Last nuclear reactors win exemption to keep running

LOS ANGELES — Government regulators Thursday granted California’s largest utility an unusual exemption that could allow the state’s last nuclear power plant to continue running after the expiration of its federal operating licenses, a key piece of a contentious proposal to keep the reactors producing electricity for years to come.

The twin-reactor Diablo Canyon plant is scheduled to shut down by 2025. But the federal exemption will permit operator Pacific Gas & Electric to keep producing power while the Nuclear Regulatory Commission reviews an expected application from the utility to extend the plant’s operating run by up to two decades.