Endorsement Review of ASME B&PV Code Section III, Division 5, "High Temperature Reactors"
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Issuance of Revision 2 to Regulatory Guide 1.87 and NUREG-2245
In January 2023, the NRC staff issued Revision 2 to Regulatory Guide (RG) 1.87, “Acceptability of ASME Section III, Division 5, ‘High Temperature Reactors.’” This RG describes an approach that is acceptable to the NRC staff to assure the mechanical/structural integrity of components that operate in elevated temperature environments and that are subject to time-dependent material properties and failure modes. It endorses, with exceptions and limitations, the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (BPV) Code (ASME Code) Section III, “Rules for Construction of Nuclear Facility Components,” Division 5, “High Temperature Reactors,” and Code Cases N-861, N-862, N-872, and N-898.
Appendix A to RG 1.87 Revision 2 provides guidance for the quality group classification of components in non-LWR designs.
The NRC also issued NUREG-2245, “Technical Review of the 2017 Edition of ASME Section III, Division 5, `High Temperature Reactors,' ” that documents the NRC staff's review of the 2017 Edition of ASME Section III, Division 5, certain portions of the 2019 Edition, and Code Cases N-861 and N-862. The technical basis for the NRC's endorsement of Code Cases N-872 and N-898 is contained in Technical Letter Report (TLR)-RES/DE/REB-2022-01, “Review of Code Cases Permitting Use of Nickel-Based Alloy 617 in Conjunction with ASME Section III, Division 5.”
Material Compatibility Interim Staff Guidance (ISG)
As stated in ASME Code Section III, Division 5, HBB 1110(g), the ASME Code rules do not provide methods to evaluate deterioration that may occur in service as a result of corrosion, mass transfer phenomena, radiation effects, or other material instabilities. Recognizing this gap, the NRC staff initiated efforts to identify information that the NRC staff should consider as part of its evaluation of a non-LWR application to review applicable design requirements including environmental compatibility, qualification and monitoring programs for safety-significant structures, systems, and components (SSCs). The actual information necessary for reviewing qualification and monitoring programs would depend on many factors, such as plant design, importance of component, specific environments, and maturity of research in a given area.
In February 2023, the NRC staff issued draft Interim Staff Guidance (ISG) “Material Compatibility for non-Light Water Reactors, DANU-ISG-2023-01”. Draft DANU-ISG-2023-01 was published for comment on March 7, 2023 in 88 FR 14186. The public comment period closes on May 8, 2023. Comments can be submitted through Regulations.gov under Docket ID NRC-2022-0215.
Background
The NRC staff recognize that the absence of an NRC-endorsed code of construction for nuclear reactors operating above 425°C (800°F) is a significant obstacle for new and advanced nuclear reactor designs. Review and approval of an elevated temperature code of construction during a licensing review of a new nuclear power plant would result in substantial costs and delays.
In a letter dated June 21, 2018, ASME, based on letters from both industry consortia and individual companies interested in developing non-LWR designs, requested that the NRC review and endorse the 2017 Edition of ASME B&PV Code Section III, Division 5 (see also the NRC response letter). Therefore, the NRC has initiated efforts to endorse the ASME B&PV Code Section III, Division 5.
In October 2018, the NRC sent the ASME BPVC Section III, Division 5 standard and the technical background documents to the Pacific Northwest National Laboratory (PNNL), Oak Ridge National Laboratory (ORNL), and NUMARK Associates, Inc. for a peer review on the technical adequacy of Section III, Division 5. The NRC staff evaluated the recommendations in the contractor reports (found below) and used its own independent technical expertise to form the basis for the findings in these reports.
The NRC published a notice of the availability of DG-1380 and draft NUREG-2245 in the Federal Register on August 20, 2021 (86 FR 46888) for a 60-day public comment period. Subsequent to the public comment period for DG-1380, the NRC staff completed its review of Code Cases N-872 and N-898, related to the use of Nickel-Based Alloy 617. On March 1, 2022, the NRC staff issued a supplemental Federal Register notice (87 FR 11490) to DG-1380 requesting public comment on the staff's proposed endorsement of Code Cases N-872 and N-898. The technical basis for the NRC's endorsement of Code Cases N-872 and N-898 is contained in Technical Letter Report (TLR)-RES/DE/REB-2022-01, “Review of Code Cases Permitting Use of Nickel-Based Alloy 617 in Conjunction with ASME Section III, Division 5,” dated January 31, 2022.
Publicly Available Contractor Reports Evaluated by the NRC
The NRC reviewed recommendations from the following contractor reports in preparing Revision 2 to RG 1.87 and NUREG-2245.
| Author Affiliation |
Topic Discussion |
Date Issued |
| Oak Ridge National Laboratory |
Oak Ridge National Laboratory Technical Input for the Nuclear Regulatory Commission Review of the 2017 Edition of the ASME Boiler and Pressure Vessel Code, Section III, Division 5, "High Temperature Reactors"
ASME Code Sections:
- Materials (HBB; HCB; & HGB–2000)
- Tables and Figures (Mandatory Appendix HBB–I)
- Guidelines for Restricted Material Specifications (Non-Mandatory Appendix HBB–U)
|
August 2020 |
| Pacific Northwest National Laboratory |
Pacific Northwest National Laboratory Technical Input for the Nuclear Regulatory Commission Review of the 2017 Edition of ASME Section III, Division 5, "High Temperature Reactors"
ASME Code Sections:
- Design, Fabrication, Examination, Testing (HBB; HCB; HGB–3000, –4000, –5000, –6000)
- Rules for Strain, Deformation, and Fatigue Limits (Mandatory Appendix HGB–I)
- Rules for Construction of Core Support Structures Without Explicit Consideration of Creep and Stress-Rupture (Mandatory Appendix HGB–II)
- Rules for Buckling and Instability (Mandatory Appendix HGB–III)
- Rules for Time-Temperature Limits (Mandatory Appendix HGB–IV)
|
September 2020 |
NUMARK Associates, Inc.
Engineering Mechanics Corporation of Columbus |
Technical Input for the U.S. Nuclear Regulatory Commission Review of the 2017 Edition of ASME Boiler and Pressure Vessel Code, Section III, Division 5, “High-Temperature Reactors” HBB-T, HBB-II, HCB-I, HCB-II, and HCB-III for Metallic Components
ASME Code Sections:
- Rules for use of SA–533 Type B (Mandatory Appendix HBB–II)
- Rules for Strain, Deformation, and Fatigue Limits (Nonmandatory Appendix HBB–T)
- Rules for Stress Range Reduction Factors (Mandatory Appendix HCB–I)
- Rules for Allowable Stress Values for Class B Components (Mandatory Appendix HCB–II)
- Rules for Time-Temperature Limits (Mandatory Appendix HCB–III)
|
December 2020 |
| NUMARK Associates, Inc. |
Technical Input for the U.S. Nuclear Regulatory Commission Review of the 2017 Edition of ASME Boiler and Pressure Vessel Code, Section III, Division 5, "High Temperature Reactors": Subsection HH, "Class A Nonmetallic Core Support Structures," Subpart A, "Graphite Materials"
ASME Code Sections:
- Graphite and Composites (Technical Requirements)
|
December 2020 |
NUMARK Associates, Inc.
Engineering Mechanics Corporation of Columbus |
Technical Input for the U.S. Nuclear Regulatory Commission Review of the 2017 Edition of ASME Boiler and Pressure Vessel Code, Section III, Division 5, "High-Temperature Reactors." Review of Code Case N-861 and N-862: Elastic-Perfect Plastic Methods for Satisfaction of Strain Limits and Creep-Fatigue Damage Evaluation in BPV-III-5 Rules
ASME Code Sections:
- Code Case N–861
- Code Case N–862
|
December 2020 |
| Argonne National Laboratory |
Historical Context and Perspective on Allowable Stresses and Design Parameters in ASME Section III, Division 5, Subsection HB, Subpart B (ANL/AMD-21/1)
The Argonne National Laboratory report references the following report developed by MPR Associates, Inc.
ASME Code Sections:
Provides the NRC with the technical basis and historical perspective on ASME BPVC Section III, Division 5 and the technical assistance to facilitate the staff’s efforts in drafting the RG and technical basis document
|
March 2021
February 2021
|