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Federal Register / Vol. 86, No. 20 / Tuesday, February 2, 2021 / Proposed Rules The NRC approved this Code Case with conditions in a 50.55a rulemaking issued in 2017 82 FR
32934, Sept. 18, 2017, and the supplement was not modified in a way that would make it possible for the NRC
to remove the conditions. Therefore, the NRC is including a condition that this Code Case can only be used for the service life of a component that had the horizontally arranged NPT Code Symbol Stamp applied during the time period from January 1, 2005, through December 31, 2015.

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Code Case N883 Supplement 5, 2017
Edition Type: New.
Title: Construction of Items Prior to the Establishment of a Section III, Division 1 Owner, Section III, Division 1.
This Code Case allows certificate holders to construct all items prior to the establishment of an Owner. Code Case N883 was developed to address international stakeholders and identify the ASME as a global standard development organization. The NRCs main concern is that without the designation of an Owner, the NRC
would not be able to provide regulatory oversight of the ASME certificate holder manufacturing the items, which is not consistent with appendix B to 10 CFR
part 50 and the requirements in 50.55a for a basic component. During discussions with the ASME staff on this Code Case, it was determined that the NRC would condition this Code Case based on regulatory oversight, as would other regulatory bodies depending on each countries specific regulations.
This is evident as this Code Case specifies that the the items have been constructed by ASME Certificate Holders who are specifically authorized by the Regulatory Authority having jurisdiction over the Owners facility to construct items using this Case. The proposed condition, This Code Case may be used for the construction of items by a holder of a construction permit, operating license, or combined license under 10 CFR part 50 or part 52, provides this specific regulatory authorization thereby ensuring the appropriate regulatory oversight.
Code Case N886 Supplement 6, 2017
Edition Type: New.
Title: Use of Polyethylene Pipe for Class 3, Section III, Division 1.
This Code Case is applicable for the use of polyethylene pipe in Section III, Class 3, Division 1 above ground applications. This Code Case refers to Mandatory Appendix XXVI of Section
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III of the ASME Code. The 2015 Edition of Appendix XXVI contains requirements for butt fusion joints for buried piping. The 2017 Edition of Appendix XXVI contains requirements for butt fusion and electrofusion joints for buried piping. Therefore, all the conditions as noted in Section III of the 20152017 Code Edition rule related to buried piping Mandatory Appendix XXVI apply to this Code Case. The same conditions as buried piping also apply to above ground application. Two additional conditions are needed for above ground applications, one on fire protection and one on carbon black distribution to protect from windows and delamination. A condition on fire protection is needed because polyethylene material is combustible and above ground uses are more susceptible to fire hazards. In addition, a condition requiring homogeneous carbon black distributiuon is needed because experiments have shown that inhomogeneous carbon black distribution can lead to windows and delamination.
2. ASME BPV Code, Section XI Code Cases DG1367/RG 1.147
Code Case N5135 Supplement 6, 2017 Edition Type: Revised.
Title: Evaluation Criteria for Temporary Acceptance of Flaws in Moderate Energy Class 2 or 3 Piping and Gate Valves, Section XI, Division 1.
Code Case N5135 contains provisions to permit temporary acceptance of flaws, in moderate energy Class 2 or 3 piping, including elbows, pipe bends, reducers, expanders, branch tees, and gate valves without performing a repair/replacement activity for a limited period. The Code Case contains provisions regarding the scope, flaw characterization, periodic leakage monitoring, flaw evaluation, and augmented examinations. The NRC
finds that the provisions of N5135 are acceptable except for the augmented examination provisions in Section 5 of the Code Case.
When a licensee applies N5135 to disposition a through-wall leak or wall thinning in a piping system, Section 5
of the Code Case requires augmented examinations for flaws and significant flaws. The augmented examination requirements in N5135 are the same as in Code Case, N5133.
In 2018, the NRC found an instance where a licensee misinterpreted the provisions in Section 5 of N5133 and did not perform the required augmented examinations to disposition a throughwall leak in a service water system pipe.

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Other licensees have similarly misinterpreted the augmented examination provisions in Section 5 of N5133. The NRC found that the issue stems from the definition of the terms flaw and significant flaw in Sections 5b and 5c of N5133, respectively. The NRC, therefore, proposes two conditions to define flaw and significant flaw as those terms are used in Section 5 of N513
5. Licensees would be required to apply these definitions to Section 5 when using the Code Case.
The first proposed condition defines a flaw as a non-through-wall planar or nonplanar flaw with a wall thickness less than 87.5 percent of the nominal wall thickness of the pipe or the design minimum wall thickness. The NRC
notes that the pipe wall thickness at the time of the plant construction may deviate from the nominal pipe wall thickness slightly as part of manufacturing process. The generally accepted deviation is 12.5 percent of the nominal pipe wall thickness or the design minimum wall thickness.
The second proposed condition defines significant flaw as any pipe location that does not satisfy the provisions of Section 3 of N5135 or if any detected flaw that has a depth greater than 75 percent of the pipe wall thickness. The NRC staff notes that the criterion of the 75 percent wall thickness criterion originates from the provisions of IWC/IWD3643 of the ASME Code, Section XI, which prohibits a flaw that exceeds 75 percent of the pipe wall thickness to remain in service. Under Section 5 of N5135, a planar flaw that exceeds 75 percent of the pipe wall thickness may remain in service; however, the licensee must perform an augmented examination.
Code Case N5165 Supplement 6, 2015 Edition Type: Revised.
Title: Underwater Welding, Section XI, Division 1.
In the rulemaking for the 2009
Addenda through 2013 Editions of the ASME Code 82 FR 32934, Sept. 18, 2017, the NRC-specified conditions that should be applied to Section XI, Article IWA4660 when performing underwater welding on irradiated materials. These conditions provide guidance on what level of neutron irradiation and/or helium content would require review and approval by the NRC because of the impact of neutron fluence on weldability. These conditions provide separate criteria for three generic classes of material: Ferritic material, austenitic material other than P-No. 8 e.g., nickelbased alloys and austenitic P-No. 8

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