ML25261A145

Presentation on Data Requirements for ASME Code Qualification of New Materials for High Temperature Reactors at the IAEA Technical Meeting, Nov 18-21, 2024, Vienna, Austria

ML25261A145
Person / Time
Issue date:	11/21/2024
From:	Sham T NRC/RES/DE
To:
Sam Sham
References
Download: ML25261A145 (25)

Text

Data Requirements on Qualification of Structural Materials in ASME Boiler and Pressure Vessel Code,Section III, Division 5, High Temperature Reactors Ting-Leung (Sam) Sham Office of Nuclear Regulatory Research U.S. Nuclear Regulatory Commission Technical Meeting on Advanced Manufacturing and Qualification Programmes for New Materials for Small Modular Reactors and Non-Water Cooled Reactors:

Safety Consideration 18-21 November 2024, IAEA Headquarters, Vienna, Austria

Disclaimer This presentation was prepared as an account of work sponsored by an agency of the U.S. Government. Neither the U.S. Government nor any agency thereof, nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for any third partys use, or the results of such use, of any information, apparatus, product, or process disclosed in this presentation, or represents that its use by such third party would not infringe privately owned rights. The views expressed in this presentation are not those of the U.S. Nuclear Regulatory Commission.

ASME BPVC Section III, Rules for Construction of Nuclear Facility Components - Division 5, High Temperature Reactors

• ASME BPVC Section III, Division 5 Scope

- Division 5 rules govern the construction of vessels, piping, pumps, valves, supports, core support structures and nonmetallic core components for use in high temperature reactor systems and their supporting systems

• Construction, as used here, is an all-inclusive term that includes material, design, fabrication, installation, examination, testing, overpressure protection, inspection, stamping, and certification

• High temperature reactors include

- Gas-cooled reactors (HTGR, VHTR, GFR)

- Liquid metal reactors (SFR, LFR)

- Molten salt reactors, liquid fuel (MSR) or solid fuel (FHR) 3

Code Case 1331, design rules for nuclear components initiated.

Code Cases 1592, 1593, 1594, 1595 and 1596, covering materials and design, fabrication and installation, examination, testing, and overpressure protection.

NRC endorsed Code Case series 1592-1596 in RG 1.87 for HTGR, LMR, GFR.

Code Case series 1592-1596 converted to Code Case N-47.

Used by Clinch River Breeder Reactor project, with additional DOE requirements.

Continued improvements of N-47.

Subsumed N-47 into a new Section III, Division 1, Subsection NH.

Consolidated Subsection NH and other nuclear Code Cases, and added construction rules for graphite core components, into a new Section III, Division 5 construction rules for high temperature reactors.

1963 Early 1970s 1975 Late 1970s

1995 2011 Division 5 Construction Rules for High Temperature Metallic Components - A Long History of Development 4

Section III, Division 5 - A Component Construction Code

• Division 5 is organized by Code Classes:

- Class A, Class B, Class SM for metallic components

- Class SN for non-metallic components

• Division 5 recognizes the different levels of importance associated with the function of each component as related to the safe operation of the advanced reactor plant

• The Code Classes allow a choice of rules that provide a reasonable assurance of structural integrity and quality commensurate with the relative importance assigned to the individual components of the advanced reactor plant 5

Section III, Division 5 Organization Code Class Sub-section Subpart ID Title Scope General Requirements Class A, B, & SM HA A

HAA Metallic Materials Metallic Class SN B

HAB Graphite and Composite Materials Nonmetallic Class A Metallic Coolant Boundary Components Class A HB A

HBA Low Temperature Service Metallic Class A B

HBB Elevated Temperature Service Metallic Class B Metallic Coolant Boundary Components Class B HC A

HCA Low Temperature Service Metallic Class B B

HCB Elevated Temperature Service Metallic Class A and Class B Metallic Supports Class A & B HF A

HFA Low Temperature Service Metallic Class SM Metallic Core Support Structures Class SM HG A

HGA Low Temperature Service Metallic Class SM B

HGB Elevated Temperature Service Metallic Class SN Nonmetallic Core Components Class SN HH A

HHA Graphite Materials Graphite Class SN B

HHB Composite Materials Composite 6

Advanced Reactors Under Development Have Drastically Different Characteristics

• Inlet/outlet temperatures

• Thermal transients

• Coolants

• Solid fuel vs liquid fuel

• Neutron spectrum and dose

• Design lifetimes

• Safety characteristics Stress (Rupture), Thermal Transients (Ratchet, Creep-Fatigue), Time at Temperature (Aging)

Coolant Effects Irradiation Effects Advanced Nuclear 7

Materials Data Requirements

• Design parameters that are required by the HTDM would drive the materials data requirements

• FRs, GCRs and MSRs have different coolants, neutron irradiation environments and operating conditions (temperature, pressure, and transients)

• Different structural materials are needed to meet different requirements of FRs, GCRs and MSRs

• FRs, GCRs and MSRs have different coolants, neutron irradiation environments and operating conditions (temperature, pressure, and transients)

• Different structural materials are needed to meet different requirements of FRs, GCRs and MSRs FR Materials High Temperature Design Methodologies MSR GCR FR 8

ASME Division 5 Approach - Stress and Temperature Effects

• Focus on structural failure modes under elevated temperature cyclic service, rather than reactor types

-Stress (Rupture), Thermal Transients (Ratchet, Creep-Fatigue),

Time at Temperature (Aging)

• Develop acceptance criteria and attendant high temperature design methodologies (HTDM) to guard against the identified structural failure modes

-Essentially cross-cutting different reactor types 9

Environmental Effects for High Temperature Materials

• Effects of coolant and irradiation on structural failure modes are different from one reactor design to another even for the same structural material

• It is very challenging to cover these effects for all reactor types, and all different design characteristics for the same reactor type, viz. molten salt reactor 10

ASME Division 5 Approach - Environmental Effects

• The Division 5 approach is for Owner/Operator to have the responsibility to demonstrate to regional jurisdiction authority that these effects on structural failure modes are accounted for in their specific reactor design

-Irradiation dose, dose rate, embrittlement, corrosion due to coolant, coolant chemistry and chemistry control, mass transfer leading to strength reduction or loss of ductility, etc.

11

Reasonable Assurance of Structural Integrity

• Division 5 is not just on design analysis, it is a Construction Code

• All Subsections (except General Requirements) have, in addition to Design, sections on:

- Material, Fabrication, Installation, Examination, Testing, Overpressure Protection, Inspection, Stamping, And Certification (heavily referencing appropriate Division 1 Subsection(s) - tied to regulations)

Section III, Division 5 Section II, Materials Spec.

Section V, NDE Conformity Assessment Section XI, ISI, RIM Nuclear Quality Assurance Qualification of Mechanical Equipment Section IX, Welds Owner/ Operator responsibility (Irradiation, corrosion, etc.)

Regional Jurisdiction Authority Others 12

Materials Data Requirements for Section III, Division 5 Components Component Class (A or B)

Structural Failure Modes Design Parameters Required Test Data 13

Temperature Boundaries For Class A & Class SM Components 14 Maximum Use Temperature Metal Temperature Design Lifetime Low Temperature Service, No Creep Effects Negligible Creep Regime Creep Does Not Reduce Cyclic Life Creep Reduces Cyclic Life (Creep-fatigue Interaction)

Division 5 Division 1, Subsection NB Rules Negligible Creep Temperature Code Temperature Boundary 700F (371C) ferritic 800F (427C) austenitic Code Temperature Boundary 371C (700F) ferritic 427C (800F) austenitic

Key Elevated Temperature Deformation and Failure Modes

• Creep mechanisms

-Dislocation creep

-Diffusional creep

• Creep curves

-Primary

-Secondary

-Tertiary Primary load (mechanical)

Creep rupture Cyclic load (mechanical and thermal)

Ratcheting Fatigue damage Creep-fatigue interaction

Examples of Elevated Temperature Testing for Design Data Continuous Cycling

A617, 800C (1472F)

Plots courtesy of Dr. Yanli Wang, Oak Ridge National Laboratory A617 Hold time during cycling significantly reduces cyclic life 950 - 1000C (1652 - 1832F)

Creep-fatigue Interaction Creep Rupture A709 600C (1112F) 330 MPa (47.9 ksi)

Structural Failure Modes for Class A Construction Time Independent Failure Mode Category Design Procedure Time Dependent Failure Mode Category Design Procedure Ductile rupture from short-term loading Load-controlled Primary load check Creep rupture from long-term loading Load-controlled Primary load check Gross distortion due to incremental collapse and ratcheting (low temp.)

Deformation-controlled Strain limits check Creep ratcheting due to cyclic service Deformation-controlled Strain limits check Loss of function due to excessive deformation Deformation-controlled Strain limits check Creep-fatigue failure due to cyclic service Deformation-controlled Creep-fatigue check Buckling due to short-term loading Deformation-controlled Buckling Check Creep-buckling due to long-term loading Deformation-controlled Buckling Check 17 Design-by-analysis Approach Providing a reasonable assurance of adequate protection of structural integrity

Design Parameters Required to Address Failure Modes for Class A Components Design Parameters Required Test Data

• : based on yield and ultimate strengths at temperature Tensile data at temperature (time-independent)

• : based on time to 1% total strain, time to onset of tertiary creep, time to rupture

• : based on stress to rupture Creep rupture data with full creep curves (time-dependent)

• : lesser of,

• 0: Tabulated -value in ASME BPVC,Section II, Part D, Table 1A/1B)

Derived design parameters Design Parameters Required Test Data

• : Stress rupture factor based on rupture strengths of base metal and weldment Stress rupture data from base metal and weldment (time dependent)

• Thermal aging factors on yield and ultimate strength Tensile data of aged material (time-dependent)

• Isochronous stress-strain curves constructed based on creep tests Tensile stress-strain curves (time-independent), and creep strain data up to 3%

(time-dependent)

Design Parameters - II Design Parameters Required Test Data

• Fatigue design curves Strain-controlled continuous cycling tests

• Creep-fatigue interaction diagram Strain-controlled cyclic tests with hold times

• EPP design parameters Two-bar and SMT tests; cyclic stress-strain curves

• Inelastic material model parameters Test data for other design parameters; and strain rate change and thermomechanical cycling

• Huddleston effective stress parameters Multiaxial creep rupture data

• External pressure charts Tensile stress-strain curves (time-independent)

• Time-temperature limits for external pressure charts Isochronous strain-strain curves

• Time-temperature limits for fabrication strains Creep rupture with pre-straining

Required Testing to Support Design Parameters Development Base Metal

• Standard Test Specimens

• Tensile, creep rupture, fatigue, creep-fatigue, constitutive

• Multiaxial creep rupture

• Key Feature Test Articles

• Simplified Model Test (SMT): solid specimen, tubular specimen with axial straining and internal pressure 20

References:

• ASME Section II, Part D, Mandatory Appendix 5

• ASME Section III, Division 5 Nonmandatory Appendix HBB-Y, Guidelines for design data needs for new materials Weldment

• Tensile, creep rupture

• Limited fatigue, creep-fatigue Thermally Aged Base Metal

• Tensile

Allowable Stresses/Design Parameters for Evaluation Procedures Limits Behavioral Trends

• Time independent allowable Stress

• Time dependent allowable Stress:

• ,, 0

• Fatigue design curves

• Isochronous stress-strain curves

• Creep-fatigue interaction envelope

• Thermal aging factors on yield and ultimate strength

• Huddleston effective stress parameters

• EPP design parameters

• Inelastic material model parameters

• External pressure charts

• Time-temperature limits for external pressure charts

• Time-temperature limits for fabrication strains

• Stress rupture factor for weldment

• More stringent requirements

• Require data from a minimum of 3 industrial heats (usually more, ~ 10)

• Requirements are less stringent

• Typically, data from 1 to 2 heats Design data generated from one wrought product form (e.g., plate) can be used for other wrought product forms having the same chemistry

Challenge: Time Dependent Data (Creep Rupture) Dominate Test Times

• Allow limited extrapolation of time for creep properties

• Well-behaved, solid-solution alloys may extrapolate in time of no more that a factor of 5 to reach intended life

• Metastable alloys, such as the creep strength enhanced ferritic/martensitic steels may extrapolate with a factor of 3

• Require metallurgical justification for 3 < extrapolation factor 5 Design Life (hours)

Minimum Time to Complete Creep Rupture Testing (years)

Solid Solution Alloys Ferritic-Martensitic Steels 100,000 2.3 3.8 300,000 6.8 11.4 500,000 11.4 19.0 22 Data for non-nuclear Codes & Standards, e.g., ASME BPVC Section VIII, Pressure Vessels are in this range

A Staged Qualification Approach Time from initiation of long-term testing (years) 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 10 10.5 11 11.5 Tests initiated at the same time Concept Design Guide Class B CC 100,000 hr CC Creep tests Creep tests for 300,000 hr CC Creep tests for 500,000 hr CC (Determination of mechanisms giving rise to time dependent properties through simulation validated by experiment could allow larger extrapolation factors)

Other mechanical properties testing common to all CCs A four-year testing program, without resource constraints, would generate data package to support:

• Conceptual design Conceptual Design Guide for 500,000-hour lifetime

• Preliminary design 100,000-hour Class A code case Class B material code case Additional creep data at 7-year mark from start:

• Final design 300,000-hour Class A code case Additional creep data at 12-year mark from start:

• Nth-of-a-kind 500,000-hour Class A code case 23

Summary

• The ASME BPVC Section III, Division 5, High Temperature Reactors was briefly introduced

• The Division 5 approach to the consideration of temperatures, stress and environment was discussed

• Focus on temperature, stress and structural failure modes to develop design rules for metallic components that crosscut multiple advanced reactor types

• Design parameters required to perform design analysis were outlined

• This in turn drives the material data requirements

• All time-dependent design parameters are obtained from time-extrapolation of relevant test data

• Durations to generate test data depend critically on the required design lifetime of the metallic components

• Staged qualification approach was introduced

Thank You Ting-Leung (Sam) Sham, Ph.D.

Senior Technical Advisor for Advanced Reactor Research Division of Engineering, Office of Nuclear Regulatory Research U.S. Nuclear Regulatory Commission One White Flint North, M/S OWFN-5-G10 11555 Rockville Pike Rockville, MD 20852-2738, USA ting-leung.sham@nrc.gov