ML111330513

Slides for May 17, 2011 Meeting

ML111330513
Person / Time
Site:	Peach Bottom
Issue date:	05/17/2011
From:	Exelon Generation Co
To:	Plant Licensing Branch 1
Hughey J, NRR/DORL, 301-415-3204
Shared Package
ML111330447	List: ML111330367 ML111330513
References
TAC ME6099
Download: ML111330513 (31)

Text

Pre-Submittal Meeting -

Neutron Absorbing Inserts Exelon Generation Company, LLC Peach Bottom Atomic Power Station Units2and3 May 17, 2011 EXe[ n I

Lx1 ri Get Agenda V Introduction (Tom Loomis ( Exelon))

10 minutes V Discussion of Inserts (Ken Lindquist (Curtiss Wright Flow Control Service Company))

- 20 minutes V Discussion of Criticality Analysis for Inserts (John Hannah (Global Nuclear Fuels)) 40 minutes V Interim Actions / Technical Specifications (TS)

(Jeff Dunlap (Exelon))

15 minutes V Concluding Comments (Tom Loomis (Exelon))

5 minutes 2

Exel Ii LJ a

introduction nt Request (LAR) in June d License m

i oo issue V

2008 to address the J8 2010 (15 letters thdraWfl Exelon)

V LAR was WI NRC AP-IN inserts exchanged d ng with NETCO-SN Salle County V Exelon Pro: as intended to dOctober 5, 2009 and V New LAR (submit e pvedJanuary282Ohl)

Fuel as our criticality analysis V Will be using G t

lant uprates vendor fuel conditions V Analysis bounds

Generation Introduction (continued)

V Intend to submit the LAR in November 2011 V Insert tests at Penn State July 2011 V Install and remove 9 test inserts in the spent fuel pool in August 2011 V Will install inserts first in rack modules with worst degradation V Installation schedule still being optimized, based on insert approval and projected degradation. Bounding dates for installation have been established:

• Unit22013-2017

• Unit32014-2018 V Estimated cost of installation is approximately $45 million

I CURTISS WRIGHT FIow Control Company NETCO NETCO-SNAP-IN Rack Inserts: Neutron Poison Replacement for Fuel Storage Applications Peach Bottom Pre-Submittal Meeting, 5/17/2011 Ken Lindquist Senior Advisor

What are NETCO-SNAP-IN Inserts?

Replace Lost Reactivity Hold-Down Extends Useful Storage Rack Life Made of Al/B 4

C Composite Material Minimal Impact on Fuel Move Operations NEItO N

4NE) 6

Project Overview K. Lindquist Issued US. Patent 6,741,669 B2 in 2004 for Absorber Insert Design

• Original Demonstration Program was a Joint Venture Between NETCO and Exelon Corp.

• Clean Pool Prototype Testing Performed at Penn State

• First Installation at Exelons LaSalle Station in 2007 (Three installed in Demonstration Program)

• Full Scale Installation at LaSalle Initiated in 2010 with 650 Installed to Date

• PWR Demonstration in June 2011 7

Description

• AI-1100/B 4

C Composite, Provided by Rio Tinto Alcan, Formed Into a Chevron Shaped Rack Sleeve; Peach Bottom will use a higher B 4

C loading

• Installed via Custom Tool from the Refueling Bridge

• Chevron is Compressed During Installation; Friction and Compression Forces Hold it in Place 8

Key Features

• Simplicity of NETCO-SNAP-IN Standard Fabrication Methods Used to Form Al/B 4

C Composite Material

• Simplicity of Installation Tool Installation force provided by tool weight alone; no Electrical or Hydraulic Systems

• Once Installed, NETCO-SNAP IN Inserts are an Integral Part of the Rack Modules 9

Application

• When Placed in Each Storage Location, the NETCO-SNAP IN Inserts Supplement the Neutron Poison in the Existing Racks Once Installed, Fuel Can Be Moved In and Out of the Storage Locations as Usual

• 650 Inserts Installed To-Date at LaSalle

• LaSalle Installation Experience and Lessons Learned will Be Applied at Peach Bottom 10

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Borated Aluminum Material Material Qualification of Alcan Through Accelerated Corrosion Testing Pre-test characterization Post-test characterization Accelerated corrosion environment 2000, 4000, 6000 & 8000-hour test results Results Show Corrosion Rates Within Measurement Uncertainty of Zero for 8000-hr Tests

• Stability of Areal Density Values Throughout Test

• Fast-Start Results (6 Pulled So Far) Show Consistency with Accelerated Test Predictions, Showing No Negative Change in Areal Density 13

N Material Performance (LaSalle)

Alcan Material Shows Consistent Performance in Neutron Attenuation Tests O.008()

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Material Surveillance

• Coupon Surveillance program will be similar to LaSalle

• Inspection Frequency and Coupon Tests will be similar to LaSalle 15

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Guidance and Regulations GDC 62: Prevention of Criticality in Fuel Storage & Handling Criticality in the fuel storage and handling system shall be prevented by physical systems or processes, preferably by use of geometrically safe configurations.

10 CFR 50.68 (b) (4)

The k-effective of the spent fuel storage racks loaded with fuel of the maximum fuel assembly reactivity must not exceed 0.95, at a 95 percent probability, 95 percent confidence level, if flooded with unborated water.

Kflzax(

95195

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0.95 HITACHI 18

Basic Analysis and Requirements

,nax(95/95) =

Nominal

• Consideration given to all credible abnormal conditions, manufacturing tc lerance implications, and computational uncertainties HITACHI

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+ AKBias + AKTOleraflce + Uncertainty AKBIz A.KB Contribution from Biases AKTOk,rwlLe Contribution from Independent Tolerances LKuncertaitty

Contribution from Independent Uncertainties Establish a peak, cold, uncontrolled, in-core lattice reactivity allowable for storage in the racks (in-core kinf criterion methodology)

All storage rack locations assumed to contain identical fuel assemblies at their most reactive state as a function of both exposure and cooling time 19

Computational Tools and Validation TGBLAO6A MCNP-05P GEH/GNF 2-D lattice physics code GEH/GNF version of LANL code MCNP5 Calculates in-core kint values Calculates in-rack kinf values Determines exposure dependent, Uses TGBLA defined peak reactivity pin-by-pin isotopic specifications isotopic specifications Utilizes ENDF/B-V cross-section Utilizes ENDF/B-VlI cross section data data 95/95 Bias and bias uncertainty of 95/95 Bias and bias uncertainty in-core kinf quantified using TGBLA quantified and applied using 96 pin to MCNP comparison, lattice in water experiments.

Reactivity penalties applied consistent with NEDQ-33374-A, including:

Depletion Isotopics Uncertainty Fission Product XS Uncertainty HITACHI

• Actinide XS Uncertainty 20

Spent Fuel Rack Model MCNP Rack Model Rack Insert Schematic HITACHI

• No credit taken for Boraflex Panels are modeled as water

• No credit taken for axial or lateral neutron leakage (2-D Analysis)

• Assumes a single lattice design at peak reactivity for full bundle height in every storage location (Kinf>

1.27)

• Stainless steel rack modeled explicitly

• Assumes a single rack insert with a minimum 95/95 areal density of 0.0102 g Bi 0/cm 2 in every storage cell 21

Design Basis Bundle Selection

. GNF2 utilized to bound all past and current fuel types in the PB SFP

. Peak, cold, uncontrolled in-core kinf just greater than 1 27 studied for all DBB candidates

. Each GNF2 lattice is analyzed independently with multiple enrichment/gad loadings considered

. The lattice/fuel loading combination resulting in the highest rack efficiency (in-rack kinf/in-core kinf) is used to:

. Define nominal in-rack kint value

. Perform bias, tolerance, and uncertainty sensitivity studies HITACHI 22

Storage Scenarios Addressed Credible Normal Conditions

• Fuel Assembly Channeling

• Eccentric Loadings

• Moderator Temperature

• Rotated Bundle Credible Abnormal Conditions

• Dropped Fuel Assembly

• Misplaced Fuel Assembly

• Alternative Depletion Conditions

• Missing Rack Insert HITACHI Manufacturing Tolerances

• Fuel Enrichment

• Fuel Pellet Density

• Gadolinia Content

• Rod Cladding Thickness

• Rack Wall Thickness

• Rack Pitch

• Rack Insert Thickness

• Rack Insert B-1O areal density Interface Effects

• Racks with Inserts Adjacent to Storage Modules without Inserts

• Storage Cells without a Poison Panel on Every Side (on module edge or next to an inaccessible location) 23

Comparison to Approved LARs Topic Consistent With:

TGBLAIMCNP Analysis Package NEDO-33374-A In-Core Kint Criterion Methodology NEDO-33374-A Criticality Code Validation NEDO-33374-A Design Basis Bundle Selection NEDO-33374-A Bias, Tolerance, and Uncertainty Studies NEDO-33374-A Rack Insert, Boraflex, and Interface Treatment ANP-2843 Statistical Rollup of K(95/95) Result NEDO-33374-A NEDO-33374-A: Safety Analysis Report for Fuel Storage Racks Criticality Analysis for ESBWR Plants September2010 (ML102860687>

ANP-2843: LaSalle Unit 2 NPS Spent Fuel Pool Storage Criticality Safety Analysis with Neutron Absorbing Inserts and without Boraflex January 2011 (ML110250051)

HITACHI 24

Compliance with Draft ISG and IN Draft DSS-ISG-2010-01 k

• Fuel Assembly Selection

• Depletion Analysis

• Criticality Analysis v.

• Criticality Code Validation Information Notice 2011-03 1

• Monte Carlo Bias Uncertainty

• Depletion Uncertainty 25 HITACHI

Summary

• Analysis performed will fulfill requirements of 10 CRF 50.68 and GDC 62 with consideration given to Draft ISG-201 0-01 and IN-201 1-03

• Consideration given to all credible abnormal conditions, manufacturing tolerance implications, and computational uncertainties in determining maximum in-rack eigenvalue

• Spent fuel racks will be demonstrated to remain

>5% subcritical for storage of current and previous fuel types with peak, cold, uncontrolled in-core reactivities < 1.27 HITACHI 26

Ex r Generation Interim Actions I TS - Jeff Dunlap EeIo V NRC review of Boraflex degradation limits to be completed through the ongoing Task Interface Agreement process V Basis for degradation limit established in Operability Evaluation 10-007 and Technical Evaluation 864431-15 V Most restrictive assembly limits Boraflex degradation to 45% from minimum certified Boraflex areal density Minimum certified Boraflex areal density is 0.021 g/cm 2

Minimum allowable Boraflex areal density is 0.01155 g/cm 2

ExeIn.

(LUi tkJ1I Interim Actions/TS V Procedure NF-PB-310-2000 describes process to administratively declare cells inoperable below 10 B areal density of 0.01155 g/cm 2

V RACKLIFE model revised every 6 months to incorporate updated power history, fuel movement, and pool chemistry, per surveillance procedures RT-R-004-990-2/3 RACKLIFE results are compared against minimum allowable areal density of 0.01155 g/cm 2

RACKLIFE model bounds peak degradation values from most recent BADGER testing V BADGER testing is performed every 4 years to validate the RACKLIFE model per surveillance procedure RT-R-004-995-2/3 BADGER results are compared against minimum allowable areal density of 0.01155 g/cm 2

Most recent BADGER tests were performed in January 2010 (Unit 2) and December 2009 (Unit 3). Minimum measured areal density from these campaigns was 0.0199 g/cm 2

28

LJeI1LL-ttlL)ri Interim Actions I TS V Unit 2 and Unit 3 Tech Specs will be the same V Proposed Tech Specs similar to LaSalle with inserts V TS 4.3.1.1 include rack inserts as part of design V TS 4.3.1.1.a.

maximum in-core of 1.27 at cold conditions V TS 4 3 11 b in-rack kff 0 95, including allowance for uncertainties described in the UFSAR (no change)

V TS 4.3,1.1.c.

nominal center-to-center distance between assemblies of 6.280 inches (no change)

V TS 4.3.1.1.d. (new) rack inserts will have a minimum certified 10 B areal density of 0.01 02 g/cm 2

V Not proposing a TS for installation V Proposing a once per month telephone conversation as a group.

29

Generation Comments 30

DRAFT Design Features 4.0 4.0 DESIGN FEATURES (continued) 4.3 Fuel Storage and/or rack inserts 4.3.1 Criticality 4.3.1.1 The spent fuel storage racks are designed and shall be maintained with:

a.

Fuel assemblies having a

maximum k-infinity of 1 77 1.362 in the normal reactor core configuration at cold conditions; b.

kef 0.95 if fully flooded with unborated water, which includes an allowance for uncertainties as described in Section 10.3 of the UFSAR; and c.

A nominal 6.280 inch center to center distance between fuel assemblies placed in the storage racks 4.3.1.2 1

e new fuel storage racks shall not be used for fuel s orage.

The new fuel shall be stored in the spent fuel s orage racks.

4.3.2

[rainage The spent f ci storage pool is designed and shall be prevent ma vertent draining of the pool below plant 219 ft.

4.3.3 Capacity The spent fu 1

storage pool is designed and shall be with a stora e capacity limited to no more than 3819 assemblies maintained to elevation maintained fuel

d. The neutron absorbing rack inserts shall have a minimum certified °B areal density greater than or equal to OO 102 g/cm 2

PBAPS UNIT 3

4

. C) -2 Amendment No.

214