Watts Bar Unit 2

Watts Bar Unit 2Tritium Production License Amendment

Pre-Application Meeting

Mark BurzynskiSeptember 26, 2017

Agenda

Purpose Introduction and Background Project Scope Licensing Amendment Request Technical Specification Changes Interface Items with New Analyses Licensing Schedule Closing

| 2Tritium Production License Amendment Pre-Application Meeting | September 26, 2017

Purpose

Pre-submittal meeting to describe the Unit 2 license amendment request (LAR) to authorize tritium production

Summarize LAR content and key results Explain where the Unit 2 LAR differs from the

Unit 1 precedents Identify key schedule milestones to support

Department of Energy (DOE) National Nuclear Security Administration (NNSA) production requirements

PLACE THE TITLE OF THE PRESENTATION HERE | 3

Introduction and Background (1/3)

Tritium Production Program Watts Bar Unit 1 tritium production began in

October 2003DOE-NNSA identified need to expand

production, which requires a second reactor In December 2015, DOE-NNSA notified TVA of

future tritium needs In June 2016, TVA agreed to assess potential

for tritium production for Watts Bar Unit 2



Watts Bar tritium production target Steady ramp-up of tritium production to

approximately 2800 grams every 18 months by December 2025

July 2016 Unit 1 license amendment authorized 1792 TPBAR production

September 13, 2016 planning meeting held with NRC to discuss Unit 2 TPBAR production



Unit 2 LAR to be submitted in December 2017 with requested approval by May 31, 2019

Approval needed to support tritium production beginning in Unit 2 Cycle 4 (currently scheduled for November 2020)


Project Scope (1/2)

Plant Modifications Replacing seven CCS and ERCW relief valves to

address post-LOCA subcriticality margin Increasing the required minimum dilution flowrate

setpoint during radioactive effluent releases from 20,000 gpm to 30,000 gpm

Reverse osmosis unit Impact on liquid radioactive effluents determined not to be

required for 10 CFR Part 20 compliance Adding to Liquid Radwaste System to provide additional

operational capabilities for effluent management


Project Scope (2/2)

TVA Engineering Documentation Westinghouse analyses PNNL engineering documentation Holtec analyses S&L revisions to affected dose calculations, FSAR,

and System Descriptions LAR to operate with 1792 TPBARs at Watts Bar

Unit 2


License Amendment Request (1/3)

Watts Bar Unit 2 LAR for tritium production based on Watts Bar Unit 1 precedents Addresses 17 plant-specific interface items from

NUREG 1672 Safety Evaluation Report for DOE Tritium Production Core Topical Report

Addresses post-LOCA subcriticality for lithium leaching effects

Updates information for two-unit tritium production for environmental assessment

Effect on thermal conductivity degradation would be treated in same manner as for Unit 1 PAD4TCD licensing issue for Unit 2 License Condition would not

be coupled with Unit 2 TPBAR LAR



Watts Bar Unit 2 LAR for tritium production addresses lessons learned from emergent industry issues Interface Item #4 includes new reactor vessel fluence

evaluations that address issues documented in RIS 2014-11

Interface Item #10 includes results of new spent fuel rack criticality analyses that uses the latest version of NEI 12-16



Watts Bar Unit 2 LAR for tritium production addresses lessons learned from the NRC review of the Unit 1 application and the Unit 2 LAR preparation Interface Item #5 includes results of new accident

analyses updated to bound the use of original and replacement steam generators and updated primary and secondary radionuclide concentrations

Interface Item #14 includes results of new radioactive effluent assessments that address effects of two unit tritium production on radioactive effluent management


Technical Specification Changes (1/3)

Proposed change revises the Unit 2 Technical Specification (TS) 4.2.1, "Fuel Assemblies," to add a limit on the number of Tritium Producing Burnable Absorber Rods (TPBARs) that can be irradiated Change is analogous to changes implemented in

Watts Bar Unit 1



Proposed change revises the Units 1 and 2 TSs affected by the new spent fuel rack criticality analysis TS 3.7.15, “Spent Fuel Assembly Storage,” revised to

simplify the fuel storage limitations on fuel assemblies by eliminating burnup–related criteria

TS 3.7.18, “Fuel Storage Pool Boron Concentration,” added to specify minimum fuel storage pool boron concentration when fuel is stored in the pool

TS 3.9.9, “Spent Fuel Pool Boron Concentration,” revised to modify the minimum fuel storage pool boron concentration during refueling operations when fuel is stored in the pool



Proposed change revises the Units 1 and 2 TSs affected by the new spent fuel rack criticality analysis (continued) TS 4.3, “Fuel Storage,” revised to replace the storage

limitations on fuel assembly initial enrichment, burnup, and storage location limitations with a single requirement to maintain a specified boron concentration in the spent fuel pool

TS 5.7.2.21, “Spent Fuel Storage Rack Neutron Absorber Monitoring Program,” added to incorporate the NRC-approved NEI 16-03-A guidance


Interface Item #4 – Reactor Vessel Integrity

New heatup and cooldown P-T limit curves generated using limiting Adjusted Reference Temperature values for WBN Unit 2

P-T limit curves generated for 32 effective full-power years using the KIc methodology detailed in the 1998 through the 2000 Addenda Edition of the ASME Code, Section XI, Appendix G Methodology is consistent with the NRC-approved

methodology documented in WCAP-14040-A, Revision 4.


Interface Item #5 – Control Room Dose Analyses

Main steam line break and steam generator tube rupture analyses updated Bounds use of original and replacement steam

generators Correct some errors affecting primary and secondary

radionuclide concentrations Tritium assumptions remain the same as for Watts

Bar Unit 1 Dose results remain well within 10 CFR Part 100 and

10 CFR Part 50 Appendix A GDC 19 dose limits.


Interface Item #10 – Fuel Rack Criticality Analyses (1/2)

Watts Bar spent fuel pool contains a single type of BORALTM racks with flux traps designed for storage of pressurized water reactor fuel.

Criticality control in the BORALTM storage racks rely on the following: Fixed neutron absorbers: BORALTM panels Storage cell spacing, i.e., flux traps between storage

cells Soluble boron


Interface Item #10 – Fuel Rack Criticality Analyses (2/2)

Criticality calculations qualify the BORALTM

storage racks uniformly loaded with fresh fuel assemblies with an initial enrichment up to 5 weight percent 235U Bounding fuel density of all types of fuel assemblies is

considered Bounding approach provides analysis simplicity and

adequate margin Neutron absorber monitoring program, will be

implemented following the NRC-approved guidance in NEI 16-03-A


Interface Item #14 – Radioactive Liquid Effluents (1/4)

New analysis of liquid and gaseous radioactive effluents performed: Included effects of tritium production in Watts Bar

Units 1 and 2 Updated primary and secondary radionuclide

concentrations Minimum dilution flow required for discharge of

radioactivity into the Cooling Tower Blowdown lines increased from 20,000 gpm to 30,000 gpm

Results demonstrate that both 10 CFR Part 20 effluent concentration limit values and 10 CFR Part 50 Appendix I dose limits are met



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Liquid Release, Mobile Demineralizer ProcessingDual Unit Operation

Design C/ECLTotal (no TPC) 5.65E-01

Total (with TPC) 8.35E-01Liquid Release, Direct SGBD Release at Maximum Appendix I

Dual Unit OperationDesign C/ECL

Total (no TPC) 5.79E-01Total (with TPC) 8.47E-01

Tritium Production License Amendment Pre-Application Meeting | September 26, 2017


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Annual Radioactive Liquid Emissions

Non-TPC Dose

TPCDose

Incremental Increase from

TPC

NRC Annual Effluent

Exposure Guideline

Maximally Exposed Individual (mrem) Total Body

0.34 0.37 0.03 3.00Total Body

Maximally Exposed Individual (mrem) Organ

0.47(Liver)

0.49(Liver) 0.02 10.00

Any Organ50-mile Population Dose (person-rem)

6.9(Thyroid)

11.0(Thyroid) 4.1 NA



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Annual Radioactive Gaseous Emissions

Non-TPC Dose

TPCDose

Incremental Increase from

TPC

NRC Annual Effluent

Exposure Guideline

Maximally Exposed Individual (mrem) Total Body

0.63 0.63 0 5.00Total Body

Maximally Exposed Individual (mrem) Organ

11.9(Bone)

12.7(Bone) 0.8 15.00

Any Organ50-mile Population Dose (person-rem)

16.0(Thyroid)

21.4(Thyroid) 5.4 NA


Licensing Schedule


Closing

LAR is scheduled to be submitted in December 2017 requesting approval to operate with 1792 TPBARs at Watts Bar Unit 2 Based on DOE need to expand tritium production

Watts Bar Unit 2 LAR for tritium production based on Watts Bar Unit 1 precedents Includes new analyses to address lessons learned

from emergent industry issues and NRC review of the Unit 1 application to simplify NRC review

TVA requests approval of the proposed License Amendment by May 31, 2019, to support TPBAR irradiation starting in Watts Bar Unit 2 Cycle 4


Watts Bar Unit 2

Documents

Transcript of Watts Bar Unit 2