3.1 Reactivity Control Systems

Question 1

3.1.1 SHUTDOWN MARGIN

Answer 1

The SDM shall be within the limits specified in the COLR (currently 1.6% Δk/k for all modes)

APPLICABILITY: MODE 2 with keff <1.0 and Modes 3, 4, and 5

ACTIONS
A. SDM not within limits
A.1 Initiate boration to restore SDM to within limits
15 Minutes

Question 2

3.1.2 Core Reactivity

Answer 2

The measured core reactivity shall be within ±1% Δk/k of the predicted values.

APPLICABILITY: Modes 1 and 2

ACTIONS
A. Measured core reactivity not within limit.
A.1 Re-Evaluate core design and safety analysis and determine that the reactor core is acceptable for continued operation
7 DAYS AND
A.2 Establish appropriate operating restrictions and SRs.
7 DAYS

B. Required Action and associated Completion Time not met.
B.1 Be in MODE 3.
6 hours

Question 3

3.1.3 Moderator Temperature Coefficient

Answer 3

The MTC shall be maintained within the limits specified in the COLR.

APPLICABILITY: MODE 1 for upper MTC limit (0 pcm/°F (0-50%RTP), 0- -3 pcm/°F(50%-100%RTP)
MODE 2 with Keff ≥ 1.0 for the upper MTC limit. Same as MODE 1
MODE 1, 2, and 3 for the lower MTC limit (-40 pcm/°F (EOL/ARO))

ACTIONS
A. MTC not within upper limit
A.1 Restore MTC within limit
24 hours
B. Required action and associated completion time of condition A not met
B.1 Be in Mode 2 with Keff < 1.0.
6 hours
C. MTC not within lower limit.
C.1 Be in MODE 4
12 hours

Question 4

3.1.4 Rod Group Alignment Limits

Answer 4

Each RCCA shall be OPERABLE AND individual indicated rod positions of each RCCA and Gray Rod Cluster Assembly shall be within 12 steps of their group step counter demand position.

APPLICABILITY: MODES 1 and 2

ACTIONS
A. One or more RCCAs inoperable
A.1 Verify SDM to be within the COLR limits OR initiate boration to restore SDM
1 hour
A.2 Be in MODE 3
6 hours

B. One rod not within alignment limits
B.1 Restore rod to alignment
1 hour with On-Line PDMS not working and 8 hours
OR
B.2.1 Verify SDM to be within the COLR limits OR initiate boration to restore SDM
1 hour
AND
B2.2 Reduce Thermal power to ≤ 75% RTP.
2 hours
AND
B2.3.1 Verify OPDMS parameters
Once per 12 hours
OR
B2.3.2.1 Verify SDM within limits 1x/12 hours AND verify peaking factors within 72 hours
AND
B2.4 Re-evaluate safety analyses and confirm results remain valid for duration of operation under these conditions
5 DAYS
C. Required action/completion time of condition b not met…Be in MODE 3 within 6 hours
D. More than one rod not within alignment limit.
D.1. Verify SDM or initiate boration within 1 hour AND be in MODE 3 within 6 hours

Question 5

3.1.5 Shutdown Bank Insertion Limits

Answer 5

Each Shutdown Bank shall be within insertion limits specified in the COLR

• NOTE -
  This LCO is not applicable while performing rod surveillance.
  ————————————————————————————————–
  A. One or more shutdown banks not within limits
  A.1 Verify SDM is within COLR limits OR initiate boration to restore SDM within 1 hour
  AND
  A.2 Restore shutdown banks to limits within 2 hours

B. Required action and completion times not met, be in MODE 3 within 6 hours

Question 6

3.1.6 Control Bank Insertion Limits

Answer 6

Control banks shall be within the insertion, sequence, and overlap limits
specified in the COLR.

• NOTES -
  1. This LCO is not applicable while performing ROD Surveillance
  2. This LCO is not applicable to Gray Rod Cluster Assembly (GRCA)
  banks for up to one hour during GRCA bank sequence exchange.
  ————————————————————————————————–
  ACTIONS.
  A. Control bank insertion limits not meet
  A.1 Verify SDM is within COLR limits OR initiate boration to restore SDM within 1 hour
  AND
  A.2 Restore shutdown banks to limits within 2 hours

B. Bank sequence or overlap limits not met
B.1 Verify SDM is within COLR limits OR initiate boration to restore SDM within 1 hour
AND
B.2 Restore control banks to limits within 2 hours

C. Required action and completion times not met, be in MODE 2 keff <1.0 within 6 hours

Question 7

3.1.7 Rod Position Indication

Answer 7

The DRPI for each control rod and Bank Demand Position indication for each group shall be OPERABLE

APPLICABILITY: MODES 1 and 2

• NOTE -
  Separate Condition entry is allowed for each inoperable DRPI and each demand position
  indication.
  ————————————————————————————————–
  A. One DRPI per group group inoperable in one or more groups
  A.1 Verify rod position using incore detectors 1x/8hours OR
  A.2 Lower power ≤ 50% RTP within 8 hours
  B. More than one DRPI per group inoperable in one or more groups
  B.1 Immediately place rod control in manual AND
  B.2 Restore DRPI to operable so that no more than one per group is inop within 24 hours
  C. One ore more rods with inoperable DRPI moved >24 steps in one direction
  C1. Verify position with incore within 4 hours OR
  C2. Lower power ≤ 50% RTP within 8 hours
  D. One or more demand position indication per bank inoperable in one or more banks.
  D.1.1 Verify the DRPIs for affected banks are OPERABLE 1x/8 hours AND
  D.1.2 Verify the most withdrawn and least withdrawn rod in the bank are within 12 steps 1x/8 hours
  OR
  D.2 Lower power ≤ 50% RTP within 8 hours
  E. Required action/completion times not me…..be in mode 3 within 6 hours

Question 8

3.1.8 PHYSICS TESTS Exceptions - Mode 2

Answer 8

During the performance of PHYSICS TESTS, the requirements of:
LCO 3.1.3 “Moderator Temperature Coefficient (MTC),”
LCO 3.1.4 “Rod Group Alignment Limits,”
LCO 3.1.5 “Shutdown Bank Insertion Limits,”
LCO 3.1.6 “Control Bank Insertion Limits,” and
LCO 3.4.2 “RCS Minimum Temperature for Criticality”
may be suspended, and the number of required channels for LCO 3.3.1,
“Reactor Trip System (RTS) Instrumentation,” Functions 1, 2, 3, and 4
may be reduced to 3 provided:
a. Reactor Coolant System (RCS) lowest loop average temperature is
≥ 541°F,
b. SDM is within the limits specified in the COLR, and
c. THERMAL POWER is ≤ 5% RTP.

APPLICABILITY: During PHYSICS TESTS initiated in MODE 2.

ACTIONS
A SDM not within limits
A.1 Initiate boration to restore within 15 minutes AND suspend Physics testing within 1 hour
B Thermal Power not within limit
B.1 Open trip breakers immediately
C RCS lower loop Tavg not within limit
C.1 Restore Temp within limit within 15 minutes.
D. Required actions and associated completion time of C not met, be in MODE 3 within 15 minutes.

Question 9

3.1.9 CVS Demin Water Isolation Valves and Makeup Line Isolation Valves

Answer 9

2 CVS Demin Water Isolation Valves and 2 CVS Makeup Line Isolation Valves shall be OPERABLE

APPLICABILITY: MODES 1, 2, 3, 4 and 5

ACTIONS

• NOTE -
  Flow path(s) may be unisolated intermittently under administrative controls.
  ————————————————————————————————–
  A. One CVS Demin Isolation Valve OR CVS Makeup Isolation Valve OR one of each inoperable
  A.1 Restore two of any of them to OPERABLE within 72 hours
  B. Required action and completion time of A not met OR
  TWO CVS Demin Isolation Valves OR TWO CVS makeup Isolation Valves inoperable
  B.1 Isolate the affected flow path from Demin to the RCS by use of a manual closed valve or de-activated automatic valve within 1 hour

Question 10

3.1.10 Rod Withdrawal Test Exception – MODE 5

Answer 10

During the performance of rod movement and rod drop time testing, the
requirements of LCO 3.4.4, “RCS Loops,” may be suspended provided
boron concentration of the reactor coolant system is greater than the all
rods out (ARO) boron concentration that provides keff < 0.99.

APPLICABILITY: MODE 5 with LCO 3.4.4 not met.

ACTIONS
A. Requirements of LCO not met
A.1 Initiate action to fully insert all rods –> Immediately
A.2 Place PLS in state incapable of rod withdrawal within 1 hour