Main Steam

Question 1

What does the main steam system provide steam to?

Answer 1

• Turbine
• MSR
• FW pump turbines
• Gland seal system
• AFA
• Aux Steam system

Question 2

What are the SG downcomer upstream block valves used for?

Answer 2

Allow remote isolation of downcomer control valves

Question 3

How do the SG downcomer control valves fail on a loss of air or power?

Answer 3

Locked as-is

Question 4

Where are the SG downcomer control valves located?

Answer 4

120’ turbine building

Question 5

What are the SG downcomer control valve bypass valve used for?

Answer 5

Used during mode 3 to control SGWL with water supplied by Aux feed novermber

Question 6

Where are the SG downcomer isolation valves located?

Answer 6

100’ MSSS

Question 7

What do the downcomer isolation valves do on a MSIS?

Answer 7

Fail closed

Question 8

How long can the downcomer isolation valves operate on backup N2 pressure?

Answer 8

8 hours

Question 9

Where are the economizer control valves?

Answer 9

120’ turbine building mezzanine area

Question 10

How do the economizer control valves fail?

Answer 10

as-is

Question 11

How much pressure is available to ‘fast close’ the economizer isolation valve?

Answer 11

5000 psig

Question 12

Where are the economizer isolation valves located?

Answer 12

120’ MSSS

Question 13

How many tubes are in the SG and how many can be plugged?

Answer 13

12580 tubes and 10% can be plugged

Question 14

Where is the economizer?

Answer 14

just above the tube sheet on the cold leg side of the SG

Question 15

What does the economizer do?

Answer 15

increases SG efficiency

Question 16

What does the wrapper plate do?

Answer 16

divides SG downcomer and evaporator sections

Question 17

How many main steam safety valves are on each main steam supply line?

Answer 17

Five

Question 18

Where are the MSIV’s located?

Answer 18

140’ MSSS

Question 19

What are the setpoints of the main steam safety valves?

Answer 19

1250, 1290, and 3 of them are 1315 psig

Question 20

On a loss of IA, what happens to the ADV’s?

Answer 20

Have 16 hours of N2 backup

Question 21

What is the purpose of the MSIV bypass valve?

Answer 21

allow warmup of piping downstream of the MSIVs, pressure equalization across the MSIV’s to allow opening, or to allow operation of the A MFP after an MSIS

Question 22

Where are the steam bypass control valves?

Answer 22

140’ Turbine Building

Question 23

Where are the wet layup recirc pumps?

Answer 23

80’ containment

Question 24

How are the wet layup recirc pumps controlled?

Answer 24

The local switch must be placed in start; then you can control them from their respective MCC’s

Question 25

On startup where does the flow go through the SG?

Answer 25

100% of all flow passes through the downcomer control valves to supply sufficient preheating for incoming feedwater at lower power

Question 26

On startup, when do the downcomer control valves begin to close and the economizer control valves begin to open?

Answer 26

Around 15% power

Question 27

What happens to the downcomer control valves around 50% power?

Answer 27

They begin to open back up to about 10%. Between 50-100% power; 10% of the feed is through the downcomer.

Question 28

What is on the tube and shell side of the SG?

Answer 28

Tube- RCS (primary coolant) | Shell- secondary coolant

Question 29

When do the blowdown isolation valves isolate?

Answer 29

SAM - SIAS - AFAS - MSIS

Question 30

What is the minimum SG water level? Why?

Answer 30

30% narrow range. To prevent uncovering the SG tubes

Question 31

What is the max allowable temperature at the outlet of the blowdown hx?

Answer 31

140 degrees F

Question 32

What is the max allowable pressure at the BFT?

Answer 32

230 psig

Question 33

What is the max allowable level in the BFT?

Answer 33

100 inches

Question 34

What is the concern with the FWP's when we are doing high rate blowdown?

Answer 34

Feedwater flow demand and resultant pressure will increase in FWPT speed which will cause FWP suction pressure to decrease.

Question 35

How many tubes are in a Steam Generator? What percentage can be plugged without affecting secondary pressure?

Answer 35

12,580 tubes | 10% can be plugged

Question 36

What does the economizer section of the SG do for us?

Answer 36

Increases SG efficiency by preheating the incoming FW before it enters the evaporator section

Question 37

What does the tube sheet and u-tubes do for us?

Answer 37

Provides the boundary between the secondary and primary.

Question 38

What does the steam outlet orfices do?

Answer 38

limit steam flow in the event of a main steam line break

Question 39

What are the utubes in the SG made of?

Answer 39

Inconel 690

Question 40

When do we get a MSIS signal?

Answer 40

960 psia in the SG or 3 psig in containment