G/TBT/N/USA/1780/Add.1  
 
8 February 2023  
(23-0935) Page: 1/2 
Committee on Technical Barriers to Trade  Original: English  
 
NOTIFICATION  
Addendum  
The following communication , dated  8 February 2023, is being circulated at the request of the 
delegation of the United States of America . 
 
_______________  
 
 
Title:  Acceptability of ASME Code Section III, Division 5, High Temperature Reactors  
 
Reason for Addendum:  
[ ] Comment period changed - date:   
[ ] Notified measure adopted - date:  
[ ] Notified measure published - date:  
[ ] Notified measure enters into force - date:  
[ ] Text of final measure available from1:  
[ ] Notified measure withdrawn or revoked - date:  
Relevant symbol if measure re -notified:   
[ ] Content or scope of notified measure changed  and text available from1:  
New deadline for comments (if applicable):   
[X] Interpretive guidance issued and text available from1:  
Regulatory guide; NUREG; issuance  
https://www.nrc.gov/re ading -rm/doc -collections/reg -guides/power -reactors/rg/division -
1/division -1-81.html  
https://www.govinfo.gov/content/pkg/FR -2023-02-07/html/2023 -02518.htm  
https://www.govinfo.gov/content/pkg/FR -2023-02-07/pdf/2023 -02518.pdf  
[ ] Other:  
https://members.wto.org/crnattachments/2023/TBT/USA/23_0993_00_e.pdf  
 
Description:  TITLE: Acceptability of ASME Code, Section III, Division 5, High Temperature Reactors  
AGENCY: Nuclear Regulatory Commission  
ACTION: Regulatory guide; NUREG; issuance  
SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is issuing Revision 2 to Regulatory Guide 
(RG), 1.87, "Acceptability of ASME Code, Section III, Division 5, 'High Temperature Reactors.' " This 
RG, accessible at https://www.nrc.gov/reading -rm/doc -collections/reg -guides/power -
 
1 This information can be provided by including a website address, a pdf attachment, or other 
information on where the text of the final /modified  measure and/or interpretive guidance can be obtained.  G/TBT/N/USA/1780/Add.1  
 
- 2 - 
 
  reactors/rg/division -1/division -1-81.html , 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 Mechani cal 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. The NRC is also issuing 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."  
DATES: Revision 2 to RG 1.87 is available on 7 February 2023.  
This regulatory guide; NUREG; issuance and the draft regulatory guide; draft NUREG; request for 
comment notified as G/TBT/N/USA/1780  are identified by Docket Number NRC -2021-0117. The 
Docket Folder is available on Regulations.gov at https://www.regulations.gov/docket/NRC -2021-
0117/document  and provides access to primary and supporting documents as well as comments 
received. Documents are also accessible from Regulations.gov  by searching the  Docket Number.  
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