General

Question 1

What is the purpose of the Control Room Ventilation & Emergency Recirculation System?

Answer 1

The Control Room Ventilation System filters, cools, heats, and exchanges the air in the Control Room to ensure habitability.

Question 2

How is flow controlled through each of the Control Room Ventilation Fans?

Answer 2

1) Supply Fan - Electro-hydraulic vortex damper
2) Return Fan - Pneumatic vortex damper
3) Emergency Recirculation Fan - Manually adjusted vortex damper

Question 3

Why does the Return Fan have an air operated vortex damper?

Answer 3

The Return Fan is not required to operate during an emergency condition so the fact that it fails on a loss of air is of no consequence.

Question 4

What system provides the cooling water to the Control Room Ventilation System?

Answer 4

The Control Complex Chill Water System

Question 5

What provides the heating for the Control Room Ventilation System?

Answer 5

There are individual heaters in the supply ducting controlled by thermostats for each of the supplied areas.

Question 6

What are the flow rates for the Normal Mode of Control Room Ventilation?

Answer 6

1) Supply Fan - 45K scfm
2) Return Fan - 39K scfm
3) Emergency Recirculation Fan - OFF

Question 7

What are the flow rates for the Smoke Clear Mode of Control Room Ventilation?

Answer 7

1) Supply Fan - 30K scfm
2) Return Fan - 30K scfm
3) Emergency Recirculation Fan - OFF

Question 8

What are the flow rates for the Emergency Recirculation Mode of Control Room Ventilation?

Answer 8

1) Supply Fan - 30K scfm
2) Return Fan - OFF
3) Emergency Recirculation Fan - 30K scfm

Question 9

What is the effect on Control Room Ventilation if there is a loss of Instrument Air?

Answer 9

The Supply Fan flow indication needs Instrument Air to detect flow. The running train of ventilation will trip due to Supply Fan low flow.

Question 10

What mode of Control Room Ventilation is the only mode that returns air to the environment?

Answer 10

The Smoke Clear Mode of operation is the only mode in which the return damper to the outside is open.

Question 11

What will cause an automatic start of the Control Room Ventilation System in the Emergency Recirculation Mode?

Answer 11

1) LOOP
2) RHRH LOCA
3) High Radiation (Airborne Radiation Monitor gas channel)

Question 12

Which Emergency Recirculation automatic start signals are divisional?

Answer 12

RHR LOCA and LOOP signals are divisional

Question 13

What is the function of the Mode Switch?

Answer 13

The Mode Switch determines which mode will initiate when the Train Control Switch is taken to ON. The Mode Switch controls damper positions and fan interlocks.

Question 14

What is the function of the Train Control Switch?

Answer 14

The Train Control Switch will start all the fans in the mode selected by the Mode Switch. Taking the Train Control Switch to STOP will override any mode at any time. This however is a spring return to auto switch.

Question 15

What is the function of the Auto Initiate Reset Pushbutton?

Answer 15

The Auto Initiate Reset Pushbutton will reset the auto-initiate logic as long as the signal has cleared. This pushbutton must be depressed to return the system to the Normal Mode of operation.

Question 16

What will cause a Control Room Ventilation “Train Trip”, and what is the result?

Answer 16

1) Loss of Power to any running fan
2) Loss of Control Power to any running fan
3) Low flow on any running fan
* A TRAIN TRIP SIGNAL WILL TRIP ALL THE RUNNING FANS**

Question 17

When, and what, “Train Trip” signals are bypassed?

Answer 17

The loss of control power and low flow signals are bypassed by an Emergency Recirculation automatic start signal.

Question 18

Are there any other ways to bypass a “Train Trip” signal?

Answer 18

The “Train Trip” signal can bypassed by taking the individual fan control switches to ON.

Question 19

What will cause a Supply Fan to trip?

Answer 19

1) Supply Duct temperature >150F
2) Overload
3) Loss of Power
4) Low flow any running fan(Train Trip)

Question 20

What will cause a Return Fan to trip?

Answer 20

1) Return Duct temperature >150F
2) Supply Fan trip
3) Emergency Recirculation initiation
4) Low flow on any running fan

Question 21

What will cause an Emergency Recirculation Fan trip?

Answer 21

1) Supply Fan trip
2) Charcoal Deluge armed
3) Low flow on any running fan

Question 22

How can a “Train Trip” signal be reset?

Answer 22

1) Supply Fan control switch taken to STOP
2) Return Fan control switch taken to STOP
3) Emergency Recirculation Fan switch taken to STOP
4) Emergency Recirculation EHC switch taken to STOP
5) Train Control Switch taken to STOP

Question 23

What is unique about the Outside Air Intake Dampers for the Control Room Ventilation System?

Answer 23

There is an A and B damper in each trains intake ducting. If there was a condition that required an automatic initiation of Emergency Recirculation and only one division were to function it ensures both intakes would be isolated. The second damper on the intake gets an isolation signal from the opposite train.

Question 24

What is the effect on the Control Room Ventilation System if a “Train Trip” signal has caused a trip and then an Emergency Recirculation automatic start signal is received?

Answer 24

The train, or trains, will start in the Emergency Recirculation Mode bypassing the “Train Trip” signal.

Question 25

What is the effect on the Control Room Ventilation System if power is lost to K-1-A and K-1-N?

Answer 25

K-1-N and K-1-A are the two power supplies to the Control Room Ventilation Airborne Radiation Monitor. If both power sources are lost both trains will start in Emergency Recirculation.