Tài Liệu luận văn cao học ngành vât lý

ourse on Plant System Safety Analysis Using PC-Based Plant Simulator,
alat University, Vietnam, November 27-30, 2017.

APWR Simulator Exercise:
Normal Operations
Kyung Doo Kim ()
KAERI


Contents
Examples of Normal Operation Simulation
3.1
3.2
3.3
3.4

Reactor power reduction
Reactor power increase
Reactor trip
Turbine trip

Course on Plant System Safety Analysis Using PC-Based Plant Simulator,
Dalat University, Vietnam, November 27-30, 2017.

2


Reactor Power Reduction

3

Reactor Power Reduction (100%80%)
Initiated by decreasing turbine load in nominal operating condition.
This can be simulated by reducing the turbine stop valve area. Reactor
regulating system and reactivity control system make the control rod
insert to reduce the reactor power corresponding to the turbine load.
1.Click the execution file ‘APWRSimulator_visa.exe’ to start a
simulation.
 It will automatically load the input file (100ic_NLOCA_r3.i) and the
corresponding restart file of 100ic.r for 100% nominal operating
condition.

2.Press “OK” button in project tab for initialization.
3.Press “Run” speed button to simulate the 100% nominal power
condition.
4.Enter the “interval recording” in the text box at the top middle part.
 a time interval (default value: 0.1 s)

5.Pause in the simulation at 20 s
 Speed pause button in upper part
Course on Plant System Safety Analysis Using PC-Based Plant Simulator,


Dalat University, Vietnam, November 27-30, 2017.

4


Reactor Power Reduction (100%80%)
6. Move to “interactive tab” to initiate the transient.

7. Change the selection box from automatic to manual in “Turbine
Load” line.
8. Enter the 80 into target edit box and -0.1 into rate edit box. Then, it
will reduce turbine load from 100% to 80% in the rate of -0.1%/s.
9. Press APPLY button at the top right. These will start to close turbine
stop valve to 80% of full opening area.
10.Then, resume the execution by speed button in top left corner.

Course on Plant System Safety Analysis Using PC-Based Plant Simulator,
Dalat University, Vietnam, November 27-30, 2017.

5


Reactor Power Reduction (100%80%)
Before initiating reactor power reduction,
 Primary side is filled with water except PRZ.
 SG secondary side:
Solid water in downcomer
The steam and water mixture in riser part
Two-phase mixture is separated in steam separator. Steam
flows to steam line and water is returned to downcomer.

Course on Plant System Safety Analysis Using PC-Based Plant Simulator,
Dalat University, Vietnam, November 27-30, 2017.

6


Reactor Power Reduction (100%80%)

Before initiating reactor power reduction,
Reactor Power

PRZ and SG Pressure

 you can confirm if the calculation is reached the steady
state condition by examining the trend graphs for reactor
power, pressurizer and steam generator pressures, etc.

Course on Plant System Safety Analysis Using PC-Based Plant Simulator,
Dalat University, Vietnam, November 27-30, 2017.

7


Reactor Power Reduction (100%80%)
At 320 s
 Turbine stop valve flow rate and reactor power is stabilized
with small change and reached to steady-state condition
because turbine load reached to 80% at 220s. Reactor
power after stabilization becomes ~80% of full power.
Reactor Power

Turbine flow

Temperature distribution at 400 s
Course on Plant System Safety Analysis Using PC-Based Plant Simulator,
Dalat University, Vietnam, November 27-30, 2017.

8

Reactor Power Reduction (100%80%)
At ~1000 s
 Power and flow through the turbine stop valve reached to
80% of full power condition and stabilized by reactor
regulating system . .
 PRZ and SG pressure and water level are increased a little
but these are recovered to the reference values by PRZ
pressure control and feedwater control system.

Turbine flow

Reactor Power

PRZ/SG Pressure

Course on Plant System Safety Analysis Using PC-Based Plant Simulator,
Dalat University, Vietnam, November 27-30, 2017.

PRZ/SG Level

9


Reactor Power Increase

10

Reactor Power Increase (80% 100%)
Before initiating reactor power increase,
 RCS condition is almost same as full power condition.
 Confirm if the calculation is reached the steady state condition
by examining the trend graphs for reactor power, PRZ and SG
pressures, etc.

Reactor Power

Turbine flow
Course on Plant System Safety Analysis Using PC-Based Plant Simulator,
Dalat University, Vietnam, November 27-30, 2017.

11


Reactor Power Increase (80% 100%)
Initiated by increasing turbine load from 80% power operating
condition. This can be simulated by increasing the turbine stop valve
area from 80% to 100%. Reactor regulating system and reactivity
control system make the control rod insert to reduce the reactor power
corresponding to the turbine load.
1.Start with the previous run which was decreased from 100% to 80%.
2.Pause when the power reached to 80% and maintained at steady
states.
 Set the time to pause.

 

Course on Plant System Safety Analysis Using PC-Based Plant Simulator,

Dalat University, Vietnam, November 27-30, 2017.

12


Reactor Power Increase (80% 100%)
6. Move to “interactive tab” to initiate the transient.
7. Change the selection box from automatic to manual in “Turbine
Load” line.
8. Enter the 100 into target edit box and 0.1 into rate edit box. Then, it
will increase turbine load from 80% to 100% in the rate of 0.1%/s.
9. Press APPLY button at the top right. These will start to open turbine
stop valve from 80% to 100% of full opening area.
10.Then, resume the execution by speed button in top middle part.

Course on Plant System Safety Analysis Using PC-Based Plant Simulator,
Dalat University, Vietnam, November 27-30, 2017.

13


Reactor Power Increase (80% 100%)
At 1130 s,
 Turbine load increased to 91%. With some delay, reactor
power is increasing by reactor regulating system.
 PRZ and SG pressures does not change much because
these are controlled by PRZ pressure control and feedwater
control. PRZ level is decreasing a little because power
increase is slower than increase of heat removal rate. But it
will be recovered by pressurizer level control.

Turbine flow

Reactor Power

PRZ and SG Pressure

Course on Plant System Safety Analysis Using PC-Based Plant Simulator,
Dalat University, Vietnam, November 27-30, 2017.

PRZ and SG level

14


Reactor Power Increase (80% 100%)
At 1320 s,
 Turbine stop valve flow rate and reactor power reaches to
100% condition and then, stabilized with small fluctuation.

Turbine flow

Reactor Power

Course on Plant System Safety Analysis Using PC-Based Plant Simulator,
Dalat University, Vietnam, November 27-30, 2017.


Reactor Power Increase (80% 100%)
At ~2000 s,

 Power and flow through the turbine stop valve reached to
100% of full power condition and stabilized by reactor
regulating system.
 PRZ and SG pressure and water level are changed little bit
in early transient but these are reached to the reference
values by PRZ pressure control and feedwater control
system. PRZ pressure is larger than reference value. But it
starts to decrease by pressurizer pressure control.

Reactor Power

Turbine flow

PRZ and SG Pressure

Course on Plant System Safety Analysis Using PC-Based Plant Simulator,
Dalat University, Vietnam, November 27-30, 2017.

PRZ and SG level

16


Reactor Trip

17


Reactor Trip
Initiated by setting the reactor scram during the nominal operating

condition. This event is an operational transient which could occur due
to reactor shutdown rod insertion by operator’s intension.
1.Click the execution file ‘APWRSimulator_visa.exe’ to start a
simulation.
 It will automatically load the input file (100ic_NLOCA_r3.i) and the
corresponding restart file of 100ic.r for 100% nominal operating
condition.

2.Press “OK” button in project tab for initialization.
3.Press “Run” speed button to simulate the 100% nominal power
condition.
4.Enter the “interval recording” in the text box at the top middle part.
5.Pause in the simulation at 10 s
 Set the time to pause.

 

Course on Plant System Safety Analysis Using PC-Based Plant Simulator,
Dalat University, Vietnam, November 27-30, 2017.

18


Reactor Trip
6. Move to “interactive tab” to initiate the transient.
7. Change the selection box from automatic to manual in “Reactor Trip”
line.
8. Press the toggle switch for trip status in target column to be true.
Then the toggle switch will change from OFF to ON.
9. Press APPLY button in the top right. These will shutdown the reactor.

10.Then, resume the execution by speed button in top left corner.

Course on Plant System Safety Analysis Using PC-Based Plant Simulator,
Dalat University, Vietnam, November 27-30, 2017.

19


Reactor Trip
Before initiating reactor scram,
 RCS condition is almost same as full power condition.
 Confirm if the calculation is reached the steady state condition by
examining the trend graphs for reactor power, PRZ and SG
pressures, etc.

Reactor Power

PRZ/SG P
Course on Plant System Safety Analysis Using PC-Based Plant Simulator,
Dalat University, Vietnam, November 27-30, 2017.

20


Reactor Trip
At 30 s after reactor scram,
 PRZ and SL pressure increase due to turbine isolation valve
closure. Reactor power is decreasing to decay heat level.
 After MFWs are isolated, AFWS is started due to low SG
narrow range levels. To control the steam header pressure,

turbine bypass valves are opened for ~10 s until excess
decay heat is removed.

PRZ and SG Pressure

Reactor Power

AFW flow

Turbine/steam bypass flow

Course on Plant System Safety Analysis Using PC-Based Plant Simulator,
Dalat University, Vietnam, November 27-30, 2017.

21


Reactor Trip
At 300 s,
 Reactor power is slowly decreasing due to decrease of
decay heat. PRZ pressure are maintained and stabilized
due to pressurizer pressure control. SG pressure is
increased due to turbine isolation valve close.
 Auxiliary feedwater flow is stabilized at ~250 s. Turbine
bypass valve flow appears in a short time when turbine
isolation valve closed to remove the decay heat.

Reactor Power

PRZ and SG Pressure

AFW flow

Course on Plant System Safety Analysis Using PC-Based Plant Simulator,
Dalat University, Vietnam, November 27-30, 2017.

Steam bypass flow

22


Reactor Trip
RCS Void Distribution before and after reactor trip
 Void in SG riser part is disappeared because the heat
transfer from primary to secondary side is decreased
substantially. .

RCS void distribution before reactor trip

RCS void distribution at 200 s after reactor trip

Course on Plant System Safety Analysis Using PC-Based Plant Simulator,
Dalat University, Vietnam, November 27-30, 2017.


Turbine Trip

24

Turbine Trip
Initiated by setting the turbine trip during the nominal operating
condition. This event is an operational transient which could be occur
due to turbine stop valve close by operator’s intension. The simulation
trend of this transient is very similar to reactor scram case.
1.Click the execution file ‘APWRSimulator_visa.exe’ to start a
simulation.
 It will automatically load the input file (100ic_NLOCA_r3.i) and the
corresponding restart file of 100ic.r for 100% nominal operating
condition.

2.Press “OK” button in project tab for initialization.
3.Press “Run” speed button to simulate the 100% nominal power
condition.
4.Enter the “interval recording” in the text box at the top middle part.
5.Pause in the simulation at 10 s
 Set the time to pause.

 

Course on Plant System Safety Analysis Using PC-Based Plant Simulator,
Dalat University, Vietnam, November 27-30, 2017.

25