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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

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.

TECHNICAL DATA

Size: 

Up to DN 200

Temperature: 

Up to 371°C

Pressure: 

Up to 200 bar

According to customer requirements and 
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

VCTDS-03163-EN 17/05

Emerson.com/FinalControl

© 2017 Emerson. All rights reserved.

Содержание Sempell PSRV VS99

Страница 1: ... 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 TECHNICAL DATA Size Up to DN 200 Temperature Up to 371 C Pressure Up to 200 bar According to customer requirements and...

Страница 2: ...PE VS99 PILOT OPERATED Pressurizer safety relief valves Containment building Blowdown tank Pressurizer Steam generator Turbine Generator Air and water vapor Condenser Water Preheater Emergency cooling system Reactor sump Reactor pressure vessel Cooling tower ...

Страница 3: ...f the pilot valves open the safety valve opens if the pilot valves close the safety valve closes Several pilot valves are assigned to each safety valve Each pilot valve has a pressure relief line and a pilot line Each pilot valve can be blocked for repair purposes The corresponding stop valves are locked by valve locking devices according to the regulations in such a way that each of the pressuriz...

Страница 4: ...4 SEMPELL MODEL PSRV PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED ...

Страница 5: ...ded to open them Each pilot valve as needed can be blocked by a stop valve In the case of the emergency cooling the system pressure must be reduced This is accomplished with a pressure relief valve type PDE which is electrically actuated and therefore can also be opened below the set pressure of the VS66 The process of the primary circuit pressure relief to ensure the emergency cooling supply is r...

Страница 6: ...6 SEMPELL MODEL PSRV PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED ...

Страница 7: ... system pressure by independent feeding lines within the main valve inlet flange No external lines are foreseen producing this compact design 4 VS99 safety valve 4 x 2 VS66 self acting spring loaded pilot valve with stop valve for the pilot line 4 x 1 PDE doubled bleed and feed valve A double motor pilot valve type PDE serves as the so called bleed and feed valve to open the main valve under the s...

Страница 8: ...8 SEMPELL MODEL PSRV PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED ...

Страница 9: ...pilot valves are assigned to one pressurizer safety relief valve The Sierion is a non floating pilot valve which functions well with a wide variety of media such as steam water two phase flows and supercooled water THE EUROPEAN EPR SOLUTION 3 VS99 safety valve 3 x 2 Sierion pilot valve with stop valves for the pilot and control line 3 x 1 DMS doubled bleed and feed valve Pressurizer Sierion Pressu...

Страница 10: ...10 SEMPELL MODEL PSRV PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED ...

Страница 11: ...d assists opening and closing During normal operation the solenoids are energized and the pilot valves are closed If a solenoid fails switch off failure the pilot valves still fulfill their function as spring loaded safety valves regardless of the solenoids The steam pilot valves operate only with system pressure no external energy is needed for the safety function The pilot valves are connected t...

Страница 12: ...he valve is installed horizontally so the inlet is vertical Reference Reactor type APR 1400 Shin Kori 3 4 Shin Hanul 1 2 Barakah 1 4 Size DN 8 200 mm Class PN Up to class 2500 PN 400 Body material A182 F316 LN 1 4406 Qualification Flow coefficient by NB USA Demonstration of function by Areva in Karlstein with steam water and two phase mixture TYPE VS 99 PRESSURIZER SAFETY RELIEF VALVE As explained...

Страница 13: ...sure System pressure through operating pressure Disc 1 Closed Chamber A System pressure Chamber B Reduced pressure Under operating conditions the same operating pressure predominates in all chambers of the safety valve including the pilot line If the system pressure exceeds the set pressure of the pilot valve the pilot valve opens therefore the pilot line opens also The steam of the pilot chamber ...

Страница 14: ... additional stroke movements In the open position of the valve disc a refill bore is enabled The size of this refill bore and the size of the other refill cross sections are dimensioned so that the entire volume of medium flowing into the relief chambers can be safely released through the control line Therefore a sufficient pressure difference remains at the actuating piston and the valve disc is ...

Страница 15: ...VS99 PILOT OPERATED 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 THE FUNCTION OF THE MAIN VALVE ...

Страница 16: ...quipped with safety locking devices which facilitate a controlled blocking Design Floating design with supplementary loading Reference PWR Germany and Brazil PWR VVER Size DN 1 25 mm Class PN class 1500 PN 250 Body material 1 4553 1 4541 Qualification Together with VS99 Stable valve performance when subject to two phase flow or low flow transient no costly loop seal required Design Floating design...

Страница 17: ...bove If the system pressure reaches the set pressure adjusted with the spring at the impulse part the impulse part opens suddenly at additional pressure increase The steam flows into chamber B strikes the impact plate and causes it to rise System pressure at operating pressure Disc 1 Closed Disc 2 Closed Chamber A System pressure Chamber B Atmosphere Chamber C System pressure System pressure throu...

Страница 18: ...ces of check disc 2 the check disc opens and immediately initiates pressure relief of pilot line C for the main valve The main valve opens and remains open as long as the pilot valve is open 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 System pressure through opening pressure Disc 1 Op...

Страница 19: ...ng pressure is reached The pressure below the impact plate of the check piece drops and check disc 2 closes to block pilot line C FUNCTION VS66 System pressure under closing pressure Disc 1 Closed Disc 2 Closed Chamber A System pressure Chamber B Atmosphere Chamber C Pressure increase System pressure at operating pressure Disc 1 Closed Disc 2 Closed Chamber A System pressure Chamber B Atmosphere C...

Страница 20: ...ith 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 Whether the medium is pure steam or a mixture of steam and water or if the system medium is already...

Страница 21: ...ing package As system pressure rises in the bellows chamber the plunger is moved below disc 1 and attempts to detach it from its seat in disc 2 Because of the Δp existing here however this cannot be accomplished at first and disc 2 is also lifted up to its seat Disc 2 is closed Disc 1 is still closed and seals to the atmosphere Disc 1 Closed Disc 2 Open Disc 3 Closed Chamber A System pressure Cham...

Страница 22: ...If disc 1 is opened chamber B is relieved above disc 3 and disc 3 opens The pilot line C to the main valve is relieved and the main valve also opens Disc 1 Open Disc 2 Closed Disc 3 Closed Chamber A System pressure Chamber B Reduced pressure Chamber C System pressure FUNCTION SIERION Disc 1 Open Disc 2 Closed Disc 3 Open Chamber A System pressure Chamber B Atmospheric pressure Chamber C Reduced pr...

Страница 23: ...gh to separate disc 2 from its seat by the coupling The pressure in the chamber above disc 2 increases and therefore also the pressure in chamber B above disc 3 Disc 3 closes again with the support of the pressure spring thus closing pilot line C to the main valve The pressure in pilot line C increases again and the main valve closes FUNCTION SIERION Disc 1 Closed Disc 2 Closed Disc 3 Open Chamber...

Страница 24: ... of external energy it is not possible to open this valve at low pressures However in order to be able to supply the emergency cooling the system pressure must be lowered This is accomplished with the so called bleed and feed valve which is electrically actuated and therefore can also be opened below the set pressure Furthermore the cold overpressure function is fulfilled with this valve In princi...

Страница 25: ...oth valves function differently Disc 1 closes the valve through the system pressure and the pressure spring below the disc while disc 2 closes the valve against system pressure by means of a motor In normal operation both valve discs 1 and 2 are closed and therefore so is the pilot line A to the main valve If the motors receive the signal to open from the pilot chamber disc 1 in the first valve is...

Страница 26: ...sed Chamber A Rising pressure FUNCTION DPDE If the falling pressure in pilot line A reaches the response pressure of the main valve the main valve opens If the signal to close the valve is given in the first valve the plunger is pulled back and with the help of the spring and system pressure disc 1 closes again At the same time in the second valve disc 2 is pressed back to its closed position ...

Страница 27: ...RELIEF VALVES TYPE VS99 PILOT OPERATED Motors Close signal Disc 1 Closed Disc 2 Closed Chamber A System pressure FUNCTION DPDE After both valves have closed again and the system pressure in pilot chamber A has risen the main valve closes again ...

Страница 28: ...ves are the most widely distributed The double solenoid valve consists of two nearly identical valves the inner valve facing the main valve and the outer valve Due to design requirements the inner valve is not completely tight while the outer valve is absolutely tight at the seat This design permits the alternating functional testing of the inner and the outer valves without actuating the main val...

Страница 29: ...B System pressure Chamber C System pressure Chamber D System pressure Chamber E System pressure If both solenoids are energized pre pilot discs 2 and 4 are lifted Therefore the pressure in chambers E above the discs is relieved and discs 1 and 3 can open The upward motion of discs 1 and 3 is supported by the system pressure below discs 1 and 3 Solenoid 1 Energized Solenoid 2 Energized Disc 1 Close...

Страница 30: ...er B Pressure relief Chamber C Pressure relief Chamber D Pressure relief Chamber E Lower pressure If the solenoids are once again de energized pre pilot discs 2 and 4 close Because of the increasing pressure in chambers E above discs 1 and 3 the discs close again Solenoid 1 De energized Solenoid 2 De energized Disc 1 Open Disc 2 Closed Disc 3 Open Disc 4 Closed Chamber A Lower pressure Chamber B L...

Страница 31: ...em pressure Chamber C System pressure Chamber D System pressure Chamber E System pressure FUNCTIONAL TEST The double design of the valve permits the functional testing of the both inner and the outer valves without actuating the main valve in the process To do so the respective solenoid is energized and the corresponding pre pilot disc is lifted Therefore the chamber E above the respective disc is...

Страница 32: ...ed 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 Thus there is a very tight seal at the seat TYPE VCA Design Solenoid valve energized open principle with integrated isolation valve in one forged body design Reference PWR Germany PWR VVER Size DN 1 25 mm Class PN class 1500 PN 250 Body material 1...

Страница 33: ...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 Solenoid 1 Energized Disc 1 Open Chamber A Start of the pressure reduction Once the solenoid is energized the solenoid plunger presses onto the bottom side of disc 1 from above and opens the disc Pilot chamber A is momentarily relieved ...

Страница 34: ...energized Disc 1 Closed Chamber A Pressure increase Because of the pressure relief in pilot chamber A the main valve opens suddenly in milliseconds If the solenoid is de energized again the anchor together with the stem moves to the upper position together with the stem disc 1 follows this movement After the VCA is closed pilot chamber A is refilled at the same time ...

Страница 35: ...V PRESSURIZER SAFETY RELIEF VALVES TYPE VS99 PILOT OPERATED FUNCTION VCA After a corresponding pressure increase in pilot chamber A the main valve closes also Solenoid 1 De energized Disc 1 Closed Chamber A System pressure ...

Страница 36: ...5 6 PWR VVER 1000 MW Czech Republic Dukovany 1 4 PWR VVER 440 MW Temelin 1 2 PWR VVER 1000 MW Finland Loviisa 1 2 PWR 440 MW Olkiluoto 3 PWR EPR 1600 MW France Flamanville 3 PWR EPR 1600 MW Hungary Paks 1 4 PWR VVER 440 MW People s Republic of China Taishan 1 2 PWR EPR 1600 MW Russia Balakovo 1 3 PWR VVER 1000 MW Novovoronezh 5 PWR VVER 1000 MW Novovoronezh II 1 2 PWR VVER 1200 MW South Korea Shin...

Страница 37: ...r industry all our customers can be sure that the quality parameters valid in their national market or field are met without fail Yet quality assurance doesn t end with delivery In addition we provide worldwide assistance and backup in installation and plant commissioning as well as detailed maintenance recommendations regularly updated parts information and individual service plans The efficiency...

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