Control Element Drive Mechanisms

Chapter 3.0

Learning Objectives1. Describe the components in the control

element drive mechanism (CEDM) that are a part of the reactor coolant system (RCS) pressure boundary.

2. Describe the power supply to the CEDMs.

3. Explain the purposes of the control element assembly control and indication system (CEAC&IS).

Learning Objectives4. List and state the purposes of the CEAC&IS

interlocks.

5. Explain the various modes of operation of the CEAC&IS.

Figure 3-2 Dual CEA Coupling

TO CEDMDRIVE SHAFT

TOTO

YOKE

TOCEA HUB

TOCEA HUB

TOP VIEW

Reed Switch Assembly

Shroud Assembly

Anti-Ejection Gripper

Ball Vent Assembly

Magnet

Upper Pressure Housing

Omega Seal

Figure 3.3 Pressure Housing and Drive Unit

Anti Ejection Gripper

Upper Gripper

Lower Gripper

Pressure Housing

Extension Shaft

CEA Nozzle

Operating Coil StackAssembly

Drive ShaftAssembly

Omega Seal

Figure 3-4 CEA Motor Assembly

Pressure Housing

CEALOGIC

CABINET

RPSREACTOR

TRIPSWITCHGEAR

RRS

CONTROL ELEMENTDRIVE SYSTEM

CONTROL PANEL

COIL POWERPROGRAMMER

CRDM

REEDSWITCH

CEA

Figure 3-8 CEDS Block Diagram

ANNUNCIATORSAND

DISPLAY

GROUP DEVIATIONOUT OF SEQUENCE

PPDIL AND PDILSYSTEM

PLANTCOMPUTER G

M480 Vac

MOTOR GENERATORCONTROL CABINET

CEA MOTORGENERATOR

Figure 3-9 CEA Power Supply

9

NON VITAL480 VAC

3 PHASE 60 HZ

240 VAC3 PHASE 60 HZ

OUTPUT BREAKERS

M

G

M

G

TOCEA COILS

UV UV

2 6

1 5

7

4

3

8

Figure 3-10 CEA Distribution Bus

UV

FROM REACTOR TRIPCIRCUIT BREAKERS

UNDERVOLTAGECOILS

(One per Bus)

TRANSFORMER

RECTIFIERSUBGROUP BREAKER

(TYPICAL OF 10)

DISTRIBUTIONBUS

UVUNDERVOLTAGE

COILS(One per Bus)

FROM REACTOR TRIPCIRCUIT BREAKERS

DISTRIBUTIONBUS

(Similar to the distributionh i thi fi )

COILSWITCH

CEDSLOGIC

CEA COIL(TYPICAL OF 5)

HOLD BUS

INDIVIDUALCEA BREAKERS

shown in this figure)

Figure 3-11 Reed Switch Assembly

2"

POWERSUPPLY

(-) (+) POSITIONSIGNAL

(-) (+)

POSITIONSIGNAL

(-) (+)

POSITIONSIGNAL

(-) (+)

POSITIONSIGNAL

(-) (+)

POSITIONSIGNAL

(-) (+)

DROPPED CEAUPPER

ELECTRICALLIMIT

135"

3.5"

LOWERELECTRICAL

LIMIT

1.5"

REED SWITCHPOSITION TRANSDUCER

(RSPT)

NOTE: The RSPT is the secondaryposition indicating system

CEA Mimic Display

Regulating CEA

UPPERLIMIT

LOWERLIMIT

REGULATING CEABETWEEN U&L LIMITS

DROPPEDCEA

Figure 3-12 CEA Four Lamp Display

RED WHITE

GREEN AMBER

RED BLUE

GREEN AMBER

Shutdown CEA

SHUTDOWN CEA BELOWEXERCISE LIMIT (129")

Figure 3-13 CEDS Control Panel

INDIVIDUAL CEASELECTIONSHUTDOWN REGULATING POWER

SHAPINGA B C 1 2 3 4 5 6 P

38 42

43

40 44

41 45

39

6

7

8

9

46

47

48

49

50

51

52

53

54

56

57

59

60

62

63

65

2

3

4

5

10

11

12

13

26

27

28

29

30

31

32

33

14

15

16

17

1

34

35

36

55

58

61

64

18

19

20

21

22

23

24

25

37 P

MODESELECTION

AUTOMATICSEQUENTIAL

AUTO

MANUALSEQUENTIAL

MS

P

POWERSHAPING

GROUPSELECTIONSHUTDOWN REGULATING

A B C

TEST

LAMP TEST

1 2 3 4 5 6

OFF

MANUALGROUP

MG

MANUALINDIVIDUAL

MI

NOTE:POWER SHAPING RODSHAVE BEEN REMOVED