ML16198A001

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Presentation Slides from Public Meeting Regarding Calvert Cliffs GSI-191 Resolution Update
ML16198A001
Person / Time
Site: Calvert Cliffs  Constellation icon.png
Issue date: 07/18/2016
From: Kimberly Green
Calvert Cliffs
To: Richard Guzman
Plant Licensing Branch 1
Guzman R
References
Download: ML16198A001 (14)
v • d • e


Text

Calvert Cliffs GSI-191 Program Zone of Influence, Debris Size Distribution, Option 2b Closure Approach, and LAR Exemption Request July 18, 2016

Agenda

  • Introductions
  • Objectives for Meeting
  • Option 2b Simplified Risk-Informed Closure Plan

- Strainer Performance Criteria

- LOCA Frequency Allocation

- LAR Exemption Request

  • Zone of Influence and Debris Size Distribution
  • Staff Questions & Concerns
  • Schedule for Future Periodic Meetings 1 Calvert Cliffs Chemical Effects Testing & Option 2b Refined Closure Plan

CCNPP Attendees

  • Doug Lauver- Senior Engineering Manager
  • Andre Drake - Lead Responsible Engineer GSI-191
  • Ken Greene - Licensing Engineer
  • Craig Sellers - Project Manager GSI-191
  • Eric Federline - Project Support 2 Calvert Cliffs Chemical Effects Testing & Option 2b Refined Closure Plan

Objectives of this Meeting

  • Discussion of Calvert Cliffs Simplified Risk-Informed Approach
  • Strainer Performance Criteria
  • LOCA Frequency Allocation
  • Discussion of Revised ZOIs and Debris Size Distributions
  • Capture Staff Issues and Concerns
  • Discuss Next Steps 3 Calvert Cliffs Chemical Effects Testing & Option 2b Refined Closure Plan

Simplified Risk-Informed Approach Strainer Performance Criteria

  • Strainer Failure Modes:

- Pump NPSH

- Structural Failure

- Deaeration - Limiting Failure Mode

  • Strainer Performance Criteria

- 1) Mass of Fine Fiber Debris

- 2) Mass of Particulate Debris

- 3) Mass of WCAP-16530 Chemical Precipitate Debris*

  • Provided sufficient fiber to cover strainer 1/16
  • Preliminary Results

- 19 of 62 Welds 30 ID Exceed Criteria of Fiber and/or Precipitate Mass

  • 7 of 19 Exceed only Precipitate Criterion

- 2 of 72 12 ID Welds Exceed Precipitate Criterion

  • Equivalent Uniform Fiber Bed Thickness ~1/23 and 1/28
  • Insufficient Debris Bed to Capture Precipitate
  • No Threat to Strainer Performance 4 Calvert Cliffs Chemical Effects Testing & Option 2b Refined Closure Plan

Simplified Risk-Informed Approach (continued)

Calculate CDF - Preliminary Results

  • Use Conservative Approach

- Smallest break that threatens strainer performance - 30 DEGB

- NUREG-1829 LOCA Frequencies

- Equally Apportion LOCA Frequency Across RCS Welds

  • Degradation mechanisms are Design and Construction for all 62 RCS welds
  • Log-Linear Interpolation LOCA Break Size Geometric Arithmetic LOCA Break Size Geometric Arithmetic Category (in.) Mean1 Mean2 Category (>in.) Mean Mean 1 0.5 1.90E-03 1.00E-02 1 0.5 1.90E-03 1.00E-02 2 1.625 4.20E-04 3.00E-03 2 1.625 4.20E-04 3.00E-03 3 3 1.60E-05 7.30E-05 3 3 1.60E-05 7.30E-05 4 7 1.60E-06 9.40E-06 4 7 1.60E-06 9.40E-06 5 14 2.00E-07 2.40E-06 5 14 2.00E-07 2.40E-06 6 31 2.90E-08 1.50E-06 5.5 30 3.25E-08 1.54E-06 Notes: 6 31 2.90E-08 1.50E-06

[1] Taken from Table 7-19 of NUREG-1829

[2] Taken from Table 7-13 of NUREG-1829 # Welds #Failed CDF GM CDF AM 62 22 1.15E-08 5.47E-07

- 62 Butt Welds 30

- 19 Welds 30 Threaten Strainer Performance

- 3 are DM Welds - Double Counted 5 Calvert Cliffs Chemical Effects Testing & Option 2b Refined Closure Plan

Simplified Risk-Informed Approach (continued)

License Amendment Request

- Similar to South Texas Project

- Do not need exemption from GDC 6 Calvert Cliffs Chemical Effects Testing & Option 2b Refined Closure Plan

Zone of Influence & Debris Size Distribution

  • CCNPP Submitted Supplemental Response to GL 2004-02 on June 8, 2016

- Addressed Revised ZOI and Debris Size Distributions for:

  • NUKON & Thermal Wrap Blanket Insulation
  • Mineral Wool Insulation in Stainless Steel Cassettes
  • Generic Fiberglass Insulation
  • Lead Wool Shielding Blankets

- Based on data accepted at other plants 7 Calvert Cliffs Chemical Effects Testing & Option 2b Refined Closure Plan

ZOI & Debris Size Distribution - NUKON & Thermal Wrap

  • 3 Zones of Influence, 4 Debris Size Distribution
  • ENERCON Approach using Insulation Centroid
  • Based on NEI 04-07 Safety Evaluation Guidance
  • Accepted at Other Plants Average (Centroid) Distance from Break Location to Target Debris Size 0D - 4D ZOI 4D - 15D ZOI 15D - 17D ZOI Fines Fraction Ffines = 0.2 Ffines = -0.01364 x C + 0.2546 Ffines = -0.025 x C + 0.425 (Ffines)

Small Pieces Fraction Fsmalls = 0.8 Fsmalls = -0.0682 x C + 1.0724 Fsmalls = -0.025 x C + 0.425 (Fsmalls)

Large Pieces Fraction Flarge = 0 Flarge = 0.0393 x C - 0.157 Flarge = -0.215 x C + 3.655 (Flarge)

Intact Pieces Fraction Fintact = 0 Fintact = 0.0425 x C - 0.170 Fintact = 0.265 x C - 3.505 (Fintact) 8 Calvert Cliffs Chemical Effects Testing & Option 2b Refined Closure Plan

ZOI & Debris Size Distribution - Mineral Wool

  • Mineral Wool at CCNPP is Transco Stainless Steel Cassette Design
  • 0.024 SS Sheath with Slotted End Panels

- Installed in Plant Tested at CEESI, Tests 22-1 to 22-3

  • Tested cassettes contained metal foil and produced none or very little transportable debris.
  • The contained material contributes no strength to the cassettes.
  • Therefore, the destruction pressure for the Transco mineral wool cassettes and RMI cassettes are considered equal.
  • To account for the difference in filler material, the ZOI for the mineral wool cassettes will be conservatively increased by a factor of 2 from 2.0D to 4.0D.
  • The debris size for the mineral wool will be conservatively assumed to be 100% fine fibers.

9 Calvert Cliffs Chemical Effects Testing & Option 2b Refined Closure Plan

ZOI & Debris Size Distribution - Generic Fiberglass

  • Anti-Sweat Insulation on Unit 1 CCW piping
  • Molded of heavy density resin bonded inorganic glass fibers
  • Jacketed with 0.010 riveted stainless steel
  • Bulk density generally greater than Nukon and Thermal Wrap.

- 3.5 to 5.5 lbm/ft3 verses 2.4 lbm/ft3

  • The mass percentage of generic fiberglass relative to total fibrous debris load is <20% for the bounding break at Calvert Cliffs.
  • Calvert Cliffs assumes that the ZOI and debris size distribution for generic fiberglass is that used for Nukon and Thermal Wrap based on the insulation density.

10 Calvert Cliffs Chemical Effects Testing & Option 2b Refined Closure Plan

ZOI & Debris Size Distribution - Lead Wool Shielding Blankets

  • Two Zones of Influence, 3 Debris Size Distribution
  • ZOI based on CESSI Air Jet Impact Tests
  • Typical Installed Configuration Size Distribution Debris Type Size 2.1D ZOI 2.1D - 5.4D ZOI Lead Blanket Cover Fines 20% 0%

Layers Closest to Pipe Break Small Pieces 80% 0%

(Open Back Configuration) Large/Intact Pieces 0% 100%

Remaining Lead Blanket Fines 0% 0%

Cover Layers Small Pieces 0% 0%

(Open Back Configuration) Large/Intact Pieces 100% 100%

Wrapped Lead Blanket Cover Fines 0% 0%

Layers Small Pieces 0% 0%

(Strong Back Configuration) Large/Intact Pieces 100% 100%

11 Calvert Cliffs Chemical Effects Testing & Option 2b Refined Closure Plan

Questions/Concerns

  • Jointly Review Issues, Questions, and Concerns for Future Communication 12 Calvert Cliffs Chemical Effects Testing & Option 2b Refined Closure Plan

Next Steps

  • Finalize Update of Deterministic Calculations
  • Present Formal Risk-Informed GSI-191 Analysis and Results
  • Desire Next Meeting - 4Q 2016 13 Calvert Cliffs Chemical Effects Testing & Option 2b Refined Closure Plan
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