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