ML13023A412

Slides for Meeting with Tennessee Valley Authority Tpbar Loading Increase LAR Pre&#8208, Submittal Meeting Watts Bar Nuclear Plant, Unit 1

ML13023A412
Person / Time
Site:	Watts Bar
Issue date:	01/23/2013
From:	Tennessee Valley Authority
To:	Plant Licensing Branch II
Hon, Andy
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ML13023A417	List: ML13023A412
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Download: ML13023A412 (22)

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Watts Bar TPBAR Loading Increase LAR PreSubmittal Meetingg N l Nuclear January 23, 2013

Agenda g

N l Nuclear

• IIntroduction d i TTerry Cribbe C ibb

• Background Mark Burzynski

• DOE TPBAR Loading Plans Curtis Chambellan

• Tritium Permeation Experience Larry Bagaasen

• Projected j Pathwayy Exposures p Mark Burzynski y

• Plant Modifications Jeff McGuire

• Licensing Activities Mark Burzynski

• PostLOCA Shutdown Margin Analysis Gregg Swindlehurst

• Licensing Activities Schedule Terry Cribbe

• Closing Comments Terry Cribbe 2

Introduction N l Nuclear

• Purpose of Meeting

- Update NRC Management on TVAs Plan to Submit a License Amendment Request q (LAR)

( ) in June 2013 to Increase Allowable TPBAR Loading for Watts Bar Unit 1 3

Background

g N l Nuclear

• Background

- License Amendment 40 Issued on September 23, 2002 Authorized Loading Up to 2304 TPBARs

• Allowed Loading Subsequently Reduced to Address Post LOCA Shutdown Margin Issues

- TVA Letter Dated March 22, 2005 Notified NRC of Interim Cumulative TPBAR Tritium Release Limits

• While Higher than Projected Permeation Rates were Investigated

- License Amendment 77 Issued on May 4, 2009 Authorized Loading Up to 704 TPBARs 4

DOE TPBAR Loadingg Plans N l Nuclear

• DOE TPBAR Loading Plans for Watts Bar Unit 1:

Cycle Date TPBAR Loading Tech Spec Limit C11 April 2011 544 704 C12 October 2012 544 704 C13 April 2014 544704 704 C14 October 2015 11041024 1696*

C15 April 2017 15041424 1696*

C16 October 2018 1696 1696*

• Proposed 5

Tritium Permeation N l Nuclear Experience (1/2)

• TVA and PNNL Performed Surveillance Of Estimated Tritium Permeation Over Last 6 Cyclesy of TPBAR Irradiation for the Tritium Readiness Program.

- Permeation Was Higher than Original Design Goal, But No Design or Production Flaws Have Been Identified.

Uncertainty U t i t bars b

represent 90%

confidence interval 6

Tritium Permeation N l Nuclear Experience (2/2)

• Original Functional Requirement for TPBAR Tritium Permeation in Cycle 6 was an Average of 1 Ci/TPBAR/Year.

• Radionuclide Releases to Environment at WBN1 will be Managed to Meet NRC Requirements in 10 CFR Part 20 and 10 CFR Part 50 Appendix I.

- Proposed Management Strategy Assumes TPBAR Tritium Permeation will be 5.0 Ci/TPBAR/year.

Ci/TPBAR/year

• Projected 7

Projected j Pathwayy Exposure p (1/2)

( )

N l Nuclear

• FSAR Chapter 11 Radiological Consequence Analyses Will Be Based on:

- Release Source Term Based on NRC NUREG0017 Methodology to Calculate an Average Maximum Hypothetical Release

- TPBAR Loading of 1700 TPBARs

- TPBAR Tritium Permeation Rate of 5 Curies/TPBAR/Year (Based on Conservative Upper Bound of Plant Data)

- Use of TVA QA Computer Codes GELC and QWATA to Calculate Dose to Maximum Exposed Offsite Individual 8

Projected j Pathwayy Exposure p (2/2)

( )

N l Nuclear

• Projected Pathway Exposures to Maximum Hypothetical Individual Remain Below NRC Regulatory Limits for All Cases.

Pathways Preliminary Projected Doses Liquid (Realistic) 0.75 mrem Total Body Liquid (Design) 0.81 mrem Total Body 1 29 mrem Total Body 1.29 Gaseous (Realistic) 10.86 mrem Critical Organ 1.29 mrem Total Body Gaseous (Design)

( es g )

11.34 mrem Critical Organ

• Applicable NRC Requirements (10 CFR Part 20 and 10 CFR Part P t 50 Appendix A di I) and d TTechnical h i l SSpecifications ifi ti Will Be Met for All Cases.

9

Plant Modifications ((1/2))

N l Nuclear

• Addition of 500,000 Gallon Tritiated Water Tank System

- Increase Flexibility to Manage RCS Feed and Bleed Under Contingency Scenarios and Time Effluent Releases to Environment

- Allows Changes to Operating Strategy for RCS Feed and Bleed to Keep Tritium Concentrations Low and Simplify Occupational Exposure Controls

- Implemented under 10 CFR 50.59 10

Plant Modifications ((2/2))

N l Nuclear

• Replace Check Valves Used for Thermal Relief on ERCW Supply Lines with relief Valves

- Eliminates PostLOCA Manual Operator Actions for Isolation Previously Approved by NRC in License Amendment Issued on March 29, 2004

- Eliminates 40 GPM Source of Unborated Water Leakage into Containment (Assumed for 16 Hours)

- Implemented I l d under d 10 CFR 50.59 50 59 11

Licensingg Activities N l Nuclear

• Update Letter Removing Interim Limit on Tritium Releases Attributed to TPBARs (Update to March 22, 2005 Letter)

- Return to Normal Effluent Controls of 10 CFR Part 20, 100 CFR Part 50 0 Appendix di I, and d Technical h i l Specifications S ifi i

- Would Include General Discussion of Expected Effluent Releases for 704 TPBARs

• License Amendment Request for 1696 TPBARs

- Update of PostLOCA Reactivity Analysis Previously Approved by NRC for License Amendment 77

- Would Include Discussion of Expected Effluent Releases (Using Realistic Source Term) and Radwaste System D i and Design d St Station ti DDose (Using (U i DDesign i BBasis i Source S

Term) for 1696 TPBARs 12

PostLOCA Shutdown N l Nuclear Margin Analysis (1/5)

• PostLOCA Reactivity Analysis will Be Consistent with ith Previously P i l Approved A d by b NRC ffor License Li Amendment 77 with the Following Key Changes:

- Elimination of Dilution of Sump Water from 40 GPM Unborated Water InLeakage

- Reduce Required RCS Boron Concentration by Increased IFBA Loading

- Modification of Simplified Assumptions on TPBAR Lithium Leaching at Time of Hot Leg Switchover Switchover.

• Time Dependent Leaching Rate Used

• Preliminaryy Results Show Sufficient Shutdown Margin for 1696 TPBARs 13

PostLOCA Shutdown N l Nuclear Margin Analysis (2/5)

• Xenon Free PostLOCA - RSAC Item 3.16B PreLOCA Cb PostLOCA Cb Limit Margin (ppm) (ppm) (ppm) (ppm)

HFP EQXE Cb = 1200 ppm (less IFBA) 544 TPBARs 937 1891 2176 285 1696 TPBARs 953 2170 2178 8 HFP EQXE Cb = 900 ppm (more IFBA) 1696 TPBAR TPBARs 736 2006 2148 142

Conclusion:

900 pp ppm core with 1696 TPBARs can accommodate cycle variations Preliminary Results 14

PostLOCA Shutdown N l Nuclear Margin Analysis (3/5)

• Hot Legg Switchover - RSAC Item 3.16A PreLOCA Cb PostLOCA Cb Limit Margin (ppm) (ppm) (ppm) (ppm)

HFP EQXE Cb = 1200 ppm (less IFBA) 544 TPBARs 937 1891 2009 118 1696 TPBARs 953 2170 2012 158 HFP EQXE Cb = 900 ppm (more IFBA) 1696 TPBARs - 736 2006 1966 40 50% Leach (Max) 1696 TPBAR TPBARs -

3% Leach (Time 736 1897 1966 69 Dependent)

Conclusion:

1696 TPBAR core at 900 ppm with time dependent leach rate meets requirements.

Preliminary Results 15

PostLOCA Shutdown N l Nuclear Margin Analysis (4/5)

• ColdLegg Recirculation - RSAC Item 3.11B PreLOCA Cb PostLOCA Cb Limit Margin (ppm) (ppm) (ppm) (ppm)

HFP EQXE Cb = 1200 ppm (less IFBA) 544 TPBARs 937 1891 2115 224 1696 TPBARs 953 2170 2119 52 HFP EQXE Cb = 900 ppm (more IFBA) 1696 TPBAR 735 2006 2064 58

Conclusion:

1696 TPBARs,, 900 pp ppm core meets requirements.

Preliminary Results 16

PostLOCA Shutdown N l Nuclear Margin Analysis (5/5)

• Reflood Recriticality - RSAC Item 3.11C PreLOCA P LOCA Cb LLarge LBLOCA IIntermediate t di t SSmallll LBLOCA (ppm) (Keff) LBLOCA (Keff)

(Keff)

HFP EQXE Cb = 1200 ppm (less IFBA) 544 TPBARs 937 0.939349 0.968402 0.982261 1696 TPBARs 953 0.964008 0.990343 1.007126 HFP EQXE Cb = 900 ppm (more IFBA) 1696 TPBARs - 736 0.955894 0.985144 1.005015 50% Leach (Max) 1696 TPBARs -

3% Leach (Time 736 0.948534 0.977298 0.996649 Dependent)

Conclusion:

1696 TPBAR core at 900 ppm with time dependent leach rate meets requirements.

Preliminary Results 17

Licensingg Activities Schedule N l Nuclear 18

Closingg N l Nuclear

• TVA Will Submit a License Amendment Request f 1696 TPBAR for TPBARs iin JuneJ 2013

- Supporting Analyses will Bound Operating E

Experience i with i h TTritium ii P Permeation i

- Supporting Analyses will Reflect Plant Modifications M d to Made t IIncrease MMargins i

- All Regulatory Requirements and Plant Technical Specifications will be met with 1696 TPBAR Core Design 19

N l Nuclear Questions 20

N l Nuclear Backup Slides 21

TPBAR Leaching Test N l Nuclear

• Leachingg Results from Dynamic y Leachingg Test on an Irradiated TPBAR Section Hot Leg Switchover 1