Containment Spray System(NS) Flashcards
What is the purpose of the Containment Spray System?
- Remove thermal energy from containment atmosphere in the event of a LOCA.
- Maintains containment pressure below the design limit of 15psig after all the ice has melted in the ice condenser and steam generated in the core continues to enter the containment
- Remove fission product iodine from the post accident containment atmosphere
What is the normal suction path alignment for the Containment Spray System?
The Containment Spray pumps are normally aligned to the FWST when in standby
When will we ever spray the Containment from the FWST?
NEVER
What features provide for protection against accidental actuation of Containment Spray?
- The spray header isolation valves are normally closed
2. Multiple redundant instruments are used for containment pressure
How many Containment Spray Pumps are there, What is the flow rated of one Containment Spray Pump, and what provides cooling to their motors?
- There are 2 containment spray pumps per unit, one per train
- Design flow rate is 3400gpm at 168psig
- KC provides motor cooling for the containment spray pumps
What is the power supply to the Containment Spray Pumps?
ETA/ETB
What is the design/purpose of the Containment Spray Heat Exchangers?
- There are two NS heat exchangers per unit, one per train
- Vertical shell and tube
- Borated water used to spray flows through the shell
- RN flows through the tubes
What system provides cooling to the Containment Spray Heat Exchangers, and how is it aligned?
- The nuclear service water system provides cooling
2. RN has to be manually aligned
What is the maximum Nuclear Service Water flow through the Containment Spray Heat Exchangers, and why?
- Maximum RN flow through the heat exchanger is 4650gpm
2. Flow is limited to prevent vibration induced stress in the tubes
How many spray headers are there in Containment?
- There are 4 spray headers from the Containment System, two per train
- There are 2 additional spray headers from the Residual Heat Removal System.The ND spray headers are not connected to the NS system
Where are the motor operated valves in the Containment Spray System?
The motor operated containment isolation(2 per train) valves are located outside of containment, and are manually opened for to actuate spray
How is water returned from Containment Spray to Lower Containment?
The refueling cavity drains(6 drains)are normally open, and they allow water from containment spray to flow back to the lower containment
What is the general rule about the Containment Spray Pump Suction Valves?
Only one source of water can be aligned at a time to the spray pump suction
What is required to open the Containment Spray Suction Valves from the Containment Sump(NS-1B and NS-18A)?
- The FWST suction valves must be closed(NS-20A and NS-3B)
2. The NI valves from the containment sump must be open(NI-185A and NI-184B)
What is required to open the Containment Spray Suction Valves from the FWST(NS-3B and NS-20A)?
The containment spray suction valves from the containment sump(NS-1B and NS-18A) must be fully closed
What is the normal status of the Containment Spray Pump to Containment Spray Header Containment Isolation Valves(NS-12B, NS-15B, NS-29A, and NS-32A)?
- Valves are normally closed during operation
2. Act as the outside of containment isolation valves
How are the Containment Spray Pump to Containment Spray Header Containment Isolation Valves(NS-12B, NS-15B, NS-29A, and NS-32A) operated to spray containment?
- Manually opened from the Control Room on MC-11
- Have to meet the CPCS permissive to open the valves(containment pressure greater than or equal to 0.9psig
- The Valves will automatically closed, and be prevented from opening, when containment pressure is less than or equal to 0.35psig
What is the affect of Containment pressure reaching 0.35psig on the Containment Spray Pump?
The Containment Spray Pump will automatically stop at less than or equal to 0.35psig in containment. It will have to be MANUALLY restarted if pressure increases to greater than 0.9psig
What is the affect of Containment pressure reaching 0.35psig on the Containment Spray Header Isolation Valves?
The spray header isolation valves will close at less than or equal to 0.35psig in containment. They will have to be MANUALLY opened if pressure increases to greater than or equal to 0.9psig
What is the configuration of the CPCS controls for the Containment Spray Pumps and Spray Header Isolation Valves?
The pumps and valves have separate CPCS instruments to ensure that a failure of one instrument will not cause an inadvertent initiation of spray
What added advantage is there to automatically closing the Containment Spray Header Isolation Valves?
By closing the containment spray header isolation valves the potential for water hammer is minimized on subsequent initiations of containment spray
How are the Residual Heat Removal Containment Spray Header Isolation Valves controlled?
- Normally closed valves, spray must be manually initiated
2. Spray can only be initiated based on CPCS signal just like the NS system
What are the requirements for opening the Residual Heat Removal Containment Spray Header Isolation Valves(NS-38B and NS-43A)?
- Requires CPCS signal of greater than or equal to 0.9psig
- Can only be opened if containment sump valves to the NI pumps are opened(NI-184B and NI-185A)
- ND hot leg recirculation isolation valve ND-36B(1B) or ND-37A(2A) is closed
How will a loss of power to a CPCS instrument affect the operation of the Containment Spray System?
Loss of power to a transmitter will cause it to go to the inhibit state to prevent an inadvertent initiation of containment spray
