Document: NRC Regulatory Guide
Document ID: a4944d20-ef6e-480b-a45d-14425bedd2e5
Document Type: regulatory_guide
Title: ASME Code Cases Not Approved for Use (Rev. 8)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2219/ML22196A065.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.193
CFR Part: 
CFR Title: 

Content:
d method. The Code Case uses the methodology and Fen equations suggested in NUREG/CR-6909. One major change in the Code Case compared to NUREG/CR-6909 is the deletion of the strain threshold. However, based on industry comments that the Fen expressions give Fen values greater than 1.0 for situations when environmental effects have no impact, there are ongoing activities at NRC to modify Fen expressions. The NRC’s Office of Nuclear Regulatory Research (RES) with the assistance of experts at Argonne National Laboratory (ANL) is pursuing this effort. 9/20/10 DG-1408, Page 28 CODE CASE NUMBER TABLE 4 ANNULLED OR SUPERSEDED UNACCEPTABLE SECTION III CODE CASE ANNULLMENT / REVISION DATE N-812 Alternate Creep-Fatigue Damage Envelope for 9Cr1MoV Steel, Section III, Division 5 Code Case N-812 utilizes Section III, Division, Subsection NH, “Class 1 Components in Elevated Temperature Service.” The NRC has not approved Subsection NH for use. 8/5/11 N-818 Use of NDE and Fracture Mechanics for Acceptance of Full Penetration Butt Welds in Lieu of Weld Repair, Class 1 and Class 2, Section III, Division 1 The NRC has been conducting research at Pacific Northwest National Laboratory on the examination of austenitic and ferritic welds. The work has shown that performing a full volume examination for fabrication flaws is significantly different from an inservice examination. For example, examination from two directions is necessary to detect certain circumferentially oriented fabrication flaws such as lack of fusion. The work has also shown that the second leg of V-path can be applied to ferritic materials on a limited basis but will be difficult to apply to austenitic materials and dissimilar metal welds. Another finding is that surface conditions are critical with respect to detecting and characterizing fabrication flaws. Additionally, the PNNL research suggests that the ability to consistently and accurately characterize fabrication flaws by type (i.e., planar or volumetric) is