SFP Cooling & Cleanup Flashcards
What is the SFP used for ?
-Stores spent fuel after it’s removed from Reactor
-Shields radiation
-Ensures fuel is stored in configuration that will allow mass to become critical
What does SFP inventory provide ?
-Adequate shielding for plant personnel from spent fuel
-Adequate decontamination of noble gases following postulated fuel handling accident
-Adequate NPSH Fuel Pool Cooling Pumps
-Reserve volume of borated water
What’re Aluminum-boron carbide metal matrix composite inserts used for in the SFP Fuel Storage ?
Installed in designated fuel cell locations to suppress SFP reactivity through neutron absorption to prevent SFP from going critical
What does the SFP Fuel Storage arrangement do ?
-Prevents extensive bulk boiling -Prevents peak clad temp from exceeding 650F
How much storage for fuel assemblies does the SFP have ?
Can store up to a maximum of 1205 assemblies
How many gallons water does SFP hold ?
-Holds approx. 340,000 gallons of borated water(138’)
What is the SFP Tech Spec for boron concentration ? What is administrative TRM boron concentration ?
Tech Spec- 2150ppm
Administrative TRM- 4000-4400PPM
Why is our Administrative TRM for boron concentration of SFP 4000-4400PPM?
-SFP is used as alternate source of borated water for Emergency Boration of RCS via CVCS
What’re the 4 ways of monitoring Spent Fuel Pool level ?
-Yard Stick
-SFP Control Panel
-Milltronics Ultrasonic Level system
-FLEX level indication
How does the Yard Stick for SFP Level monitoring work ?
-Mounted on inside of SFP for local monitoring
-Camera is pointed at it so Control Room can see
What is the SFP Control Panel ?
Local control panel with high & low level alarms that’ll alert operators a change in SFP level as well as annunciate a trouble alarm Control Room
What is the Milltronics Ultrasonic Level System ?
-Ultrasonic level detection & indicating system installed to monitor SFP
-Two level detectors installed along plant north wall of SFP
-Each one has a dedicated readout installed on side of Local Control Panel
For Milltronics Ultrasonic Level System how does main display indication for SFP level ?
-Indicated SFP level in feet as a decimal number
What’re the what does the signal on left side of display indicate ? (A symbol with top & bottom brackets)
Indicates normal operation of system
What does it mean when the symbol doesn’t have bottom or top bracket?
Indicates that transceiver is in Fail-Safe and non functional for use
What does vertical bar on right side of display for Milltronics Ultrasonic Level System indicate ?
Indicates level in %, with 0% being the top of the fuel racks at 113.5’ & 100% being at 138.5’
What will should do next to the bar on the right side of the display screen for Milltronics Ultrasonic Level System ??
-When level alarm is activated a up or down arrow will be next to bar graph
-A LO-LO level I’ll display two down arrows
How do the circles at bottom of display for Milltronics Ultrasonic Level System ?
PCN-LIT-0003 has two contacts:
#1 contact for High lvl alarm @138.17’
#2 contact for Low lvl alarm @137.5’
PCN-LIT-0005 has one contact:
#1 contact is for LO-LO lvl alarm @137’
What kind water is used for SFP Makeup ? What is normal makeup to SFP ?
-Can come from borated or non borated water sources
-Normal makeup to SFP is unborated source
What’re the unborated makeup water sources to the SFP ?
-LRS Recycle Monitor Tank (Normal makeup source, due to evaporation)
-Condensate Transfer Tank (Backup makeup sources due to evaporation)
-Reactor Makeup Water Tank(RMWT)
-Demineralized Water(DW)
What is the Borated Makeup Water sources to SFP ?
-Refueling Water Tank
Used to fill other pools:
-Refueling Pool, Transfer Canal, Cask Load Pit
What’re Beyond Design Basis Makeup sources for the SFP ?
FLEX modifications are available to add either Fire Protection or Circulating Water to SFP via Hoses,Fire Trucks, installed spray nozzles above SFP
What’re the Spent Fuel Pool Gate Seals used for ?
-Separates SFP from Cask Load Pit & Fuel Transfer Canal
-A gate separates Cask Load Pit from Decontamination Pit
What does SFP Gate Seals allow Cask Load Pit & Transfer Canal ?
Allows Cask Load Pit & Transfer Canal to be drained while not affect SFP LVL
What kind of seals do the SFP Gate Seals have ?
All SFP gates have TWO Q-Class bladder seals:
-One ‘A’ train seal
-One ‘B’ train seal
Why are the Gate Seals redundant with a ‘A’ & ‘B’ train seal ?
-Loss of ONE seal will not allow any leakage past gate
What’re the Seal Bladders normally pressurized from? What is used as a backup pressurization method for Seal Bladders ?
-Normally pressurized by Instrument Air at 42psig
-Pressurized by two class nitrogen bottles at 38psig
When are the Class Nitrogen bottles automatically put into service for pressurizing seal bladders ?
Check valve separates two supply headers, if Instrument supply header drops to 38psig then nitrogen bottles automatically take over
What happens if nitrogen bottles become insufficient,unavailable, or inaccessible ?
There is a FLEX connection to install backup nitrogen bottles on plant north end
What must be matched prior to removing gate ?
Water level & boron concentration between two sides must be matched
How do you match water level between SFP & Transfer canal, since transfer canal doesn’t have level indication ?
-AOs count gate ribs to determine level on each side
-Then
What is the concern for Transfer Canal being raised above 138.25’ 3” ?
Could spill over into the New-Fuel Elevator Cable tray & damage electric motor for New-Fuel Elevator
What is the SFP concern for filling it above 138’ 3”?
If SFP Transfer Canal Gate is removed then it could damage motor for New Fuel Elevator Cable Tray
What happens if Refueling pool level is above 138’ 2”?
May introduce water to In-Core-instrument tubing shield resulting in admission of borated water in ICI chase area
What should the Fuel Storage Pool Water Level be during movement of Fuel Assemblies ?
Fuel Storage Pool Water Level shall be >23ft over top of Fuel Assemblies seated in storage racks
What should the Fuel Storage Pool Boron Concentration be ANYTIME a Fuel Assembly is inside pool ?
Fuel storage pool boron concentration shall be >2150ppm
What borated sources should be functional during shutdown? (A minimum of ONE shall be functional)
As a minimum either SFP or RWT shall be FUNCTIONAL during shutdown in MODES 5&6
What’re the requirements for SFP to be considered FUNCTIONAL ?
-SFP temp >60F & <180F
-Boron concentration is >4000 & <4400ppm
-Volume of borated water source is >33,500 gallons
What’re the Borating sources during operation that have to be functional?
-SFP shall be FUNCTIONAL in modes 1-4
What’re boron injection flow paths that shall be FUNCTIONAL during shutdown? (A minimum of ONE shall be functional to meet TLCO)
-A flow path from SFP via a gravity flow connection to charging pump to the RCS
-Flow path from RWT via either w Charging Pump,HPSI,or LPSI to the RCS
What’re following requirements for boration flow paths to be considered functional during Shutdown ?
Each valve in flow path that isn’t locked,sealed, or secured in position, is in its CORRECT position
What is the Fuel Transfer Tube used for ?
What do the inner & outer pipe act as for the Fuel Transfer Tube ?
Inner Tube- Acts as refueling tube
Outer Tube- Acts as housing
How is the Fuel Assembly maneuvered as it’s being sent through Fuel Transfer Tube?
1.)Placed vertically on Transfer Carriage
2.)Lowered to horizontal position
3.)Move through Fuel Transfer Tube on Transfer Carriage via when & track system
4.) Then restored to vertical position
How many Fuel Assemblies are permitted to transfer through Fuel Transfer Tube ?
Only one irradiated Fuel Assembly is permitted
What is used to prevent leakage from Transfer Canal to Refueling Pool ?
Tube is fitted with double-gasketed blind flange
At least 2 of 3 boron injection flow paths shall be functional during operation, what’re they ?
1.) Gravity feed from either RWT or SFP, through valve 536 & charging pump to the RCS
2.)Gravity feed from RWT through valve 327 & a charging pump to RCS
3.)Flow path from either RWT or SFP through 164 utilizing gravity feed & Charging Pump to RCS
What is the Fuel Transfer Tube Canal Isolation Valve used for?
Used to isolate Transfer Canal from Fuel Transfer Tube
Where is the manual hand wheel at for the Fuel Transfer Tune Canal Isolation Valve ? How many turns is this isolation valve ?
-Maintained in High Risk Area of SFP for operation of V118
-700+ turns are required for full disc travel of the valve
How is Motor Operator used in place for manual hand wheel for the Fuel Transfer Tube Isolation Valve ?
Motor can be used but must be removed before reaching either open or closed & remaining operation must be done manually
What is the Fuel Transfer tube sealed by ?
Sealed by means of remotely operated Quick Operating Closure Device located inside containment
What does Quick Operating Closure Device do for Fuel Building & containment ?
-Forms the Class pressure boundary between Fuel Building & Containment
-Prevents Fuel Transfer Tube from seeing Containment pressure during Reactor Operation
Who operates Quick Operating Closure Device ?
Fuels group(RAMS)
What is the advantage of Quick Operating Closure Device ?
Is reduction in time & dose associated with opening & closing Fuel Transfer Tube
What kind of FLEX indication do we have ?
Two FLEX SFP level indicators installed during design basis accidents
Where are the flex indicators installed at ?
-One is installed in Control Room envelope
-Another is installed at entrance to RCA
How long do the Class Nitrogen Bottles last for the gate seals ? When do they need to be changed out ?
-Each set of bottles should last a minimum of 18 days
-They need to be changed out when they reach 300psig
What is Appendix A Internal SFP makeup ?
-Provide at least 500gpm makeup to SFP from existing Fire Protection header and Hose Stations via filling device positioned over edge of SFP
How does NN interface with SFP?
NN provides control power to SFP Local Control Panel
How does NK interfaces with SFP ?
NK provides power to SFP Local Annunciator Panel
How does QA interface with SFP ?
QA provides power to underwater lighting in SFP,Transfer Canal, Cask Loading Pit
How does SFP interface with Chemical & Volume Control System (CH)?
-CH can supply borated water from RWT to the SFP,Transfer Canal, & Refueling pool
-SFP provides 33,500gallons dedicated for emergency boration source which can inject into RCS
How does Condensate Transfer & Storage (CST) interface with SFP ?
CST provides non borated water to SFP
How does Instrument Air(IA)interface with SFP ?
IA pressurizes gate seals between SFP & transfer canal & between Cask Load Pit
How does Liquid Radwaste System(LR) interface with SFP ?
LR Recycle Monitor Tanks provide non borated makeup water to SFP
How does Safety Injection(SI) interface with SFP ?
SI transfers between RWT & Refueling pool when filling & draining Refueling Pool
How does Radiation Monitoring interface with SFP ?
SFP & Refueling pools are continuously monitored by area radiation detectors
How does HVAC interface with SFP ?
-HF Normal HVAC maintains temp within desired comfort range
-HF Essential HVAC available to treat Fuel Building air in event of fuel handling accident
