Ice Condenser Flashcards
What happens on a low-low lvl in the glycol expansion tank?
- VCR 10/20 will close (outside containment)
- VSO 20/21 will close
When do Glycol CIVs close automatically? (VCR-10/11, 20/21)
- Phase “A” signal
What will auto start a glycol pump?
- Low Disch # at 95#
What are the glycol chiller trips?
- High or Low refrigerant pressure
- Low NESW water flow
- Low Glycol flow
- Low refrigerant temperature (freeze protection)
What do we add to the ice and why?
- sodium tetra-borate for pH control, neutron poison, and to keep iodine in solution
What is sublimation?
- Solid (ice) passes to the vapor state without first becoming a liquid
Describe the purpose of the Ice Condenser?
- absorbs and retains released iodine.
- heat transfer medium for containment core cooling.
- additional neutron poison for reactivity control following a LOCA
What is the flow path of steam through the ice condenser during a LBLOCA?
- 1 Pound per square foot opens lower inlet doors.
- Steam directed by turning vanes to bottom of baskets through flow channels
- Steam exits ice baskets through intermediate and top deck doors into upper containment.
- Steam mixture condensed by CTS and goes back to lower containment thru cavity drains
- Condensed steam / melted ice collect on ice condenser floor and drain (21 drains) to containment lower volume (flapper valves auto open @ 36” of water)
On a Guillotine shear of Cold Leg how many Ice Bays and Inlet Doors do we need to have by design?
- 24 bays with 24 pairs of Inlet Doors
The ice capacity large enough to do what?
- to absorb twice the energy released
Describe the containment pressure curve in response to a LBLOCA
Pressure initially peaks between 6-12#, then drops to 3-7# when ice melt is complete. Then rises during recirculation until CTS brings pressure back down.
How are the glycol pump auto starts aligned (per unit)
- Pumps 1-3 sense low pressure in U1
- Pumps 4-6 sense low pressure in U2
