LOT 110.01 Operating Limits

Question 1

• LCO 3.1.1.1 SDM*
• • *

When is LCO 3.1.1.1 SDM Applicable?

Answer 1

MODES 1 - 5

Question 2

• LCO 3.1.1.1 SDM*
• • *

What must SDM be greater than in MODES 1 -2?

Answer 2

> 1.3 % ∆p

SDM: The instantaneous amount of reactivity by which the reactor is subcritical or would be subcritical from its present condition assuming:

• All RCCAs fully inserted
• Highest reactivity RCCA fully withdrawn

Question 3

• LCO 3.1.1.1 SDM*
• • *

What is the bases for the different regions of the SDM curve in the COLR?

Answer 3

Constant SDM Region (1.3 % ∆p)

Protect against uncontrolled C/D from SLB

Variable SDM Region

Protect against boron dilution accident

Question 4

• LCO 3.1.1.1 SDM*
• • *

When must SDM be verified prior to criticality?

Answer 4

MODE 2 w/ keff < 1

Within 4 hrs prior to criticality

Also performed prior to operations > 5% RTP after refueling.

Question 5

• LCO 3.1.1.1 SDM*
• • *

While in MODES 3-5, SDM must be evaluted once per 24 hrs. Which factors must be taken into consideration?

Answer 5

RCS Boron Concentration

Xenon Concentration

RCCA position

T_avg

Fuel Burnup

Question 6

• LCO 3.1.1.1 SDM*
• • *

What are your ≤ 1 hour action(s) if SDM is not within the limits specified in the COLR?

Answer 6

• LCO 3.1.1.1 SDM*
• Action A*
• • *

Initiate Boration to restore SDM [15 min]

Question 7

LCO 3.1.1.3 MTC

When is LCO 3.1.1.3 MTC Applicable?

Answer 7

BOL (+MTC) Limit

MODES 1-2

EOL (-MTC) Limit

MODES 1-3

Question 8

• LCO 3.1.3.1 Movable Control Assemblies*
• • *

When is LCO 3.1.3.1 Movable Control Assemblies Applicable?

Answer 8

MODES 1 and 2

All S/D and Control Banks shall be OPERABLE AND within ± 12 steps of their group step counter demand position.

Question 9

• LCO 3.1.3.1 Movable Control Assemblies*
• • *

What are your ≤ 1 hour action(s) if ≥ 1 rods inoperable due to being immovable due to friction / mechanical interference or is known to be untrippable?

Answer 9

• LCO 3.1.3.1 Movable Control Assemblies*
• Action A*
• • *
• Determine SDM [1 hr]

Question 10

• LCO 3.1.3.1 Movable Control Assemblies*
• • *

What are your ≤ 1 hour action(s) if 1 rod is trippable but inoperable due to something other than being immovable due to friction / mechanical interference OR > ± 12 steps from it’s group counter?

Answer 10

• LCO 3.1.3.1 Movable Control Assemblies*
• Action B*
• • *

Power Operation may continue provided:

• Rod restored to OPERABLE status [1 hr]

OR

• Rod declared INOPERABLE [1 hr]
• Remainder of Rods in group aligned to within ± 12 steps on group counter while maintaining rod sequence and insertion limits of COLR [1 hr]
• Thermal power restricted per LCO 3.1.3.6 Control Rod Insertion Limits [1 hr]

OR

• Rod declared inoperable [1 hr]
• Verify SDM [1 hr]

Question 11

• LCO 3.1.3.1 Movable Control Assemblies*
• • *

What are your ≤ 1 hour action(s) if > 1 rod is trippable but inoperable due to something other than being immovable due to friction / mechanical interference?

Answer 11

• LCO 3.1.3.1 Movable Control Assemblies*
• Action D*
• • *

Power Operation may continue provided that:

• Remainder of Rods in group aligned to within ± 12 steps on group counter while maintaining rod sequence and insertion limits of COLR [1 hr]
• Thermal power restricted per LCO 3.1.3.6 Control Rod Insertion Limits [1 hr]

Question 12

• LCO 3.2.1 AFD*
• • *

When ≥ 90% RTP, what are your ≤ 1 hour action(s) if AFD is outside the target band?

Answer 12

• LCO 3.2.1 AFD*
• Action A.1*
• • *
• Restore AFD to target band [15 min]

OR

• Reduce RTP to < 90% RTP [15 min]
• • *

​Target band is +5 / -10

• Note:*
• Considered outside target band if ≥ 2 excore instruments indicating outside band.*

Question 13

• LCO 3.2.1 AFD*
• • *

When < 90% RTP but ≥ 50% RTP, what are your ≤ 1 hour action(s) if AFD is outside the target band?

Answer 13

• LCO 3.2.1 AFD*
• Action A.2*
• • *

Power operation may continue if:

• Been outside target band ≤ 1 hr during last 24 hrs (Cumulative) [1 : 1 ratio]
• AFD in accepatable region in COLR

Otherwise:

• Reduce RTP < 50% RTP [30 min]
• Reduce Power Range Flux High Trip ≤ 55% RTP [4 hrs]

​> 15% RTP but < 50% RTP with AFD outside the target band cumulates time in a 2 min : 1 min penalty ratio.

• Note:*
• Considered outside target band if ≥ 2 excore instruments indicating outside band.*

Question 14

• LCO 3.2.1 AFD*
• • *

When is LCO 3.2.1 AFD Applicable?

Answer 14

MODE 1, > 15 RTP

Question 15

• LCO 3.2.2 Heat Flux Hot Channel Factor F_Q(Z)*
• • *

When is LCO 3.2.2 Heat Flux Hot Channel Factor F_Q(Z) Applicable?

Answer 15

MODE 1

^{Peak kW/ft}⁄_{Average kW/ft}

Question 16

• LCO 3.2.2 Heat Flux Hot Channel Factor F_Q(Z)*
• • *

What are your ≤ 1 hour action(s) if F_Q(Z) is exceeding its limit?

Answer 16

• LCO 3.2.2 Heat Flux Hot Channel Factor F_Q(Z)*
• Action A*
• • *

Reduce RTP 1% for each 1% F_Q(Z) exceeds the limit [15 min]

May Continue power operation for 72 hrs if:

• Lower OT∆T Rx trip 1% for each 1% F_Q(Z) exceeds the limit

Question 17

• LCO 3.2.3 Nuclear Enthalpy Rise Hot Channel Factor*
• • *

When is LCO 3.2.3 Nuclear Enthalpy Rise Hot Channel Factor Applicable?

Answer 17

MODE 1

Question 18

• LCO 3.2.4 QPTR*
• • *

When is LCO 3.2.4 QPTR Applicable?

Answer 18

MODE 1 > 50% RTP

^{Max Upper Excore}⁄_{Average Upper Excore}

OR

^{Max Lower Excore}⁄_{Average Lower Excore}

Question 19

• LCO 3.2.5 DNB Parameters*
• • *

When is LCO 3.2.5 DNB Parameters Applicable?

Answer 19

MODE 1

• T_avg ≤ 595 ˚F
• PZR Pressure > 2200 psig
• Thermal Design Flow ≥ 392,000 gpm
• Thermal Design Flow (COLR) > 403,000 gpm