This rule would amend the Nuclear Regulatory Commission's (NRC) regulations to incorporate by reference the 2015 and 2017 Editions of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code and the 2015 and 2017 Editions of the ASME Operations and Maintenance (OM) Code. The NRC has a well-established practice of approving and/or mandating the use of certain parts of editions and addenda of ASME Codes in 10 CFR 50.55a through the rulemaking process of incorporation by reference. This practice increases consistency across the industry and demonstrates that the NRC will continue to support the use of the most updated and technically sound techniques developed by the ASME to provide adequate protection to the public. This rulemaking also enhances the efficiency and effectiveness of the NRC's regulations by making use of current voluntary consensus standards and is consistent with applicable requirements of the National Technology Transfer and Advancement Act. The title was revised to address that the rulemaking entitled, "2017 Edition of the American Society of Mechanical Engineers Operations and Maintenance Code" (RIN 3150-AJ90; NRC-2017-0019) was added to the scope of this rulemaking. The scope of the rulemaking was also expanded to include the rule titled 2017 Edition of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code” (RIN 3150-AJ91; NRC-2017-0020).