L-2025-158, Cycle 33 Core Operating Limits Report
| ML25294A006 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 10/20/2025 |
| From: | Mack K Florida Power & Light Co |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| L-2025-158 | |
| Download: ML25294A006 (1) | |
Text
U.S. Nuclear Regulatory Commission ATTN : Document Control Desk Washington, DC 20555-00001 Re:
St. Lucie Nuclear Plant, Unit 1 Docket 50-335 October 20, 2025 Cycle 33 Core Operating Limits Report L-2025-158 10 CFR 50.36 Pursuant to St. Lucie Unit 1 Technical Specification (TS) 5.6.3, Florida Power & Light Company (FPL) is submitting the Core Operating Limits Report (COLR) for operating Cycle 33.
Should you have any questions regarding this submission, please contact Ms. Maribel Valdez, Fleet Licensing Manager, at 561-904-5164.
~~ ~?-
Ke A. M Director, Licensing and Regulatory Compliance Florida Power & Light Company
Enclosure:
St. Lucie Unit 1, Cycle 33 Core Operating Limits Report cc:
USNRC Regional Administrator, Region II USNRC Project Manager, St. Lucie Nuclear Plant USNRC Resident Inspector, St. Lucie Nuclear Plant Mr. Clark Eldridge, Florida Department of Health Florida Power & Light Company 6501 S. Ocean Drive, Jensen Beach, FL 34957
ST. LUCIE UNIT 1, CYCLE 33 CORE OPERATING LIMITS REPORT Revision O Co-Prepared by: A.Ja:t:Juu.t, / ~o-d, N. Tanzosch Co-Prepared by:_...;;;~_....;.,,,,.;:=-__;,;;;;,,
A. Cuesta Leyva Verified by:
R. Hunter Approved by:--~-~---~----
I. Sayre
~
St. Lucie Unit 1 CYCLE 33 COLR Rev.O 9/19/25 Date 09/16/2025 Date 09/19/2025 Date 09/22/2025 Date Page 1 of 13
Table of Contents Description Page 1.0 Introduction 2.0 Core Operating Limits 2.1 Moderator Temperature Coefficient (MTC) 2.2 Control Element Assembly (CEA) Alignment 2.3 Regulating CEA Insertion Limits 2.4 Linear Heat Rate (LHR) and Axial Shape Index (ASI) 2.5 TOTAL INTEGRATED RADIAL PEAKING FACTOR (F/)
2.6 RCS Pressure, Temperature and Flow Departure 3
4 4
4 4
5 from Nucleate Boiling (DNB) Limits 5
- 2. 7 Boron Concentration 5
2.8 SHUTDOWN MARGIN (SOM) - Tavg Greater Than 200 °F 6
2.9 SHUTDOWN MARGIN (SOM) - Tavg Less Than or Equal To 200 °F 6
2.10 Reactor Core Safety Limits (SLs) 6 Table 3.2-1 Fig 3.1-1a Fig 3.1-2 Fig 3.2-1 Fig 3.2-2 Fig 3.2-3 Fig 3.2-4 List of Tables and Figures DNB Margin Limits Allowable Time To Realign CEA vs. Initial F/
CEA Insertion Limits vs. THERMAL POWER Allowable Peak Linear Heat Rate vs. Burnup AXIAL SHAPE INDEX vs. Maximum Allowable Power Level Allowable Combinations of THERMAL POWER and F/
AXIAL SHAPE INDEX Operating Limits vs. THERMAL POWER St. Lucie Unit 1 CYCLE 33 COLR Rev.O Page 2 of 13 Page 7
8 9
10 11 12 13
1.0 INTRODUCTION
This CORE OPERATING LIMITS REPORT (COLR) describes the cycle-specific parameter limits for the operation of St. Lucie Unit 1. It contains the limits for the following, as provided in Section 2.0:
Moderator Temperature Coefficient (MTC)
Control Element Assembly (CEA) Alignment Regulating CEA Insertion Limits Linear Heat Rate (LHR) and Axial Shape Index (ASI)
TOTAL INTEGRATED RADIAL PEAKING FACTOR - F?
RCS Pressure, Temperature and Flow Departure from Nucleate Boiling (DNB) Limits Boron Concentration SHUTDOWN MARGIN (SOM) - Tavg Greater Than 200 °F SHUTDOWN MARGIN (SOM) - Tavg Less Than or Equal To 200 °F Reactor Core Safety Limits (SLs)
This report also contains the necessary tables and figures which give the limits for the above listed parameters.
Terms appearing in capitalized type are DEFINED TERMS as defined in Section 1.0 of the Technical Specifications.
This report is prepared in accordance with the requirements of Technical Specification 5.6.3.
St. Lucie Unit 1 CYCLE 33 COLR Rev.O Page 3 of 13
2.0 CORE OPERATING LIMITS 2.1 Moderator Temperature Coefficient (TS 3.1.3)
The moderator temperature coefficient (MTC) shall be less negative than -32 pcm/°F at RATED THERMAL POWER.
The maximum positive limit shall be:
- a.
+7 pcm/°F with THERMAL POWER :5 70% RTP, and
- b.
+2 pcm/°F with THERMAL POWER> 70% RTP.
2.2 Control Element Assembly (CEA) Alignment (TS 3.1.4)
The time constraints for full power operation with the misalignment of one full length CEA by 15 or more inches from any other CEA in its group are shown in Figure 3.1-1 a.
2.3 Regulating CEA Insertion Limits (TS 3.1.6 and 3.1.7)
The regulating CEA groups shall be limited to the withdrawal sequence and to the insertion limits shown on Figure 3.1-2, with CEA insertion between the Long Term Steady State Insertion Limits and the Power Dependent Insertion Limits restricted to:
- a.
~ 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> per 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> interval,
- b.
~ 5 Effective Full Power Days per 30 Effective Full Power Day interval, and
- c.
~ 14 Effective Full Power Days per 365 EFPD.
2.4 Linear Heat Rate (TS 3.2.1) and Axial Shape Index (TS 3.2.4)
The linear heat rate shall not exceed the limits shown on Figure 3.2-1.
The AXIAL SHAPE INDEX power dependent control limits are shown on Figure 3.2-
- 2.
During operation, with the linear heat rate being monitored by the Excore Detector Monitoring System, the AXIAL SHAPE INDEX required by TS 3.2.1 shall be maintained within the limits of Figure 3.2-2.
During operation, with the linear heat rate being monitored by the lncore Detector St. Lucie Unit 1 CYCLE 33 COLR Rev.O Page 4 of 13
Monitoring System, the Local Power Density alarm setpoints shall be adjusted to less than or equal to the limits shown on Figure 3.2-1.
The AXIAL SHAPE INDEX required by TS 3.2.4 shall be maintained within the limits shown on Figure 3.2-4.
The instrumentation AXIAL SHAPE INDEX (Y1) used for the trip and pretrip signals in the reactor protection system is the AXIAL SHAPE INDEX value (YE) modified by an appropriate multiplier (A) and a constant (B) to determine the true core axial power distribution for that channel (Y1 = AYE + B). Where YE is the power level detected by the lower excore nuclear instrument detectors (L) less the power level detected by the upper excore nuclear instrument detectors (U), divided by the sum of these power levels, [YE= (L-U) / (L +U)].
2.5 TOTAL INTEGRATED RADIAL PEAKING FACTOR - F/ (TS 3.2.2)
The calculated value of F/ shall be limited to.:::. 1.65 The power dependent F? limits are shown on Figure 3.2-3.
2.6 RCS Pressure. Temperature and Flow Departure from Nucleate Boiling (DNB)
Limits (TS 3.4.1)
The following DNB-related parameters shall be maintained within the limits shown on Table 3.2-1:
- a.
Cold Leg Temperature
- b.
Pressurizer Pressure 2.7 Boron Concentration (TS 3.9.1)
With the reactor vessel head unbolted or removed, the boron concentration of all filled portions of the Reactor Coolant System, the refueling canal, and the refueling cavity shall be maintained uniform and sufficient to ensure that the MORE RESTRICTIVE of the following reactivity conditions is met:
- a.
Either a Keff of 0.95 or less, which includes a 1000 pcm conservative allowance for uncertainties, OR
- b.
A boron concentration of,:: 1900 ppm, which includes a 50 ppm conservative allowance for uncertainties.
St. Lucie Unit 1 CYCLE 33 COLR Rev.O Page 5 of 13
2.8 SHUTDOWN MARGIN - Tava Greater Than 200 °F (TS 3.1.1)
The SHUTDOWN MARGIN shall be greater than or equal to 3600 pcm.
2.9 SHUTDOWN MARGIN-Tava Less Than or Equal To 200 °F (TS 3.1.1)
The SHUTDOWN MARGIN shall be greater than or equal to 2000 pcm.
2.10 Reactor Core Sls (TS 2.1.1.2)
The fuel melt limit is specific to the methodology used and is defined as follows:
[(2790 - 17.9 x P - 3.2 x B) x 1.8 + 32] °F, according to the RODEX2 methodology per XN-NF-79-56(P)(A) Revision 1 and Revision 1 Supplement 1, where Pis the maximum weight percent of Gadolinia (%) and Bis the maximum pin burnup (GWD/MTU).
St. Lucie Unit 1 CYCLE 33 COLR Rev.O Page 6 of 13
Table 3.2-1 DNB MARGIN LIMITS PARAMETER Cold Leg Temperature Pressurizer Pressure*
FOUR REACTOR COOLANT PUMPS OPERATING
~ 2225 psia Limit not applicable during either a THERMAL POWER ramp increase in excess of 5% per minute of RATED THERMAL POWER or a THERMAL POWER step increase of greater than 10% of RATED THERMAL POWER.
St. Lucie Unit 1 CYCLE 33 COLR Rev.O Page 7 of 13
I-LL
"'O (I)
C
.Ql 1.67 1.65 1.63
~ 1.61
~
I (I) a_
"'O (I)
- i 1.59 en ro (I)
~
1.57 1.55 (60, 1.65)
I I
I I
0 10 20 30 40 50 60 Time at Full Power to Realign CEA, Minutes FIGURE 3.1-1a Allowable Time to Realign CEA vs. Initial Fr1 St. Lucie Unit 1 CYCLE 33 COLR Rev.O Page 8 of 13 70
1.00 a::
W 0.90
~
0 a.
0.80
...J
<t
~
a::
w
- I:
l-o w
~
a::
- u.
0 z 0
j::
0 c2
- u.
0.70 0.60 0.50 0.40 0.30 0.20 0.10 (Group 7@ 103 in., 1.00) d ~.
- gl
.s m
(!)
- I
@)
.f:
l'-
81 g-
@~ ~
l'-1 ~
c LONGTERM
~ I STEADY STATE (5 I INSERTION LIMIT C:
3: I ~*
- 51
- 3: I
.s;.~
~ I SHORT TERM
@:I STEADYSTATE r--. I INSERTION LIMIT
- §L -
E
('.)
s 0
.E
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C.
- , e
~
o-------------------------------------------------
7 GROUPS 137 110 82 55 28 137 110 St. Lucie Unit 1 CYCLE 33 COLR 137 6
82 55 5
110 82 55 28 28 137 110 CEA GROUP POSITION (INCHES WITHDRAWN)
FIGURE 3.1-2 137 110 4
82 55 28 CEA Insertion Limits vs. THERMAL POWER (4 Reactor Coolant Pumps Operating)
Rev.O 3
82 55 28 Page 9 of 13
Allowable Peak Linear Heat Rate, kw/ft 17.0 ~---------------~
16.0 UNACCEPTABLE OPERATION 15.0 ~----------------ll>
ACCEPT ABLE OPERATION 14.0 13.0 _.__ _______________
BO L Cycle Life EOL FIGURE 3.2-1 Allowable Peak Linear Heat Rate vs. Burnup St. Lucie Unit 1 CYCLE 33 COLR Rev.O Page 10 of 13
1.10 -,------------------,-------,------,
1.00 cu 0.90 (I)
..J I,.,
~
- a. 0.80 (I) :c
~
< 0.70 E
E
~ 0.60 C:
0
(.)
I:!! 0.50 LL Region of Unacceptable Operation
(-0.08,0.85) <r----ti> (0.05,0.85).
I
(-0.5,0.45)
I I
(.o.of,o. 78)
(o.os, o Jal I
Region of Acceptable Operation Region of Unacceptable Operation (0.5,0.45)
I 0.40 -L---&---'------'------'--------'-------'----~---'
-0.6
-0.4
-0.2 0.0 0.2 0.4 Peripheral AXIAL SHAPE INDEX (Not Applicable Below 40% Power)
Note: AXIAL SHAPE INDEX limits for Linear Heat Rate when using Excore Detector Monitoring System)
FIGURE 3.2-2 AXIAL SHAPE INDEX vs. Maximum Allowable Power Level St. Lucie Unit 1 CYCLE 33 COLR Rev.O Page 11 of 13 0.6
1.1 1.0 0.9 0.8 Allowable Fraction O 7 of RATED THERMAL POWER (P) o.6 0.5 0.4 0.3 0.2
{1.65, 1.0)
~
Unac
~eptable Operat1 on
........... ~
~
~ --~ --
Accept able Op4 ffation 1.65 1.70 1.75 1.80 1.85 1.90 1.95 Measured F rT Fl= 1.65 X [1+0.48 X (1 - P)]
FIGURE 3.2-3 Allowable Combinations of THERMAL POWER and FrT
--......... ~
{2.05, 0.50) 2.00 2.05 (The expression specified in the Figure may be used for F? at all power levels)
St. Lucie Unit 1 CYCLE 33 COLR Rev.O Page 12 of 13
1.10 -.-------,-------.------,-----,-,------,----,-----,
1.00 Cl:'.'.
~ 0.90 0
0...
_J
<(
~ 0.80 Cl:'.'.
w I l-o w
~ -
0 0.70 C
0.60 0
0.50 Region of Unacceptable Operation
(-0.08, 1.0)
Region of Acceptable Operation.
(0 15, 1.0)
Region of Unacceptable Operation (0.5,0.65)
I I
0.40 -'----e)---'-------'------+------"-'-----..l..---&-----'
-0.6
-0.4
-0.2 0.0 0.2 Peripheral AXIAL SHAPE INDEX (Y1)
(Not Applicable Below 40% Power)
(AXIAL SHAPE INDEX limits for DNB)
FIGURE 3.2-4 0.4 AXIAL SHAPE INDEX Operating Limits vs. THERMAL POWER (Four Reactor Coolant Pumps Operating)
St. Lucie Unit 1 CYCLE 33 COLR Rev.O Page 13 of 13 0.6