The Nuclear Regulatory Commission (NRC) is amending its regulations for combustible gas control in power reactors applicable to current licensees and is consolidating combustible gas control regulations for future reactor applicants and licensees. The final rule eliminates the requirements for hydrogen recombiners and hydrogen purge systems, and relaxes the requirements for hydrogen and oxygen monitoring equipment to make them commensurate with their risk significance. This action stems from the NRC's ongoing effort to risk- inform its regulations, and is intended to reduce the regulatory burden on present and future reactor licensees. Additionally, the final rule grants in part and denies in part a petition for rulemaking (PRM-50-68) submitted by Mr. Bob Christie. This notice constitutes final NRC action on PRM-50-68. The final rule also denies part of a petition for rulemaking (PRM-50-71) submitted by the Nuclear Energy Institute. The remaining issue in PRM-50-71 that is not addressed by this final rule will be evaluated in a separate NRC action. The NRC has updated a guidance document, "Control of Combustible Gas Concentrations in Containment" to address changes in the rule. A draft regulatory guide containing the revisions was published for comment with the proposed rule.