1

- Condensate pump and feed pump trip!- Turbine trips!

2

- Condensate pump and feed pump trip!- Turbine trips!- Temperature and pressure in the primary loop is increasing!

3

- Relief valves opens in the pressurizer !

OPEN

4

- Control rods are inserted !

OPENINSERTED

5

- Pressure in the primary loop is decreasing !

INSERTED

6OPEN

- Emergency feed pump is now in operation !

INSERTED

OPERATION

7OPEN

- Relief valve is closed !

INSERTED

OPERATION

8

- Pressure in the primary loop is decreasing !

INSERTED

OPERATION

9

- Water level in the stream generator is decreasing !

INSERTED

OPERATION

10

- Pressure in the primary loop is decreasing !

INSERTED

OPERATION

11

INSERTED

OPERATION

12

- Water level in the pressurizer is gradually increasing !- Pressure in the primary loop is decreasing !

INSERTED

OPERATION

13NO WATER

- There is no water in the steam generator !

INSERTED

OPERATION

14NO WATER

- Water level in the pressurizer is gradually increasing !- Pressure in the primary loop is decreasing !

INSERTED

OPERATION

15NO WATER

- Why is pressure in the primary loop decreasing even though water level is increasing?

INSERTED

OPERATION

16NO WATER

- Water level in the pressurizer is gradually increasing !- Pressure in the primary loop is decreasing !

- Emergency core cooling system is now in operation !

INSERTED

OPERATION

WATER IS INJECTED

17NO WATER

- Water level in the pressurizer is increasing !- Pressure in the primary loop is decreasing !

INSERTED

OPERATION

WATER IS INJECTED

18NO WATER

- It might be dangerous if the amount of water is too much in the primary loop…

INSERTED

OPERATION

WATER IS INJECTED

19NO WATER

- Water level in the pressurizer is increasing !- Pressure in the primary loop is decreasing !

INSERTED

OPERATION

WATER IS INJECTED

20NO WATER

- Emergency core cooling system is operated by the manual mode from now !

INSERTED

OPERATION

WATER IS INJECTED

21NO WATER

- Water level in the pressurizer is increasing !- Pressure in the primary loop is decreasing !

INSERTED

OPERATION

WATER IS INJECTED

22NO WATER

- One of two emergency core cooling systems is manually stopped and the injection water from the other one is reduced.

INSERTED

OPERATION

WATER IS INJECTED

23NO WATER

- Water level in the pressurizer is increasing !- Pressure in the primary loop is decreasing !

INSERTED

OPERATION

WATER IS INJECTED

24NO WATER

- Water level is reaching the top of the pressurizer !

INSERTED

OPERATION

WATER IS INJECTED

25NO WATER

FULL WATER

- Water in the pressurizer is full, but measurement data at other positions in the primary loop do NOT show consistent results…

INSERTED

OPERATION

WATER IS INJECTED

26NO WATER

FULL WATER

INSERTED

OPERATION

WATER IS INJECTED

27NO WATER

FULL WATER

- Water level is at the top of the pressurizer !- Pressure of the primary loop is decreasing !

- Water level is at the top of the pressurizer !- Pressure of the primary loop is decreasing !- Water in the containment sump is moved to the auxiliary building.

INSERTED

OPERATION

WATER IS INJECTED

28NO WATER

FULL WATER

- The block values on the emergency feed water line pump have been CLOSE ! Why !

- Now it is OPEN !

INSERTED

OPERATION

WATER IS INJECTED

29FULL WATER