Rod Control Flashcards by robert lohse

C-1 _______
Inputs_____
Purpose___
When blocked___

IR High flux rod stop

> 20% on 1/2 IR. Stops outward rod motion in auto and manual. Rod stop is blocked when the IR high flux trip is blocked.

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C-2_____
Input____
Purpose___
When blocked ____

PR high flux rod stop

> 103% Prx on 1/4 PR
Stops outward rod motion in auto and manual. Rod stop is blocked when the rod stop bypass switch is selected to the PR channel causing the rod stop annunciator.

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C-3 ____
Input____
Purpose____
Can it be blocked?

OT delta T high rod stop
2/4 delta T> OTdeltaT setpoint -3%

Stops outward rod motion in auto and manual.
Can not be blocked. Alarm on 1/4 channels.

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C-4____
Input____
Purpose___

OPdeltaT high rod stop

2/4 delta T > OPdeltaT setpoint-3%

Stops outward rod motion in auto and manual. Can not be blocked. 1/4 gives alarm

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C-5_____
Input____
Purpose____
Location of alarm____
Can this interlock be blocked?

Turbine low power interlock

Impulse pressure<15% turbine power.

Stops outward rod motion in auto ONLY. Can not be blocked.

Alarm is on the bypass permissive panel

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C-11____
Inputs____
Purpose___
Alarm is generated by_______
Can this be blocked?

Control bank D rod stop

CBD=223 steps.

Stops outward rod motion in auto only. Can not be blocked.

Alarm is generated by the process computer.

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Control rods are typically made of ____

Silver indium cadmium alloy

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Bank overlap automatically overlaps control banks for _____ and _____

Uniform flux distribution
and
DRW

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Continuity (is/is not) required through the rod stop circuit to allow control rods to auto or manually withdraw.

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If control rods can not be inserted or withdrawn, a problem exists not in the _____ but in the _____.

Rod stop circuitry

Rod drive system

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All ____ rod withdrawal capabilities are lost when AC bus ___ is de-energized.

Failure of buses ____, ___, and ____ will prevent _______ rod withdrawal until the rod stop is bypassed on the affected NI channel.

Auto; 111

112, 113, 114; manual and auto

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All _____ rod withdrawals capabilities are lost when AC bus ____ is de-energized with N35 or N36 above 20% power.

Manual

Bus 114

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Rod speeds
Auto_____
Manual____
Bank select CB ____
Bank select SB_____

8-72 spm

48 spm

64 spm

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Rods are in _____ when power_____ with/without main gen synched.

Rods are in _____ when power _____ with/without main gen synched.

Auto; >15% with main gen

Manual <15% without main gen

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Reactor control unit compares ______ and ______ to determine a power mismatch.

Validated 2nd highest Q (nuclear power)
-and-
Validated 1st stage pressure

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The Tref programmer receives input from _______

validated 1st stage pressure

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Summing unit compares _______ with ________ to determine rod speed program.

Validated 2nd highest Tave
-with-
Mismatch/T ref program
-and-
Q/Turb FSP

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Effects of failures on rods

Tave high____

PR NI high____

P-imp Low____

P-imp High___

Tave low or PR NI low_____

Tave, no effect validated Tave signal
PR NI high Rod stop C2 will actuate
P-imp low, no effect validated Impulse pressure
P-imp high, no effect validated impulse pressure
Tave low or PR NI low- no effect

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In automatic, rod speed is _____ at a ____temperature deviation. Rod speed is _____ at a _____ temperature deviation.

8 spm at 3F
72spm at 5F

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The reactor control unit develops _____ and _____ signals for the logic cabinet.

Rod speed and direction

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Alternate action for both _____ and ______ will block rods in and out logic, rods will move in manual.
Alternate action for _____ will zero the power mismatch and move in ____ only on temperature error.

RCS Tave and Turbine impulse pressure

NI power; Auto

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Logic cabinet - non urgent alarm causes (5)

-Failure of one redundant power supply or redundant controller
- Failure of IO module not required to support rod motion
- Failure of network media converter
- High temperature
- High humidity

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Logic cabinet urgent alarm causes- (2)

-Failure of coincident inputs
-Failure of IO module required to support rod motion

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The power cabinet designations are ____.(5)

1AC
2AC
1BD
2BD
SCDE

Bypass Breakers are of identical construction to the Rx Trip Breakers Except:

SSPS does not energize the shunt trip coils on a trip signal.

A SSPS “General Warning” is generated when a bypass breaker is racked in and closed and a reactor trip will occur if ______.

A Reactor Trip will occur if both bypass breakers are racked in and closed.

An SSPS “P-4” (“P” stands for “Permissive”) signal is generated when _______.

A reactor trip breaker and its associated bypass breaker are open or racked out.

A P-4 signal causes the following:

-Turbine Trip -Feedwater Isolation (FWI) when combined with low Tave of 564° F. -Allows auto SI to be blocked after an SI.

DC hold cabinet energizes ________ coils in one power cabinet at a time with ____VDC (latch) or _____VDC (hold). ____VDC from cabinet is used to reset steps counters.

stationary 125VDC 70VDC 24VDC

Rod insertion limit comparator: 0% reference height_____ 30% reference height_____ 100% reference height_____

47 steps on control bank C 0 steps on control bank D 161 steps on control bank D

Rod insertion limit comparator also generates the ______ Interlock whenever _____. Resets____.

C-11 CBD >223 steps 221 steps

To calculate an expected CBD RIL approximately

CBD RIL=(Prx-30%)*2.3

RIL Basis (3 items)

Provides adequate SDM Acceptable power distribution Potential effects of a rod misalignment minimized (ejected rod worth)

How blown fuses affect the gripper coils. Stationary____ Lift_____ Movable_____

S-Affected rod drops L-Affected rod will not move M-Affected rod(s) will ratchet into core when withdrawn or inserted

If a Lift coil or movable fuse blows how many rods are impacted? What if a stationary fuse blows?

More than one rod may be affected. Only one rod can be affected.

RIL calculator uses ______ to determine calculated RIL.

Validated delta T (2nd highest)

Rod control non-urgent failure: DRPI (LEAF) Power cabinet (F) Logic cabinet (FFFHH) Will any of these prevent rod motion in auto or manual?

DRPI: Loose or missing card, error in data A or B, Accuracy mode switch not in A+B, Failure of one redundant PS PC: Failure of one redundant PS Logic cabinet: Failure of one redundant PS or controller, Failure of a IO module not required for rod motion, failure of network media converter, high temp >=110F, high humidity >=95% None of the above will prevent rod motion

Rod control urgent failure in DRPI (will or will not) prevent rod motion. Power cabinet urgent failure (will or will not) prevent rod motion. Logic cabinet (will or will not) prevent rod motion.

DRPI will not prevent rod motion. PC will prevent rod motion only in affected cabinet. LC will prevent ALL rod motion.

Startup reset switch (4 functions) Where located? Possible alarms if actuated?

-Reset power cabinet alarms -Reset total group count/total bank count -Reset master cycler -Reset rod group step counters -Possible RIL low and RIL low-2 alarms MCB and soft key

Alarm reset pushbutton (3 functions) Where located?

-Reset power cabinet alarm -Reset logic cabinet alarm -Cause stationary gripper full current for 160 msec MCB and soft key

RIL low alarm comes in at ______ and RIL low-2 @______.

within 10 steps of calculated delta T rod position Low-2 comes in when < delta T rod position

3.1.4 Rod Group Alignment Limits LCO 3.1.4 All shutdown and control rods shall be OPERABLE. AND Individual indicated rod positions shall be within________ of their group step counter demand position. APPLICABILITY: MODES 1 and 2.

12 steps

LCO times for the following: A.1.1 Verify SDM is within the limits specified in the COLR. OR A.1.2 Initiate boration to restore SDM to within limit. AND A.2 Be in MODE 3.

Within one hour Within one hour and mode 3 within 6 hours

One rod not within alignment, what are the LCO actions and times?

B.1.1 Verify SDM is within the limits specified in the COLR. one hour OR B.1.2 Initiate boration to restore SDM to within limit. one hour AND B.2 Reduce THERMAL POWER to <= 75% RTP. 2 hours

3.1.5 Shutdown Bank Insertion Limits LCO 3.1.5 Each shutdown bank shall be within the insertion limits specified in the COLR.

<=16 steps below the RIL for SD banks determine SDM and initiate boration if not met

3.1.6 applies to ______

CB RILs

3.1.7 DRPI

LCO 3.1.7 The Digital Rod Position Indication (DRPI) System and the Demand Position Indication System shall be OPERABLE.

What are the 3 electromagnets which act together to accomplish rod motion?

Stationary gripper, moveable gripper and lift coil.

What two parameter comparisons are made to determine rod speed and direction?

Tave vs. Tref. Rate of Rx power change vs. rate of turbine load change

What is the function of the Power Mismatch Rate Comparator?

Speed up response of Rx control unit during transients

What two signals are provided by the logic cabinet to the Power Cabinets?

Current orders and multiplexing signals

The rod drive motor trips on ______ and the generator trips on ______.

Overcurrent Overcurrent, Overvoltage, Directional Overcurrent

Lift coil disconnect switches are used for ______.

Individual rod movement or rod recovery.

Rod Deviation Power Range Tilt alarm causes (5)

Any Bank Greater than All Rods Out (ARO)/PARK position in COLR. C/B D >223 steps. Rod Sequence or overlap error >1 step (Group Misalignment) on demand. Digital Rod Position (DRPI) vs Demand (RD System) > 12 steps.

How many CRDMs?

53 total, 28 SDB and 25 CB

Summing unit error signal to the rod speed programmer determines rod speed and direction. Magnitude of error_____ Polarity of error________

Speed Direction

The non linear gain unit ______. The variable gain unit______.

Converts the power mismatch signal to a temperature error signal and compensates for larger errors by increasing the output. Compensates for the power mismatch from a given reactivity change at various power levels. Gain goes down as power rises.

The startup reset switch performs which functions?

Reset power cabinet alarms Reset total group count/total bank count Reset master cycler Reset rod group step counters Possible RIL low and RIL Low-2 alarms