RCS Flashcards
What is the Normal RCS pressure?
Design pressure?
Safety Limit?
2250 psia
2500 psia
2750 psia
What is normal Rated Thermal Power (MWth)?
3990 MWth
What RCP components does NC cool?
Motor Air Cooler
Motor lube oil cooler
thrust bearing lube oil cooler
seal cooler
What inputs does the reactor vessel level monitoring system (RVLMS) provide to QSPDS?
Inadequate Core Cooling (ICC) instrumentation
for determining approach to the ICC when the core is uncovered
When does the TRM require a reactor trip for SPS pressurizer pressure?
> 2409 psia
What is the trip logic of the RTSG breakers?
2/4
at least one on each power supply flow path (1 from A/C and 1 from B/D)
During a reactor startup, how is heat added to the system initially?
starting RCPs
What is the purpose of the RCP flywheel?
Raises pump coast down time and reduces the rate of decay of coolant flow when electrical power to the motor is lost
What is the purpose of the RCP Anti-rotation device?
Withstand reverse power leads and accident conditions
Has both a rotating and stationary member with sprags in between them that engage through friction during reverse rotation
What is the allowable number of running RCP combinations when the RCS is </= 200*F?
</= 500*F?
Why is this limitation in place?
no more than 2
no more than 3
prevent core lift due to high density of water at lower temperatures
Describe the flow path, flow rates, and pressure changes of the RCP seals.
6.6 gpm from charging enters the high-pressure piping
Seal water flows through the jet pump and mixes with approx 16 gpm from journal bearing cavity (22.6 gpm)
combined flow goes through the high-pressure seal cooler
3 seals with pressure drops of 42%, 42%, and 16% across each seal, respectfully. with each seal able to provide 100% pressure drop in the case of failure of previous seal
20 gpm goes back to RCS, 2.6 gpm goes through seals, back to VCT (per RCP)
What is the interlock between the RCPs and the seal bleedoff isolation valves?
valve will not close if the RCP breaker is closed
What happens to the seals if we lose seal injection?
reduced seal life due to intro of contaminants from RCS water
What are the RCP pre-start permissives?
Bone
Bleedoff valve fully open
Oil flow sufficient
NC flow sufficient
No Electrical/motor faults
How does the RCP Lift Oil pump act in regard to RCP operation?
Before RCP started, lift oil pump manually started to lift thrust bearing pads
When RCP is started a time delay is started, lift oil pump should secure automatically within 2 minutes
If lift oil pump is required to be operating when the RCP is in service, you have to hold the handswitch to start.
After RCP stops, lift oil pump auto starts and runs until manually secured
Can you secure an RCP without a lift oil pump available?
yes
may shorten the life of rotating equipment but not cause catastrophic failure
What are the starting requirements for RCP’s to minimize potential for lifting of an LTOP relief valve?
Level of pressurizer </= to 33%, the 1st RCP may be started only if SG temperature does not exceed any RCS cold leg temperature by 20 degrees F. After starting first RCP pressurizer level may be raised.
Level of pressurizer > 33% or in a water solid condition, the 1st RCP shouldn’t be started if SG temp is greater than any RCS cold leg temperature.
What is the purpose of the pressurizer?
Maintains RCS in subcooled condition
Surge volume to minimize pressure changes during transients
Ensures primary system integrity by preventing over pressurization
Surge line (12” line connects the pressurizer to the Loop 1 hot leg
How is pressurizer level maintained?
by PLCS as a function of Tavg
Level is kept with the normal band to ensure Pressurizer heaters remain covered and level is raised as Tave rises to accommodate a larger out-surge on a post trip cooldown.
Heaters covered and space for spray (pressure control)
What is the purpose of maintaining a small amount of continuous spray flow in the pressurizer?
Maintain constant temperature in the surge and spray lines to prevent thermal shock
Limit thermal stratification in the horizontal piping runs
Help to circulate the pressurizer water with the reactor coolant loops to maintain uniform water chemistry and temperature in the pressurizer
What provides the motive force for pressurizer main spray?
When do they spray valves start opening?
When are they fully open?
DP across the Reactor provided by the RCPs
2275 psia
2300 psia
What is the purpose of the pressurizer safety valves?
When do they lift?
Overpressure protection for RCS
Limit RCS to less than T.S. limit of 2750 psia
2475 psig
where do the pressurizer safety valves relieve to?
RDT
How is pressurizer safety valve status monitored?
How do the B04 lights illuminate based on valve position?
acoustic monitoring (NNN-D11)
Green - 0% - Closed
Red - 9% - Valve >9% open
Red - 100% - Valve fully open
What are the pressurizer Heaters rated at?
How many individual heaters are there?
50 kW each
36
How are the pressurizer heaters grouped together?
8 banks
- 2 banks of proportional heaters (P1, P2)
– 3 heaters in each bank (150kW per bank)
- 6 banks of backup heaters
– Backup banks (B1-B6), B1 and B2 are identical to P1 and P2 (class powered)
–Banks B3-B6 have 6 heaters each (300 kW per bank)
Where do the pressurizer heaters get power from?
B1 and B2 - PGA and PGB
all others from NG
When do the class powered pressurizer heaters trip?
SIAS
can be overridden
What can happen if an RCP is started when any DG is paralleled to the same startup transformer?
damage to the DG
Why should you not start an RCP for the first time, post-outage, if it is suspected that there is a pocket of dilute water in the RCS?
could dilute the entire RCS
approval from OPS management required
What is the normal power alignment of the RCP High pressure seal cooler inlet/outlet isolation valves?
open with power removed
