ML042920186

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10/8/04, Watts Bar, Unit 1, Attachment 2, Meeting Summary of 8/26/04
ML042920186
Person / Time
Site: Watts Bar Tennessee Valley Authority icon.png
Issue date: 10/08/2004
From: Robert Pascarelli
NRC/NRR/DLPM/LPD2
To:
Tennessee Valley Authority
Pascarelli,R J,NRC/NRR/DIPM,415-1245
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ML042920096 List:
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Download: ML042920186 (19)
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II Steam Generator Replacement Project Status/issues August 26, 2004 L.

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I Purpose

  • Expectations

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  • Increased tube surface area
  • Integral loose parts strainer provided for FW/AFW
  • Reduced moisture content at exit steam
  • Advanced tube support grid to reduce contact length w/tubes
  • Shellside recirculation nozzle and sparger for chemical cleaning
  • Additional access handholes
  • Snaplock Nozzle Dams provided for dose reduction
  • Electro Polished Head Bowls for dose reduction rI

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Uprate capability from 3475MWt to 3720MWt (future)

  • Nozzles compatible with high chromium content piping
  • Preheater designed to eliminate warmup during startup
  • "Tempering Flow" for Aux FW nozzle warming eliminated 4 i,
  • Shellside blowdown from hot or cold side or combination
  • Increased steam pressure of-50 #
  • 12% Tube plugging margin vs 8%-10%
  • 50 year fatigue life F

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Parameter OSG RSG Steam Pressure (Thermal Design)

Max Moisture Carry Over Nominal Tube OD Tube Wall Thickness Number of Tubes Min. U-Bend Radius Tube Bundle Length Max Plug Level Tube Material Secondary Side HT Area Primary Side Volume / SG Secondary Side Volume / SG Total RCS Volume Dry Weight Secondary Side Liquid Mass 100% Power Secondary Side Steam Mass 100% Power 980 psia

.25%

0.75 in.

0.43 in.

4674 2.25 in.

27.39 ft.

10%

1600 48,000 sq. ft.

935 cu. ft.

5947 cu. ft.

11,789 cu. ft.

352 tons 95,000 Ibm 9,000 Ibm 1030 psia

.10%

0.75 in.

0.43 in.

5128 3.188 in.

37.04 ft.

12%

Alloy 690 68,000 sq. ft.

1193 cu. ft.

5618 cu. ft.

12,821 cu. ft.

380 tons 109,549 Ibm 7,618 Ibm Upg

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  • One Piece Replacement like SQN
  • Major Activities Involved:

Obtain & Assemble Large Crane Build Support Facilities Defuel Reactor Cut holes in Shield Building, Steel Containment Vessel (SCV),

and SG Compartment Roofs Remove Old SGs Install Replacement SGs Restore SG Compartments, SCV, and Shield Building Refuel Reactor Pressure Test to Demonstrate Restored Containment Integrity 4..

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  • Shield Building, SCV and SG Compartment Modifications are Similar to SQN and Will Use Same Methodology
  • Safe Load Paths and Load Drop Analysis for Crane Components, Steam Generators, and Other Heavy Loads under Development
  • Using Lessons Learned From SQN Movement of Material to SCV Dome
  • N-1 Design Packages - Issued or in final review to issue
  • SGRO Design Packages - Several reaching 10% Status i Coordinating with Security to maintain compliance with DBT Security Order

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Input Parameters

  • Primary Reactor Operating Conditions for 0%, 12% SG Tube Plugging
  • Best Estimate Steam Parameters for Turbine/BOP Cycle Safety
  • LOCA Mass & Energy/Containment Integrity
  • MSLB Mass &Energy/Containment Integrity
  • SG Tube Rupture
  • Steam Releases for Dose Analysis Control Systems
  • Margin to Trip Analysis
  • Low Temp Over Pressure Protection System
  • RCS and Steam Pressure Control Systems Components
  • Component Reviews Pumps, Valves, Tanks, Heat Exchangers Fuel Design Reactor Coolant Loop Piping Systems
  • Fluid Systems NSSS/BOP Interface Review

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  • Steam Generator Component Replacement Performed via 10 CFR 50.59 Plan to demonstrate original and replacement SG equivalence and compliance w/existing NRC acceptance criteria
  • Seismic Spectra B+C used per UFSAR
  • Use coupled analysis of interior concrete structure & NSSS loop 2 0 F Tavg Reduction 2% Increase in Pressurizer Level Operating Range SG FW Operational Changes

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  • Known License Amendment/Relief Requests Use of Bar-Lock Mechanical Couplers instead of Cadwelds for Rebar Splicing during Shield Building Restoration Opening of Penetrations in Shield Building Dome during Modes 1-4 for Material Handling SGTR Operator Action to Prevent Overfill Additional Ice Bed Total Weight (Ice Bed Tech Spec)

SG Water Level Setpoints

Revise APC Specifications Use of Pressure Test rather than CILRT for PMT of restored Steel Containment Vessel like SQN

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  • y hi; *Potential License Amendment Requests Compensatory Measures due to Load Drop i-
  • WBN evaluating whether a license amendment and compensatory measures for rigging and transport of steam generators are needed SQN License Amendment Requests Not Required for WBN SG Compartment Restoration
  • License amendment for a code change not required, since existing WBN design is more robust compared to SQN
  • Will use design similar to SQN I

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Items Of Note

1. Use of Bar-Lock Mechanical Couplers instead of Cadwelds for Rebar Splicing during Shield Building Restoration Propose not performing pre-use qualification testing
  • Same application as NRC approved for SQN
  • Couplers purchased from same vendor and dedicated same as SQN
  • Material, process and QA program are same
  • Sister splice testing will verify adequacy of installed couplers p

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Opening of Penetrations in Shield Building Dome K;

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-One-time change to Tech Spec 3.6.15 (Shield Building)

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1. _t Allows material movement to SCV dome through Shield Building dome versus through Auxiliary Building and up ladder K.

iin annulus

- 1Will reduce time spent in annulus and minimize personnel dose Will reduce congestion and delays at annulus ladder Will reduce potential for damage of SSCs along path through Auxiliary Building and annulus s-Offsite Dose Impacts Mission Dose Impacts L

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3. NSSS Reactor Coolant Loop Reanalysis Replacement Steam Generator (increase in mass and change in stiffness) constitutes a modification to Reactor Coolant Loop K

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For New/Modification of items, UFSAR requires use of Seismic Spectra Set B+C rather than previous Spectra Set A evaluated to Spectra B.

Couple Interior Containment Structure (ICS) with the Reactor Coolant Loop (RCL)

.* Original:

4-Loop RCLlsupports model (uncoupled)

Set A Amplified Response Spectra (ARS) input at highest loop support location t

Reanalysis:

4-Loop RCUsupports coupled with ICS A

Set B+C ARS input at basemat elevation

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,.replacement (Wolf Creek, Callaway, Farley, McGuire, Catawba) 3-D Seismic Analysis Methodology

  • Original:

2-D input/combination methodology per original FSAR

  • Reanalysis: 3-D input/combination methodology per UFSAR
  • WBN piping and supports analyzed using 3-D method for Sets B and C Seismic Input.
  • UFSAR specifies 3-D for new design and modification analyses
  • Consistent with SRP 3.7.2 k

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G PIPESTRESS Computer Code used for RCL Reanalysis Original; WESTDYN-7 4

  • Reanalysis:

PIPESTRESS

  • Approved for analysis of AP600 piping systems.

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  • License Amendment Submittal Schedule j;

Open Temporary Holes in Shield Building Dome - 11/04 SGTR Operator Action to Prevent Overfill - 12/04 Load Drop Compensatory Measures (if required) - 5/05 Additional Ice Mass - 7/05 SG Water Level Setpoints - 8/05 Revise APC Specifications - 8/05 Use of Pressure Test rather than CILRT - 8/05

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  • Implementing SQN Lessons Learned and Best Practices
  • Addressing Licensing/Design Basis differences with SQN
  • Plan is to provide minimum of 1 year staff review time H0 4-~V

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