The U.S. Nuclear Regulatory Commission (NRC) is denying a petition for rulemaking (PRM or the petition), PRM-50-108, submitted by Mr. Mark Edward Leyse (the petitioner). The petitioner requested that the NRC require power reactor licensees to perform evaluations to determine the potential consequences of various postulated spent fuel pool (SFP) accident scenarios. The evaluations would be required to be submitted to the NRC for informational purposes. The NRC is denying the petition because the NRC does not believe the information is needed for effective NRC regulatory decisionmaking with respect to SFPs or for public safety, environmental protection, or common defense and security.