Aux. Steam Flashcards
Where is Aux Steam supplied to?
Supplied to:
-Gas Stripper for degasification
-LRS for Water reclamation
-BAC Boron Reclamation
-MSR for steam blanketing
-Provides Gland Sealing Steam to Main Turbine & Main FW pumps during startup
During normal operation where is Aux. Steam supplied from ?
Normally supplied from the units Main Steam system
During shutdown or startup where is Aux. Steam supplied from ?
Supplied from other operating units
What does the Aux. Steam Condensate Receiver Tank do ?
Receives condensate and acts as a surge tank & suction point for Condensate Transfer Pumps
What is the Vent Condenser used for ? What is the Vent Condenser cooled by ?
-Used to condense any steam left in the Aux. Receiver Tank & vent any non-Condensable gases to Radwaste Building Ventilation
-Cooled by NC
Where can the Condensate Transfer pumps discharge to ? When would you be discharged to LRS TDS Holdup Tank ?
-Main Condenser
-LRS TDS Holdup Tank: Discharges when RU-7 detected radiation by inlet to Aux Steam Receiver Tank
When Main Steam enters supplies Aux. Steam what does it go through? What is the pressure reduced to ?
-Main steam goes through 1of3 Pressure Reducing Valves
-Pressure is reduced from 1000-1150psig to 250psig
What is the relief valves setpoints on the 250psig Aux. Steam line?
The relief valve setpoint is 275psig
What’re the loads that is supplied by the 250 psig Aux. Steam line?
Supplies:
-MFWP Turbines(Overspeed Testing)
-Gland Seal Steam
-Condensate Spargers
-‘A’ Aux FW Pump Turbine(Overspeed Testing)
What is the Condensate Cross-Tie used for at the discharge of the Condensate Transfer Pumps ?
Used to transfer condensate back to the unit it came from during startup & shutdown
What happens if the Condensate Receiver Tank radiation monitor is unavailable?
Must take samples before being sent back to Main Condenser
What happens if NC is unavailable to the Vent Condenser ?
NC will have to secured until NC can be restored
What does the Aux. Steam provide to the MSRs during shutdown ?
Provides steam blanketing to prevent corrosion to the tubes
When does Aux. Steam provide Gland Seal Steam to the turbine ?
Provides its during startup & power operation
How does Aux. Steam interface with FW Heater Extraction Steam & Drain ?
Sends Aux. Steam condensate drains to ED system blowdown stack
What buildings does the Aux. Receiver Tank receive Aux. Steam from ?
Receives Aux. Steam from Aux. Building & Radwaste Building
What’s flow path is provided for the Condensate Transfer Pumps to prevent overheating ?
There is a 5gpm mini flow line to the Aux Steam Receiver Tank to prevent overheating
When is each Condensate Transfer Pumps started/stopped ?
-Lead pump will starts on HI LVL in aux. receiver tank
-Standby pump will start on HI-HI LVL in Aux. Receiver Tank
-Both pumps stop on a LO LVL
What is the maximum operating temp for the Condensate Transfer pumps mechanical Seals? What is the max operating pressure limit for Aux. Receiver Tank?
-Mechanical seals max operating temp is 250F
-15psig
What is the automatic feature associated with RV-11A & B, during a high rad on RU-7?
-RV-11A going to the main condenser will isolate on high rad
-RV-11B will open to direct flow to LRS TDS Holdup Tank
If high radiation redirects flow to LRS TDS Holdup Tank, how would you reset flow back to main condenser once High Radiation alarm clears ?
Must be manually reset by lifting latch upward until it engages with latch
What will trip the Aux Steam Supply Header cutout valves (PV-331,332) closed ?
-Trip on ruptured Aux Steam Line in Aux Building, CST Pipe Tunnel, or HUT Pipe Tunnel indicated by HI Pressure
What do the 20 pressure switches throughout Aux. Building & Pipe Tunnels provide for the Aux Steam cutout valves ? How do you reset a shutoff valve once the over pressurization has been corrected ?
-Any of these switches can cause these cutoff valves to close isolating Aux Steam Loads
-Cutoff valve must be manually reset by lifting latch upward until it engages
How does the three position local control switch for the Aux Steam Condensate Transfer Pumps work ?
Start- Will start pump & send condensate to main condenser or TDS Holdup Tank
Stop- Pump will stop
Auto-controlled by alternator by level switches on receiver tank
When will the Aux Steam Condensate transfer pumps trip ?
-Lead pump stops on LO level
-LO LO level will trip pump
When will the Condensate transfer pumps Start/Stop ?
-Lead pump starts on HI level in receiver tank
-Standby pump will start on HI-HI level
-Both pumps trip on low level
Why does a HI-HI level in the Aux Steam Receiver Tank have to be investigated ?
Receiver tank is connected to Aux. Building Vent. which could possibly flood the ductwork
Where is the condenser Aux Steam being used for the MFWP, Gland Seal Regulator, MSRs, & AFWP returned to ? How does the condensate get returned back to the unit it came from ?
-All will collect in condenser, except AFWP will exhaust to atmosphere
-Will be returned by Main Condensate pumps
Why do the units normally have there Aux Steam systems cross connected?
Cross connected to allow for rapid restoration of turbine gland seal steam in event of a MSIS
In event of a unit shutdown where is the Aux Steam Receiver Tank flow routed to ?
Routed through Condensate crosstie valve back to supplying unit
What valve supplies steam to the unit during start up or shutdown ?
V-15 will be supplying the steam
What is water hammer defined as ?
A pressure change in closed conduit resulting from change in liquid velocity
What’re operator actions to prevent water hammer ?
Limited to slow throttling valves with access solid systems, voided lines,or lines with liquid/steam interfaces
What is needed to reduce voids & steam bubble collection?
Preliminary venting/vacuum breaking of systems
