N-16 System Flashcards
List the three critical functions of the N-16 System.
- Measure neutron levels.
- Acts as heat sink to cool PALM U-Cup Seal
- Provide pressurized water source to fill ATR vessel level transmitter, standing leg, and associated impulse lines.
What is the function of neutron level detection from the N-16 system?
Data is supplied to the Lobe Power Calculation and Indication System to determine power offset and display power split information to the RO.
What N-16 lobe powers are required for plant startup?
NE
SE
NW
SW
C
C/2
Draw the N-16 system.
What are the two supplies to N-16?
BPD and LDW
What is the function of PRV-18-186?
PRV-18-186 regulates BPD pressure from 300 psig to 100 psig for supply to PRV-8-136.
What is the function of PRV-8-136?
Lowers suction pressure to N-16 pumps from 100/120 psig to 20 psig.
What is the function of N-16 strainers M-134/135?
80 mesh strainers that strain suction source to N-16 pumps.
What is the design flow and pressure for the N-16 pumps?
18 GPM @ 510 psig
What is the function of PRV-18-7?
PRV-18-7 provides recirculation flow from N-16 discharge at 6 GPM/250 psig to ensure stable system pressure.
What is the function of PCV-18-9?
Pressure control to N-16 station 11 at 12 GPM/400 psig
What is the N-16 flowrate to PALM test seals when in use?
1.5 GPM
Describe flow distribution through N-16 station 11.
Flow at station 11 is divided and metered into 10 individual streams of 1.15 GPM.
Where does station 11 effluent from the reactor go?
N-16 water from the beta counting chambers is routed to the gland seal water feed tank.
When is BPD used as source to N-16?
Preferred source during reactor operation.
When is LDW used as source to N-16?
- If BPD flow transmitter FT-18-29 is OOS
- During outages when PCS is depressurized and BPD isolated
- BPD water activity is too high
Where is FT-18-29 BPD to N16 Total Flow Transmitter located?
BPD Corridor (Second Basement)
Where is N-16 PRV-18-186 located?
South wall of the HDW Room.
What is the fail position of PRV-8-136?
PRV-8-136 fails closed.
Describe M-130/131 N-16 Pumps.
Single stage, gear-driven centrifugal inline pumps
30 GPM@470 psig
Normal 18 GPM@510 psig
Describe N-16 pump cooling.
Pump oil sumps are cooled with raw water supplied from the canal HX raw water supply (return to canal HX discharge)
Describe impact of abnormally high or low flow through N-16 pumps.
- <18 GPM - causes excessive vibration and pressure surging
- > 30 gpm - causes substantial drop in output pressure (potential motor overload)
What is the purpose of the LDW line backflow preventers concerning N-16 system?
Prevents contamination of the LDW supply piping from N-16.
What is the purpose of the suction strainers in the N-16 system?
Prevent particulate matter from entering the fine flow control valves of station 11.
What are the power supplies to the N-16 pumps?
Fed directly from E-107. Diesel side fed from E-9, Commercial side fed from E-7
What is the normal electrical alignment for N-16 pumps?
Running pump on Diesel (E-9), Standby pump on Commercial (
Where is power supply selected for N-16 pumps?
From DCS Auxiliary Console
What auto-starts standby N-16 pump?
Standby pump auto-starts when pump discharge pressure drops below 405 psig on PT-18-1C.
What time delay is associated with N-16 pumps?
A 10-second time delay is programmed into DCS to allow pump to come up to normal speed and discharge pressure and not start the standby pump. If discharge pressure is not greater than 405 psig 10 seconds after starting a pump, the standby will auto start.
Where are N-16 pumps normally started and stopped from?
Normally started from the local Start/Stop switches next to the pumps.
Normally secured from the RCR via DCS.
Describe N-16 to GSW Crosstie.
GT-18-9 cross ties N-16 to GSW. Not currently used. Allows N-16 to supply GSW if GSW pumps OOS.
How would a loss of PALM cooling from N-16 impact the PALM system?
U-cup seal could be damaged and leakage of high temp/ high pressure loop coolant could result. First indication of abnormal supply would be increased temperature on U-cup seal TC indication.
What would high activity levels on N-16 indicate?
- Depletion/breakdown of BPD resin
- Fission break in the PCS
What is the purpose of GB-18-169 N16 Vessel Level Xmtr Fill Valve?
Used to fill the PPS vessel level transmitter impulse lines following tank work that involves adjusting level to the lower drain. Located in the ATR motor floor room.
Describe N-16 PCV-18-9.
Reduces pressure from 510 to 400 psig for station 11. IA to close valve that fails open on loss of air.
Describe flow control through N-16 chambers.
One inlet FT and associated monitor installed for each flow channel.
Local indication used when adjusting manual control valve for 1.15 GPM each channel
All flow indicators/monitors are powered from 120V Diesel/Comm LP-12
Where does N-16 effluent go?
Normal to GSWFT
Alt to Warm Waste System
Where does N-16 from PALM experiment cooling go?
Warm Waste System
What N-16 equipment is located in the Motor Floor?
PCV-18-9
Station 11
10 Online Beta Chambers
Spare Beta Chamber
Isolation Valve GB-18-169 (LT and standing leg fill line)
Inlet Beta Chamber
PRV-18-9 Pressure relief valve
N-16 flow indicators
What is the function of the N-16 inlet chamber?
Monitor activity levels of water entering N-16 station 11.
Describe overpressure protection on the N-16 system.
PRV-18-116 installed on the inlet header and will lift at 430 psig.
What is the power supply to the inlet flow monitors?
120V Diesel/Comm
How many N-16 channels are there? How many are required per TSR?
There are 10 individual N-16 channels.
6 are required per the TSR.
