SBCS (Steam Bypass Control System) Flashcards
Unit 1 is operating in mode 3 following a reactor trip. SBCS is maintaining RCS temperature in remote auto. A loss of instrument air (including nitrogen back-up) occurs. Based on these conditions, the SBCS valves will…
A. remain open and controllable for about 13 hours.
B. fail as is.
C. remain open and controllable for about 4 hours.
D. fail closed.
Answer: D
Main generator output is 700 MW(e) Condenser vacuum indicates: 4.5 in Hg in A shell and degrading, 4.8 in Hg in B shell and degrading, 5.0 in Hg in C shell and degrading. Steam bypass control system is in “REMOTE/AUTO” and a SBCS permissive has been received. The Crew is coordinating manual insertion of CEAs while unloading the Main Turbine. 20 gpm Boration in progress. Tave is 4 degrees greater than Tref. Tave continues to diverge and exceeds Tref by greater than 5 degrees. In accordance with 40AO-9ZZ07, the required Crew response would be to…
A. place CEDMCS in AS to stabilize Tave.
B. control secondary pressure with SBCS valves 1007 and 1008.
C. stop the turbine load reduction until Tave matches Tref ±4°F.
D. allow automatic SBCS actuation to stabilize Condenser vacuum.
Answer: B
With RRS Tavg selected to AVERAGE, which of the following will generate a Reactor Regulating System Automatic Motion Inhibit (AMI):
A. Th > 575°F.
B. Tavg deviation > 5°F.
C. Tc > 575°F.
D. Tavg - Tref > 6°F.
Answer: B
Unit 1 is operating at rated power when backpressure in the Main Condenser starts to rise. Regulating Group 5 is at 135 inches. Turbine load is being shifted to SBCS valve 1007 in an effort to stabilize backpressure. CEDMCS is inadvertently left in AUTO SEQUENTIAL. Assuming Steam Demand remains constant. The Operating Crew should expect CEAs to…
A. start stepping in.
B. start stepping out.
C. remain in their present position due to AMI.
D. remain in their present position due to AWP.
Answer: A
Unit 1 is operating at rated power. RPCS is in service with subgroups 4, 5 and 22 selected. A Main Feed Pump trips. In an unrelated failure, a Steam Header Pressure Transmitter (PT- 1024) fails low. Based on this, the RPCS will drop selected CEAs and the Main Turbine will ____________.
A. Setback, Continuously Runback.
B. Setback, Not Runback.
C. Not Setback, Not Runback.
D. Not Setback, Continuously Runback.
Answer: A
Unit 1 plant power being lowered due to a Main Condenser Circ Water leak CRS is currently performing actions in accordance with section 4 of 40AO-9ZZ10, Condenser Tube Rupture Plant systems are aligned per section 4 of 40AO-9ZZ10 Rx power currently 65% Secondary Operator reports an EHC malfunction resulting in current Tave being 5°F off program low Based on current plant conditions and no additional Operator actions taken which of the below listed circumstances would cause a Quick Open block to be generated…..
A. Main Feed Pump “B” trip
B. Main Turbine trip
C. Loss of NNN-D15
D. Reactor Trip
Answer: D
