Federal regulators on Tuesday rejected a request from PG&E that would have eased the utility company’s efforts to keep operating California’s last nuclear power plant longer. The Nuclear Regulatory Commission (NRC) sent the utility company a letter on Tuesday spelling out the steps it must take to keep operating Diablo Canyon Power Plant past 2025, when it’s scheduled to close. PG&E originally applied for license renewal for Diablo Canyon in 2009 — only to withdraw and terminate that application in 2018 after announcing plans to close the San Luis Obispo County nuclear power plant and replace …