• Hot and cold overpressure protection on
liquid, steam, gas and steamwater-mixture
• Depressurization of reactor coolant system
following an accident
Emerson.com/FinalControl
TECHNICAL DATA
Size:
Up to DN 200
Temperature:
Up to 371°C
Pressure:
Up to 200 bar
According to customer requirements and
specifications.
© 2017 Emerson. All rights reserved.
FEATURES
• Extremely high sealing force, ensuring leak
tightness up to the set pressure.
• Very precise reproducibility of set pressure
and small operating pressure differences,
accuracy of pilot set pressure opening value
with repeats better 1%.
• All parts essential for function are kept at
operating temperature, thus no thermal shock.
• The disc piston is the only moving part in the
main valve, providing reduced maintenance.
• Low or high pressure in-situ test during
operation to preventive maintenance.
• Compact design from forged stainless steel.
• Redundancy of pilot valves and diversity of
function principle of pilot valves according to
specification.
• Suitable for all types of nuclear reactors.
VCTDS-03163-EN 17/05
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Summary of Contents for Emerson Sempell PSRV VS99
- Page 1 • Pressurizer relief for normal operating According to customer requirements and transients specifications. • Hot and cold overpressure protection on liquid, steam, gas and steamwater-mixture • Depressurization of reactor coolant system following an accident VCTDS-03163-EN 17/05 Emerson.com/FinalControl © 2017 Emerson. All rights reserved.
- Page 2 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED Pressurizer safety relief valves Containment building Generator Turbine Pressurizer Blowdown tank Steam generator Air and water vapor Reactor pressure vessel Condenser Cooling tower Water Preheater Reactor sump Emergency cooling system...
- Page 3 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED INTRODUCTION HISTORY Pilot operated safety relief valves are used to protect the pressurizer against overpressure. In 1970 First delivery of pilot-operated safety pressurized water reactors, the energy of the primary circuit is transferred to the secondary valves to NPP Stade in Germany steam system by the steam generators.
- Page 4 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED...
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Page 5: Valve Assembly
SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED THE GERMAN KWU-PWR SOLUTION DN 80 Spring DN 80 loaded pilot valves VS66 ETS1 ETS1 DN 25 DN 25 DN 25 DN 25 DN 50 DN 50 DN 50 DN 50 DN 25 DN 25... - Page 6 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED...
- Page 7 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED THE KOREAN APR1400 SOLUTION DN 80 DN 80 DN 150 DN 80 DN 80 DN 150 DN 80 DN 80 Springloded DN 150 pilot valve VS66 VS66 VS66 VS66 Pilot valve...
- Page 8 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED...
- Page 9 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED THE EUROPEAN EPR SOLUTION Sierion Sierion Sierion Sierion Sierion Sierion VS99 VS99 VS99 DN400 DN150 DN150 Pressurizer Pressurizer relief tank VALVE ASSEMBLY At the reactor type EPR, three pressurizer safety relief valves type VS99 are mounted directly to VS99 safety valve the side of the pressurizer.
- Page 10 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED...
- Page 11 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED THE RUSSIAN VVER SOLUTION DN 50 DN 50 DN 50 DN 50 DN 50 Spring-loaded pilot valve VS66 DN 25 VCA NICO4000 VCA NICO4000 NICO4000 Solenoid Motor Solenoid Motor Solenoid Motor...
- Page 12 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED TYPE VS 99 PRESSURIZER SAFETY RELIEF VALVE As explained above, each construction of the pressurizer safety relief valve requires an individual solution. The solution is oriented to the construction of the reactor, the technical demands and the customized specifications.
- Page 13 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED THE FUNCTION OF THE MAIN VALVE System pressure at operating pressure Disc 1 Closed Chamber A System pressure Chamber B System pressure Under operating conditions, the same operating pressure predominates in all chambers of the safety valve including the pilot line.
- Page 14 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED THE FUNCTION OF THE MAIN VALVE System pressure through opening pressure Disc 1 Open Chamber A System pressure Chamber B Further reduced pressure The pressure continues to drop in pilot chamber B and pressure differences arise at the actuation piston.
- Page 15 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED THE FUNCTION OF THE MAIN VALVE System pressure at operating pressure Disc 1 Closed Chamber A System pressure Chamber B System pressure The same operating pressure again predominates in all chambers of the safety valve including the pilot line.
- Page 16 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED TYPE VS66 SELF-ACTING SPRING-LOADED PILOT VALVE The design of the spring-loaded steam pilot valve is adapted completely individually to the corresponding construction of the main valve. At least two pilot valves per main valve are required, because one valve is always switched active while the other is blocked.
- Page 17 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED FUNCTION VS66 System pressure at operating pressure Disc 1 Closed Disc 2 Closed Chamber A System pressure Chamber B Atmosphere Chamber C System pressure Under operating conditions, the steam pilot valve is closed.
- Page 18 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED FUNCTION VS66 System pressure through opening pressure Disc 1 Open Disc 2 Open Chamber A System pressure Chamber B Pressure increase Chamber C Pressure relief The pressure transfers its opening force through the impact plate to the check disc 2 of the pilot part.
- Page 19 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED FUNCTION VS66 System pressure under closing pressure Disc 1 Closed Disc 2 Closed Chamber A System pressure Chamber B Atmosphere Chamber C Pressure increase If system pressure drops, the pilot valve closes again when the set closing pressure is reached.
- Page 20 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED TYPE SIERION PILOT VALVE AREVA NP has developed a new pilot valve especially for application in EPR pressurizer systems and together with Sempell, has brought it to functional maturity and through all required qualification. The special feature of this valve is that after opening, it is closed to flow. Due to its design, it could be achieved that the pilot valve featured nearly identical functional values for all different media states.
- Page 21 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED FUNCTION SIERION Disc 1 Closed Disc 2 Open Disc 3 Closed Chamber A System pressure Chamber B System pressure Chamber C System pressure In normal operation, pre-pilot disc 1 is closed and disc 2 opened.
- Page 22 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED FUNCTION SIERION Disc 1 Open Disc 2 Closed Disc 3 Closed Chamber A System pressure Chamber B Reduced pressure Chamber C System pressure When the set pressure is reached, the opening force on disc 1 is greater then the Δp existing there and disc 1 opens suddenly.
- Page 23 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED FUNCTION SIERION Disc 1 Closed Disc 2 Closed Disc 3 Open Chamber A System pressure Chamber B Atmospheric pressure Chamber C Reduced pressure Because the plunger below disc 1 is directly dependent on pressure, as pressure decreases it lowers and pushes disc 1 back to its seat in disc 2.
- Page 24 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED BLEED AND FEED VALVE WITH MOTOR Because the VS99 safety valve, according to requirements, must be actuated by a pilot valve independently of external energy, it is not possible to open this valve at low pressures.
- Page 25 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED FUNCTION DPDE Motors Close signal Disc 1 Closed Disc 2 Closed Chamber A System pressure The DPDE consists of a body with two valve inserts for reliable closing function. Both valves function differently.
- Page 26 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED FUNCTION DPDE Motors Open signal Disc 1 Open Disc 2 Open Chamber A Reduced pressure If the falling pressure in pilot line A reaches the response pressure of the main valve, the main valve opens.
- Page 27 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED FUNCTION DPDE Motors Close signal Disc 1 Closed Disc 2 Closed Chamber A System pressure After both valves have closed again and the system pressure in pilot chamber A has risen, the main valve closes again.
- Page 28 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED BLEED AND FEED VALVE WITH SOLENOID The products DMS 5/6 and EMS 5/6 were developed especially for nuclear applications and were first used on the FSA-station (main steam valve set) of the KWU pressurized water reactors.
- Page 29 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED FUNCTION DMS 6 (energized open principle) Solenoid 1 De-energized Solenoid 2 De-energized Disc 1 Closed Disc 2 Closed Disc 3 Closed Disc 4 Closed Chamber A System pressure Chamber B System pressure Chamber C...
- Page 30 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED FUNCTION DMS 6 (open circuit principle) Solenoid 1 Energized Solenoid 2 Energized Disc 1 Open Disc 2 Open Disc 3 Open Disc 4 Open Chamber A Pressure relief Chamber B Pressure relief Chamber C...
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Page 31: Functional Test
SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED FUNCTION DMS 6 (open circuit principle) Solenoid 1 De-energized Solenoid 2 De-energized Disc 1 Closed Disc 2 Closed Disc 3 Closed Disc 4 Closed Chamber A System pressure Chamber B System pressure Chamber C... - Page 32 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED BLEED AND FEED VALVE WITH SOLENOID The VCA solenoid valve is used solely to actuate the VS99 pressurizer safety relief valve. In de-energized state, it is always closed. Because the disc is always pressed against the seat from below by a small spring and this is supported by system pressure, there is no pressure relief.
- Page 33 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED FUNCTION VCA Solenoid 1 De-energized Disc 1 Closed Chamber A System pressure In normal operation, the solenoid is de-energized and disc 1 is closed. System pressure predominates in pilot line A, which keeps the solenoid valve and the main valve closed.
- Page 34 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED FUNCTION VCA Solenoid 1 Energized Disc 1 Open Chamber A Reduced pressure Because of the pressure relief in pilot chamber A, the main valve opens suddenly in milliseconds. Solenoid 1 De-energized Disc 1...
- Page 35 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED FUNCTION VCA Solenoid 1 De-energized Disc 1 Closed Chamber A System pressure After a corresponding pressure increase in pilot chamber A, the main valve closes also.
- Page 36 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED WORLDWIDE REFERENCES Federal Republic of Germany Biblis A 1200 MW Biblis B 1300 MW Brokdorf 1200 MW Emsland 1300 MW Grafenrheinfeld 1300 MW Greifswald 1 - 4 PWR - VVER 400 MW Grohnde 1400 MW...
- Page 37 SEMPELL MODEL PSRV - PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED QUALITY CERTIFICATIONS AND STANDARDS Our Quality Management System ranges from raw materials purchasing and rigorous preliminary checks on blanks, semi-finished products etc., and through all other manufacturing stages. Throughout, international quality standards apply with strict controls ensuring they are met at all times. Therefore, regardless of country or industry, all our customers can be sure that the quality parameters valid in their national market or field are met without fail.