ML12017A048

Handout for 1-17-12 Meeting Re. a Future Application for Amendment Concerning Fuel Storage Criticality Analysis

ML12017A048
Person / Time
Site:	Monticello
Issue date:	01/17/2012
From:	George Adams Northern States Power Co, Xcel Energy
To:	Office of Nuclear Reactor Regulation
Tam P
Shared Package
ML12017A093	List: ML12017A048 ML12017A085
References
TAC ME7372
Download: ML12017A048 (30)

Text

Monticello Nuclear Generating Plant (MNGP)

Fuel Storage Criticality Safety Analysis (CSA)

Pre-Application Public Meeting January 17, 2012 1

Agenda

• Objectives

• Background

• Schedule

• License Amendment Request (LAR)

- Scope

- Content

- ISG Compliance

• Summary of Actions 2

Meeting Objectives

• Agreement on LAR content

• Agreement on schedule targets

- Concurrent review with Areva Transition LAR

• NRC feedback

- LAR content

- Analysis methods

• Actions 3

LAR Objectives

1. Address Areva ATRIUM 10XM fuel type

2. Adopt Areva CSA methodology

3. Improve analysis to meet NRC expectations

4. Address legacy issues 4

Background - Spent Fuel Pool Low-Density Un-Poisoned Racks

• Aluminum construction

• 6.625 assembly pitch, 11.875 row High-Density Temporary Rack

• Eliminating High Density Boral Racks

• Stainless Steel construction

• 6.563 fuel assembly pitch 5

Background - Areva Fuel Transition

• Transition to Areva ATRIUM-10XM (2015)

- Previously-licensed fuel at other plants

- Areva new long-term fuel supplier for MNGP

- Add fuel type to fuel storage CSA

• Transition to Areva safety analysis month review time for Areva Transition LAR year review time for Areva CSA 6

Background - LAR Scope

• CSA methodology - new for MNGP

- Previously-approved methods

- Align with Interim Staff Guidance (ISG)

• Some administrative changes, clarifications 7

Background - LAR Scope No Complicating Factors:

• No significant change in fuel design

• No credit for rack inserts

• No rerack, no rack design changes

• No burnup credit

• No Boraflex

• No new SFP loading restrictions

• No New Fuel Vault analysis 8

Schedule - Related LARs 2011 2012 2013 2014 2015 NRC Review of EPU to 2004 MWt Key:

= Submittal

= NRC Action NRC Review of MELLLA+

= NRC Approval

= Implementation Spent Fuel Pool Criticality LAR AREVA Fuel Transition EPU Escalation to 2004 MWt Load AREVA Fuel in pool Cycle 26 Cycle 27 Cycle 28 RFO25 RFO26 EPU Phase II Mods RFO27 9

Schedule - Concurrent Reviews

• CSA amendment does not depend on Fuel Transition amendment

• Fuel Transition does not depend on CSA amendment

• Reviews are independent 10

LAR Scope - Proposed Changes

• Revised Criticality Safety Analysis for SFP

• Technical Specification (TS) Changes

• Operating License clarification 11

LAR Scope - Other Evaluations

• SFP cooling

- Expect no change to fuel assembly decay heat

- Expect no change to fuel assembly flow channel

• SFP structural seismic qualification

- ATRIUM-10XM bounded by legacy fuel weight

• Material effects of new fuel type

- ATRIUM-10XM uses no new materials 12

LAR Content

• Cover letter

• Enclosure 1 (justification of changes)

• Enclosure 2 (TS changes)

• Enclosure 3 (TS Bases markup - info only)

• Enclosure 4, 5, 6 Analysis

- QA product, audited

• No new commitments 13

LAR - License Changes

• OL Condition 2.B.2 Clarification

- Broad statement to define fuel quantity limit

- Reconcile it with current licensing basis, Part 72

• TS Design Feature 4.3.1.1 (SFP)

- Eliminate core k-infinity as a limit for SFP

- Revised description of fuel to include ATRIUM

- Eliminate description of 8x8 temporary rack

- Align low-density rack criterion to 50.68 14

LAR - Proposed Changes

• TS Design Feature 4.3.1.2 (NFV)

- Prohibit loading the NFV

• TS Design Feature 4.3.3

- Reduce SFP capacity by 64 assemblies based on elimination of the 8x8 temporary rack

- Reduce SFP capacity by 20 additional assemblies (legacy contingency) 15

CSA Acceptance Criteria

• Acceptance criteria per 10 CFR 50.68(b)

Normal and Accident conditions:

• k95/95 < 0.95 for unborated conditions 16

CSA Methods

• Follows NRC guidance DSS-ISG-2010-01

• Performed under Arevas QA program

• Precedent (2011) 17

CSA Methods - General

• Define an ATRIUM 10XM reference bounding fuel assembly

- More reactive (lifetime maximum basis) than all previous MNGP fuel designs (including assembly modifications)

- Uses Arevas standard moderator void dependent in-core depletion method

- Depletes U-235 and gadolinium, builds in plutonium and fission products

- Reactivity comparisons performed using spent fuel pool model (in-rack) conditions 18

CSA Methods - General (continued)

• Define a reactivity equivalent assembly at beginning of life conditions

- Same geometry, but no integral neutron absorbers

- More reactive than the reference bounding assembly and associated uncertainties

- Reactivity comparisons performed using spent fuel pool model (in-rack) and limiting moderator temperature conditions 19

CSA Methods - ISG Compliance

• IV.1.a, Limiting Fuel Assembly

- ATRIUM 10XM RBL is more reactive than legacy fuel designs

• IV.2.a, Depletion Uncertainty

- Defined and conservatively applied

• IV.2.d, Rodded Operation

- Sensitivity shows unrodded operation is limiting 20

CSA Methods - ISG Compliance

• IV.3.b.ii Neutron Absorber Efficiency

- Minimum Boron-10 Areal density

• IV.3.b.iii Neutron Absorber Degradation

- Conservative representation of blistering

• IV.3.c, Rack Interfaces

- Multiple rack types will be evaluated 21

CSA Methods - ISG Compliance

• IV.3.d, Normal Conditions

- Normal fuel handling configurations

- Orientation variations in the racks

• IV.3.e, Accident Conditions

- Standard credible accident scenarios

- Limiting event - missing Boral plate 22

CSA Methods - ISG Compliance

• IV.4.a.i, Criticality Code Validation - HTC

- HTC benchmarks not used because REBOL used

• IV.4.c.i, Variance about the mean

- Performed per NUREG-6698

• IV.4.d, Lumped fission products

- Lumped fission products not credited in RBLs

• IV.4.e, Code-to-Code Comparisons

- Use comparisons to KENO results as one method to quantify CASMO-4 uncertainty 23

CSA Methods - ISG Compliance

• IV.5.a, Precedents

- CSA methods

- TS k-infinity change 24

Summary of Actions

• Xcel Actions

- Points of Emphasis for LAR content

• NRC Actions 25

26 TS Markup - Spent Fuel 27

TS Markup - New Fuel 28

TS Markup - SFP Capacity 29

Renewed OL Clarification B. Subject to the conditions and requirements incorporated herein, the Commission hereby licenses: . . .

2. Pursuant to the Act and 10 CFR Part 70, NSPM to receive, possess, and use at any time special nuclear material as reactor fuel, in accordance with the limitations for storage and amounts required for reactor operations, as described in the Final Safety Analysis Report, as supplemented and amended, and the licensee's filings dated August 16, 1974 (those portions dealing with handling of reactor fuel) and August 17, 1977 (those portions dealing with fuel assembly storage capacity)

Points to clarify for this license condition:

• Invokes USAR: SFP capacity 2301 assemblies

• Invokes 1977 filing: SFP capacity at that time < 2301 assemblies

• Does not invoke TS 4.2.1: Additional 484 assemblies in core

• Does not invoke Independent Spent Fuel Storage Installation

- Unlimited amount of storage under 10 CFR 72 General License 30