TS 3.1.5 Control Element Assembly (CEA) Alignment

Question 1

LCO 3.1.5 All FSCEA’s shall be OPERABLE, and all FS and PSCEAs shall be aligned to within ___ inches (indicated position of all other CEAs in their respective groups.

APPLICABILITY: ___

Answer 1

6.6 inches

Applicable in Modes 1 and 2.

Question 2

If a CEA is discovered to be immovable but remains triable and aligned, the CEA is considered OPERABLE or NOT OPERABLE?

Answer 2

OPERABLE

Question 3

If a CEA is immovable, a determination of ___ of that CEA must be made, and appropriate action taken.

Answer 3

Trippability (OPERABILITY)

Question 4

Each CEDM moves its CEA one step (~ ___) at a time…

Answer 4

(~3/4 inch)

Question 5

The ___ CEAs also provide reactivity (power level) control during normal operation and transients.

Answer 5

Regulating CEAs

Question 6

The part strength CEAs are used solely for ___

Answer 6

ASI control

Question 7

The ___ CEA position indicating system indicates CEA position to the actual step, if each CEA moves one step for each command signal.

Answer 7

Pulse Counting

• If each CEA does NOT follow commands, system will incorrectly reflect position of affected CEA (COLSS Operability potential)

Question 8

The acceptance criteria for addressing CEA inoperability or misalignment are that:
There shall be NO violations of:
1.___
2.___

Answer 8

1. Specified acceptable fuel design limits, or

2. RCS Pressure boundary integrity

Question 9

Three types of misalignment are distinguished. They are ___, ___ and ___

Answer 9

Misalignment within deadband (<6.6 inches)
Misalignment in excess of deadband and,
CEA/subgroup drop

Question 10

The last type of misalignment occurs when one CEA or subgroup drops partially or fully into the reactor core. This event causes ___

Answer 10

Initial power reduction followed by return towards original power due to positive reactivity feedback from negative MTC.

• Increased peaking during the power increase may result in erosion of DNB margin

Question 11

Misalignments within deadband are evaluated to ensure ___ are NOT exceeded.

Answer 11

Specified acceptable fuel design limits (SAFDLs)

Question 12

The most rapid approach to the DNBR SAFDL or the fuel centerline melt SAFDL is caused by ___ with CEACS In-Service and either a ___ or ___ with CEACS OOS.

Answer 12

A Single full strength CEA drop with CEACS IS

12 finger or subgroup drop with CEACS OOS

Question 13

Failure to meet the requirements of this LCO may produce unacceptable ___, ___, and ___ or unacceptable ___, all of which may constitute initial conditions inconsistent with the safety analysis.

Answer 13

Power Peaking factors, DNBR and LHRs

or unacceptable SDMs

Question 14

The requirements on CEA OPERABILITY and alignment are applicable in MODES 1 AND 2 because these are the only MODES in which ___, and the OPERABILITY and alignment of CEAs have the potential to affect the safety of the plant.

Answer 14

Neutron (or fission) power is generated

Question 15

LCO 3.1.5 Condition
A. One or more CEAs trippable and misaligned from its group by >6.6 inches and <9.9 inches OR

One CEA trippable and misaligned from its group by >9.9 inches

Answer 15

A.1 Reduce THERMAL POWER in accordance with the limits in the COLR (1 Hour) AND

A.2 Restore CEA alignment (2 Hours)

Question 16

Per the COLR. Figure 3.1.5-1 Core Power reduction after CEA deviation requires what power reductions?

Answer 16

100% to 80% - 20%
70% to 80% - 15%
45% to 70% - 10%
< 45% - 5%

• At 35% RTP, further reduction isn’t required

Question 17

No Power reduction is required for a single CEA misalignment if the following conditions are continuously met from the time of deviation:
\_\_\_\_
\_\_\_\_
\_\_\_\_
\_\_\_\_

Answer 17

1. > 95% RTP
2. COLSS In-Service and CEACs IS
3. Azimuthal Power Tilt is < 3%
4. All CEAs remain > 142.5” withdrawn by Pulse Counters and > 140.1” withdrawn by RSPT Indication

Question 18

Per Action A.2 (Restore CEA alignment), the 2 hour period is sufficient to:
___
___
___

Answer 18

a. ID cause of misaligned CEA
b. Take appropriate corrective action to realign the CEAs
c. Minimize effects of Xenon redistribution

Question 19

LCO 3.1.5 Condition

B. Only 1 CEA position indicator channel OPERABLE for 1 CEA per CEA group

Answer 19

B.1 Restore at least 2 position indicator channels to OPERABLE status (6 Hours) OR

B.2 Verify the CEA Group(s) with the inoperable position indicators are fully withdrawn or fully inserted while maintaining the insertion limits of LCO 3.1.6, 3.1.7 and 3.1.8 (6 Hours AND Once per 12 Hours thereafter)

Question 20

At least 2 of the following 3 CEA position indicator channels shall be OPERABLE for each CEA:

a. ___
b. ___
c. ___

Answer 20

a. CEA (RSPT 1) with capability of determining absolute CEA positions < 5.2”
b. CEA (RSPT 2) with capability of determining absolute CEA positions < 5.2”, AND
c. The CEA Pulse Counting position indicator channel

Question 21

Additionally, the ___ CEA reed switches provide an acceptable indication of CEA position for a fully withdrawn condition.

Answer 21

Upper Electrical Limit (UEL)

Question 22

LCO 3.1.5 Condition
C. Required Action and associated Completion Time of Condition A or B not met OR

One or more FSCEAs untrippable

Answer 22

C.1 Be in MODE 3 (6 Hours)

Question 23

The allowed Completion Time of 6 hours is reasonable, based on OE, for reaching MODE 3 from full power conditions in an orderly manner and without challenging plant systems. The specified ramp rate is intended to ensure ___ are not challenged.

Answer 23

DNBR SAFDLs

Question 24

Continued operation is allowed with a untrippable PSCEAs if the ___ and ___ are met.

Answer 24

Alignment and Insertion Limits are met

Question 25

LCO 3.1.5 Condition

D. 2 or more CEAs trippable and misaligned from their group by >9.9 inches

Answer 25

D.1 Open the reactor trip breakers (Immediately)

Question 26

With 2 or more CEAs misaligned more than 9.9”, this is a situation outside the ___ and immediate action would be required to prevent any ___

Answer 26

Design Basis

prevent any potential fuel damage

Question 27

Per SR 3.1.5.3, individual FSCEA’s are exercised to provide confidence that all FSCEAs continue to be trippable. A movement of ___ is adequate to demonstrate motion without exceeding the alignment limit when only 1 FSCA is being moved.

Answer 27

5 inches

Question 28

SR 3.1.5.5 Verify each FSCEA drop time ___

Answer 28

Is Less than or Equal to 4 seconds

• 4 seconds is MAX time for fully withdrawn FSCEA to reach 90% insertion position when electrical power is interrupted to CEDM’s with RCS Tcold > 550F and all RCPs operating