N32 - EHC Flashcards
What is the EHC system mainly controlling?
Reactor pressure to control reactivity
What happens if turbine limit (setpoint) is exceeded?
Bypass valves open
What happens if EHC pump ‘B’ < 1600 psig @ >26% power?
Turbine trip and reactor SCRAM
how many overspeed protection systems are required?
Both of them:
DOPS and back-up overspeed (ovation)
How many bypass valves are there?
3 bypass valve.
How much can bypass valves bypass?
30%, (10% each valve)
How many bypass valves are required? why?
2 required
thermal limit penalty imposed by MCPR and LHGR
How many stop and control valves are required?
ALL of them
If EHC is ingested, what should be done?
induce vomiting
What PPE should be used when around EHC fluid?
Glove, face shield, respirator
What type of respirator should be used when handling EHC fluid?
Air purifying
What level should not be exceeded when filling EHC reservoir? why?
34” to prevent overfilling tank
when will the standby EHC pump auto-start?
<1800 psig on running pump OR header if pump is in Auto-STBY
What are the EHC pump trips?
< 15” EHC tank level LO-LO
MPD
What are the heater start permissives?
> 15” tank level
Recirc pump must be running
< 105 deg F heater start
> 115 deg F heater stop
When will the main turbine trip relative to EHC pressure
<1600 psig
What does the cornsilk color mean?
it is selected
When does the high filter DP alarm come in?
> 72 psid
What’s the primary purpose of the stop valves?
prevent overspeed of turbine on turbine trip
on a turbine trip, what controls Rx pressure?
Bypass valves
What must be done for a setpoint to be active?
Enable or confirm it
How do control/bypass/stop valves operate?
Fluid to open, spring to close
what valves are fast close, and which are fast opening?
Fast close – stop and control valves
Fast opening – bypass valves
What’s the power supply to EHC pumps?
A - 13AD
B - 14AE
What’s the power supply to Ovation?
and control power?
Inverter power 120 VAC (BOP)
What’s the tech spec part of EHC? (safety function)
BYPASS VALVES
What cools EHC
TBCW
How does the Temp control valve fail?
OPEN (max cooling)
What needs to be running to run the EHC heater?
Recirc pumps
What temp does the heater maintain?
105 - 115 deg F
What the SCRAM setpoints? (EOC RPT) and (EHC pressure)
TSV < 675 psig
TCV < 970 psig
<1600 psig header pressure
When are the SCRAM setpoints bypassed?
< 26% Rx power
What type of SCRAM is the EHC scram?
RPS scram
What is temp maintained at when running by temp control valve?
115 - 130 deg F
