ML18122A150

Pre-Submittal Meeting for St. Lucie Nuclear Plant, Unit 2 - Spent Fuel Pool Criticality Analyses - April 30, 2018

ML18122A150
Person / Time
Site:	Saint Lucie
Issue date:	04/30/2018
From:	Nextera Energy
To:	Plant Licensing Branch II
Buckberg P, NRR/DORL/LPL2-2, 415-1447
Shared Package
ML18122A240	List: ML18122A150 ML18122A195
References
EPID L-2018-LRM-0023
Download: ML18122A150 (25)

Text

Pre-Submittal Meeting for St. Lucie Unit 2 Spent Fuel Pool Criticality Analyses April 30, 2018

2

• Describe the planned scope and methodology for the proposed St. Lucie Unit 2 Spent Fuel Pool Criticality Analysis License Amendment Request

- Partial criticality analysis for cask pit rack only

• Seek feedback from NRC staff Purpose

3 Agenda Current Condition New Criticality Analysis Technical Specification Changes Closing Summary

4

• Safety Evaluation for St. Lucie Unit 2 Spent Fuel Pool Criticality Analysis LAR was issued in September 2012 (ML12263A224) o Analysis was performed in support of Extended Power Uprate project

• Analysis performed with CASMO-4 and MCNP5

• Analysis complies with DSS-ISG-2010-01 Current Condition - SFP Criticality Analysis

5 Current Condition - Spent Fuel Pool

• Analysis covers three regions in the St. Lucie Unit 2 Spent Fuel Pool o

Region 1 o

Region 2 o

Cask Pit Rack 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 AP AP Cask Area Rack AN AN C15 C14 C13 C12 C11 C10 C9 C8 C7 C6 C5 C4 C3 C2 C1 AM AM CR CR AL AL CP CP AK AK CN CN AJ AJ CM CM AH AH CL CL AG AG CK CK AF AF CJ CJ AE AE CH CH AD AD CG CG AC AC CF CF AB AB CE CE ZZ ZZ CD CD YY YY CC CC XX XX CB CB WW WW CA CA TT TT C15 C14 C13 C12 C11 C10 C9 C8 C7 C6 C5 C4 C3 C2 C1 SS SS RR RR PP PP NN NN Region 2 Region 1 MM 22 21 20 19 18 17 16 15 14 13 12 11 10 9

8 7

6 5

4 3

2 1

LL LL LL KK KK KK JJ JJ JJ HH HH HH GG GG GG FF FF FF EE EE EE DD DD DD CC CC CC BB BB BB AA AA AA Z

Z Z

Y Y

Y X

X X

W W

W T

T T

S S

S R

R R

P P

P N

N N

M M

M L

L L

K K

K J

J J

H H

H G

G G

F F

F E

E E

D D

D C

C C

B B

B A

A A

38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9

8 7

6 5

4 3

2 1

6 Current Condition - Technical Specifications

• Technical Specifications contains allowable storage patterns for each region

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• Storage patterns included in criticality analysis were developed based on estimates for future storage needs under EPU conditions

• Current storage patterns are not optimal o Reliance on empty cells limits capacity o Not aligned with fuel storage needs under EPU conditions Current Condition - Fuel Storage Limitations

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• NextEra Energy considered various options to improve storage capacity o new cask pit rack o additional dry storage casks o full criticality re-analysis partial criticality analysis Current Condition - Options

9 Agenda Current Condition New Criticality Analysis Technical Specification Changes Closing Summary

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• Our plan is to perform a partial criticality analysis that will fully replace the parts of the current analysis addressing the cask pit rack only o Follows precedent from Duane Arnold criticality analysis

• All other parts of current analysis remain the same o No changes to current Technical Specifications for Regions 1 and 2

• Partial criticality analysis will be performed in-house New Criticality Analysis

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• Partial criticality analysis will follow o NRC Guidance DSS-ISG-2010-01, Staff Guidance Regarding the Nuclear Criticality Safety Analysis for Spent Fuel Pools o NEI 12-16, Guidance for Performing Criticality Analyses of Fuel Storage at Light-Water Reactor Power Plants

• Codes will be PARAGON 1.2.0b and MCNP6.1 with ENDF/B-VII.1 cross section library

• As for current analysis, the partial analysis will ensure that keff 0.95 with the pool flooded with borated water, and keff 1.0 with unborated water, with 95% confidence / 95% probability New Criticality Analysis

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• No significant changes or factors to address o No change in fuel design o No change in operating conditions o No change in rack design o No Boraflex

• Will revalidate all analysis parameters o Reactor depletion parameters o Boral areal density o Axial burnup shape New Criticality Analysis

13

• Will re-perform all analyses for cask pit rack o Design basis assembly o Tolerances o Uncertainties o Accidents o Code validation

• No interfaces with Region 1 nor Region 2 will need to be addressed New Criticality Analysis

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• New storage patterns have been preliminarily developed o 3 out of 4 fresh assemblies, crediting integral burnable absorber o 4 out of 4 irradiated assemblies with one CEA, burnup credit o 3 out of 4 irradiated assemblies, burnup credit o 1 fresh and 2 irradiated assemblies To address interface between first two patterns New Criticality Analysis 1

1 1

1 FBA FBA FBA 1

FBA 1

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• For the fresh fuel category crediting integral burnable absorber, it would require n number of rods at a minimum concentration o If condition is not met, fresh assembly would then be stored in current 2 out of 4 configuration in Region 1 New Criticality Analysis

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• As done today for all NextEra Energy PWRs, PISCES code will be used as supplementary verification tool o After move plans are prepared and reviewed

• PISCES code o Determines fuel category for all fuel assemblies & non-fuel items o Tracks all inserts and panels (credited and non-credited) o Evaluates configuration/proposed moves against Technical Specification requirements o Provides summary & graphical output files New Criticality Analysis - Implementation

17 Agenda Current Condition New Criticality Analysis Technical Specification Changes Closing Summary

18

• Technical Specification Figures 5.6-4, Allowable Cask Pit Storage Rack Patterns, will be replaced o

New storage patterns, definitions and notes will be added

• Technical Specification Table 5.6-1, Minimum Burnup Coefficients, will be modified o

Values for fuel type 8 will be modified o

New fuel types will be added o

Values for fuel types 1-7 will NOT be modified Technical Specification Changes

19 Technical Specification Changes

20 Technical Specification Changes

21 Agenda Current Condition New Criticality Analysis Technical Specification Changes Closing Summary

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• Schedule of LAR submittal o Plan to submit in December 2018

• Summary of path forward

• Review action items Closing Summary

23 Backup Slides

24 Current Condition - Fuel Storage Needs Fresh fuel stored in 2 out of 4 configuration in R1 or CPR Once burnt fuel stored in 3 out of 4 configuration in CPR Twice burnt fuel stored in 3 out of 4 configuration in any of the three regions

25 Current Condition - Cask Pit Rack