Nuclear Boiler Instrumentation - .5 Flashcards
Describe Narrow Range Level Detectors
1) 0” to +60”
2) Calibrated hot at 1000#, 135°F in Drywell, and 75°F in Rx building.
3) If indicated level is steady, actual level goes down with Rx pressure going up.
Describe Wide Range Level Detectors
1) -150” to +60”
2) Calibrated hot at 1000#, 135°F in drywell, and 75°F in Rx building.
3) ECCS initiation goes off of wide range instruments.
4) Largest disparity between indicated and actual level occurs when cooling down
Describe Upset Range Level Detectors
1) 0” to +180”
2) Calibrated hot at 1000#, 135°F drywell, and 75°F Rx Building
3) Indicates higher when cooling down
Describe Shutdown Range Level Detectors
1) 0” to 400”
2) Calibrated cold at 0#, 120°F Water, 80°F drywell, and 75°F Rx building.
3) Indicates lower when cooling down because it is calibrated colder, more dense, higher D/P.
Describe Fuel Range Level Detectors
1) -311” to -111”
2) Calibrated for accident: no jet pump flow, 0# in vessel and drywell, saturated steam water mixture, and 75°F in Rx building.
3) When in refueling, the absence of the Fuel Pool Low Level Alarm indicates that level is >22’ 5” above the RPV flange.
Wide Range Pressure Detectors
0-1200# OR 0-1500#
Narrow Range Pressure Detectors
850-1050#
Low Range Pressure Detectors
0-50#
Describe PAMS Recorders
1) Channels A&B - They have the shortest vertical run of piping in the drywell and are less affected by accident conditions. Preferred instrument during accident. (See EOP Caution 1)
2) Shifts to fast speed on Level 3 (12.5” OR 1037#). Can return to slow speed by pressing button next to recorder when above 12.5” or below 1037#.
Level 8
+54”
(4 turbine trips)
-Main Turbine trip (NR)
-RFP Turbines trip (NR)
-HPCI Turbine trip (WR)
-RCIC “Trip” (WR). (F045 shuts => secures steam)
Level 7
+39”
-Hi Level Alarm (NR)
Level 5/6
+35”
-Normal Operating Level
Level 4
+30”
-Low Level Alarm
-Interim (45%) Recirc Runback (IF concurrent w/ a RFP trip)
Level 3
+12.5”
-Rx Scram
-Lowers FWLC setpoint set down (14”)(.5 sec TD)*
-Full recirc runback
-ADS Confirmatory signal
-RHR sample and discharge to RW isolation
Why is the FWLC setpoint lowered during Level 3?
Prevent over feeding on a scram/low level.
Level 2
-38”
-RCIC & HPCI initiate.
-RRCS Input: ARI, RPT (9 sec TD), start 3.9 minute SLC timer.
-A&B SACS pumps start
-RBVS isolates, supply and exhaust fans trip.
-FRVS fans start
-Radwaste supply and exhaust fans trip
-EIAC trips
-PCIS isolations
-NSSSS Isolations: RWCU F001/F004, Recirc sample 4310/4311, TIPS retract and isolate.
What are the PCIS Isolations for Level 2?
-RC boundary leak detection system
-H2/O2 analyzers
-CPCS/N2ME/DW purge valves
-H2 recombiner
-TWCU
PCIG (minor)
-Drywell floor and equipment drains
Level 1
-129”
-CS & LPCI initiate
-Signal to ADS Logic
-CRD trips
-A-D EDG, SACS, and SSW start.
-PCIG trips
-FPC, PCIG, TACS SACS cross ties close
-RACS pumps A&B Trip, SSW to RACS Isol.
-RACS to Turb and Aux bldgs isolates
-TSC Chillers Start
-CREF aligns and both loops start
-Non 1E MCCs Trips
DW Coolers Trip
MT LO Pumps and Lift Pumps Trip
RFP LO Pumps Trip
-NSSSS Isolations
MSIVs and MSIV Drains (F016 & F019)
-PCIS Isolations
Chilled Water to DW
RACS to Recirc Pump Pedestal
CRD to Recirc Seal Purge
What happens if drywell temp is hotter than vessel temp?
Indicated water level will indicate higher due to boiling in the reference leg.
Rx Flange level
+217.5”
Steam Lines Level
+118”
Top of Moisture Separators level
+80”
TAF Level
-161”
Level Zero
-211”
