Contaiment Air Release And Addiition System(VQ)

Question 1

What is the purpose of the Containment Air Release and Addition System?

Answer 1

The Containment Air Release and Addition System provides a means of controlling containment pressure between the administrative limits of +0.25psig and -0.08psig during normal plant operations, including startup and shutdown evolutions

Question 2

What is the system designator for the Containment Air Release and Addition System?

Answer 2

VQ

Question 3

Is the Containment Air Release and Addition System safety related?

Answer 3

The system is not safety related with the exception of the containment isolation valves.

Question 4

What is the normal pressure band maintained inside Containment?

Answer 4

+0.25psig to -0.08psig

Question 5

How many Containment Air Release Fans are there, and what is there flow rate?

Answer 5

1. There are two Containment Air Release Fans

2. The normal flow rate is a maximum of 200-300cfm

Question 6

What will cause a Containment Air Release Fan to trip?

Answer 6

Low flow 80cfm to prevent the fan from overheating

Question 7

Will the Containment Air Release Fans trip on low pressure in the Containment to prevent exceeding the design vacuum limit?

Answer 7

No, they will continue to run regardless of the pressure in Containment

Question 8

What it’s the purpose of the Containment Air Release Valve(VQ-10)?

Answer 8

1. The Containment Air Release Valve modulates to control the release rate.
2. VQ-10 is controlled from a controller in the Control Room at the HVAC panel.

Question 9

What conditions must be met to open the Containment Air Release Valve(VQ-10)?

Answer 9

1. Containment pressure is greater than 0psig

2. The VQ-10 controller has been re-zeroed by placing the controller in MANUAL and setting demand to zero.

Question 10

What conditions will cause the Containment Air Release Valve(VQ-10) to automatically close?

Answer 10

1. Containment pressure is 0psig decreasing
2. High radiation is sensed in the VQ system ventilation exhaust(EMF-35 or EMF-36 trip 2)
3. The VQ totalizer becomes inoperable
4. Fails closed on loss of instrument air

Question 11

What indications/controls are located on the Containment Air Release Valve(VQ-10) Controller?

Answer 11

1. Used in Automatica Mode to set the discharge limit(max 350cfm)
2. Totalizer measures the total volume released in SCF(zeroed with “reset total” button)
3. Display toggles between flow rate, total flow, and valve position

Question 12

What will cause the Air Addition Valve(VQ-13) to automatically close?

Answer 12

Containment pressure increasing to 0psig

Question 13

What is the requirement to open the Air Addition Valve(VQ-13)?

Answer 13

Containment pressure less than 0psig

Question 14

What will cause the Containment Air Addition and Release System Containment Isolation Valves to automatically close?

Answer 14

Containment Ventilation Isolation Signal(S sub h)

Question 15

What is required to start an Exhaust Fan?

Answer 15

The heater breaker must be closed in the filter train for the exhaust fan for it to be allowed to start

Question 16

What is the purpose of the heater in the filter unit?

Answer 16

The heater is for temperature and humidity control

Question 17

How does the Operator Aid Computer average containment pressure?

Answer 17

1. Uses eight narrow range and two wide range pressure transmitters
2. If pressure is within narrow range span, then uses the average of the narrow range
3. If pressure is not within the narrow range span, then it uses the average of the wide range

Question 18

What inputs will generate a Containment Ventilation Isolation Signal?

Answer 18

1. Manual “Phase A”(1.2# Containment Pressure) - train related
2. Manual “Phase B, VX Initiate, Containment Vent Isolation” - train related
3. Safety Injection Signal
4. EMF-38 and EMF-39L Trip 2 - Either will actuate both trains of containment ventilation isolation signal

Question 19

What affect will a Containment Ventilation Isolation Signal have on the Containment Air Addition and Release System?

Answer 19

1. Air release in progress - CLOSES containment isolation valves. Fans trip on low flow.
2. Air addition in progress - CLOSES containment isolation valves.

Question 20

What are the power supplies to the Containment Isolation Valves in the Air Release path?

Answer 20

VQ-2A: EMXK

VQ-3B: EMXB

Question 21

What is the power supply to the Containment Isolation Valves in the Air Addition line?

Answer 21

VQ-16A: EMXK

VQ-15B: EMXB

Question 22

How can you remember the power supplies for the containment isolation valves?

Answer 22

Outboard valves are EMXB and are both ‘B’ valves

Inboard valves are EMXK and are both ‘A’ valves

Question 23

What is the power supply to the Containment Air Release Fans?

Answer 23

A - MXK

B - MXZ

Question 24

What is the power supply to the Containment Air Release Filter Heaters?

Answer 24

Heater A - SMXA

Heater B - SMXB

Question 25

What type of alarms are associated with the Containment Air Addition and Release System, and where are they received?

Answer 25

1. Alarms:
   A. Containment pressure annunciators: High, Hi-Hi, Low, and Lo-Lo
   B. Filter high temperature annunciators
2. Alarms are received in the Control Room and on the OAC

Question 26

What components are contained in the filter units?

Answer 26

1. One pre-filter
2. One HEPA filter
3. Three carbon trays
4. A deluge connection