Term
| Stator cooling standby pump start |
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Definition
| Standby pump will automatically start when pressure sensed drops by 10 PSI at the pump discharge. A backup pressure switch starts the standby pump on a drop of 20 PSI. |
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Term
| Two functions of stator cooling |
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Definition
Circulate low conductivity water through stator windings Provide cooling water to exciter rectifier banks.
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Term
| If the stator cooling unit is not available, what is the current limit (at 45 psig Hydrogen)? |
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Definition
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Term
| Purpose of stator cooling pressure control valve |
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Definition
| Maintain stator inlet pressure 3 PSID below machine gas pressure. |
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Term
| Flow range over which stator cooling pressure control valve operates |
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Definition
| Per B-manual: 277-307 gpm |
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Term
| Functions of Stator cooling surge tank |
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Definition
Pump NPSH; Surge volume; Removal and venting of gases from stator cooling water.
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Term
| Reason stator cooling pumps are tripped on Generator Differential Current Relay (287X) |
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Definition
| Minimizes damage to generator if fault is caused by water leakage into the generator from stator cooling or circulation of high conductivity water due to stator cooler leak. |
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Term
| Reason stator cooling pumps are tripped on Generator Lockout Relay (286G) |
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Definition
| Prevents generator circulating water temperature from dropping below minimum recommended operating temperature of 40 degrees Celsius. |
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Term
| List the turbine runback initiation signals |
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Definition
Low inlet pressure (245 GPM stator cooling flow --> 45.8 psig); High stator outlet temperature (86 degrees C); Inadequate flow for comparable stator current (15% below minimum for given current)
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Term
| What happens on turbine runback? |
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Definition
Any turbine runback signal will cause turbine SPEED/LOAD CHANGER to reduce load until stator current drops below 3720 Amps. NOTE: This will likely result in control valve closure. Without a change in reactor power, bypass valves will open. |
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Term
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Definition
NO. If the initiation signal clears, then runback will stop. |
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Term
| Discuss turbine runback time delays |
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Definition
A turbine trip will occur if, during a runback, current does not fall below: 13,240 amps within 2 minutes and 3,720 amps after 3.5 minutes (from initiation signal).
DOES NOT SEAL IN. Therefore, if signal clears, runback stops. |
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Term
| How does pressure control respond during a turbine runback? |
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Definition
| Turbine speed/load changer controls the Turbine control valves while the bypass valves will operate in response to a signal from EPR (or controlling pressure signal). |
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Term
| When must stator cooling be in operation? |
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Definition
| "Whenever the generator is on line, except as allowed in C.4 procedure." |
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Term
| When should the air purge generator be in service? |
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Definition
| Whenever Stator Cooling is in operation and Generator is filled with hydrogen. |
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Term
| Purpose of air purge gas generator |
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Definition
Counteract hydrogen blanketing effect in stator water storage tank by injecting low CO2 air into stator cooling water to keep oxygen concentration levels at desired levels. |
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Term
| What happens when generator lockout relay is reset (w.r.t. stator cooling pumps) |
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Definition
| Pumps will restart automatically unless otherwise held out. |
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Term
| Power supply to Stator Winding Liquid Cool Pump A |
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Definition
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Term
| Power supply to Stator Winding Liquid Cool Pump B |
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Definition
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Term
| Power supply to Hydrogen and Stator Cooling Control Panel |
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Definition
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