Inadvertent PPS actuation Flashcards
State the non-obvious entry condition associated with inadvertent PPS actuations
During a controlled plant cooldown, when MSIS or SIAS/CIAS was actuated due to failure to reset Pzr or SG pressure variable setpoints.
Determine the impact of an inadvertent PPS actuation on the operability of equipment that has been overridden.
Equipment that was placed in override or antipumped condition will be considered inoperable based on plant conditions and MODE of applicability.
What would the impact be of an inadvertent AFAS actuation and what are the actions needed to restore plant stability?
An AFAS actuation will feed cold CST water into the SGs which would lead to a positive reactivity insertion.
Operators will override and operate AFW valves to control SG level. AFAS will isolate SG blowdown which would need to be addressed due to effects on JSCALOR and SG chemistry.
State why AFA operation less than 1000RPM is detrimental to the pump.
Sustained low speeds can damage pump sleeve bearings and pump internals due to loss of lubrication. The shaft driven oil pump requires > 1000RPM to fully circulate oil.
Operation > 5 minutes with speed < 1000RPM is prohibitied and requires tripping AFA.
Determine the impact of inadvertent CIAS and actions needed to restore from it.
Only enter inadvertent CIAS if the actuation was ONLY a CIAS. If accompanied by a SIAS, use the SIAS section.
Isolates LD, WC to CMNT, RCS sampling, CMNT sumps and RU-1.
Reduce CHPs to 1, perform Loss of LD to control Lpzr, check and reset the CIAS and restore WC, CMNT sump isolations and RU-1.
Determine impact of inadvertent CSAS actuation and teh actions needed to restore.
Initiates CS flow into containment, wetting electrical equipment and support structures with borated water. It also isolates NC to RCPs and isolates seal bleedoff.
Operations will stop the CS pump by antipumping the breaker, closing any open spray header isolation valves, and restoring NC CMNT isolations to open. If NC is not restored within 10 minutes, a Rx trip and stop of all RCPs is required. IA to containment must also be restored.
Describe how a CS pump that has been stopped will be restarted.
If a CS pump needs to be restarted and a SIAS has not actuated, the AO must cycle control power to the breaker. Resets antipump condition.
If a CS pump needs to be started and a SIAS actuated, the RO will place the CS pump switch to start, release the switch and place it to start again.
First start places it in override, removing the close signal, second start starts the pump.
Discuss the hazard with attempting to close a CS valve while it is still stroking open.
The valve breaker may trip on overload and allow the valve to be stuck throttled, creating a gravity drain flowpath.
Describe how NC to containment is restored in the AOP.
Open the return isolations, then open the supply isolation. Prevents lifting the NC reliefs in containment.
State the required TCAs associated with a loss of NC to RCPs.
From the time of the loss of NC, power must be reduced or cooling water isolated and the RCP shutdown within 30 minutes. This is to protect the motor and bearings from a loss of cooling to the lubricating oil, or motor assy bearing seizure may occur.
State the TCA associated with a loss of NC to priority loads, the loads affected and the consequences of not meeting the TCA.
From the time of the loss of NC due to a LOOP or unaffecting leak in the NC(isolated from the priority loads), EW must be cross connected to supply NC priority loads within 10 minutes. Those loads are the Normal chiller, RCS sample coolers, RCP loads and CEDM normal ACUs. If not done seal damage and thrust bearing damage damage including possible seizure.
Why is it necessary to place the handswitches in CLOSE for LD and blowdown isolation valves after an inadvertent CSAS actuation?
Restoring air to containment would allow these valves to go open. Placing them in CLOSE allows controlled restoration of LD and blowdown.
Describe the impact of an inadvertent MSIS and the actions necessary.
Loss of ability to steam and feed the SGs. Isolates blowdown and sampling.
Rx trip
GO TO SPTAs
If < 5% then control SG pressure with ADVs and AFA or AFB.
Describe the actions associated with an inadvertent RAS actuation and actions needed to restore.
In the lower modes when aligned to SDC, a loss of SDC flow and core cooling would occur.
During this case, operations will:
Throttle LPSI SDCHX bypass valve to 20% open
Close both LPSI inj valves on the appropriate train.
Open SDC Loop warmup bypass valve
Override and start the LPSI pump
Restore SDC.
In the upper modes, it would align a suction path to the CMNT sumps and would need to be isolated.
Determine the impact of an inadvertent SIAS actuation and the actions needed to restore.
Starts HPSI, LPSI and CS, opens inj valves, starts SP EW and EC, DG’s and major changes to Control, Fuel and Aux bldg ventilations. Isolates SG blowdon, LD and will sias LS M19,20,71,72.
Operations must override and stop HPSI, LPSI and CS(SDC required?), reset Pzr heaters, address the loss of LD(AOP, 1 CHP, control Lpzr), Restore CEDM cooling and reset and stop previously running equipment.
