PC- Fuel Pool Flashcards
What is the primary purpose of the spent fuel pool?
to store used fuel after its been removed from the reactor for 1) shield radiation and 2) remove thermal heat generated from rad decay of fission products
What does the layout of the fuel in the spent fuel pool prevent?
so the mass doesn’t go critical
What is the water capacity of the SFP and what is the concentration PV holds boron at vs the tech specs?
340,000 gal
PV: 4000-4400 ppm
Tech specs: >2150 ppm
What is the maximum number of fuel assemblies that can be stored in the SFP?
1205
How is the spent fuel pool monitored?
yardstick type level device with a camera seen by CR
high and low level alarms —> local + CR trouble alarm
digital level indication (norm SFP level = 138.82’)
What happens when the SFP transfer canal gate is removed and the transfer canal level reaches 138’ 3”?
flood new fuel elevator cable tray
What is the purpose of the new fuel elevator?
lower new fuel from operating floor to the bottom of the pool
In the refueling pool, what happens if the pool level goes above 138’ 2”?
water intrusion to the in-core-instrument tubing shield
What is the tech spec related to fuel pool water level?
when moving spent fuel, water level shall be 23’ or more over the top of the fuel
What is the tech spec related to the boron concentration in the fuel pool?
concentration shall be 2150 ppm or higher
What is the tech spec related to the spent fuel pool being a borated water source, operating or shutdown?
fuel pool must be functional in the case the RWT is unavailable
SPF also meets:
Temp 60-180F
Boron concen 4000-4400 ppm
Volume >33500 gal
What is the required temperature range for the SFP?
60F-180F
What is the required volume of the SFP borated water source?
33,500 gal
What is the purpose of the SFP gate seals?
1 gate seals off the SFP from the cask loading pit and transfer canal so they can be drained if necessary
1 gate seals decontamination pit from cask loading pit
The gate seals on the sides of the SFP gates are Q class and pressurized with:
instrument air 42 psig
2 pressurized nitrogen bottles for back up 38 psig
How does the SFP interface with NN?
Provides control power to SFP local control panel PCN-E02
How does the SFP interface with NK?
Powers SFP local annunciator panel PCN-EO2
How does the SFP interface with CH?
RWT supplies borated water to SFP system
33,500 gal of the SFP is dedicated for emergency boration to RCS
How does the SFP interface with CT?
non-borated water make up to SFP
How does the SFP interface with FH (fuel handling and storage)?
conveys fuel assemblies to and from SFP, stores assemblies in storage racks, provides spent fuel cask handling and storage
How does the SFP interface with IA?
pressurizes SFP gate seals
How does the SFP interface with LR (liquid radwaste)?
RMTs (recycle monitor tanks) make up non-borated water to SFP
How does the SFP interface with QA?
underwater lights in SFP, Transfer Canal and Cask Loading Pit
How does the SFP interface with SI?
transfers water to and from the RWT and refueling pool
How does the SFP interface with SQ (radiation monitoring)?
Continuous monitor the SFP and refueling pool via area rad detectors
What are the entry requirements for the high risk area around the SFP?
quality log entries
FME control
What is the purpose of the fuel pool cooling system?
cool the SFP
What powers the SFP cooling pumps?
PG
What is the temp range of the spent fuel pool?
75-125*F
What is SFP cooling pump discharge pressure maintained at?
45-55 psi (can throttle discharge valve to achieve appropriate flow through PC hx)
how long do you have to align EW and SP to the SFP so temperature stays less than 167*F?
8 hours
describe the fuel pool cooling pump controls
3 position switch for each pump
discharge indication is on SFP control panel (this is above PC cleanup hand switches)
high and low discharge pressure alarms
During outage, What is cooling the SFP HXs?
one hx is cooled by NC, which is then cooled by PW Tmod
the other hx is cooled by EW at 1340 gpm, which is then cooled by SP
Does the control room have SFP temperature indication?
no
What is the purpose of the SDC augment to the fuel pool cooling system?
If total SFP decay heat load is exceeding >125F) ability of PC cooling to maintain bulk temp <145F then—> SDC cooling is aligned to PC cooling augment decay heat removal
*pc cooling system not designed to be capable of removing design basis decay heat load + full core off-load at 100 hours post reactor trip) and fully loaded SFP
What pumps can be used for, and what pump is preferred for SDC augment?
CS or LPSI pump
CS preferred because LPSI piping may cause runout & lack of flow instrumentation in discharge path of LPSI requires temp flow instrumentation be installed
*sys only cross-connected while PC cooling is actively augmented or could result in unacceptable level of volumes in these areas
How does the Fuel pool cooling interface with PG?
FP cooling pump power
How does the Fuel pool cooling interface with PK?
FP cooling pump control power
How does the Fuel pool cooling interface with NC?
cools HXs
How does the Fuel pool cooling interface with EW?
Back up flow for NC
cools one HX during outage
How does the Fuel pool cooling interface with SI?
SDC augment
transfers water to and from RWT and refuel pool
How does the Fuel pool cooling interface with RD (radioactive waste drain)?
receives PC equipment drainage
What would happen if SFP cooling was lost?
SFP temperature would rise (hi alarm 125F and hi-hi alarm at 145F in CR + local)
Temp at 180F —> all non-essential personnel leave the fuel bldg
start losing water level to evaporation and damage stored fuel —> high rad level