Steam Bypass

Question 1

SBCS To what shells are the SBCS valves aligned?

Answer 1

Shell A: 1001, 1002, 1003
Shell B: 1004, 1005,
Shell C: 1006
Atmosphere: 1007, 1008

Question 2

SBCS
What are the controller outputs coinciding with the SBCVs opening?

Answer 2

1001: 0-25%
1004: 25-50%
1003/1006: 50-66.7%
1002/1005: 66.7-83.3%
10078/1008: 83.3-100%

Question 3

SBCS
How do the SG steam flow detectors (FT-1011/1012), or steam header PT 1024 impact the operation of the SBCS?

Answer 3

1. FT 1011/1012: affects the modulation Setpoint. If the FT fails low, the modulation Setpoint will rise. If the FT fails high, the modulation Setpoint will lower.
2. PT 1024 If it fails low and a main feed pump trips, you will have a setback and continuous runback.
   If it fails high, you will have 100% demand signal. (Still need a permissive to open valves)

Question 4

SBCS
What happens to the master controller on a loss, then return of power?

Answer 4

The master controller will return in manual, and the system might be in emergency off.

Question 5

SBCS
What is a Condenser Interlock, and what does it do?

Answer 5

Comes in at 5.5” HgA in 2/3 condenser shells.
Prevents SBCVs 1001-1006 from opening.
1007/8 will still work

Question 6

SBCS What is the effect on SBCS if the PPCS master controller PIC 100 output fails to 0%?

Answer 6

The SBCVs will modulate open at a lower pressure.

Question 7

SBCS
How does tripping a MFP affect the SBCS?

Answer 7

Prevents a quick open on both X and Y valves

Question 8

SBCS
What generates a quick open block to both the X and Y valves?

Answer 8

A reactor trip with a low Tavg (573.5F)