Steam Dumps Flashcards
1
Q
Design bases of SD system
A
- Allow load rejections that exceed 5%/min and 10% step
- Turbine / reactor trip without lifting SG safeties
- Maintain steam pressure during startup
- Control plant cooldown
2
Q
Described the SD modes of operation
A
Tavg (load rejection): controls Tavg to Tref (based on Pimp)
Tavg (plant trip): cools to Thzp
Steam pressure mode: maintains header P
3
Q
How many Pimp transmitters are used in each SD mode? Why?
A
Tavg (load reject): 2 so a single failure doesn’t activate the SD system
Tavg (plant trip): None. The P4 signal arms, and Tref is set to Thzp
Steam P: None. Error is based on pressure, not power.
4
Q
Which system is mainly used to increase to ~15% power? How?
A
SDs in Psteam mode Pull rods Tavg increases Psteam increases SDs open slightly to maintain Psteam setpoint Do until power ~15% Slowly open turbine control valve Psteam decreases SDs close slightly Do until SDs shut
