Rod Control System

Question 1

Auto Rod Control system is designed to

Answer 1

Keep Tavg consistent with Tref.
Uses Tavg and compares to First stage turbine pressure

Question 2

When in AUTO is there any OUTER motion?

Answer 2

NO OUTER MOTION IN AUTO

Question 3

Rod Control

Auto Rod Contorl system is designed to do what?

Answer 3

REstore program Tavg folowing a scheduled or transient step shange in load of 10% or ramp change of 5% per minute within the range of 15-100% power

Question 4

1 step is how much movement?

Answer 4

5/8 inch

Question 5

ITS Maximum time for rod drop?

Answer 5

1.8 seconds

Question 6

CRDM Out Sequence

Answer 6

1. Hold on stationary gripper
2. Latch on movable gripper
3. Unlatch on stationary gripper
4. Pull up the lift armature, raising the drive rod 5/8”
5. Latch the stationary gripper
6. Unlatch the movable gripper
7. Drop the lift armature

Question 7

CRDM in sequence

Answer 7

1. Hold on stationary gripper
2. Pull up the lift armature
3. Latch the movable gripper
4. Unlatch the stationary gripper
5. Drop the lift armature, lowering the drive rod 5/8”
6. Latch the stationary gripper
7. Unlatch the movable gripper

Question 8

How long does it take for a single step to be performed?

Answer 8

780 milliseconds (.78 seconds)

Question 9

Rod Drive Motor Generator
Powered from, output?

Answer 9

480V Bus 2B/3
Outputs 260V at 58.3 hertz

Question 10

If a bank is individually selected to move, what does this do?

Answer 10

No bank overlay. Must be returned to the position held before individual banks were moved.

Question 11

Reading Power Cabinets
1AC is?

Answer 11

Group 1 in Shutdown Bank A
Group 1 in Control Bank A
Group 1 in Control Bank C

Question 12

Reading Power Cabinets
2BD is?

Answer 12

Group 2 Shutdown Bank B
Group 2 Control Bank B
Group 2 Control Bank D

Question 13

Power Cabinet Urgent Alarm does what?

Answer 13

1. Energizes red light on affected Power Cabinet
2. Stops all rod motion in affected Power Cabinet
3. Loss Overlap in unaffected cabinets
4. RTGB alarm

Question 14

Power Cabinet Urgent alarm caused by?

MR. LLP

Answer 14

• Multiplexing Error
• Regulation Failure
• Logic Error
• Loose or missing Card
• Phase Failure

Question 15

Can you still move rods on a Urgent Power Cabinet alarm?

Answer 15

Not on effected cabinet but if you select an infidivual bank you can move that bank but you loose designed overlap

Question 16

If you misposition a rod bank out of overlap what must be done before returning to MANUAL OR AUTO on the selector switch

Answer 16

Whatever bank was moved must be moved back to correct postion per procedure

Question 17

Power Cabinet Non-Urgent alarm does what?

Answer 17

Loss of Power supply causes an urgent alarm if INWARD rod motion is demanded. (causes a logic error)
If OUTWARD rod motion is demanded will ratchet or drop

We place rods in manual and do not attempt any motion until repairs comp

Question 18

A Logic Cabinet Urgent alarm does what?

Answer 18

• Inhibits all rod motion
• Energizes red light at logic cabinet
• RTGB alarm

Question 19

A Logic Cabinet Urgent alarm is caused by?

SLO

Answer 19

• Secondary Cycler
• Loose or missing card
• Osciallator

Question 20

Power Cabinet and Logic Cabinet non urgent alarms are caused by?

Answer 20

Power supply failure

Question 21

Overlap works how?

Answer 21

1. Control Bank A out 128
2. Control Bank A/B out 100
3. A stops at 228 steps total
4. B goes 28 steps (now its at 128 steps)
5. B/C go out 100
6. B Stops when its at 228 steps out
7. C goes 28 more steps (128 steps)
8. C/D goe 100 steps
9. C Stops at 228 steps
10. D goes 118 more steps (Stays at 218 steps out)

Total of 602 steps

Question 22

Rod Control Logic compares what?

Answer 22

Median Tavg to Tref

Question 23

How much difference does Tavg have to be above Tref before Rod movement? when does movement stop?

Answer 23

1.5 degrees F. starts Rod insertion, once Tavg and Tref are within 1 degree of each other Rod movement stops

Question 24

Rod Insertion Limits setpoint comes from?

Answer 24

Linear function of Median Delta T

Question 25

Rod Insertion Limits do what?

Answer 25

* Ensure adequate SDM * LImit the worth of ejected rod * Ensure Proper Axial Flux

Question 26

Start up Push Button does what?

Answer 26

Resets: Primary Cycler counter Secondary Cycler counter P-A converter Internal memory and alarm circuits Group step counters on RTGB Bank overlap counter

Question 27

S/D Banks A & B move how fast? | Individual banks selected only

Answer 27

68 steps a minute

Question 28

Control Banks move how fast? | Individual banks selected or in manual

Answer 28

45 steps a minute

Question 29

When in auto how fast do Rods move?

Answer 29

* 8-72 steps a minute * 8 steps from 1.5-3 degrees difference * ramps up to 72 steps from 3-5 degree difference which at top speed is 45inch/min

Question 30

DC hold cabinet supplies what? and holds how many rods?

Answer 30

125/70 VDC 125 for latching 70 fo holding 5 Rods can be held at one time

Question 31

Define SDM

Answer 31

The instantaneous amount of reactivity by which the Rx is subcritical or would be subcritical from its present condition assuming all full-length rod cluster assemblies (shutdown and control) are fully inserted except for the single rod cluster assembly of highest reactivity worth that is assumed to be fully withdrawn.

Question 32

# Rod Control RCCAs in each group?

Answer 32

A,B,C all have 8 D has 5 Shutdown banks A/B have 16

Question 33

# Rod Control Fans that cool the CRDM?

Answer 33

HVH-5A/B, which are cooled by CCW. Remember backwards cooling.

Question 34

# Rod Control What defines a fully inserted rod?

Answer 34

20 steps or 12 inches withdrown, the same as the Rod Bottom Light Setpoint