main steam Flashcards
main steam
STATE the functions of the MS system
Transport Steam Produced in the Steam Generators to the Turbine Generator for Conversion to Electrical Power.
• Conduct steam from the steam generators to the Main Turbine, Main Feed pump turbines, Emergency Feed pump turbine, Reheaters, Turbine Gland Sealing Steam, Steam Dump and Auxiliary Steam System.
• Provide a means to dissipate heat generated from the Nuclear Steam Supply System, during all modes of normal plant operation, including turbine trip at full load.
• Isolate containment from the Main Steam Supply system and provide for Main Steam line warmup.
• Provide overpressure protection for the steam generators.
• Control Steam Generator pressure during startup, shutdown and while the condenser is not available.
STATE the function of the following MS system component
steam flow restrictors
- Reduces pipe whip after a steamline break.
- Minimizes the maximum flowrate that the MSIV must close against.
- Limits RCS cooldown rate.
- Provides d/p to measure steam flow signal.
- Made up of 7 venturi’s
STATE the function of the following MS system component
atmospheric relief valves
Regulate S/G pressure (RCS temp) when the Main Condenser and/or Steam Dumps are unavailable
STATE the function of the following MS system component
safety valves
– Ensures that Secondary System Pressure will be limited to 110% (1320 psia) of its design pressure during the most severe transient.
(100% load rejection with no Rx Trip and No Steam dumps)
– Total relieving capacity is 109.8% of the total secondary steam flow at 100% RTP.
STATE the function of the following MS system component
EFW pump steam supply
• Supplied from Steam lines A and B • Upstream of the MSIV • Opposite pipe chases • Automatically open on: – SI – LOP – Low Steam Generator level – ATWS mitigation
STATE the function of the following MS system component
steam line radiation monitors
- Provides means to detect and measure radioactivity in the event of a steam generator tube rupture
- Alarm and Indication is provided to Control Room
STATE the function of the following MS system component
main steam isolation valves
– Automatically isolates steam flow in the event of a steam line break upstream or downstream of MSIV
STATE the function of the following MS system component
MSIV bypass valve
• used to equalize pressure across MSIV prior to opening
STATE the function of the following MS system component
main steam line drains
Group A:
• Drains main and reheat steam piping.
• Closed when the generator is synchronized to the grid per MPE.
Group B:
• Drain turbine control valves downstream header and extraction steamlines.
• Closed at 15% power by MPE
Group C:
• Drains the extraction steamlines, crossaround piping, and MSR drain piping.
• Closed at 30% per the MPE.
DRAW the main steam system and ARRANGE the components in the order in which they appear from the steam generators through the main steam manifold
Steam Generator Rad Detector ASDV EFW pump tie in Safeties MSIVS To Bottle
STATE which main steam lines are in the east and west main steam and feedwater pipe chase, and which steam lines feed the steam driven emergency feed pump
- A & D steam lines in West Chase
- B & C steam lines in East Chase
- A & B supply the EFW Pump
STATE the opening and closing motive force for a main steam isolation valve.
Closing: N2 gas
Opening: Hydraulic fluid
STATE where the motor operated main steam line drain valves can be individually operated.
These valves are operated in groups from the MCB or individually from CP-66.
DESCRIBE the testing of a Main Steam Isolation Valve (OX1430.02).
• Depress and Hold the MSIV Valve Test push-button at the MSIV Test Panel
( MCB G rear)
• Release Valve Test push-button as soon as MSIV closing travel indicated
• Verify MSIV reopens
• Retract the Slow Flow Restrictor
• Lock open the Hydraulic return isolation valve
• Exit the TS Action Statement
DESCRIBE how to locally close an MSIV.
• Isolate the air supply to the Air motor
• Override the main dump pilot solenoid
• Isolate Hydraulic supply
– pump discharge
