ML16320A523
| ML16320A523 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 09/07/2016 |
| From: | Dominion |
| To: | Division of Operating Reactor Licensing |
| Cotton K, NRR/DORL/LPLII-1, 415-1438 | |
| References | |
| Download: ML16320A523 (66) | |
Text
Surry Power Station Carbon Fiber Reinforced Polymer (CFRP)
Alternative Request Pre-submittal Meeting September 7, 2016 1
Introductions
o NRC Attendees o Licensee Project Team Attendees o Dominion Surry Nuclear Station - Licensee o Gary Miller (Licensing) o Janean Sealey (Projects) o John Henderson (Design Manager) o Lars Gordon (Engineering) o Structural Technologies, LLC - CFRP Material Manufacturer o Jason Alexander, Anna Pridmore and Leo Nadeau o Simpson Gumpertz & Heger (SGH) - CFRP Designer o Rasko Ojdrovic o Public Attendees 2
Presentation Agenda
- 1. Purpose of Todays Meeting
- 2. Overview of CFRP Process & Procedure
- 3. Scope of Proposed Alternative Request
- 4. Technical Basis
5. Duration of Proposed Alternative
- 6. Precedents
- 7. References
- 8. Regulatory Procedures 3
Purpose of Todays Meeting o
Surry Power Station intends to submit an inservice inspection alternative request in 2016 for the use of a Carbon Fiber Reinforced Polymer (CFRP) composite repair system for internal structural upgrade of selected safety related piping systems.
o Todays meeting serves as a pre-submittal discussion of the scope and content of the forthcoming alternative request.
4
Carbon Fiber Reinforced Polymer (CFRP) Pipe Repair o No excavation o Standalone design (no reliance on host pipe) o Rapidly implemented o Targeted or continuous repairs o Minimal diameter reduction and effect on flow 5
Overview of CFRP Process and Procedure
History of Carbon Fiber Reinforced Polymer (CFRP) o 1950s: CFRP for aerospace applications o 1980s: CFRP is used to repair civil infrastructure o 1990s - early 2000s: Various utilities start using CFRP to internally repair large diameter pipe o Mid-2000s: CFRP repair of pipe is widespread o 2009: AWWA Concrete Pressure Pipe Committee appoints a subcommittee o 2011: AWWA Standards Council approved the development of a standard o 2011: Water Research Foundation awards the first research project to form the technical basis of the standard o 2012: ASME Task Group formed for Code Case Repair of Class 2 and 3 Piping by Carbon Fiber Reinforced Polymer Composite, ASME Section XI, Division 1 o 2013 - 2015: Additional research on watertightness, degree of cure, etc.
o 2015: AWWA Draft Standard for CFRP Renewal and Strengthening of PCCP is complete (currently balloted) o 2016: ASME draft Code Case Repair of Class 2 and 3 Piping by Carbon Fiber Reinforced Polymer Composite, ASME Section XI, Division 1 (in progress) 6 Overview of CFRP Process and Procedure
Carbon Fiber Reinforced Polymer (CFRP) Pipe Repair o Effective in repair of buried pipes which are 24 in. diameter and larger o In use nearly 20 years on buried pipes o More than 500 internal CFRP repairs on steel, prestressed concrete cylinder pipe (PCCP) and reinforced concrete pipe (RCP) pipes including numerous non-safety pipes at nuclear power plants 7
Overview of CFRP Process and Procedure
Scope of Proposed Alternative Request o Piping included: Surry Unit 1&2 Safety related Circulating Water System Inlet Piping and Service Water System pipe headers o Anticipated construction timeframe: Spring 2018 - Fall 2025 o Requested date of approval: Within 12 months of submittal date o American Society of Mechanical Engineers (ASME) Code Class:
ASME Code Class 3 8
Scope of Proposed Alternative Request o Affected piping in Surry Power Station Units 1 & 2 o 96 diameter Circulating Water System Inlet Piping (CW) from the Station Inlet Canal to the Main Steam (MS) Condenser and 24, 30, 36, 42, and 48 diameter Service Water (SW) System pipe headers from the CW system to the supply lines to the Recirculation Spray Heat Exchangers.
o All of these lines are concrete encased and buried. The concrete encasement of the piping systems was designed as a Seismic Category l structure and provides the seismic support for these pipes. The piping was fabricated in accordance with American Water Works Association (AWWA)
C201 Standard Specification for Electric Fusion Welded Steel Water Pipe with carbon steel materials conforming to American Society for Testing Materials (ASTM) A-283 Gr. B. The piping was designed and installed in accordance with ANSI B31.1 -1967 Power Piping Code.
o A detailed listing of the piping sections to be replaced will be provided, which identifies the pipe number, size, configuration, preliminary construction schedule and function.
9
Scope of Proposed Alternative Request o Applicable Code Edition and Addenda o ASME Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, 2004 Edition No Addenda o Applicable Code Requirement o During the process of repairing this carbon steel piping, Article IWA-4000, subparagraph IWA-4221(b) requires that items used during a repair/replacement activity meet the original construction code.
o Reason for Request o The use of CFRP piping for ASME applications is a recent technology improvement which was not available in the 1960s or 1970s to meet the original construction code. There are no provisions in ASME Section XI or in an approved Code Case for installing CFRP piping as a replacement for carbon steel piping during a repair/replacement activity. Dominion is therefore submitting an ISI Alternative Request for NRC approval to use CFRP material for the repair of pipe sections.
10
Components Affected-Unit 1 Scope of Proposed Alternative Request 11
Components Affected-Unit 2 Scope of Proposed Alternative Request 12
Sample Project Scope Detail Unit 1-Spring 2018 Outage Pipe Designation Pipe Number(s)
Diameter (in.)
Pipe Length (ft.)
Preliminary CFRP Design Additional notes Alpha inlet elbow 96"-WC-1-10 96 66.00 1D+2H+1L+1W+2H plus extra longitudinal CFRP layer through elbow and 10ft. beyond elbow (approx 32 ft.)
Includes one 90 degree vertical elbow. Surry to weld plates over two 4in. connections prior to installation of CFRP.
Manhole riser attached to Alpha inlet elbow Manhole riser attached to Alpha inlet elbow 30 7.25 1D+1H+1L+1W+1H Includes tie-in detailing between manhole and 96in. pipe.
End View:
Elevation View:
Scope of Proposed Alternative Request 13
14 Sample Concrete Encasement around Pipelines Scope of Proposed Alternative Request
Technical Basis Enclosures Included in Alternative Request o ASME Code Components Affected (Enclosure 2-scope, schedule, definition of terms) o Material inspection and controls (Enclosure 3-materials inspections, controls and qualification testing) o Design basis (Enclosure 4-drawings), (Enclosure 5-calculations)
(Enclosure 6-design specification) o Installation (Enclosure 7-sample project installation procedures )
o Examination and Testing (Enclosure 8-sample project quality plan and QA/QC forms) o Qualifications and Training (Enclosure 9-sample qualification and training package) o Operational Experience (Enclosure 10- successful and failed applications) o In-service Inspection (Enclosure 11-sample in-service inspection) 15
CFRP = Carbon Fiber Reinforced Polymer GFRP = Glass Fiber Reinforced Polymer o Carbon Fiber provides structural strength.
o Glass fiber provides water-tightness and dielectric barrier o Epoxy resin provides durability.
16 Technical Basis Material Inspection and Controls
o Saturating epoxy: 100% solids epoxy used to saturate the glass and carbon fiber fabrics o Primers: low viscosity 100% solids epoxy used to promote adhesion between host pipe and CFRP o Thickened epoxy: silica fume mixed with epoxy and used to create smooth surface o Structural reinforcing fabric: unidirectional carbon fiber fabric o Non-structural fabric: glass fiber fabrics used as dielectric barrier, intermediate layer and water barrier o Finish layer: thickened epoxy used to provide resistance to abrasion, chemical, flow, debris, etc.
o Termination materials: corrosion resistant metal expansion rings with rubber gaskets used to mechanically press CFRP against pipe at ends of repair(optional) 17 Technical Basis Material Inspection and Controls
Epoxy o Two-part o Ambient cure thermoset o 100% solids o Volatile organic compound (VOC) compliant Technical Basis Material Inspection and Controls 18
Primer o Low viscosity epoxy providing an adhesive bond for the thickened epoxy.
Saturating epoxy o Used to impregnate the reinforcing fabrics.
Thickened epoxy o Typically made up of the saturating epoxy and silica fume mixed together in accordance with the manufacturers procedure. The thickened epoxy filler is used to even out the pipe substrate and it is also used in between layers of CFRP.
Application of primer coat 19 Technical Basis Material Inspection and Controls
Fabrics o Unidirectional carbon fiber fabric layers applied longitudinally and circumferentially as strengthening component o Glass fiber used as dielectric barrier and water-tightness layer Glass fiber Carbon fiber 20 Technical Basis Material Inspection and Controls
o Epoxy components and carbon fiber material are manufactured as QA Category 1 in accordance with 10CRF 50 Appendix B and ASME NQA-1.
o The materials are controlled using a comprehensive process that includes; o Technical performance criteria.
o Qualification testing at the component and end state levels.
o Testing methods that assure components are verifiable and traceable from the manufacturer to installation.
o Quality Control and Quality Assurance methods and records that verify manufacturing, storage and installation of epoxy and carbon fiber components as specified by the Design Authority.
o Materials are delivered in factory sealed and labeled containers that bear the manufacturers name, product identification, component designation, lot number, date of manufacture, and shelf life.
Technical Basis Material Inspection and Controls 21
Design Approach for CFRP Lining o
CFRP liner is designed to take all the loads acting on the host pipe without reliance on the host pipe for structural integrity except at the termination locations.
Technical Basis - Design Basis 22
23 Water Research Foundation (WRF) Research Projects (2011-2015) o Full-scale tests o Hydrostatic pressure o Three-edge bearing o Laboratory tests o Shear bond strength o Degree of cure o Water-tightness o Finite element analysis (FEA) of CFRP-lined pipe o Based on Simpson Gumpertz
& Heger research including Water Research Foundation project #4352, 4510 and 4592 Technical Basis - Design Basis
24 Full-Scale Hydrostatic Pressure Tests 54 in.
pipe 48 in.
pipe Technical Basis - Design Basis
25 Full-Scale 3-Edge Bearing Tests 48 in. pipe 54 in. pipe 48 in. pipe - Control Technical Basis - Design Basis
26 Sequential analysis of buried CFRP-lined pipe that continues to degrade Buckling analysis Finite Element Analysis (FEA) Validation Technical Basis - Design Basis
Material Verification & Testing o Witness panels - ASTM D3039 o Validate tensile strength o Validate elastic modulus o Validate ultimate strain 27 Technical Basis - Design Basis
28 Shear Bond Strength on Steel Substrate Technical Basis - Design Basis
Degree of Cure o Cure Testing - ASTM E2160 o Differential scanning calorimetry (DSC) on epoxy 29
=
Technical Basis - Design Basis
30 Progression of Cure Varies by material Technical Basis - Design Basis Need minimum 85% cure before placing pipe back in service
31 Water-tightness Test o Testing is performed to ensure that water will not permeate through the CFRP laminate o Allows testing of laminates on a project-by-project basis o 500 psi capacity test equipment Sample Strain gages Pressure gage Technical Basis - Design Basis
Water-tightness Acceptance Criteria 32 o Depending on layers of CFRP installed, dedicated water-tightness layer or coating will be utilized Specimen with water-tightness layer, with no leaks at 400 psi Specimen without water-tightness layer, with multiple weeps at 150 psi Technical Basis - Design Basis
Durability Testing o Material adjustment factors established for each CFRP system through long-term exposure, testing for the retained strength, and extrapolating the test results out to the design life for the system (50-year service life).
o Time effect factor accounts for the creep rupture strength of CFRP.
33 Technical Basis - Design Basis
34 o Material properties based on tension tests of single-ply CFRP cured laminate (min 50 samples, ASTM D3039) o Characteristic values of strength and modulus is the lower 5 percentile value with 80% confidence (ASTM D7290)
Determination of Material Properties Technical Basis - Design Basis
Multi-Ply Strength o Strength depends on the number of layers.
o Calculate the load-deformation relationship for an n-layer laminate by increasing deformations until the first lamina fails, and continue up to ultimate load.
o Ultimate tensile strength of the n-layer laminate is the ultimate load divided by the initial area of the laminate.
o Repeat sufficient number of times to obtain the probability density function (PDF) of tensile strength of the multi-ply laminate.
35 Technical Basis - Design Basis
Factor of Safety o Based on reliability analysis in WRF 4352 report o Provide a desired probability of failure of 10-6 per calendar year in accordance with NEI 96-07 o Desired minimum reliability index is 3.9 o Strength reduction factor
0.65 for axial strain (average workmanship) o Working pressure load factor is 1.4 o Safety factor is 1.4÷0.65
2.15 o Conservative factors of safety are provided 36 Technical Basis - Design Basis
Unidirectional Design o CFRP is designed independently in both circumferential and longitudinal directions.
o Circumferential CFRP minimum number of layers nminc (corresponding to min. wall thickness) o =
2 o = diameter of neutral axis of circumferential CFRP o = design working pressure o = C*Su/4 allowable stress in the circumferential direction o = nominal thickness of one CFRP layer in circumferential direction o = time effect factor 37 Technical Basis - Design Basis
Combined Stress o Check independently circumferential and longitudinal stresses for applicable load combinations.
o Consider all loads that can act at the same time.
o Consider long term and short term loads to account for load duration effects.
38 Technical Basis - Design Basis
Combined Circumferential Stress o A limit state is considered satisfied when the following is met:
=
=
C
+
C
+
C
+
C 1
o
= 3.0 safety factor for sustained working pressure o
= 2.5 for transient pressure, 2.0 for service level C or D transient internal pressures, thermal stresses or earthquake induced stresses.
o
= 4.7 for sustained flexural loads (e.g. earth load), 4.0 when includes the effects of service level B transient internal pressures or thermally induced stresses, temporary soil surcharge loading, or negative internal pressure Rc = re-rounding factor
= time effect factor
= material adjustment factors
= stress from hoop and flexural loads, long and short term 39 0
0 Technical Basis - Design Basis
Circumferential Buckling o CFRP repair designed to resist sustained compressive hoop stresses without buckling failure as follows:
+ + +
- = 3.0
- P - external pressures o and concurrently occurring sustained and transient loads without buckling failure as follows:
+ + + + +
- = 2.75 o Consider Glock model for critical buckling pressure for pipe constrained by concrete encasement 40 0
0 0
0 0
0 0
Technical Basis - Design Basis
Longitudinal Stresses o Similar approach as for circumferential stress 41 Technical Basis - Design Basis
Sample Drawing Package Sample CFRP layup for different pipe diameters 42 Technical Basis - Design Basis
Sample Drawing Package Schematic cross section of pipe and overlaps (Not to Scale) 43 Technical Basis - Design Basis
Sample Drawing Package Schematic detailing for different pipe configurations (Not to Scale) 44 Technical Basis - Design Basis
Pre-installation requirements:
o Identify and verify repair areas o Verify controlled storage of materials o Verify materials o Verify installation of environmental controls 45 Material storage trailers Environmental control unit Technical Basis - Installation
CFRP installation requirements:
o Surface preparation o Saturation of dry FRP fabric o Application of primer o Installation of GFRP o Dielectric barrier o Water-tightness layer o Installation of CFRP o Fabric alignment and overlaps o Termination requirements o Finish and top coat requirements o Repair of fittings, other configurations o Defect repair requirements o System curing requirements 46 Mechanical saturator Technical Basis - Installation
Sample Surry Procedures Developed o SU-PROC-000-417012-01.3-Project Quality Plan o SU-PROC-000-417012-02.6-Project QA/QC Forms o SU-PROC-000-417012-03.3-V-Wrap Installation Procedure o SU-PROC-000-417012-04.1-Surface Preparation Procedure o SU-PROC-000-417012-05.2-Compression Seal Installation Procedure 47 Technical Basis - Installation
48 Inspections and tests:
o Visual inspection o Prior to installation o During installation o Post-installation o Instrument calibration o Surface preparation verification o UT readings of substrate at terminations o Chloride testing o Weight ratio test o Adhesion test (ASTM D4541) o Tensile test (ASTM D3039) (panels fabricated on site, tested off site) o Material cure testing o Acceptance criteria o Qualifications of inspection personnel o Records Fabrication of witness panels Technical Basis - Examination and Testing
Key Project Step: Quality Control Program o Multiple QA/QC Personnel o 3rd Party inspector o Full time Quality Assurance Manager o Project Oversight o Multiple Owner Representatives o Design Engineering Representative o Documentation for each stage of implementation o Material verification o Temperature and humidity controls o Surface preparation o Mixing and saturation o CFRP liner installation o End details and special detailing o Top coat o Final cure 49 Technical Basis - Examination and Testing
Key Project Step: Mixing and Saturation Installation Steps:
o Materials arrive on site in premeasured containers for part A and B components o Designated mixing region is an isolated area to avoid material contamination o Mechanical saturator ensures consistent application of epoxy to carbon fiber Examination and Testing:
o Lot numbers of fabrics and epoxies are documented o Gap between saturator rollers measured and calibrated using weigh test o Weigh test verifies ratio of fabric to epoxy is within tolerance Technical Basis Examination and Testing 50
Key Project Step: Surface Preparation Installation Steps:
o Surface preparation using abrasive blasting o Water intrusion mitigation prior to CFRP installation o Weld repairs as needed o Chlor-rid rinse as needed to reduce chloride content on pipe substrate Examination and Testing:
o Minimum surface roughness documented o Surface preparation is verified by performing an adhesion test per ASTM D4541 on the prepared pipe o UT measurements performed at terminal ends o Document as-found pipe substrate 51 Technical Basis Examination and Testing
Installation Steps:
o Mechanically saturated carbon and glass fiber fabric installed in both longitudinal and circumferential directions o CFRP design serves as stand alone system to resist all loads without reliance on host pipe o In-process identification, documentations, and repairs of installation anomalies Examination and Testing:
o Air temperature, surface temperature, and humidity during installation documented o Alignment of CFRP layers verified o Development lengths and overlaps verified o Document repair of anomalies Key Project Step: CFRP Installation 52 Technical Basis Examination and Testing
Key Project Step: CFRP Final Cure Installation Step:
o After top coat is installed, final cure of CFRP system is performed at elevated temperature Examination and Testing:
o Air temperature, surface temperature, and humidity during CFRP cure recorded o Degree of cure testing performed to verify degree of cure achieved for CFRP system 53 Technical Basis - Examination and Testing
Technical Basis - Qualifications and Training o Qualification and training programs are in place for the following personnel:
o Installer o Installation Supervision o 3rd Party Inspector o Qualification process o Learning Objectives o Training o Knowledge Test o Performance Test 54
Recent Nuclear Piping CFRP OE Pipe Type Diameter Project Dates PCCP 66, 114-inch 1997-2016 PCCP 144-inch 2013-2016 Steel 84-inch 2013-2016 Steel 36, 42-inch 2013-2016 PCCP 138-inch 2015-2016 PCCP 144-inch 2015-2016 Steel 30, 42, 96-inch 2015-2016 PCCP 138-inch 2015-2016 Steel 36, 48, 54-inch 2015-2016 PCCP = Prestressed concrete cylinder pipe Technical Basis - Operational Experience 55
Technical Basis - Operational Experience 56 Failures from previous CFRP Installations (done by others)
Mitigating actions to prevent similar failures (Alternative request team has had NO failures)
Improper saturation of fabric Use of mechanical saturator, written procedure, training and qualifications, QA/QC verifications Unqualified contractor Training, qualifications, quality control programs, NQA1 vendor, extensive successful performance Improper materials Material qualifications testing Insufficient surface preparation Written procedure, training and qualifications, QA/QC verifications Inadequate design Extensive research and development for design validation (WRF program), training and qualifications Inadequate environmental controls Written procedure, training and qualifications, QA/QC verifications Lack of QA/QC oversight Written procedure, training and qualifications, QA/QC verifications
Technical Basis - Surry Operational Experience o Surry has implemented multiple projects involving CFRP repairs with the same project team on approximately 600 LF of 30-inch, 42-inch, and 96-inch steel pipelines with similar configurations o These projects were non-safety, enhanced quality projects performed in preparation for the upcoming proposed safety related applications o Developed and tested QA/QC forms, procedures, 3rd party inspection methods and project oversight o After each outage, lessons learned were incorporated 57
Surry Unit 1 CW 96-inch Discharge 58 Technical Basis - Surry Operational Experience
Unit 1 - CC SW 42-inch Discharge End Cap 59 CC SW 30-inch Risers Technical Basis - Surry Operational Experience
Unit 1 CC SW 30-inch Riser 60 Technical Basis - Surry Operational Experience
Technical Basis - In-service Inspection 61 o For CFRP piping installed under this ISI Alternative, Inservice Inspection requirements will include the following:
o Demonstration of CW and SW system integrity in accordance with the Inservice Inspection Program for buried CW components by documenting adequate flow through the 96-inch CW piping and the major SW supply piping.
o Internal visual inspection of CFRP piping performed on a refueling frequency.
o The visual inspection will include the following activities.
o Determination of the extent of biological fouling, sediment buildup, and corrosion (including microbiologically influenced corrosion-MIC) o Assessment of the effectiveness of biofouling control mechanisms o Monitoring the material integrity of metallic components, CFRP, concrete, concrete to concrete, concrete to steel joints, Weko-Seals, and other joint seals
Duration of Proposed Alternatives 62 o The proposed alternative is requested for the Unit 1 fifth 10-year Inservice Inspection (ISI) Interval that began on December 14, 2013 and ends on October 13, 2023, except for a common Unit 1
& 2 SW line which will be completed at the start of the sixth 10-year ISI Interval. The proposed alternative is requested for the Unit 2 fifth Inservice Inspection Interval which began on May 10, 2014 and ends on May 9, 2024.
Precedents 63 o None. The requested Alternative is a first-of-a-kind installation of CFRP in nuclear safety related piping.
References 64 o ASME Section XI, Rules for In-service Inspection of Nuclear Power Plant Components, 2004 Edition No Addenda o ANSI B31.1 -1967 USAS Code for Pressure Piping
Regulatory Procedure o Dominion is planning to submit an alternative request in accordance with 10 CFR 50.55a(z)(1), Acceptable level of quality and safety.
65
Questions 66