ML18267A098
| ML18267A098 | |
| Person / Time | |
|---|---|
| Issue date: | 09/24/2018 |
| From: | Robert Tregoning NRC/RES/DE |
| To: | |
| Shared Package | |
| ML18267A083 | List: |
| References | |
| Download: ML18267A098 (12) | |
Text
EPRI Collaboration on EAF Component Testing Project Overview Jean Smith, Ph.D., P.E.
Principal Technical Leader U.S. Nuclear Regulatory Commission Public Meeting on Environmentally Assisted Fatigue Research September 25, 2018 Rockville, Maryland
© 2018 Electric Power Research Institute, Inc. All rights reserved.
EAF Component Testing Objectives:
Understand the effect of light water environments on the fatigue life and resultant CUF on component materials, Reconcile the differences between the current CUF methodology results and the fleet operating experience with respect to EAF failures, and Provide the technical basis for an improved CUF analytical methodology for EAF Program jointly funded by EPRI, EDF, Rolls-Royce, Naval Nuclear Labs 2
© 2018 Electric Power Research Institute, Inc. All rights reserved.
EAF Component Testing - Test Component Test Material
- Type 304L stainless steel compliant with ASME BPVC IIA and RCC-M SA-312 specifications
- As-received surface condition
- Thorough characterization of test material Chemical composition Metallurgical evaluation Mechanical testing (including fatigue)
Test Environment
- PWR primary water
- 325 °C to 38 °C to allow for thermal transients 3
© 2018 Electric Power Research Institute, Inc. All rights reserved.
EAF Component Testing - Test Fixture Preliminary Fixture Design Test fixture designed to accommodate different test component geometries and loading methods to facilitate extension to other PWR, BWR, and new plant components Straight pipe, multiple-stepped pipe, component with wetted-surface notches Thermal strains applied without mechanical loading 4
© 2018 Electric Power Research Institute, Inc. All rights reserved.
EAF Component Testing - Proposed Transients Transient #1 - Thermal Shock
- Simulates sudden injection of cold water into a hot PWR nozzle pipe during a turbine roll
- High surface strain is expected to readily initiate cracks
- Environmental effects may not be observed do to the high strain rate
- Thermal shock equivalent to ~ 333,000-344,000 °C/h produced by rapid injection of a slug of cold water (38°C) into hot pipe (325°C) over 1 to 3 seconds and reverse transient Transient #2 - Moderate Ramp
- Crack initiation and growth under this moderate strain, strain rate, and gradient to provide intermediate data required to validate the best fit model
- Moderate ramp of ~39,000-41,000 °C/h shall be produced by ramping from hot (325°C) to cold (38°C) over ~25s and reverse transient Transient #3 - Slow Ramp
- Slow-rising strain simulates normal plant cooldown of a PWR nozzle pipe and is expected to allow assessment of environmental enhancement effects
- Slow ramp of ~10,000 °C/h produced as a slow decrease from hot (325°C) to cold (38°C) over ~100s and reverse transient 5
© 2018 Electric Power Research Institute, Inc. All rights reserved.
EAF Component Testing - Overall Process Five-year test program consists of four phases Program begins 2018 and finishes in 2022 FEA Modelling Commissioning Testing Integration into and Design FEA Models
- Define
- Thermal and
- Initiate fatigue
- ET for crack initiation
- Define
- NDE detection
- Calculate transient calibration
- Propagate through-wall parameters
- FEA fatigue cracks crack growth
- Component alignment
- UT for crack FEA model
- NDE crack growth outputs siding monitoring
- Predict calibration
- Post-test fatigue
- Revise fatigue examinations behavior predictions 6
© 2018 Electric Power Research Institute, Inc. All rights reserved.
EAF Component Testing - FEA Modelling and Design Component FEA Model Outputs Define Component For each of the four components and three Parameters water transients Define Transient
- Component Geometry
- Water transient temperature as a function Parameters
- Notch Geometry of time and distance from inlet
- Material Parameters
- Water transient parameters
- Metal wetted surface and thru-wall
- Fluid parameters temperature and stress/strain state in test components f(time, thru-wall position, axial distance)
Predict Fatigue Repeat process to ensure fatigue Behavior crack initiation/growth
- Predict fatigue crack - Changing fluid transient parameters initiation and crack growth - Modifying component Geometry rate Commissioning
- Apply NUREG/CR-6909 - Adding stress raisers (ID notches)
Rev. 1 to predict life - Applying mechanical loads Commissioning 7
© 2018 Electric Power Research Institute, Inc. All rights reserved.
EAF Component Testing - Commissioning Fabricate Test Components Construct Test Fixture Upgrade Flow Loop Thermal & Strain FEM Benchmarking Install 4 instrumented components Perform water transients Acquire detailed thermal and strain data for input into FEA model NDE Calibration FEA Alignment Baseline NDE data Adjust FEA model inputs (material and fluid properties)
Initiate crack via Transient #1 and FEA model parameters Inspect with ET Re-calculate predicted wetted surface and thru-wall Grow crack with Transient #3 thermal and strain history Monitor with UT Iterate until the FEM matches experimental values NDE Crack Sizing Calibration Revise Fatigue Post-test examination to align NDE Predictions methods with actual crack depths 8
© 2018 Electric Power Research Institute, Inc. All rights reserved.
EAF Component Testing - Test Process Initiate Fatigue Cracks Test Set-Up Test 1: Thermal Transient NDE Inspections for Crack 4 test components #1 (thermal shock) Initiation Baseline NDE Test 2: Thermal Transient Periodic ET from ID
- 2 (moderate ramp)
Grow Fatigue Cracks Test Termination Criterion Test #1: Thermal Transient NDE Inspections for Crack Reached
- 1 (thermal shock) Growth Post-test NDE, destructive Test #2: Thermal Transient Encoded UT from OD exams, and calculations
- 3 (slow ramp) 9
© 2018 Electric Power Research Institute, Inc. All rights reserved.
EAF Component Testing - Integration into EAF Models The difference between the calculated number of cycles that result in CUF = 1.0 and Calculate Calculate CUF the measured test cycles to produce a fatigue Through-Wall (Initiation) crack will be used to calculate a factor to Crack Growth represent the difference between predicted fatigue life using a laboratory specimen Analyses to align fatigue curve and the fatigue life of actual Analyses to align a predicted crack growth calculated CUF = 1.0 components to initiation of a crack with measured crack growth in a test in a test component The difference between the number of cycles component that cause fatigue crack growth to depths observed in the testing and the test cycles as a function of crack depth will be used to calculate a factor to represent the difference between the calculated fatigue crack growth and the fatigue crack growth of actual components 10
© 2018 Electric Power Research Institute, Inc. All rights reserved.
EAF Component Testing - Summary Comprehensive program including FEA modeling and design, commissioning (NDE calibration and FEA alignment),
testing (two sets of test conditions on four specimens), and EAF modeling Bridge the gap between small specimen, separate-effects testing and operating plant components Define factors for fatigue life and fatigue crack growth to allow transference of small specimen data to plant components 11
© 2018 Electric Power Research Institute, Inc. All rights reserved.
TogetherShaping the Future of Electricity 12
© 2018 Electric Power Research Institute, Inc. All rights reserved.