ML120590646

February 9, 2012 - Summary of Meeting with Exelon Nuclear Regarding Future Submittal of Amendment to Use Netco Spent Fuel Pool Inserts

ML120590646
Person / Time
Site:	Quad Cities
Issue date:	03/05/2012
From:	Joel Wiebe Plant Licensing Branch III
To:	Exelon Generation Co
Wiebe, Joel NRR/DORL/LPL3-2, 415-6606
Shared Package
ML120590649	List: ML120590646
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Download: ML120590646 (35)

Text

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Exelon Generation Company, LLC FACILITY:

QUAD CITIES NUCLEAR POWER STATION, UNITS 1 AND 2

SUMMARY

OF FEBRUARY 9, 2012, MEETING WITH EXELON NUCLEAR REGARDING FUTURE SUBMITTAL OF AMENDMENT TO USE NETCO SPENT FUEL POOL INSERTS On February 9, 2012, a public meeting was held between the U.S. Nuclear Regulatory Commission (NRC) and representatives of Exelon Nuclear at NRC Headquarters, Two White Flint North, 11545 Rockville Pike, Rockville, Maryland. The purpose of the meeting was to discuss the future submittal of an amendment to use NETCO spent fuel pool inserts at Quad Cities Nuclear Power Station (QCNPS) Units 1 and 2. A list of attendees is provided in.

The licensee presented the information contained in Enclosure 2. The NRC staff provided feedback* regarding the scope of information that will likely be required during the acceptance review and detailed review of the future submittal. This information included but was not limited to:

• Addressing the requests for additional information involved with the staff review of the LaSalle County Station submittal regarding NETCO inserts.

• Addressing the requests for additional information involved with the staff review of the Peach Bottom Atomic Power Station subrnittal regarding NETCO inserts. These requests haven't been issued yet, but are expected prior to the QCNPS submittal.

• BADGER testing results and discussion of RACKLIFE calculations.

• Provide details of how the LaSalle Fast Start Program eliminates the need for a Fast Start Program at QCNPS. Include fuel pool chemistry similarities and differences.

Misplaced fuel assembly into a restricted position unless physical barriers prevent it.

• Information required for the staff to perform the review discussed in DSS-ISG-2010-01, "Staff Guidance Regarding the Nuclear Criticality Safety Analysis For Spent Fuel Pools" (Agencywide Document and Management System Accession No. ML110620086).

Members of the public were not in attendance. Public Meeting Feedback forms were not received.

- 2 Please direct any inquiries to me at 301-415-6606, or JoeI.Wiebe@nrc.gov.

OlJV;fr oel S. Wiebe, Senior Project Manager Plant Licensing Branch 111-2 Division of Operating Reactor Licensing Office of Nuclear Reactor 'Regulation Docket Nos. 50-254 and 50-265

Enclosures:

1. List of Attendees

2. Licensee Handout cc w/encls

LIST OF ATTENDEES FEBRUARY 9,2012, PUBLIC MEETING REGARDING THE FUTURE SUBMITTAL FOR THE USE OF NETCO SPENT FUEL POOL INSERTS AND QUAD CITIES NUCLEAR POWER STATION A. Pulvirenti K. Wood E. Wong A. Obodoako J. Zimmerman J.Wiebe J. McGhee, by phone B. Cushman, by phone Exelon C. Schneider R. Carmean B. Khorsandi (Holtec)

J. Bauer S. Anton (Holtec)

J. Dunlap S. Leuenroth (NETCO)

G. Klone, by phone B. Larkin, by phone B. McGaffigan, by phone D. Schumacher, by phone D. Collins, by phone B. Brickner, by phone (Holtec)

B. Gutherman, by phone (Gutherman Associates)

Exelonoo Nuclear Pre-Submittal Meeting Neutron Absorbing Inserts Exelon Generation Company, LLC Quad Cities Nuclear Power Station Units 1 and 2 February 9,2012

r Nuclear Agenda

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Exelon.

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Objectives LAR Overview NETCO-SNAP-IN Rack Inserts Criticality Analysis Interim Actions Technical Specification Changes Summary, Questions, NRC Feedback Joe Bauer Joe Bauer Rosanne Carmean Scot Leuenroth Dr. Stefan Anton Rosanne Carmean Rosanne Carmean Joe Bauer

Exel Nuclear

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Objectives

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./ Provide the NRC with a clear summary of the LAR scope, content and analysis methodology

./ Obtain NRC feedback

• LAR content

• Proposed dates for LAR submittal and approval

• Identify LAR gaps and* follow-up actions

LAR Overview

./

Purpose:

Submit a LAR to use NETCO-SNAP-IN inserts to permanently resolve the spent fuel pool (SFP) Boraflex degradation issue without crediting Boraflex

./ Submittal target date: June 2012

./ Approval target date: June 2013 (requested)

./ BADGER Testing and RACKLIFE model calculations being used to confirm TS compliance and trend Boraflex degradation

./ Clean pool insert installation tests scheduled for February 2012

./ Insert installation testing scheduled for summer 2012 at Quad Cities

./ Rack installation performed in accordance with 10 CFR 50.59 V' Installation schedule prioritized based on projected Boraflex degradation from RACKLIFE model. Preliminary installation periods have been established:

• Unit 1: 2012 - 2015

• Unit 2: 2013 - 2016 V' No credit taken for NETCO inserts until LAR approved by NRC

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Exelon Nuclear LAR Overview - Lessons Learned ~~-

./ Peach Bottom submitted License Amendment Request (LAR) in June 2008 to address the spent fuel pool issues

• The long-term Criticality Analysis credited Boraflex; Unacceptable; LAR withdrawn

./ LaSalle submitted LAR to use NETCO-SNAP-IN neutron absorbing inserts on October 5, 2009

• Did not submit an interim criticality analysis for Boraflex

• Resulted in a required accelerated insert installation

• LAR subsequently approved January 28, 2011 with License Conditions restricting use of SFP cells without NETCO inserts

./ Peach Bottom submitted new LAR on November 3, 2011 following LaSalle's LAR (using NETCO-SNAP-IN inserts)

• Submittal included interim criticality analysis for Boraflex

• Acceptance Review Supplemental Information requested to address seismic and structural issues

Exelon Nuclear LAR Overview - Lessons Learned (continued) vi" Criticality Analysis

• Holtec I nternational will perform the Quad Cities interim Boraflex and NETCO insert criticality analyses vi" Quad Cities LAR will:

• Analysis will bound fuel conditions for the planned power uprate

• Utilize the recent Peach Bottom LAR as a template

• Utilize NETCO-SNAP-IN inserts

• Include an interim criticality analysis crediting Boraflex

- Appropriately model Boraflex parameters

• Include a revised criticality analysis crediting NETCO inserts

• Address seismic and structural issues

• Include License Conditions similar to the Peach Bottom LAR

Exelon4D Nuclear LAR Overview - Submittal Outline ~

,/ Technical Evaluation of Proposed Changes

,/ Mark-up of Proposed TS Pages

./ Figure of NETCO-SNAP-IN Insert

./ NETCO Report, Material* Qualification of Alcan

./ Criticality Analysis with Rack Inserts (proprietary and non-proprietary versions)

,/ Criticality Analysis with Boraflex (proprietary and non-proprietary versions)

./ Example of Completed Rack Module with Inserts

./ Summary of Commitments

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Project Overview

• K. Lindquist Issued U.S. Patent 6,741,669 B2 in 2004 for Absorber Insert Design

• Original Demonstration Program was a Joint Venture Between NETCO and Exelon Generation Company

• Prototype Testing and On-Site Demonstration Performed for LaSalle and Peach Bottom

• Testing Rigor to Continue for Quad Cities Inserts.

• First I nstallation at Exelon's LaSalle Station in 2007 (Three inserts installed in Demonstration Program)

• Full Scale Insert Installation at LaSalle Unit 2 Completed in 2011 with 4022 Spent Fuel Assembly Storage Locations 10

Description AI-1100/B4C Composite, Provided by Rio Tinto Alcan, Formed Into a Chevron Shaped Rack Sleeve

• Installed via Custom Tool from the Refueling Bridge

• Chevron is Compressed During Installation; Friction and Compression Forces Hold it in Place 11

Key Features Hoist

• Simplicity of NETCO-SNAP-IN

- Standard fabrication methods used to form AI/B4C composite material

• Simplicity of Installation Tool

- I nstallation force provided by tool weight alone; no electrical or hydraulic systems

• Once Installed, NETCO-SNAP IN I nserts are an Integ ral Part of the Rack Modules Snap-In Load Bearlna Surface Attachment Point Head Assembly 12

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

• Insert Installation Complete at LaSalle Unit 2

• Prior Installation Experience and Lessons Learned are Being Applied at Quad Cities

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LaSalle Installation

• No clearance issues were encountered during installation; further use has validated acceptable clearance with irradiated fuel

• Same manufacturing technique used to fabricate the Quad Cities inserts 14

Borated Aluminum Material

• Material Qualification of Alcan Through Accelerated Corrosion Testing

- Pre-test characterization

- Post-test characterization

- Accelerated corrosion environment

- 2000, 4000, 6000 and BOOO-hour test results

• Results Show Corrosion Rates Within Measurement Uncertainty of Zero for 8000-hr Tests

• Stability of B-1 0 Areal Density Values Throughout Test

• Fast-Start Results Show Consistency with Accelerated Test Predictions, Showing No Negative Change in Areal Density 16

Material Performance (LaSalle)

Alcan Material Shows Consistent Performance in Neutron Attenuation Tests c

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Material Surveillance

• Coupon Surveillance program will be similar to LaSalle

• Fast Start Program

- Results of the LaSalle Program eliminate need for fast start program at Quad Cities

• Long Term Surveillance Program

- General, Bend and Galvanic coupons will be included in surveillance program Pre-Characterizations will include visual, dimensional, weight and areal density testing

• Removal Inspection

- Insert with the highest fuel move frequency will be removed every 10 years to inspect for wear and overall performance 18

Quad Cities Spent Fuel Pool Criticality Analysis NRC Pre-Submittal Meeting Dr. Stefan Anton February 9, 2012 HOLTEC INTERNATIONAL 19

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, ifflooded with unborated water.

K max(95/95) < 0.95 HOLTEC INTERNATIONAL 20

Basic Analysis and Requirements K max(95/95)== KNominal + M Bias + MTOlerancetUncertainty

~Bias= L~Bi Contribution from Biases i=1 Contribution from Independent LI1K~i + LI1K~i 11KTolerance+Uncertaint y Tolerances and Uncertainties i=l i=l

• All storage rack locations assumed to contain identical fuel assemblies at their most reactive state as a function of exposure

• Consideration given to all credible abnormal conditions, manufacturing tolerance implications, and computational uncertainties HOLTEC INTERNATIONAL 21

Computational Tools and Validation CASMO-4 Studsvik 2-D lattice physics code Determines exposure dependent, pin-by-pin isotopic fuel compositions Utilizes ENDF/B-V cross-section data Not used for k-inf calculations HOLTEC INTERNATIONAL MCNP5 LANL code Calculates in-rack k-calc values Uses CASMO-4 pin-specific isotopic specifications to establish peak reactivity Utilizes ENDF/8-VII cross section data 95/95 Bias and bias uncertainty quantified and applied standard benchmark experiments (including HTC)

Uncertainties applied consistent with previous Holtec analyses, including:

- Depletion Isotopics Uncertainty

- Fission Product/Lumped Fission Product Uncertainty 22

Spent Fuel Rack Cell Model - Rack Inserts

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Rack Insert Schematic HOLTEC INTERNATIONAL

• No credit taken for B4C in Boraflex - Panels are modeled as water

• No credit taken for lateral neutron leakage

• Design basis analyses assume a single lattice design at peak reactivity for full bundle height in every storage location

• Stainless steel rack cell modeled explicitly

• Assumes a single rack insert with a minimum (95/95) areal density of 0.0116 9 8-10/cm2 in every accessible storage cell 23

Spent Fuel Rack Cell Model - Boraflex

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MCNP Rack Model HOLTEC INTERNATIONAL

• Credit taken for degraded Boraflex - model includes various degradation mechanisms

• Only used for racks without inserts

• No credit taken for lateral neutron leakage

• Design basis analyses assume a single lattice design at peak reactivity for full bundle height in every storage location

• Stainless steel rack cell and degraded Boraflex modeled explicitly 24

Design Basis Bundle Selection

• Optima 2 fuel is shown to bound all past and current fuel types in the Quad Cities SFP

• Each Optima 2 lattice is analyzed independently

• The lattice resulting in the highest in rack k-eff is used to:

- Define nominal in-rack k-eff value

- Perform bias, tolerance, uncertainty sensitivity, interface, accident evaluations H 0 L T 'E C INTERNATIONAL 25

Storage Scenarios Addressed Credible Normal Conditions

• Final Pool Configuration (Inserts only)

• Interim Pool Configuration (Inserts and Degraded Boraflex)

• Fuel Assembly Channeling (except for Optima 2 assembly)

• Eccentric Positioning

• Moderator Temperature

• Bu nd Ie Orientation Credible Abnormal Conditions

• Dropped Fuel Assembly

• Mislocated Fuel Assembly

• Missing Rack Insert HOLTEC INTERNATIONAL 26

Storage Scenarios Addressed Manufacturing Tolerances, Including

• Fuel Enrichment

• Fuel Pellet Density

• Gadolinium Content

• Rod Cladding Thickness

• Rack Wall Thickness

• Rack Pitch

• Rack Insert Thickness

• Rack Insert 8-10 areal density I nterface 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)

HOLTEC INTERNATIONAL 27

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

• Fuel Assembly Selection

• Depletion Analysis

• Criticality Analysis

• Criticality Code Validation Information Notice 2011-03

• Monte Carlo Bias Uncertainty

• Depletion Uncertainty HOLTEC INTERNATIONAL 28

Summary

• Analysis performed will fulfill requirements of 10 CFR 50.68 and GOC 62 with consideration given to OSS-ISG-201 0-01 and IN-2011-03

• 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 >50/0 subcritical for storage of current and previous fuel types with defined enrichment and Gadolinium distribution

• Analyses will include final and interim SFP configuration HOLTEC INTERNATIONAL 29

Nuclear Interim Actions Exel~ne

./ RACKLIFE model revised every year to incorporate updated assembly power history, fuel movement, and pool chemistry

• RACKLIFE model is also benchmarked against BADGER results following each BADGER campaign

• Current RACKLIFE model conservatively bounds peak degradation values from most recent 2009 BADGER testing

./ RACKLIFE results compared against minimum allowable areal density

./ BADGER testing is performed every three years to validate the RACKLIFE model

• BADGER results are compared against minimum allowable areal density

• Most recent BADGER tests performed in November 2009 (both units)

• BADGER campaign performed in January; results pending

Nuclear Interim Actions Exelon.

./ Interim Boraflex analysis

• Similar to interim analysis performed for Peach Bottom

• Will address Boraflex degradation mechanisms and issues

- Shrinkage and Edge Dissolution

- Undetected Cracking

- Gaps

- Experimental and Measurement Uncertainties (from BADGER and RACKLIFE methodology)

- Boraflex particle self-shielding

- Non-uniform panel thinning

- Effects of a seismic event on degraded Boraflex

./ Analysis will establish the degradation acceptance criteria and ~onfirm TS compliance

• RACKLIFE and BADGER results will be compared to the minimum acceptable areal density analyzed

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Nuclear Technical Specification Changes

./ Unit 1 and Unit 2 TS will be the same

./ Proposed TS similar to LaSalle with inserts

./ TS 4.3.1.1 - include rack inserts as part of design

./ TS 4.3.1.1.a. - in-rack keff S 0.95, including allowance for uncertainties described in the UFSAR (no change)

./ TS 4.3.1.1.b. - nominal center-to-center distance between assemblies of 6.22 inches (no change)

./ TS 4.3.1.1.c. (new) - rack inserts will have a minimum certified 8-10 areal density of 0.0116 g/cm2

./ License Conditions - will establish restrictions on using SFP storage cells without NETCO Inserts

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ML120590649 Meeting Summary Accession No. Ml12059064 6 Joel S. Wiebe, Senior Project Manager IRA!

Plant Licensing Branch 111-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Meeting Notice Accession No. ML120110334 licensee Handout Accession No.: Ml120590691 NRC-001 OFFICE LPL3-2/PM LPL3-2/LA LPL3-2/BC LPL3-2/PM NAME JWiebe KGoldstein JZimmerman JWiebe DATE 3/01/12 3/01/12 3/05/12 3/05/12