Ice Condenser

Question 1

What happens on a low-low lvl in the glycol expansion tank?

Answer 1

• Containment Isolation valves outside containment, VCR 10/20 will close
• Expansion Tank outlet valves VSO 20/21 will close

Question 2

When do ALL Glycol CIVs close automatically? (VCR-10/11, 20/21)

Answer 2

Phase “A” signal

Question 3

What will auto start a glycol pump?

Answer 3

Low Disch pressure at 95 psi

Question 4

What are the glycol chiller trips?

Answer 4

• Overload
• Low Glycol Flow
• Low temperature (freeze protection)
• High/Low Refrig PressureLow Oil Pressure

Question 5

What do we add to the ice and why?

Answer 5

sodium tetra-borate for pH control and to keep iodine in solution

Question 6

What is sublimation?

Answer 6

Solid (ice) passes to the vapor state without first becoming a liquid

Question 7

Describe the purpose of the Ice Condenser?

Answer 7

• absorbs and retains released iodine.
• heat transfer medium for containment core cooling.
• additional neutron poison for reactivity control following a LOCA

Question 8

What is the flow path of steam through the ice condenser during a LBLOCA?

Answer 8

• 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 is recirculated by CEQ Fans 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)

Question 9

The ice capacity is large enough to do what?

Answer 9

absorb twice the energy released

Question 10

Explain what containment pressure does and why on a DBA.

Answer 10

1. Containment pressure spikes
2. Seconds into event, pressure begins to lower as lower inlet doors open & ice bed absorbs heat, assisted by CEQ Fans.
3. Over an hour into the even, pressure starts to rise again as recirc sump is placed in service & ice bed melt is done.
4. As decay heat lowers, pressure lowers.

Question 11

What is the desired flowpath for the steam/water released as a result of a LOCA is from lower containment to:

Answer 11

ice condensers to upper containment to recirculation sump.

Question 12

The Ice Condenser Air Handling Unit Fans are run to maintain Ice Condenser temperature within limits but must be STOPPED when?

Answer 12

when Distributed Ignition System (DIS) is placed in service