The move comes as the existing storage facility, which was approved in 2001, will soon reach its capacity, the company said in the application.
SCE claimed that the expansion project would require up to 80 more steel-and-concrete-encased canisters, also known as dry storage technology.
Currently the nuclear facility’s two-thirds of used fuel is stored on site in steel-lined, concrete storage pools known as wet storage while approximately one-third is already in dry storage.
SCE Decommissioning vice president Chris Thompson said: "Local community leaders and a wide range of stakeholders in California have told us they want San Onofre’s used nuclear fuel moved to dry storage as expeditiously as possible.
"We want to be responsive to that preference while continuing to safely manage this fuel until the federal government does its job and opens a used nuclear fuel repository."
Thompson said that the approval of the independent spent fuel storage installation, which currently comprises 51 canisters, expansion project is required before SCE can complete the transfer to dry storage in next four years.
As part of the expansion project, SCE has also selected Holtec International’s below-ground dry fuel storage technology for the San Onofre nuclear power plant.
The nuclear plant is located on the Pacific coast of California, in the northwestern corner of San Diego County, south of San Clemente, and situated in Nuclear Regulatory Commission Region IV.
