The purpose of the quench spray system is to:
lower containment pressure to reduce offsite radiological doses following a LOCA
After running an RSS pump for testing, why is the RSS system dewatered?
to minimize corrosion in the RSS system due to the borated water
Why is makeup to the RSS seal water system carefully throttled?
to prevent overpressurizing the seal water system
Why is trisodium phosphate stored in baskets distributed around the containment sump?
to minimize stress corrosion cracking on mechanical systems and components by raising recirculated water pH >= 7, and to help maintain iodine in solution
A LOCA has occurred
a CDA has actuated
the 11 minute timer has time out in the RSS pump start logic
the RSS pumps have not yet started, since RWST level has not yet reached 520,000 gallons
What is the purpose of the 11 minute timer portion of the RSS pump start logic?
to allow time to establish sufficient sump water for RSS pump suction
A large break LOCA occurs, resulting in a CDA.
What automatic OPEN signal, if any, do the RSS containment sump suction valves receive?
valves receive an OPEN signal immediately upon receipt of the CDA
What is the cooling medium for the containment recirculation system heat exchangers?
service water
The QSS operates to lower the containment pressure to approximately atmospheric within ____ minutes of the worst case DBA.
60
Which of the following is a concern if a SI or CDA were to occur during RSS pump surveillance testing?
RSS pump suction valves are deenergized CLOSED and if the pump starts before the lineup is restored, it will run without a suction flow path
A LBLOCA has occurred. ECCS is being aligned for cold leg recirculation.
Why are the “A” and “B” recirc spray pumps preferred over the “C” and “D” recirc spray pumps when aligning for cold leg recirculation?
the “A” and “B” RSS pumps have recirculation valves which protect the pumps on medium-break LOCAs
During a refueling outage, a surveillance is performed on the TSP stored on the floor or in containment. The surveillance fails due to the TSP being below the min allowed volume.
If a LOCA has occurred prior to shutting the plant down for refueling, what adverse effect could the low TSP volume have on the accident?
excessive corrosion in CTMT and excessive radioactive iodine in the CTMT atmosphere
A RSS pump suction can be aligned to:
the RWST OR the containment sump
When the plant is at 100% power, the normal position of 3RSS*MOV23A (RSS pump suction MOV) is _____. When a CDA signal occurs, the valve position _____.
open; remains open
What is the normal position of “D” RSS spray header isolation valve at 100% power, and what happens to the valve on a CDA signal?
the valve is normally open. and remains open on a CDA
The A and B RSS pumps are equipped with motor-operated recirculation valves 3RSSMOV38A/B. When the plant is at 100% power, the position of 3RSSMOV38A/B is ____. The logic which changes the position of *MOV38A/B is interlocked with _____.
closed; associated RSS*MOV20 closed
What ESF signal will cause the QSS pump discharge valve 3QSS*MOV34A/B to auto open?
CDA
3QSS*MOV34A/B (QSS pump discharge MOV) are ESF injection valves. These valves are normally CLOSED because:
they are credited as containment isolation valves
The QSS pump discharge MOVs (*MOV34A/B) have auto opened due to a CDA signal.
What signals, if any, will automatically close the MOVs?
low RWST level of approximately 69,000 gallons
All of the following valves are butterfly valves which receive an OPEN signal when CDA actuates except:
3SILMV8809A and 3SWPMOV54A
Which of the following conditions would trip a running refueling water recirculation pump, 3QSS-P1A/B?
closure of RWST recirc suction valve 3QSS*AOV27
A large break LOCA has occurred in containment and CDA has actuated.
What will cause the running QSS pumps to auto stop?
RWST level drops to 69,000 gallons
