Residual Heat Removal Flashcards
What are the Safety Related functions of RHR?
- Transfer heat from the RCS to the CCW system via the RHR HX’s. (Forced cooldown)
- Used as a part of ECCS.
- Used as a part of CTS.
- Provides RCS LTOP during shutdown conditions. (450# relief)
What are the RHR pump auto starts?
- SI (Train Specific)
- Load shed with SI (Train Specific)
What are the RHR pump trips?
- Load shed
- RWST Lo-Lo (9.6%) with respective suction valve open (IMO-310/320)
- Overcurrent
- Overload
What are the requirements to open IMO-128/ICM-129? (RCS Loop 2 Hot Leg to RHR Suction)
To open these valves, RCS # must be < 410#
- NPS-122 -> IMO-128
- NPS-121 -> ICM-129
What is the setpoint for SV-103 (RHR Suction relief valve) and what is its purpose?
- 450# at 900gpm
- Provides LTOP and RHR suction overpressure protection
What is the setpoint for IMO-312/322? (RHR pump recirc valves)
Open and Close:
- Unit 1: 820gpm and 1335gpm
- Unit 2: 900gpm and 1500gpm
What are the fail positions for the air operated valves in the RHR system?
- IRV-311 (RHR HX Bypass Flow Control Vlv) -> Fail Open
- IRV-310/320 (RHR HX Outlet Recirc Line Shutoff) -> Fail Open
- IRV-300 (RHR HX to CVCS Demin Shutoff) -> Fail Closed
What is ICM-305/306?
Recirc Sump to RHR/CTS Pump Suction Valves
What is IMO-340/350?
East/West RHR HX to CCP/SI Pump Suction Valves.
What is IMO-330/331?
East/West RHR Spray Supply Valves
What is IMO-310/320?
East/West RHR Pump Suction Valves
What is IMO-215/225?
RWST to East/West CTS Pump Suction Valves
What is IMO-262 and -263?
CCP to SI Pump Suction X-Connect Valves
What are the interlocks to open ICM-305/306?
- IMO-310/320 Closed
- IMO-215/225 Closed
What are the interlocks to open IMO-340/350?
- ICM-305/306 Open
- IMO-262 OR 263 Closed
What are the interlocks to open IMO-330/331?
- ICM-305/306 Open
What are the interlocks to open IMO-310/320?
- ICM-305/306 Closed
- IMO-340/350 Closed
- IMO-330/331 Closed
What prevents dead heading an RHR pump (weak pump) during the injection phase following a LOCA?
Check valves between the tee for the RHR pump recirc valve and the tee for RHR spray and IRV-310/320.
What level is Reduced Inventory?
618’ 1.5”
What level is Mid Loop?
614’
What does Hot Leg Recirc do for the RCS?
Prevents boron precipitation is the RX Vessel.
When can RHR be placed in service following a RX Shutdown?
- RCS# less than or equal to 400#
- RCS Temp < 350F
What are the time restrictions for transferring to Hot Leg Recirc and why?
- Minimum: 5.5 Hours, to avoid core uncovery due to high decay heat.
- Maximum: 7.5 Hours, to prevent boron precipitation in the RX vessel head.
Why must RHR Loop Injection Valves be closed prior to aligning RHR Spray?
Prevent RHR pump run-out.
How many RHR pumps can be ran at Reduced Inventory and why?
- One
- Prevents air entrapment due to vortexing at the suction.
Upon SI, what does the CCW outlet of the RHR HX throttle to? (CMO-419/429)
3000-3500 gpm
What is the purpose of Hot Sleeve Fans?
Cools concrete around containment penetrations to prevent dryout.
What is the LCO requirement for RCS Loops in MODE 4? (LCO 3.4.6)
Two loops consisting of any combination of RCS loops and RHR loops shall be OPERABLE, and one loop shall be in operation.
What 1 hour or less actions are required if one required tech spec loop is INOPERABLE while in MODE 4?
- Initiate action to restore a second loop IMMEDIATELY.
What 1 hour or less actions are required if two required tech spec loops are inoperable OR the required loop is not in operation?
- Suspend ops that would cause introduction of coolant < required boron concentration IMMEDIATELY
AND - Initiate action to restore one loop to OPERABLE status and operation IMMEDIATELY
What is the LCO requirement for RCS Loops in MODE 5, Loops Filled? (LCO 3.4.7)
One RHR loop shall be OPERABLE and in operation, and either:
- One additional RHR loop shall be operable
OR
- SGWL of 2 S/G’s shall be above the lower tap of the wide range instrumentation by greater than or equal to 420 inches.
What is the LCO requirement for RCS Loops in MODE 5, Loops NOT Filled? (LCO 3.4.8)
Two RHR loops shall be OPERABLE and one RHR loop shall be in service.
