[CP] Containment Hydrogen Purge

Question 1

[CP]
2 subsystems of the CP system?
Purposes?

Answer 1

Refueling/Power Access Purge

Refueling Purge
– provides ventilation air for personnel comfort when the plant is shutdown during refueling operations and maintenance

Power Access Purge
– provides ventilation air to allow operator access for limited periods during power operation. Also controls pressure in the containment by periodically venting a portion of the containment air to plant vent

Question 2

[CP]
What provides cooling to Refuel Purge AHU?
How is it controlled?

Answer 2

[NC] Normal Chilled Water

Automatically - maintains inlet air temperature at preset value

Question 3

[CP]
When does [WC] provide cooling to Power Access Purge AHU?

Answer 3

High O/S Temp

Question 4

[IA] interaction with [CP]?

Answer 4

Air for:
Dampers, valves, controllers, and CIVs

Question 5

How is the system affected by a loss of IA?

Answer 5

Air operated dampers and valves fail closed, which will cause associated AHUs, AFU, supply or exhaust fans to trip

Question 6

When is Refueling Purge Supply AHU operated?
Where is it located?

Answer 6

Mode 5/6

AB Roof

Question 7

[CP]
How does the Power Access Purge Supply AHU do if O/S temp is too low?

Answer 7

Electric heating coils energize.

Question 8

[CP] Power Access Purge Supply AHU controlled from?
Where is it located?

Answer 8

Control Room

AB Roof

Question 9

[CP]
Why is there a heater installed up stream of the Power Access Purge Normal Exhaust AFU?

Answer 9

Prevents humidity from damaging charcoal filter down stream.

Question 10

Concerning the Power Access Purge Normal Exhaust AFU, what is the purpose of the charcoal filter and second HEPA filter?

Answer 10

Charcoal filter removes fission product gases (mainly iodine) by adsorption
Second HEPA filter removes any carbon dust emitted from the charcoal filters

Question 11

[CP]
Which [SQ] monitors Purge Discharge to Plant Vent?

Answer 11

RU-37/38

Question 12

[CP] Auto functions for RU-37 and RU-38 with High Radiation?

Answer 12

CPIAS

Question 13

What isolates [CP]? (2)

Answer 13

1 - CIAS
2 - RU-37/38 High Rad (CPIAS)

Question 14

[CP] Two modes of Power Access Purge?

Answer 14

1 - Venting/Depressurization

2 - Power Access Purge

Question 15

[CP] Purpose of Venting mode?

Answer 15

Depressurize CNTMT atmosphere during normal power operation or before power access purge

Question 16

How is the CP system affected by a loss of Class 120 VAC?

Answer 16

Causes the CP system to shutdown and isolate from the containment

Power is lost to RU-37 (A Train) or RU-38 (B Train), which are used to generate CPIAS

Question 17

How is the CP system affected by a loss of Non-Class 125 VDC?

Answer 17

Containment Refueling Purge AHU outlet dampers fail closed which will prevent operation of the AHU

Containment Power Access Purge AHU inlet damper fails closed which prevents operation of the AHU

Question 18

Where does the containment purge system purge the containment atmosphere to? Where does the filtered and treated make-up come from?

Answer 18

plant vent stack

outside air

Question 19

What is the flow path of the Containment Purge refueling purge subsystem?

Answer 19

outside air is drawn in through a single AHU with two fans. sends air through dampers and isolation valves to containment

two exhaust fans drawn air out of containment through dampers to the plant vent

some of the exhaust air flow goes through rad monitors with two external rad monitors as well

Question 20

What does the containment purge refueling purge subsystem AHU consist of?

Answer 20

filter, heating and cooling coils two fans

Question 21

In both of the containment purge subsystems, what happens when the exhaust rad monitors sense high radiation levels? The external rad monitors?

Answer 21

alarm

system isolates

Question 22

[CP] Power access purge Flowpath?

Answer 22

O/S air
1 AHU
CNTMT Atmo

CNTMT Atmo
CIV
Heater
Exhaust AFU
Plant Vent w/ RU (internal and external)

Question 23

What does the containment purge power access purge AHU consist of?

Answer 23

inlet damper
moderate & high efficiency filters,
coils,
fan
exhaust damper

Question 24

[CP] Power access purge exhaust AFU
components (4)?
Where is it controlled from?
Location?

Answer 24

HEPA (Moderate)
charcoal,
HEPA filters
fan

Control Room

AB Roof

Question 25

[CP] How many refueling purge exhaust fans are normally running while the system is in operation?

Answer 25

two, keeping containment at a slight negative pressure

Question 26

What 2 systems operate together for containment clean-up? Power Access purge and ________________.

Answer 26

[HC] Pre-access Normal AFUs