CVCS

Question 1

What happens to the CVCS system on a Phase A?

Answer 1

These valves goes closed.
►Letdown Orifice Isolations QRV-160, QRV-161, and QRV-162 ►Letdown line Containment Isolations QCR-300 and QCR-301
►RCP Seal Water Returns QCM-250 and QCM-350

Question 2

What happens to the CVCS on a SI?

Answer 2

Both Centrifugal Charging Pumps Start.

Goes Open - IMO-910 and IMO-911 Chg pump Suct from RWST, ICM-250 and ICM-251 Boron Injection Tank Outlets,
IMO-255 and IMO-256 Boron Injection Tank Inlets.

Goes closed - QMO-451 and QMO-452 Chg pump Suct from VCT,
QMO-200 and QMO-201 Chg flow to Regen Heat Exchanger,
QMO-225 and QMO-226 CCP ELOs.

Question 3

What are the VCT automatic level actions?

Answer 3

78% -  Auto divert letdown to CVCS HUTs starts 
87% - Full divert of letdown 
14% -Auto Makeup Starts 
24% -Auto Makeup Stops   
2.5% -Refueling Water Sequence

Question 4

What will cause the letdown isolation valves QRV-111 and QRV-112 to close?

Answer 4

Low Pressurizer level @17%

Question 5

What happens to CVCS on loss of power without an SI?

Answer 5

►Charging Pump Trips – Must be manually restarted

►Letdown Orifice Isolations QRV-160, QRV-161, and QRV-162 Close – Due to loss of running Charging Pump.

Question 6

What happens when you lower to 2.5% in the VCT.

Answer 6

Refueling water sequence.
IMO-910 and 911 will open, When one of them open QMO-451 and 452 will close.

Question 7

What will automatically open QRV-302 ?

Answer 7

Letdown temp at 143deg to bypass Demins.

Question 8

What cools the Letdown Heat Exchanger?

Answer 8

CCW

Question 9

What cools the Excess letdown Heat Exchanger?

Answer 9

CCW

Question 10

How does water temperature affect demins?

Answer 10

At higher temperature the risen will shed boron.
At lower temperature the risen will absorb boron.

Question 11

What does QRV-301 do?

Answer 11

Provides backpressure so the water doesn’t flash to steam.