ML14184B509
| ML14184B509 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 07/02/2014 |
| From: | Exelon Generation Co |
| To: | Nadiyah Morgan Plant Licensing Branch 1 |
| Morgan N | |
| References | |
| Download: ML14184B509 (68) | |
Text
Calvert Cliffs GSI-191 Program Chemical Effects Testing Refined Closure Approach Ninth Discussion With NRC Staff July 2, 2014
Agenda
- Introductions
- Objectives for Meeting
- Summary of CCNPP Program
- Discussion of Autoclave Chemical Effects Test Results
- Discussion of Option 2a Refined Closure Plan
- Staff Questions & Concerns
- Schedule for Future Periodic Meetings 1 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
CCNPP Attendees
- Benjamin Scott - General Supervisor Design
- Tom Konerth - Supervisor Mechanical & Civil Design
- Ken Greene - Licensing Engineer
- Jim Landale - PRA Lead RI GSI-191
- John Swailes - Project Manager GSI-191
- Craig Sellers - Project Manager RI GSI-191
- Steve Kinsey - Chemical Effects Testing
- Josh Wargo - Chemical Effects Testing
- Eric Federline - Project Support & Testing By Phone
- Andy Henni - Lead Design Engineer RI GSI-191
- Bob Peterson - Project Consultant
- Helmut Kopke - Strainer Bypass and Fuel Blockage 2 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Objectives of this Meeting
- Introduce CCNPP Risk Informed GSI-191 Resolution Project
- Discuss Previously Submitted Documents
- CCNPP-CHLE-008 Considerations for Using Zinc in Chemical Effects Testing
- CCNPP-CHLE-009 Considerations for Using Marinite in Chemical Effects Testing
- CCNPP-CHLE-010 Concrete Autoclave Test Plan
- CCNPP-CHLE-011 Long Term Autoclave Test Plan
- Discuss Autoclave Test Results
- CCNPP-CHLE-005 High Temperature Tests
- CCNPP-CHLE-007 Alkyd Coatings Tests
- CCNPP-CHLE-011 Long Term Autoclave Tests
- Status of Integrated Chemical Effects Test Facility
- Present Option 2a Refined GSI-191 Closure Approach
- Status of Risk-Informed Approach
- Capture Staff Issues and Concerns
- Establish Schedule for Future Meetings 3 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Introduction to CCNPP RI GSI-191 Project SECY-12-0093 Option 2
- Parallel Deterministic and Risk-Informed Resolution Paths
- Replaced Select Fibrous Insulation to Support Deterministic Closure
- Option 2a Refined Closure Approach - Close by April 2015
- Refined Testing and Analysis to Support Deterministic Resolution - Close by December 2015
- Risk-Informed Testing and Analysis Partnered with STP - Close by December 2019 4 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Introduction to CCNPP RI GSI-191 Project (Continued)
- Plant Modifications Completed to Date
- Aluminum Minimization
- Partial Insulation Replacement with SS RMI
- Scissor Lift Removal
- Scaffolding Materiel Removal
- NPSH Assurance
- New Large 6,000 sq. ft. CCI Pocket Strainer with Structural Reinforcement
- Multiple Large-Scale Strainer Head Loss Tests
- 2009 Chemical Effects Testing Demonstrated Minimal Chemical Effects Head Loss
- Extensive 2013/2014 Autoclave Testing Yielding No Detectible Precipitates
- Refueling Cavity Drain Enlargement
- Debris and Chemical Effects Reduction
- Removal of Specific Mineral Wool in ZOI
- Removal of Specific Generic Fiberglass in ZOI
- Removal of Some Calcium Silicate and Double-Banding of that Remaining in ZOI
- Replaced TSP Buffer with NaTB
- Containment Aluminum Minimization 5 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Introduction to CCNPP RI GSI-191 Project (Continued)
- Downstream Effects
- Ex-Vessel
- Complete in Accordance With WCAP-16406-P-A
- Replaced HPSI Pump Cyclone Separators
- In-Vessel
- 2007 Strainer Bypass Testing
- LOCADM Evaluation
- PWROG Comprehensive Test and Analysis Program
- Current Activities
- Testing
- Integrated Chemical Effects Testing
- Extensive Interaction with NRC Staff
- Establish Agreement on Methods/Protocols and Acceptance of Results
- Strainer Penetration (Bypass) Testing
- Small-Scale Sensitivity Testing
- Strainer Head Loss Testing, as Required
- Re-Evaluation of Downstream Effects 6 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Introduction to CCNPP RI GSI-191 Project (Continued)
- Industry Activities
- Partnered in STP RI GSI-191 Resolution Project
- CCNPP Best-Estimate Calculations
- Containment Water Mass
- Pool Temperature Profiles for VS, S, M, L, and VL LOCAs
- Debris Generation, including CRUD Debris
- Debris Transport
- Pool Boron Concentration
- Pool Lithium Concentration
- Pool Strong Acid Production
- Pool pH
- Copper and Galvanized Steel Surface Areas
- Submerged Concrete Surface Area
- Calculations Support Deterministic and Risk-Informed Resolution Approaches
- CCNPP Risk-Informed Analyses
- Hybrid LOCA Frequency
- Initial Risk-Assessment Quantification
- Potential Closed Form Solution PRA
- Participant in PWROG Comprehensive Analysis and Test Program
- Member of PWROG GSI-191 Challenge Board
- Participating with PWROG GSI-191 TIGER Team 7 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Introduction to CCNPP RI GSI-191 Project (Continued)
Overview of On-Going Chemical Effects Test Program
- Objective
- Demonstrate Minimal Chemical Effects
- Identify Chemical Effects P on Detector
- Determine Time and/or Temperature at Which Chemical Effects Are Detected or Not
- Used as Basis for Deterministic and/or Risk-Informed Resolution of GSI-191
- Approach
- Long-Term Integrated Chemical Effects Tests
- Demonstrate Repeatable and Sensitive Detector
- Extensive Autoclave Testing to Refine Design of Experimental Protocols
- Begin with Design Basis Chemical Effects Tests
- DEGB LBLOCA Conditions w/Post 2014 RFO Insulation Configuration
- Post 2018 RFO Insulation Configuration, as required
- Potential Negligible Chemical Effects Outcome
- Permits Deterministic Resolution of GSI-191
- Risk-Informed Testing, As Necessary
- Medium & Small Break Chemical Effects Testing, as Necessary
- Aligned with STP RI Approach 8 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Introduction to CCNPP RI GSI-191 Project (Continued)
Autoclave Test Program - More Than 50 Autoclave Tests
- CCNPP-CHLE-005 High Temperature Experiment [Complete, Results Herein]
- Address Initial High Temperature (>195°F) Portion of LOCA (<10 hours)
- CCNPP-CHLE-006 Metals Experiments [Complete, Results Previously Discussed]
- Single and Synergistic Corrosion Effects of Differing Metal Combinations
- Observed Reduced Release of Aluminum, Magnesium, & Silicon with Zinc Present
- CCNPP-CHLE-007 Alkyds Coating Experiments [Complete, Early Results Herein]
- Investigate Chemical Effects Impact of Alkyd Coatings
- CCNPP-CHLE-010 Concrete Experiments [Complete, Results Previously Discussed]
- No Synergistic Corrosion Effects Between Concrete and Insulation Observed
- CCNPP-CHLE-011 Long-Term Autoclave Experiments [Complete, Results Herein]
- Determination of Duration for Long-Term Integrated Experiments Day Autoclave Simulation of Full Integrated Test 9 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Introduction to CCNPP RI GSI-191 Project (Continued)
- Option 2a Refined Closure Plan
- Minimal Chemical Effects Based on Current and Past Chemical Effects Testing
- Establish Design Basis Head Loss to Account for Minimal Chemical Effects and Uncertainties
- Qualify Strainer with Current Tests & Analyses
- Strainer Head Loss
- NPSH Margin
- Deaeration
- Strainer Structural Qualification
- Strainer Bypass
- 2007 Bypass Tests
- Approach Similar to Accepted Salem Analysis
- Long-Term Core Cooling
- WCAP-16793 Testing & Analysis
- Consideration of SE Limitations and Conditions
- LOCADM 10 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Documents Previously Submitted
- CCNPP-CHLE-008 Considerations for Using Zinc in Chemical Effects Testing
- CCNPP-CHLE-009 Considerations for Using Marinite in Chemical Effects Testing
- CCNPP-CHLE-010 Concrete Autoclave Test Plan
- CCNPP-CHLE-011 Long Term Autoclave Test Plan 11 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Use of Zinc in Chemical Effects Tests - CCNPP-CHLE-008
- Zinc Used as Surrogate for Zinc-Rich Coatings Debris
- Autoclave Testing Showed Reduced Aluminum Release with Zinc Present
- Large Quantity of Zinc not Conservative for Chemical Effects Testing
- Unqualified Inorganic Zinc (IOZ), Degraded Qualified IOZ and Qualified IOZ Coatings in ZOI
- Modeled as IOZ Coated Coupons with 2x Surface Area
- 50% Surface Area Modeled on Substrate
- 50% Modeled as Submerged in Pool
- Unqualified Organic Zinc Coatings
- Modeled as Coupon Coated with Same Coating & Scaled Surface Area, or
- Modeled as Zinc metal coupon with a Surface Area = 10 µm Spheres
- CCNPP Plans to use Zinc-Coated Coupons 12 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Use of Marinite in Chemical Effects Tests - CCNPP-CHLE-009
- Marinite Used as Cable Tray Fire Barrier
- Fine Debris Modeled as 10 µm Spheres for Head Loss Testing
- Results in Large Surface Area
- Fines Debris Modeled as Solid Marinite in Chemical Effects Tests
- Surface Area Based on 44 µm Spheres
- Mass Quantity of 44 µm Spheres based on As-Fabricated Density of 46 lb/ft3
- Number of 44 µm Spheres based on Pulverized Density of 24.5 lb/ft3
- Small and Large Pieces of Marinite Modeled as is 13 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Concrete Autoclave Test Plan - CCNPP-CHLE-010
- Objective to Investigate Dissolution of CCNPP-specific Concrete in the Presence of Fibrous Debris
- Investigate Whether Concrete Contributes to or Inhibits Dissolution and Corrosion of Fibrous Debris.
- The Following Autoclave Tests Were Planned and Executed
- Insulation and Concrete
- Insulation Only
- Concrete Only
- 48 Hour Tests at LOCA Profile
- Buffered Borated Water
- Chemical Sampling
- Vacuum Filtration 14 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Long-Term Autoclave Tests - CCNPP-CHLE-011
- Objective to Investigate Long-Term Release Rates over 10-days to Determine Whether Test Duration less than 30 Days is Sufficient
- Fully Integrated Tests 280
- Insulation 270
- Marinite 260 250
- Concrete 240
- Metals 230
- Lead Wool 220
- Buffered Borated Water Temp (F) 210 200
- LOCA Profile for 10 Days 190 180
- Same as CCNPP-CHLE-007 170 But Longer & Without Alkyds 160 150 140
- Chemical Sampling 130 0 24 48 72 96 120 144 168 192 216 240 Time (hr)
- Vacuum Filtration CHLE-011 Test Temperature AOR Sump Temperature 15 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Autoclave Testing Results
- CCNPP-CHLE-005 High-Temperature Test Results
- CCNPP-CHLE-007 Alkyds Test Preliminary Results Synergistic Interactions Filtration Results
- CCNPP-CHLE-011 Long-Term Test Preliminary Results 16 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
High Temperature Portion of LOCA - CCNPP-CHLE-005
- Testing with a Maximum Temperature of 195°F was given a 14 Hour Head Start start on the LOCA to Allow Extra Dissolution/Corrosion Such That the Constant 195°F Test Reaches LOCA Conditions at 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br />
- Chart Nomenclature
- Red Line, Round Mark: Concentration at Time for Temperature Profile > 195°F
- Black Line, Square Mark: Concentration at Time for Temperature Maintained at 195°F
- Green Line, Diamond Mark: Concentration at Time from 10-Day Integrated Tests
- Time = 0: Beginning of 24 Hour Constant 195°F
- 14 Hour Advanced Start on High Temperature Profiles
- Final Concentration of Red and Green Lines is at 195°F 17 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
High Temperature Portion of LOCA (Continued)
Aluminum
- Delta Between 195°F Tests and CCNPP-101/CCNPP-102 = 0.75 ppm
- Delta Between 195°F Tests and CCNPP-501 - 504 = 1.01 ppm 1600 Aluminum 1200 Concentration (ppb)
CCNPP-101/102 - Profile 800 CCNPP-104/105 - 195F CCNPP-501 to 504 - Profile 400 0
-3 0 3 6 9 12 15 18 21 24 27 30 Time (hr) 18 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
High Temperature Portion of LOCA (Continued)
Calcium
- Ca 195°F Exceeds Ca From Profile 5000 Calcium 4000 Concentration (ppb) 3000 2000 1000 CCNPP-101/102 - Profile CCNPP-104/105 - 195F CCNPP-501 to 504 - Profile 0
-3 0 3 6 9 12 15 18 21 24 27 30 Time (hr) 19 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
High Temperature Portion of LOCA (Continued)
Copper 600
- Peak Cu Short by ~0.1 ppm Copper
- Cu in Heat Exchange Units 400 Concentration (ppb)
- Unlikely Galvanic Couple
- CCNPP-CHLE-006 Metals Tests
- Observed Reduced Al Release With Other 200 Metals Present CCNPP-101/102 - Profile CCNPP-104/105 - 195F CCNPP-501 to 504 - Profile 0
-3 0 3 6 9 12 15 18 21 24 27 30 Time (hr) 20 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
High Temperature Portion of LOCA (Continued)
Lead
- Delta Between 195°F Tests and CCNPP-101/CCNPP-102 = 0.65 ppm
- Lead in 195°F Tests and CCNPP-501 - 504 Identical
- Lead Concentration Low
- Lead Repeatability Poor 1600 Lead 1200 Concentration (ppb) 800 400 CCNPP-101/102 - Profile CCNPP-104/105 - 195F CCNPP-501 to 504 - Profile 0
-3 0 3 6 9 12 15 18 21 24 27 30 Time (hr) 21 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
High Temperature Portion of LOCA (Continued)
- Poor Lead Repeatability
- Lead Wool Based on As-Fabricated Macro Surface Area
- Variable Mass in Same Size Samples 1800 Lead 1200 1600 Lead 1400 1000 Concentration (ppb) 1200 Concentration (ppb) 800 1000 501 26.9 g 800 600 502 23.8 g 600 503 23.6 g 400 504 18.4 g 400 Ave 200 200 0
-3 0 3 6 9 12 15 18 21 24 0 Time (hr) 0 24 48 72 96 120 144 168 192 216 240 Time (hr) 101 102 103 104 105 22 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
High Temperature Portion of LOCA (Continued)
Magnesium
- Delta Between 195°F Tests and CCNPP-101/CCNPP-102 = 0.27 ppm
- Delta Between 195°F Tests and CCNPP-501 - 504 = 0.27 ppm 1000 Magnesium 800 Concentration (ppb) 600 400 200 CCNPP-101/102 - Profile CCNPP-104/105 - 195F CCNPP-501 to 504 - Profile 0
-3 0 3 6 9 12 15 18 21 24 27 30 Time (hr) 23 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
High Temperature Portion of LOCA (Continued)
Silicon
- Si 195°F Comparable to Si From Profile 25000 Silicon 20000 Concentration (ppb) 15000 10000 CCNPP-101 - Profile 5000 CCNPP-103 to 105 - 195F CCNPP-501 to 504 - Profile 0
-3 0 3 6 9 12 15 18 21 24 27 30 Time (hr) 24 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
High Temperature Portion of LOCA (Continued)
Zinc
- Zn 195°F Comparable to Zn From Profile 10000 Zinc 8000 Concentration (ppb) 6000 4000 2000 CCNPP-101/102 - Profile CCNPP-104/105 - 195F CCNPP-501 to 504 - Profile 0
-3 0 3 6 9 12 15 18 21 24 27 30 Time (hr) 25 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
High Temperature Portion of LOCA (Continued)
If Lower Temperature Tests are Performed, CCNPP Proposes to Add Metal Salts to Account for Increased Release at High Temp
- CCNPP-REP-CHLE-005 Provides Bases for
- Addition of Aluminum and Magnesium
- No Addition of Calcium, Copper, Lead, Silicon, and Zinc
- Candidate Salts:
- Aluminum Nitrate Nonahydrate
- Magnesium Nitrate Hexahydrate
- Each has High Solubility in Water
- Avoids New Chemistry
- Nitrates Consistent with Nitric Acid Addition
- Required Quantities Added to 750 Gallon Fluid Volume (192,000 Tablespoons)
- Aluminum
- Required Boost = 1.0 ppm 36.3 grams Aluminum Nitrate (<1.5 Tablespoons)
- Magnesium
- Required Boost = 0.3 ppm 11.7 grams Magnesium Nitrate (~0.4 Tablespoons) 26 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Autoclave Testing of Alkyd Coatings - CCNPP-CHLE-007
- CCNPP Performed Two Integrated Autoclave Tests with Alkyd Coatings
- Seven Day Tests
- Insulation & Marinite Debris
- Concrete
- Aluminum, Galvanized Steel, Copper, Lead Wool, Zinc (IOZ)
- Two Alkyd Coatings
- Glidden Professional Alkyd
- Sherwin Williams Industrial Enamel HS
- Typical of CCNPP Alkyd Coatings
- Periodic Chemistry Sampling & Analysis
- Vacuum Filtration
- Objective - Determine if Alkyd Coatings Contribute to Chemical Effects 27 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Autoclave Testing of Alkyd Coatings (Continued)
- Test Deviation
- Power Interruption ~8 hours Before End of 168 Hour Test
- Reset Temperature Control System
- Restarted High Temperature Profile
- Chemistry Results Show Effects of Temperature Increase
- Test Completed as Normal
- Results
- Good Repeatability
- Decreased Release of Organic Carbon at Reduced Temperature
- No Chemical Effects Impact Observed 28 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Autoclave Testing of Alkyd Coatings (Continued)
Repeatability 16000 1600 14000 Calcium 1400 Aluminum 12000 Concentration (ppb) 1200 Concentration (ppb) 10000 1000 8000 401 800 401 6000 402 600 402 4000 400 2000 200 0
0 -1 0 1 2 3 4 5 6 7
-1 0 1 2 3 4 5 6 7 Time (days)
Time (days) 700 600 600 Lead Copper 500 Concentration (ppb) 500 Concentration (ppb) 400 400 300 401 300 401 402 402 200 200 100 100 0
0 -1 0 1 2 3 4 5 6 7
-1 0 1 2 3 4 5 6 7 Time (days)
Time (days) 29 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Autoclave Testing of Alkyd Coatings (Continued) 3000 35000 Magnesium 30000 2500 Silicon Concentration (ppb) Concentration (ppb) 25000 2000 20000 1500 401 15000 401 1000 402 402 10000 500 5000 0 0
-1 0 1 2 3 4 5 6 7 -1 0 1 2 3 4 5 6 7 Time (days) Time (days) 25 8000 TOC 7000 Zinc 20 6000 Concentration (ppm) Concentration (ppb) 15 5000 4000 401 401 10 402 3000 402 5 2000 1000 0
0
-1 0 1 2 3 4 5 6 7
-1 0 1 2 3 4 5 6 7 Time (days)
Time (days) 30 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Autoclave Testing of Alkyd Coatings (Continued)
- Titanium Investigated
- TiO2 Common Alkyd Pigment
- TiO2 Very Stable
- Concentration Well Below Cleanliness Criterion 500 450 400 Titanium 350 Concentration (ppb) 300 250 401 200 402 150 100 50 0
-1 0 1 2 3 4 5 6 7 Time (days) 31 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Autoclave Testing of Alkyd Coatings (Continued)
Comparison to Long-Term Integrated Tests 20000 2000 Calcium Aluminum 16000 Concentration (ppb) 1600 Concentration (ppb) 12000 1200 8000 800 400 4000 0 0 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10 Time (days) Time (days) 501 502 503 504 401 402 501 502 503 504 401 402 1200 600 Copper Lead 1000 500 Concentration (ppb)
Concentration (ppb) 800 400 600 300 400 200 200 100 0
0 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10 Time (days)
Time (days) 501 502 503 504 401 402 501 502 503 504 401 402 32 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Autoclave Testing of Alkyd Coatings (Continued) 4500 35000 4000 Magnesium Silicon 30000 3500 Concentration (ppb) 25000 Concentration (ppb) 3000 2500 20000 2000 15000 1500 10000 1000 500 5000 0
0 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10 Time (days)
Time (days) 501 502 503 504 401 402 501 502 503 504 401 402 9000 8000 Zinc 7000 Concentration (ppb) 6000 5000 4000 3000 2000 1000 0
0 1 2 3 4 5 6 7 8 9 10 Time (days) 501 502 503 504 401 402 33 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
CCNPP-CHLE-011 Long-Term Integrated Simulation
- Four Autoclave Tests
- Simulated Integrated Tests
- All Materials Included Sample Filtration Times from 10-Day
- Insulation, Metals, Concrete, etc. Integrated Test Simulations
- Filtration Times
- PWROG Filtration Time for NaTB Buffered Borated Water Ranged 60 Between ~10 to ~20 Seconds 50
- No Increase in Filtration Time Filtration Time (s)
Above NaTB Buffered Borated 40 Water 30 501 20 502 10 503 504 0
Sample Description 34 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Status of Integrated Chemical Effects Test Facility
- Facility Fabrication Complete
- Shakedown Testing Nearing Completion Initial Prep Tank Primary Reaction Chamber Vertical Head Loss Loop Heat Exchanger Loop 35 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Integrated CHLE Test Plans - Reaction Chamber CFD
- Pump Recirculation to Assure Flow Across
- CFD Simulation Coupons and Tank Mixing 36 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Option 2a Refined Closure Plan
- Minimal Chemical Effects Based on Chemical Effects Testing to Date
- Establish Head Loss Margin to Account for Uncertainties
- Qualify Strainer with Current Tests & Analyses
- Strainer Head Loss
- NPSH Margin
- Deaeration
- Strainer Structural Qualification
- Strainer Bypass
- 2007 Bypass Tests
- Similar to Accepted Salem Analysis
- Long-Term Core Cooling
- WCAP-16793 Testing & Analysis
- Consideration of SE Limitations and Conditions
- LOCADM 37 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Option 2a Refined Closure Plan (Continued)
Minimal Chemical Effects
- 2009 Elevated Temperature Vertical Head Loss Loop Testing
- More than 25 Tests
- Test Durations 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> to 120 hour0.00139 days <br />0.0333 hours <br />1.984127e-4 weeks <br />4.566e-5 months <br />
- Range of Aluminum & Silicon Ion Concentrations
- Step-wise Temperature Reduction
- Chemical Effects PIRT Issues
- Addressed for ALDEN Integrated CHLE Testing
- Readdressed for 2013/2014 Autoclave Testing (Slides 44-48)
- 2013/2014 Autoclave Chemical Effects Testing
- >50 Total Autoclave Tests
- 8 Tests with Full Complement of Materials, LOCA Profile, 2 to 10 Day Duration
- Chemistry Analysis
- Low Concentrations of Dissolved Metal Ions, except Calcium
- Coupon Mass Loss
- Small and/or Not Detectible
- Vacuum Filtration Time
- Filtration Times Consistent with Clean NaTB Buffered Borated Water
- No Precipitates Observed
- No Increased Head Loss Detected
- No Increased Filtration Times 38 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Option 2a Refined Closure Plan (Continued)
Minimal Chemical Effects (Continued)
- 2009 Vertical Head Loss Loop Chemical Effects Testing
- Objective to Identify Temperature for Incipient Chemical Effects Head Loss
- >25 Vertical Head Loss Loop Tests
- Use of WCAP-16530 Corrosion Product Ions in the form of Salts
- Range of Al & Si Concentrations
- Temps from 135°F to 55°F
- Buffered Borated Water
- Both TSP and NaTB Tested
- Tests Ranged from 12 to 120 Hours
- No Chemical Effects Head Loss Detected or Precipitates Observed 39 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Option 2a Refined Closure Plan (Continued)
Minimal Chemical Effects (Continued)
- 2009 Vertical Head Loss Loop Chemical Effects Testing
- Detector Debris Bed
- Sensitive 40 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Option 2a Refined Closure Plan (Continued)
Minimal Chemical Effects (Continued)
- 2013/2014 Autoclave Test Program
- Initial Objective to Refine Plans for Integrated Chemical Effects Head Loss Test
- >50 High Temperature Autoclave Tests
- Chemistry Analysis
- Low Concentration of Key Metals
- Concentrations Far less than WCAP-16530 Predictions
- Autoclave Tests Best Available Tests to Identify Chemical Effects
- Coupon Mass Loss
- Small Mass Losses
- Some Not Detectible
- Vacuum Filtration
- Filter Times Equivalent to Clean NaTB Buffered Borated Water
- Filtered Mass Small or Not Detectible
- Filtered Species Expected - Aluminum, Copper, Zinc
- No Precipitates Observed and no Filtration Times Indicative of Chemical Effects 41 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Option 2a Refined Closure Plan (Continued)
Minimal Chemical Effects (Continued)
- CCNPP Filtration Times from 8 Integrated Simulations
- PWROG Filtration Criteria
- >100 Second - Indication of Potential for Some Chemical Effects
- Filtration Testing of Borated Demineralized Water Buffered with NaTB
- Low Filtration Time = 8.4 Seconds
- High Filtration Time = 17.3 Seconds Filtration Times 100 90 80 70 PWROG Indication of Some Filtration Time (s) 60 Chemical Effects PWROG Borated/NaTB High 50 Filtration Times 40 CCNPP Average Time from 8 30 Integrated Simulations PWROG Borated/NaTB Low 20 Filtration Times 10 0
8 32 56 80 104 128 152 176 200 224 Sample Time (hr) 42 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
PWROG Filtration Data - 24 Hour Autoclave Tests
- Same Data Provided to NRC by PWROG on April 16, 2014
- Slide 15 Of The Chemical Effects Autoclave Testing Presentation
- The Difference Is That The Plot Has Filtration Time Plotted On A Log Scale
- Calvert Cliffs is Test Number 03-01 43 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Option 2a Refined Closure Plan (Continued) - PIRT Summary
- PIRT Items previously discussed under context of Integrated Chemical Effects Test Plan (CHLE-002)
- Identify and Resolve PIRT Items to be readdressed under Autoclave Only Chemical Effects Closure Plan
- PIRT Items to be addressed:
PIRT 1.1 - RCS Coolant Chemistry Conditions and Break PIRT 1.4 - Containment Spray CO2 Scavenging and CO2/O2 Air Exchange PIRT 2.1/2.2/2.4 - Radiological Concerns PIRT 3.3 - Debris Bed Mix Particulate/Fiber Ratio PIRT 3.5 - Containment Spray Transport PIRT 4.1/5.1 - Polymerization/Inorganic Agglomeration PIRT 4.2/7.2 - Heat Exchanger: Solid Species Formation, Deposition, and Clogging PIRT 4.4 - Particulate Nucleation Sites 44 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Option 2a Refined Closure Plan - PIRT Summary (Continued)
PIRT 1.1 - RCS Coolant Chemistry Conditions at Break
- Primary Concern - The chemical makeup and temperature variation of the containment pool can influence corrosion rates and solubility limits.
- CHLE-002 Resolution - Prototypic Boron, Lithium and NaTB concentrations to be used in the test fluid. High temperature portion (>195F) of LOCA to be addressed with autoclave testing.
- Autoclave Test Resolution - Prototypic chemistry and LOCA temperature profile used throughout the test duration. Temperature profile matches design basis AOR. Obviates Need to Boost Certain Ionic Concentrations PIRT 1.4 - Containment Spray CO2 Scavenging
- Primary Concern - Containment Spray increases CO2 absorption promoting formation of carbonate solid species and enhance nucleation/precipitation
- CHLE-002 Resolution - Explicit inclusion of CS Spray loop and left reaction tank open to atmosphere
- Autoclave Test Resolution - Air addressed through direct air burst injection for fluid agitation 45 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Option 2a Refined Closure Plan - PIRT Summary (Continued)
PIRT 2.1/2.2/2.4 - Radiological Concerns
- Primary Concern - Radiolysis reactions form HCl and HNO3, impacting pool pH and promoting increased corrosion
- CHLE-002 Resolution - Explicit inclusion of strong acids produced from radiolysis into the reaction tank
- Autoclave Test Resolution - Updated analyses show strong acids decrease pH by a maximum of 0.03 pH units. Impact is negligible.
PIRT 3.5 - Containment Spray Transport
- Primary Concern - Containment spray washes down corrosion products and contributes to chemical effects in pool.
- CHLE-002 Resolution - Explicit inclusion of containment spray and exposed coupons.
- Autoclave Test Resolution - Sprayed coupons conservatively included as submerged in agitated autoclave.
46 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Option 2a Refined Closure Plan - PIRT Summary (Continued)
PIRT 3.3 - Debris Mix Particulate/Fiber Ratio
- Primary Concern - Differences in debris bed composition could impact how the bed forms and captures chemical precipitates.
- CHLE-002 Resolution - Debris bed was specially formed to be sensitive detector and not scaled to a strainer chemical effects head loss.
- Autoclave Test Resolution - Filtration medium has 1µm pore size and higher capture efficiency.
Precipitation at material nucleation sites investigated visually.
- 2009 Vertical Loop Tests used fiber/particulate debris beds with high aluminum and silicon concentrations - No increased head loss detected.
PIRT 4.1/5.1 - Polymerization/Inorganic Agglomeration
- Primary Concern - Larger clumps may form from smaller particulate or precipitates resulting in tangible effects on ECCS performance.
- CHLE-002 Resolution - Polymerization and agglomeration allowed to occur in prototypical conditions. Any larger particles that dislodge from nucleation sites or form in solution would register as chemical head loss on the detector debris bed.
- Autoclave Test Resolution - Polymerization and agglomeration allowed to occur in prototypical conditions. Larger particles would register as longer filtration times. Material nucleation sites are inspected in post-test condition for presence of precipitate.
47 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Option 2a Refined Closure Plan - PIRT Summary (Continued)
PIRT 4.2/7.2 - Heat Exchanger: Solid Species Formation, Deposition and Clogging
- Primary Concern - Temperature drop across Heat Exchanger inlet and outlet causes precipitation at lower temperatures impacting ECCS performance and heat transfer across fuel bundles.
- CHLE-002 Resolution - Explicit inclusion of Heat Exchanger loop in and turbidity measurement at inlet and outlet.
- Autoclave Test Resolution - Filtration samples taken from autoclave and held at temperatures down to 70F to promote lower temperature precipitation.
PIRT 4.4 - Particulate Nucleation Sites
- Primary Concern - Particles within containment create nucleation sites for chemical precipitate.
- CHLE-002 Resolution - Chemical precipitation modeled under prototypical conditions.
Nucleation is allowed to occur naturally and would register as head loss upon transport to or formation within the debris bed.
- Autoclave Test Resolution - All post-test materials investigated for chemical precipitation at nucleation sites visually. Any uncertainties associated with particulate nucleation sites addressed with deterministic margin applied to conventional debris head loss.
- 2009 Vertical Loop Tests used fiber/particulate debris beds with high aluminum and silicon concentrations - No increased head loss detected.
48 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Option 2a Refined Closure Plan (Continued)
Minimal Chemical Effects (Final)
- Autoclave Testing Filtration Times and Related Testing Sufficient to Justify Minimal Chemical Effects Design Basis Head Loss Accounting for Minimal Chemical Effects and Uncertainties
- 10 Strainer Head Loss Tests Performed 2008 - 2010
- Various Debris Loads
- Various Flow Rates
- Bounding Conventional Debris Head Loss - 0.25 ft-water (3 inches) including clean strainer
- Design Basis Head Loss Accounting for Minimal Chemical Effects and Uncertainties
- 0.75 ft-water (9 inches)
- Added to Bounding Conventional Debris Head Loss
- Total Strainer Head Loss - 1.0 ft-water Including Minimal Chemical Effects and Uncertainties 49 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Option 2a Refined Closure Plan (Continued)
Strainer NPSH Margin
- NSPH Analyses Indicate Considerable Strainer Head Loss Margin Throughout LOCA
- Design Basis Head Loss is 1.0 ft Including Minimal Chemical Effects and Uncertainty
- No Credit Taken for Containment Accident Pressure 50 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Option 2a Refined Closure Plan (Continued)
Strainer Deaeration
- Incipient Deaeration May Occur When The Pressure At The Downstream Face Of The Strainer Is Less Than The Pressure at the Pool Surface
- This Occurs If The DP Across The Strainer Face Is Greater Than Strainer Submergence
- Concern That Gas Accumulation Could Eventually Cause Draining Behind The Strainer
- Minimum Pool Elevation = 15.35 ft
- Max Strainer Height Level = 13.06 ft
- Submergence = Min Pool Elevation - Max Strainer Elevation = 2.29 ft
- Design Basis Head Loss with Uncertainty = 1.0 ft < 2.29 ft
- Therefore no deaeration 51 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Option 2a Refined Closure Plan (Continued)
Strainer Structural Qualification
- Structural Qualification to 1.0 Atmosphere Differential Pressure
- Structural Modifications Implemented 52 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Option 2a Refined Closure Plan (Continued)
Plant Specific Fiber Bypass Testing
- Two bypass tests performed by CCI in May 2007
- Utilized CCIs Multi-Functional Test Loop (MFTL)
- Prototypical strainer test module
- 1/16 inch perforation size
- 200 mm pocket depth
- 36 total pockets (4 wide by 9 tall)
- Prototypical fiber debris load (equivalent)
As-Tested Plant Current Plant Fiber Type Configuration Configuration Nukon 496 ft3 343 ft3 Transco Thermal Wrap 837 ft3 307 ft3 Generic Fiberglass 345 ft3 67 ft3 Temp-Mat 38 ft3 5 ft3
- Scaled based on 6000 ft2 strainer (6060 ft2 installed)
- Strainer flow rate of 5000 gpm (equivalent) 53 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Option 2a Refined Closure Plan (Continued)
Fiber Bypass Testing Procedure
- Ambient temperature test loop
- Tap Water
- Fiber preparation via standard CCI practice
- Baked in oven at 300°C (572°F) for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />
- Hand-cut into ~2 inch by ~2 inch pieces
- Weighed
- 0.1 to 0.14 ft3 batches soaked in 2 liters (1/2 gallon) water
- Decomposed using 100 bar (~1500 psi) water jet for ~4 minutes
- Approach substantially consistent with January 2012 NEI fiber preparation procedure
- Fiber debris addition
- 10 batches added (10% per batch)
- Approximately 1/3 inch theoretical bed thickness per batch
- 3 minutes between each batch
- Fiber debris settling
- Guide plate installed upstream of strainer to create turbulence
- Ensures minimal debris settling
- Grab samples to determine fiber size determination
- 500 mL grab samples
- Samples taken every 2 minutes until time = 30 minutes, then every 30 minutes to 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> 54 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Option 2a Refined Closure Plan (Continued)
Fiber Bypass Testing Procedure (Continued)
- Test duration
- Approximately 19 hours2.199074e-4 days <br />0.00528 hours <br />3.141534e-5 weeks <br />7.2295e-6 months <br /> from 1st fiber addition to test termination
- Approximately 50 test loop turnovers
- Approximately 9-10 plant turnovers prior to hot leg switchover (11 hours1.273148e-4 days <br />0.00306 hours <br />1.818783e-5 weeks <br />4.1855e-6 months <br /> post-LOCA)
- Fiber bypass measurement
- Fibers which bypass strainer are captured on a 0.31 mm (310 mm) mesh screen
- Capture screen not removed / changed-out during testing
- Bypass mass = Final Dry Weight (with captured fiber) - Initial Dry Weight (clean)
- Bypassed fiber size distribution
- Based on grab samples
- Visual inspection / counting under microscope
- Similar to fiber bypass testing performed for other plants with CCI strainers 55 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Option 2a Refined Closure Plan (Continued)
CCI Multi-Functional Test Loop 56 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Option 2a Refined Closure Plan (Continued)
Unmodified Fiber Bypass Result
- Mass of bypassed fiber
- Test 4: 0.003 kg
- Test 5: 0.006 kg
- Design using maximum bypass case
- Bypass per strainer area = 0.65 lbm fiber / 1000 ft2 strainer
- Appropriate for high fiber plants since strainers become fiber saturated
- 3.9 lbm (1778 g) total fiber bypass for 6060 ft2 strainer
- 217 fuel assemblies (FAs)
- 8.2 g fiber / FA
- No Credit Taken for Flow Split Out Break or to Containment Spray
- Size distribution of bypassed fiber Size Class 1 2 3 4 Fiber Length range (mm) 0.1 - 0.5 0.5 - 1.0 1-2 >2 Test 4 87% 7% 4% 2%
Test 5 63% 27% 8% 2%
Average of Tests 4 & 5 75% 17% 6% 2%
57 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Option 2a Refined Closure Plan (Continued)
Previous NRC Concerns with CCI Fiber Bypass Testing
- CCI performed fiber bypass testing for numerous plants in the U.S.
- Testing protocols were similar at most plants
- NRC issued 18 questions to Salem about the CCI bypass testing (ML12338A366)
- Questions meriting a CCNPP specific response
- Addressed herein
- Generic questions regarding test protocol
- Responses provided by Salem applicable to CCNPP
- Questions specific to the Salem testing and results
- Not applicable
- Most plant specific information requested presented in bypass test description, e.g. fiber batch addition sizes and test termination criteria
- Two issues warrant further discussion
- How is it ensured that fiber does not bypass the 0.31 mm mesh fiber bypass capture screen?
- How could potential velocity gradients impact the bypass quantity?
58 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Option 2a Refined Closure Plan (Continued)
Previous NRC Concerns with CCI Fiber Bypass Testing (Continued)
- How is it ensured that fiber does not bypass the 0.31 mm mesh fiber bypass capture screen?
- Potential for fibers bypassing the capture screen accounted for through a multiplier
- Multiplier assumes all fibers < 0.5 mm bypass the capture screen
- Equation to determine mass fraction of fibers < 0.5 mm reduces to:
P1 L1 M1 P1 L1 P2 L 2 P3 L3 P4 L 4 where:
- Mx = % of fiber in size class by mass, Lx = average length of fiber in size class, and Px = % of fiber in size class by count
- M1 = 47% of fibers < 0.5 mm in CCNPP bypass tests
- Apply multiplier of 1.47 to unmodified bypass to obtain design bypass amount
- How could potential velocity gradients impact the bypass quantity?
- CCNPP strainer has 3 trains attached to a radial duct which connects to the sump
- Higher bypass is expected initially in the modules nearest the radial duct due to high velocities prior to full/uniform debris loading
- Transient, temporary phenomenon
- Not significant for high fiber plants which will have fiber saturated strainer
- Bypass testing gives an appropriate result for design 59 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Option 2a Refined Closure Plan (Continued)
Fiber Bypass Results Addressing Previous NRC Concerns
- Bypass per strainer area = 1.47
- 0.65 lbm fiber / 1000 ft2 strainer
- 5.8 lbm (2613 g) total fiber bypass for 6060 ft2 strainer
- 217 fuel assemblies
- 12 g fiber / FA
- No Credit Taken for Flow Split Out Break or to Containment Spray (CS Continuous) 60 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Option 2a Refined Closure Plan (Continued)
In-Vessel Effects Background
- Fuel Characteristics
- 217 fuel assemblies
- 14x14 fuel rod bundle
- AREVA fuel
- HTP/HMP spacer grids with FUELGUARD lower end fitting
- Post-LOCA Recirculation Flow Rate
- Only HPSI and CS systems operate post-RAS (Recirculation Actuation Signal)
- 1055 gpm HPSI flow (maximum flow to core including uncertainty)
- Post-RAS Maximum Flow per Fuel Assembly
- 4.9 gpm = 1055 gpm / 217 FA
- LOCADM Results
- Total deposition thickness < 12 mils
- Maximum cladding temperature < 326°F 61 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Option 2a Refined Closure Plan (Continued)
NRC Accepted Fuel Blockage Acceptance Criterion
- 15 grams fiber / FA per NRC Safety Evaluation (SE) of WCAP-16793-NP, Rev. 2
- Based on AREVA Test
- AREVA fuel with FUELGUARD lower end fitting
- 44.7 gpm/FA
- Fiber, particulate, and industry bounding chemical effects debris included
- Particulate to fiber (p:f) ratio = 1.0
- Pre- and Post-chemical DP measured
- Comparison to Calvert Cliffs
- AREVA tests used similar fuel assembly
- 44.7 gpm/FA >> 4.9 gpm/FA
- Large Chemical Effects >> CCNPP Minimal Chemical Effects
- Conclusion
- 15 grams fiber / FA Extremely Conservative for CCNPP 62 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Option 2a Refined Closure Plan (Continued)
Basis for Increased Fuel Blockage Acceptance Criterion
- Most FA tests performed at ~45 gpm/FA
- Representative of Westinghouse ECCS recirculation flow
- Very conservative for CE plants
- CCNPP Maximum Flow Rate = 4.9 gpm/FA
- Reynolds number < 400 through FA
- Assume linear relationship between debris bed DP and flow
- Similar to NUREG/CR-6224 debris bed HL correlation
- CCNPP Has Minimal Chemical Effects
- Base acceptance criterion on test DP values prior to chemical effects
- CCNPP uses AREVA fuel with FUELGUARD lower end fitting
- Numerous tests using very similar fuel performed by AREVA
- AREVA testing acknowledged as more conservative than Westinghouse testing in WCAP-16793-NP, Rev. 2
- Base revised fuel acceptance criterion on most limiting AREVA test with FUELGUARD lower end fitting 63 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Option 2a Refined Closure Plan (Continued)
Increased Fuel Blockage Acceptance Criterion
- AREVA tests of FAs with FUELGUARD performed at 3 flow rates: 3, 11, & ~45 gpm/FA
- Linearly scale pre-chemical effects HL based on 4.9 gpm/FA
- 75 g/FA test DP result at 3 gpm scaled to 4.9 gpm is similar to 15 g/FA at 44.7 gpm
- Details not provided due to fuel assembly test reports being proprietary
- Considerations
- p:f ratio = 1 not tested at flow rates most similar to CCNPP
- WCAP-16793-NP, Rev. 2, indicates that p:f = 45 is limiting for cold leg breaks (3 gpm/FA)
- p:f=53 (near 45) shows 150 g/FA almost acceptable
- Scaled tests at ~45 gpm/FA with p:f=1 less limiting than tests presented above
- Missing p:f 1 not necessarily significant
- Post-LOCA sump temperature 100°F
- Scaled HL conservatively ignores temperature effects
- Conclusion
- CCNPP can utilize fuel blockage acceptance criterion > 15 g/FA
- 75 g/FA acceptance criterion justified for CCNPP
- CCNPP will address requisite limitations associated with use of an increased fuel blockage acceptance criterion as defined in NRC SE for WCAP-16793-NP, Rev. 2.
64 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Status of Risk-Informed Approach
- Performing More Detailed Initial Quantification
- Using Simplified Approach Similar to that Discussed in June 16, 2014 NEI Meeting
- Scheduled for Completion 4Q2014 65 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Questions/Concerns
- Jointly Review Issues, Questions, and Concerns for Future Communication 66 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan
Future Meetings
- Calvert Cliffs Desires Next Meeting 3Q14 67 Calvert Cliffs Chemical Effects Testing & Option 2a Refined Closure Plan