A federal board has ruled partly in favor of an environmental group that wants an extended hearing on the plan to restart the troubled San Onofre nuclear power plant in California.

It's not immediately clear how Monday's ruling by the Nuclear Regulatory Commission's Atomic Safety and Licensing board will impact the pending restart proposal, but it has the potential to further delay a decision that has left the plant offline for more than a year. An appeal is possible.

San Onofre hasn't produced power since January 2012, after a small radiation leak led to the discovery of unusual damage to tubing that carries radioactive water.