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Federal Register / Vol. 86, No. 20 / Tuesday, February 2, 2021 / Proposed Rules
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III. Discussion This proposed rule would incorporate by reference NUREG2228 and the latest revisions of the NRCs RGs that list the ASME BPV and OM Code Cases that the NRC finds to be acceptable, or acceptable with NRC-specified conditions conditionally acceptable.
Regulatory Guide 1.84, Revision 39
DG1366 would supersede the incorporation by reference of Revision 38; RG 1.147, Revision 20 DG1367
would supersede the incorporation by reference of Revision 19; and RG 1.192, Revision 4 DG1368 would supersede the incorporation by reference of Revision 3.
The ASME Code Cases that are the subject of this proposed rule are the new and revised Section III and Section XI
Code Cases as listed in Supplements 0
through 7 to the 2015 Edition of the ASME BPV Code, Supplements 0
through 7 to the 2017 Edition of the ASME BPV Code, Supplements 0 and 1
to the 2019 Edition of the ASME BPV
Code, and the OM Code Cases listed in the 2020 Edition of the ASME OM Code.
The latest editions and addenda of the ASME BPV and OM Codes that the NRC
has approved for use are referenced in 50.55a. The ASME also publishes Code Cases that provide alternatives to existing Code requirements that the ASME developed and approved. This proposed rule would incorporate by reference the most recent revisions of RGs 1.84, 1.147, and 1.192, which allow nuclear power plant licensees, and applicants for combined licenses, standard design certifications, standard design approvals, and manufacturing licenses under the regulations that govern license certifications, to use the Code Cases listed in these RGs as suitable alternatives to the ASME BPV
and OM Codes for the construction, inservice inspections, and inservice testing of nuclear power plant components. Because the NRC is proposing to require the use of NUREG
2228, Weld Residual Stress Finite Element Analysis Validation: Part II
Proposed Validation Procedure, within a condition on Code Case N847, the NRC is also incorporating by reference NUREG2228. The ASME publishes the OM Code Cases and lists the Code Cases in the ASME OM Code edition. In contrast, the ASME publishes BPV Code Cases in a separate document and at a different time than the ASME BPV Code Editions. This proposed rule identifies the Code Cases by the edition of the ASME BPV Code or ASME OM Code under which they were published by the ASME.

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The following general guidance applies to the use of the ASME Code Cases approved in the latest versions of the RGs that are incorporated by reference into 50.55a as part of this proposed rule. Specifically, the use of the Code Cases listed in the latest versions of RGs 1.84, 1.147, and 1.192
are acceptable with the specified conditions when implementing the editions and addenda of the ASME BPV
and OM Codes incorporated by reference in 50.55a.
The approval of a Code Case in the NRCs RGs constitutes acceptance of its technical position for applications that are not precluded by regulatory or other requirements or by the recommendations in these or other RGs.
The applicant or licensee is responsible for ensuring that use of the Code Case does not conflict with regulatory requirements or licensee commitments.
The Code Cases listed in the RGs are acceptable for use within the limits specified in the Code Cases. If the RG
states an NRC condition on the use of a Code Case, then the NRC condition supplements and does not supersede any conditions specified in the Code Case, unless otherwise stated in the NRC condition.
The ASME Code Cases may be revised for many reasons e.g., to incorporate operational examination and testing experience and to update material requirements based on research results.
On occasion, an inaccuracy in an equation is discovered or an examination, as practiced, is found not to be adequate to detect a newly discovered degradation mechanism.
Therefore, when an applicant or a licensee initially implements a Code Case, 50.55a requires that the applicant or the licensee implement the most recent version of that Code Case, as listed in the RGs incorporated by reference. Code Cases superseded by revision are no longer acceptable for new applications unless otherwise indicated.
Section III of the ASME BPV Code applies to new construction i.e., the edition and addenda to be used in the construction of a plant are selected based on the date of the construction permit and are not changed thereafter, except voluntarily by the applicant or the licensee. Hence, if a Section III
Code Case is implemented by an applicant or a licensee and a later version of the Code Case is incorporated by reference into 50.55a and listed in the RG, the applicant or licensee may use either version of the Code Case subject, however, to whatever change requirements apply to its licensing basis e.g., 50.59 until the next mandatory
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inservice inspection or inservice testing update.
A licensees inservice inspection and inservice testing programs must be updated every 10 years to the latest edition and addenda of the ASME BPV
Code, Section XI, and the OM Code, respectively, that were incorporated by reference into 50.55a and in effect 18
months prior to the start of the next inspection and testing interval.
Licensees that were using a Code Case prior to the effective date of its revision may continue to use the previous version for the remainder of the 120month inservice inspection or inservice testing interval. This relieves licensees of the burden of having to update their inservice inspection or inservice testing program each time a Code Case is revised by the ASME and approved for use by the NRC. Code Cases apply to specific editions and addenda, and Code Cases may be revised if they are no longer accurate or adequate, so licensees choosing to continue using a Code Case during the subsequent inservice inspection or inservice testing interval must implement the latest version incorporated by reference into 50.55a and listed in the RGs.
The ASME may annul Code Cases that are no longer required, are determined to be inaccurate or inadequate, or have been incorporated into the BPV or OM
Codes. A Code Case may be revised, for example, to incorporate user experience.
The older or superseded version of the Code Case cannot be applied by the licensee or applicant for the first time.
If an applicant or a licensee applied a Code Case before it was listed as superseded, the applicant or the licensee may continue to use the Code Case until the applicant or the licensee updates its construction Code of Record in the case of an applicant, updates its application or until the licensees 120month inservice inspection or inservice testing update interval expires, after which the continued use of the Code Case is prohibited unless NRC
authorization is given under 50.55az.
If a Code Case is incorporated by reference into 50.55a and later a revised version is issued by the ASME
because experience has shown that the design analysis, construction method, examination method, or testing method is inadequate, the NRC will amend 50.55a and the relevant RG to remove the approval of the superseded Code Case. Applicants and licensees should not begin to implement such superseded Code Cases in advance of the rulemaking.

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