Moisture separator Flashcards
What is the purpose of the MSR system?
To improve quality of the HP turbine exhaust steam before it enters the LP turbine
what is meant by “drying and reheating” and why do we do it?
MSR mechanically removes moisture and then reheats the dried steam by passing it across the 1st and 2nd stage reheater tube bundles.
Minimizes erosion of the LP turbine buckets as well as the momentum losses due to excessively moist steam, which increases plant efficiency and life of the LP turbine
What does the SG provide for the MSRs?
2nd stage reheat steam
What provides the 1st stage reheat steam?
3rd stage extraction steam
what is the purpose of the chevron vanes in the MSRs?
put wet steam thru abrupt changes in direction and causes heavy moisture droplets to impinge on the vane hooks, separate from steam flow and drop into a divided drain trough common to both vane banks
Where does the water in the trough go?
Directed to a center drain pipe that goes to the MSR drain tank
What happens if the MSR drain tank level is too high?
Level controller will direct tank discharge to the condenser
What will happen if water in the drain line backs up to within 3” of the MSR vessel?
2 of 3 logic and will initiate a turbine trip to prevent water induction in the turbine
Where does the 1st stage reheater condensate drain to?
The 1st stage drain tank which in turn drains to the 6th point heater or if level is too high to the condenser
Where does the 2nd stage reheater condensate drain to?
The 2nd stage drain tank which in turn drains to the 7th point heater or if level is to high to the condenser
MSR drain tank, when turbine power is less than 10% and turbine shell warming is not in progress, which controller will be utilized?
High level dump valve will be failed open
What if turbine power is greater than 10%?
High level dump valve closes and the normal level control valve begins to maintain level
how is the MSR drain tank affected by loss of IA?
Normal level control valve will fail closed and high level fails open
