ML26015A041

From kanterella
Jump to navigation Jump to search
Unit 1, Startup Report Unit 1 Cycle 26
ML26015A041
Person / Time
Site: Braidwood 
Issue date: 01/15/2026
From:
Constellation Energy Generation
To:
Office of Nuclear Reactor Regulation
Shared Package
ML26015A039 List:
References
BW260005
Download: ML26015A041 (0)
v • d • e


Text

ATTACHMENT 1 BRAIDWOOD STATION UNIT 1 CYCLE 26 STARTUP REPORT

Purpose This technical evaluation documents the Braidwood Unit 1 Cycle 26 (A 1 C26) Startup Physics Test Report in accordance with the Low Power Physics Test Program Procedure. It is provided as information only.

Discussion Introduction, Summary and Fuel Design The A 1 C26 fuel reload was completed in October 2025, and went critical on October 22, 2025, at 1748. The core map detailed in Reference 1 at the end of the discussion section shows the final core configuration of the loaded core. Reference 1 documents that Cycle 26 uses a low leakage core loading pattern consisting of 88 Region 28 Fresh Fuel assemblies, 89 Region 27 and 26C once-burned fuel assemblies and 16 Region 26B twice-burned fuel assemblies. The 88 Region 28 fuel assemblies are the Framatome 17x17 GAIA fuel assembly design and the remaining 105 fuel assemblies are the Westinghouse 17x17 OFA VANTAGES+

design. This is the first cycle that GAIA fuel is being used at Braidwood Unit 1.

Only 55 fuel assemblies contain inserts, consisting of 53 rod cluster control assemblies (RCCAs) and 2 secondary source assemblies (SSAs). Figure 2 documents the locations of these RCCAs and SSAs.

Subsequent operational testing milestones were completed as follows:

Hot Rod Drops Initial Criticality Low Power Physics Testing Completed

<50% Power Testing Completed 90% Power Testing Completed 100% Power Testing Completed Flow Measurement Completed Control Rod Drop Time Measurements 10/22/2025 10/22/2025 10/23/2025 10/23/2025 10/26/2025 10/29/2025 10/29/2025 As directed by the Rod Drop Time Procedure, the drop time of each control rod was measured in MODE 3 before criticality in order to verify that the time to the entry of the rod into the dashpot was less than or equal to an acceptance criteria of 2.1 seconds on a

Technical Specification limit of 2.7 seconds. All 53 RCCAs passed the Technical Specification acceptance criteria with the summary table listed below.

Table 1: Hot Rod Drop Time Summary Slowest Rod(s)

Fastest Rod (s)

Averages Rod Type Sec Rod Type Sec Type M02 T1 (2.1 s max) 1.65 H12 T1 (2.1 s max) 1.41 T1 (2.1 s max)

M02 Ttotal (2.7s max) 2.18 H12 Ttotal (2.7s max) 1.88 Ttotal (2.7s max)

Low Power Physics Testing The low power physics testing program for Cycle 26 is defined and completed per the Low Power Physics Test Procedure. The program consists of the following: Core Reactivity Difference determination, Dynamic Rod Worth Measurement and the isothermal temperature coefficient measurement. Low power physics testing was performed at a low power level below the point of adding heat to avoid nuclear heating reactivity feedback effects.

Dynamic Rod Worth Measurements were required due to the significant design change resulting from the introduction of the GAIA fuel type and the use of a different burnable neutron poison, Gadolinium.

The core reactivity difference determination verifies the Technical Specification Surveillance Requirement 3.1.2.1. The measured critical boron concentration is compared to the predicted critical boron concentration with control bank D at all rods out. The calculated core reactivity difference was measured at 0.2488 % 6k/k on an acceptance criteria of 1 % 6k/k.

Table 2: Summary of Measured Core Reactivity Determination Difference Differential Control Rod Insertion Total Total Sec 1.49 1.97 Critical Boron Boron Worth BankD Difference Difference Difference Concentration (pcm)

Position (pcm)

(pcm)

(% ~k/k)

Predicted 1921 231 Actual 1874 311.4 197

-62.6 248.8 0.2488 The Isothermal Temperature Coefficient (ITC) data was measured with Control Bank D at 197 steps withdrawn. The design acceptance criteria of+/- 2 pcm/°F from measurements to predicted was met.

Table 3: Isothermal and Moderator Temperature Coefficient Results I

Technical Average Acceptance Average Specification Predicted ITC Measured Criteria Calculated MTC Limit (pcm/ °F)

ITC (pcm/ °F)

Difference (pcm/ °F)

(pcm/ °F}

(pcm/ °F)

-2.8

-2.95

-0.31

+/-2

-0.82 6.44 The integral reactivity worths of all RCCA control and shutdown banks were measured using the Dynamic Rod Worth Measurement method with the Advanced Digital Reactivity Computer. The design criteria of the measure worth of the individual banks are +/-15% or 100 pcm, whichever is greater. The rod worth acceptance criteria is defined as the sum of the measured worths of all banks shall be greater than or equal to 90% of the sum of their predicted worths.

Table 4: Summary of Individual Bank Worths Measured Predicted Rod Group Worth (pcm)

Worth (pcm)

Difference

% Difference CBA 264.3 260.7 3.6 1.4%

CBB 669.7 693.8

-24.1 3.5%

CBC 770.5 796.3

-25.8 3.2%

CBD 523.2 492.4 30.8 6.3%

SBA 246.1 236.6 9.5 4.0%

SBB 870.1 913.3

-43.2 4.7%

SBC 379.1 370.4 8.7 2.3%

SBD 374.2 365.3 8.9 2.4%

SOE 439.7 438.9 0.8 0.2%

Total 4536.9 4567.7

-30.8 0.7%

The measured results of the individual bank worths and the total bank worth met the acceptance criteria.

Power Ascension Testing The core power distribution was measured through the performance of flux maps per the Movable lncore Detector Operation Procedure during power ascension. The results of the flux maps were used to verify compliance with the limits specified in the BR1 C26 Core Operating Limits Report (COLR). The relevant maps are included in this document as references. A summary of the measured axial offset (AO) and maximum average in core tilt are provided below. A summary table of the comparisons between the Steady State and

Transient Heat Flux Hot Channel Factor (Fq) and the Nuclear Enthalpy Rise Hot Channel Factor (FNllH) against the COLR limits are also provided. As summarized below, all Technical Specification Limits were met.

Table 5: Summary of Measured Axial Offset and Maximum Average lncore Tilt Power Burn up CBD AO%

Maximum

(% RTP)

{MWd/t)

Position Average lncore (Steps)

Tilt 49.36 7

150

-0.31 1.019 89.12 58.6 186 o.39 I 1.002 99.48 226.3 I

202 0.71 1.007 I

Table 6: Summary of Measured Fq to respective Limits Fq Steady Measured Power Burnup Measured Fq Steady State Max Transient Transient Transient Fq

(% RTP)

(MWd/t) Fq Sate Limit Assembly Fq Fq limit Max Assembly 49.36 7

2.186 5.2 J-14 2.543 5.2 J-14 89.12 58.6 1.905 2.917 H-02 2.205 2.917 H-02 99.48 226.3 1.916 2.614 B-11 2.262 2.614 B-11 Table 7: Summary of Measured F~H to F~H Limit Power Burnup Measured F~h Assembly

(% RTP)

(MWd/t)

F~h Limit 49.36 7

1.382 1.86 K-05 89.12 58.6 1.323 1.668 G-12 99.48 226.3 1.554 1.703 B-11 Reactor Coolant System {RCS) Flow Measurement The RCS Flow was measured within the requirements ofTechnical Specification Surveillance Requirement 3.4.1.4 per the Reactor Coolant System Flow Measurement Procedure. The measured flow at 99.5% RTP was 403,247 gpm on a minimum required flow of 386,000 gpm.

All Technical Specification Limits were met.

Conclusion All results associated with A 1 C26 startup and power ascension testing were acceptable and within Technical Specification Limits.

References

1. Braidwood Unit 1 Cycle 26 Core Loading Plan
2. Braidwood Unit 1 Cycle 26 Core Verification Work Order

CLP Braidwood 1 Rev. 8 Figure 1 Braidwood Unit 1 Cycle 26 Region IDs and Assembly IDs R

p

~~

M L

k

~I H

G F

E D

C B

A 2ti8 27C:

27B 21:iC 278 27C 26B N63.X.

MO.A.

A.78A N44_>::_

26B 278 28A 28/'<.

28.A.

2:SA 278 268 2

N4GX.

A44M CL07 CL.31 CL26 CL02

.MOM t~4*1X 268 28A L.?.H.

288 27C 288 27A 28.A.

268

3 N42X CL43 A30L CM71

.A.74.A.

CM58

.A.25L CL.38 N60.:\

278 27.A.

288 278 288 278 28B 27.A 278 4

.A.38M AOSL CM67

.A.37tu1 CM46

.A.4Gtu1 CM62

.AC(::L A52M 268 28A 28.A.

27.A.

288 27A 288 278 288 27.A.

288 27A 28.A.

28A.

258 5

N43X CLO:j CL39 A06L CM87 A*11L CM55

.Af.t2M CM50 A1BL CMf36 AD5L CL42 CL08 NMX 27C 28.A.

27A.

288 27A 288 27.{!.,,_

28B 27.ti.

288 27A.

288 27A.

28.A.

27C 6

A77A CL27

.A24L CM63 A'13L CMB3

.1.'.i23L CM74

.A26L CM:32 A10L CM66

.A35L Cl38

.ABtiA.

27B 288 278 28B 27.A.

2~:8 27.A.

2:38 27A 288 278 289 278 7

.A57M CM59 A4or,.,1 CM51 A28L C:M7Q P<.14L CM7:::

.A22L CM54

.A5*lt1.11 CM70 A5Cit1,11 25[

27C 288 278 288 27A 27C 27A.

288 278 288 27C 26C 0

A75A CM47 A54M CM75

.A20L Ae4A.

A09L CM73.A59M CM45

,AB5A

' N77Z 90° 278 288 278 288 27A.

288 27.A.

2:::8 27.A.

288 27B 288 27B g

.A5:3t,;1 CM72 A46t,,i CM56 A2!~L C~,i:::O A12L c~~n A27L CM49.A47M CM57

.A51M 27C 28A 27.A.

28B 27.A.

288 27.A 288 27.A.

2:::B 27A 288 27P..

28A 27C 10

.A.7QA CL32 A32L CM68 A'15L CM84.A21L CM76

.A.33L C:M81 A17L CM6*1 A31L Cl25

.A.75.A.

268 28A 28A 27.A.

28B 27ft.

288 278 288 27.A.

288 27.A.

28A 28A 258 11 N57;:(

CLO$

CL'l4

.AJJ*1L Ct1.118t:

P.-1:::L CM52 A60M CM53 A*19L CME:5

.A.o?L CL37 CLO'!

t.53X 27B 27.~.

288 278 288 27B 288 Lt.I-I..

27B

'12

.A.48M

.A.02L CM64.A.39M CM4:::

.A.42M CM65

.AD4L

.A.45M 258 2t:A 27.A.

288 27C 288 27.A.

23A 26B 1 3 tl6-1X CL"10 A.34L CM60

.A:33A.

CM69 A.35L CL4*1 NB2X 21:iB 27B 28A 28.A 28.A.

28A 278 268 14 tl55X.A4'1M CL04 CL28 CL29 C.I.D5

.A.43M l-l5*1X 268 27C:

27C 268 15 t,46X

. ABBA A.87.A. tl45/.

oo LEGEND

[;]

REGION IDENTIFIER 26B--4.8 %

27C--4.4 %

FUEL ASSEMBLY IDENTIFIER 26C--4.5 %

28A-- 4.95 %

  • N70Z From Cycle 24 Location H-12 27A-- 4.9 %

28B -- 4.75 %

  • N76Z From Cycle 24 Location D-08 27B--4.6 %
  • N77Z From Cycle 24 Location M-08
  • NSOZ From Cycle 24 Location H-04 Note: Color shades indicate fresh fuel sub-batch differences Page 1 Constellation Proprietary Framatome Proprietary and Restricted

CLP Braidwood 1 Rev. 8 Figure 2 Braidwood Unit 1 Cycle 26 Assembly Inserts and Gadolinium Loadings R

F' M

L

,_I H

F E

D C

RCC.A.

RCCA RCCP..

RCCA.

~,

8x4 16x5 16x13 8x4

.L 4x2 4x2 RCCA RCCA.

RCCA RCCA 3

24XO 115:43 16>-.B 24:<:8 4x4 8x4 8x:4 4x4 RCCA RCCA 4

16:x:8 16>2 18:x:8 8,::4 8x4 8x4 RCCA.

RCC.A.

5 8x4 24:>:B

  • 11:i>::8 18:x:8 16:x:8
  • 11:i::<:3 24:-:--3 4x4 12:A 8:,:4 8x4
  • 12"4 4"4 RCC.A.

RCC..e..

F:CCA RCCA 6

16;.fi 16x8 16::-::8 16>::8

-1 tt~:8 16>-.'8 4x2 8x4 12x4

  • 12x4
  • 12:x:4 8x4 RCCA RCCA 7

15/41 16£ 16:,$

  • 16:,$

15x:8

  • 16J-.B Sx4 8x4 1b:4

-12,::4 SJ-.4 8x4 6:;S.A. RCCA F:CC.A.

RCCA.

RCCA RCCA 6SS.A 8

16~3 16::-B 16:,,B 16x8 90° 8x4

  • 12x4 12x4 8>-.'4 RCCA RCCA

~j 15),:8

  • 16:r.B je;:(8
  • 15::-B 15x:8 18:,B 8x4 8x4 12:A 12x4 8~~4 8:x:4 RCCA RCCA.

RCCA RCC.A.

10 16:.fi

  • 16x8 16,<3 1fo:8 16>:2

'16x8 4,,2*

8x4 12:A

  • 12:A
  • 12:A 8x4 RCC.A.

11 8x4 Je;;.:8 16:43 16>£

  • 18,B 24A3
  • 12>:4 8:<4 8x4
  • 12:A 4x4 RCCA 12 16£ if;i:,13 16£ 8x4 8x4 8x4 RCCA RCCA RCCP..

RCCA 13 24:S 1foil

  • te>;S 24x:8 4,::4 8x4 8x4 4x4 F:CCA.

RCCA RCC.A RCCA.

14 8x4

  • 16x13 16x6 8:,(4 4x2 4x2 15 oo LEGEND TYPE COMPONENT TYPE AAxB - AA Rods at B Gadolonium Enrichment CCxD - CC Rods at D Gadolonium Enrichment AAxB NUMBER OF GADOLONIUM RCCA-Rod Control Cluster Assembly CCxD RODS AND ENRICHMENT
  1. SSA - Number of Rodlets on Secondary Source Assembly Note: Color shades indicate fresh fuel sub-batch differences Page 2 Constellation Proprietary Frarnatome Proprietary and Restricted B

RCC.A.

8x4 RCCA 15x6 4,Q RCCA

  • 16x13 4x2 8>::4 RCCA

Station BRAIDWOOD A

B C

D N51X A43M RCCA N62X A66A CL21 A45M CL17 A65A RCCA RCCA N53X CL01 CL37 A07L RCCA A75A CL25 A31L CM61 RCCA A61M CL09 CM57 A47M RCCA N77Z CL33 ASSA CM45 RCCA ss RCCA A56M CL14 CM70 A51M RCCA A86A CL30 A36L CM66 RCCA N59X CLOG CL42 A05L RCCA A52M CL22 A68A RCCA RCCA N60X A71A CL18 N41X AS0M RCCA ATTACHMENT 4 Byron/Braidwood Reactor Core Inventory Page 1 of 1 Date 10/16/2025 ICA RW1 E

F G

H J

K L

M N N45X A87A A53M NB0Z A63M ABBA N46X CLOS CL29 CL13 CL36 CL12 CL28 CL04 A41M N55X RCCA RCCA RCCA RCCA CL41 A35L CM69 A83A CM60 A34L CL40 CL20 A70A RCCA RCCA RCCA RCCA A04L CM65 A42M CM48 A39M CM64 A02L A72A CL24 RCCA RCCA CM85 A19L CM53 A60M CM52 A18L CM88 A01L CL44 RCCA A17L CM81 A33L CM76 A21L CM84 A15L CM68 A32L RCCA RCCA RCCA CM49 A27L CM77 A12L CM80 A29L CM56 A46M CM72 RCCA A59M CM73 A09L A84A A20L CM75 A54M CM47 A76A RCCA RCCA RCCA RCCA ss CM54 A22L CM78 A14L CM79 A28L CM51 A40M CM59 RCCA A10L CM82 A26L CM74 A23L CM83 A13L CM63 A24L RCCA RCCA RCCA CM86 A16L CM50 A62M CM55 A11L CM87 A06L CL39 RCCA A03L CM62 A49M CM46 A37M CM67 A0BL A69A CL19 RCCA RCCA CL38 A25L CM58 A74A CM71 A30L CL43 CL23 A67A RCCA RCCA RCCA RCCA CL02 CL26 CL10 CL34 CL15 CL31 CLO? A44M N49X RCCA RCCA RCCA RCCA N44X A78A A55M N70Z A64M A80A N63X N

Byron Unit 1/Braidwood Unit 2 S

Braidwood Unit 1/Byron Unit 2 Inventoried by:

fh 1~

I JO 16-J >

S_N_M~C~-------------____,D_a_t_e~~---

Approved by: -A,;../,/11'-'1'---=-

/l-'--.--

-~--,,<'------------/

_f_d /_(_6_/2_0_2-_s-=

/JL~

Date NF-AP-.B0-5201 Revision 3 Page 33 uf 38 p

N61X A48M RCCA CL08 CL32 RCCA CL16 CL35 RCCA CL 11 CL27 RCCA CL03 A38M RCCA N42X R

N57X A79A A58M N76Z A57M A77A N43X 15 14 13 12 11 10 9

8 7

6 5

4 3

2 1

Retrieved from "https://kanterella.com/w/index.php?title=ML26015A041&oldid=5542757"