Feedwater System Flashcards
What are the feedwater pump trips?
- L8, RPV level >202.3” (2 out of 3 NR)
- Bearing oil pressure Low (<8psig for 10sec)
- Suction Pressure Lo-Lo (<265#) (2 of 2 pressure switches) (‘A’ 5 sec, ‘B’ 3 sec, ‘C’ 1 sec)
- Slow Transfer
- Motor Electric Fault
- Bus Undervoltage
What percent open does the feedwater pump min flow valve need to be before the FWP will start?
15% (19% per procedure)
Where does FWP seal water come from?
Condensate Booster Pumps
What happens when less than 2 FWPs are running and Rx Pwr is >72% (based on steam flow)
Reactor Recir Flow Control Valve Runback. Valve runs back to 10% open position.
What is FWP Flow Limiter Logic and what is its purpose?
When FWP suction pressure is <280psig it limits the LV10 to 40% with a Turbine Trip. It will auto clear when >280psig. This is used to prevent cavitation of the FWPs.
For DFWLC, when does High Power Mode transition to Low Power Mode?
15% Rx Pwr
For DFWLC, when does Low Power Mode transition to High Power Mode?
20% Rx Pwr
What level indication would be provided on a Variable Leg (NR B & C) break?
False LOW Level
What is Setpoint Setdown and its purpose
Prevents a L8 trip of the FWP following a SCRAM by automatically lowering the level setpoint to 153” for 60 seconds and then slowly ramps to 175” over another 60 seconds in the control units following a SCRAM.
What happens to the LV55s during a Setpoint Setdown?
LV55s are rejected to Manual with a one time full close signal applied.
What happens to Setpoint setdown if controlling Rx level with the LV55s?
Operator action is required to control level
What happens when the SUSPEND button is utilized?
It will stop LOADING 2FWS-LV10A(B,C) if plant conditions require its use. The valve will stop moving and remain in MANUAL at the position it was at when SUSPEND was depressed. To complete loading 2FWS-LV10A(B,C) will need to be operated in manual (M).
What position do the FWP min flow valves fail?
Fail Open
On a loss of IAS, what position does the CNM-LV137 and LV55 fail?
Fail AS-IS
Why must the ZIP skid be isolated when FPs are off?
Flow will reverse
How many elements are used in High Power Mode?
3 (level, feed flow, steam flow)
How many elements are used in Low Power Mode?
1 (level)
What happens to the FWS when 2/3 NR instruments read Level 8 (202.3”)?
- LV137 and LV55 shift to Manual
- FWPs Trip
On a loss of IAS, what position does the FWP min flow valve FWR-FV2 fail?
Fail OPEN
What causes LV10 to lock-up
- Loss of IAS
- Loss Demand Signal
- Loss of Position Feedback
- Demand to Position Deviation
- Loss of Power Supply
What causes LV55 to lock-up
- Loss of IAS
- Loss Demand Signal
- Loss of Position Feedback
- Demand to Position Deviation
When does an RRCS Feedwater Runback initiate?
25 seconds after a High Pressure (1065psig) initiates
What happens to the FWS during a Feedwater Level Control Valve Runback?
Close signals are applied to all Level control Valve actuators. Min flow valves go full open. Manual or Automatic control of Level control valves returns 25 sec after feedwater runback initiation.
When do LV10s start to open on a startup?
When LV55s are 80% open.
What do LV55s throttle close to as the LV10s open?
32% open
When do LV55s go full shut on a startup?
When total steam flow reaches 3.7 Mlbm/hr (approx 27%) and Reactor Press is >900psig.
How many Channels are required to be OPERABLE to meet the LCO of Tech Spec 3.3.2.2 Feedwater System and Main Turbine High Water Level Trip (L8) Instrumentation?
3 of 3 NR channels are required to be OPERABLE. (2 out of 3 initiate a TRIP)
What would an extended loss of CCS do to the operating FW pump?
Cause elevated motor and lube oil temps. As well as high seal temps.
What is the primary control panel for HWC?
Operator Interface Unit (OIU) [2HWC-PNL500]
Where does HWC inject?
Suction of CBPs to combine with excess oxygen.
What must be done with ZIP when supplying Rx with 2CNM-LV137?
ZIP system must be isolated by closing 2ZIP-V10 and 2ZIP-V11. There are no check valves installed in the ZIP supply and return piping. With a condensate booster pump supplying the Reactor vessel, flow through the ZIP system will bypass 2CNM-LV137 and be an uncontrolled source of makeup water.
What happens if HWC injection valves are not opened slowly?
excess flow valve at the hydrogen skid can trip and cause excessive H2 into the Feedwater System possibly causing a Main Steam Line Radiation Monitor alarm and trip of the mechanical vacuum pumps.
What happens to H2 on a loss of OFI?
H2 goes up
Where can HWC be shutdown?
PNL500 and MCR
What is the TD for HWC AOV218
5 min
What happens to the FWS if V21s are closed?
Isolate feed if MOV122 (FWP bypass for low energy cleanup) fails open
What cools the seal water for the FWPs?
CCS
What happens to FWP on a loss of Service Water?
FWP bearing temps rise
What are HWC S/D signals?
- Low O2 pressure
<=75 psig - Purge Switch in PURGE
When is CNM-LV137 used?
Low Flow
Low Pressure
S/U to 500# RPV
When are both LV10s utilized?
55% - 100%
(2nd FWP is started at 55%)
