GA: Service Gases

Question 1

What is the purpose of the 6 N2 storage bottles out by the N2 Skid?

Answer 1

They increase the operating time of the ADVs to 16 hours during a Station Blackout.

Question 2

How is the High Pressure N2 Header pressure maintained?

Answer 2

With 2 PCVs

One set at 650 psig with a backup set a 630 psig

Question 3

When will the high pressure alarm for the H2 header announce in the Control Room?

Answer 3

110 psig

Question 4

Where do we send H2 in the plant?

Answer 4

To the Main Generator

To the VCT

Question 5

What will trip the N2 Pumps?

Answer 5

Cavitation
High Discharge Pressure - 2400#
Low Vapor Temperature - < -20 F
Low Storage Tank Level - 25”

Question 6

When will the HP N2 Header alarm in the Control Room?

Answer 6

On High Pressure at 690 psig

Question 7

How long will the HP N2 Storage Cylinders supply the header?

Answer 7

They are designed for 7 days

Question 8

When will the low pressure alarm for the H2 storage banks announce in the Control Room?

Answer 8

200 psig

Question 9

Can the High Pressure N2 Header supply the Low Pressure N2 Header?

Answer 9

Yes, via PV-41

Question 10

Do the N2 Pumps supply the Low Pressure N2 Header?

Answer 10

No

Question 11

What happens when a N2 pump first starts?

Answer 11

It goes through a 15 minute cool down cycle

Liquid N2 flows into the pump

Question 12

When will the HP N2 cylinders alarm on low pressure in the Control Room?

Answer 12

750 psig on either bank

Question 13

How is the H2 header pressure maintained?

Answer 13

With 2 PCVs

One set at 105 psig with a backup set a 95 psig

Question 14

Describe how the N2 Pumps maintain HP N2 cylinder pressure.

Answer 14

Positive displacement pump starts when pressure in the cylinders reaches 1400 psig. The pump will automatically stop when pressure in the tanks reaches 2100 psig.

Question 15

What is the power supply to the N2 Pumps?

Answer 15

NH

NHN-M30

Question 16

What is the power supply to the N2 Containment Isolation Valves?

Answer 16

PKA

Question 17

When will the standby N2 pump start?

Answer 17

It won’t because it has its local disconnect open

Question 18

What does N2 supply in Containment?

Answer 18

The SITs

The RDT

Question 19

How is the Low Pressure N2 Header pressure maintained?

Answer 19

With 2 PCVs

One set at 115 psig with a backup set a 110 psig

Question 20

Are the solenoid operated N2 Containment Isolation Valves inside Containment or outside?

Answer 20

Outside. The lines have check valves inside Containment

Question 21

What is the administrative limit for H2 Storage Bank pressure?

Answer 21

300 psig

Question 22

How are the HP N2 storage cylinders arranged?

Answer 22

Total of 8 cylinders
Two banks of 4
Each bank has a PCV
Banks are isolated from one another

Question 23

What will cause the N2 Containment Isolation Valves (GAA-UV-1 and GAA-UV-2) to close automatically?

Answer 23

CIAS

Question 24

Describe the High Pressure N2 flowpath.

Answer 24

From the N2 Storage Tank, to one of two positive displacement pumps, to the HP vaporizer, to the 8 storage cylinders, to the HP N2 header.