Media Contact: Maureen Brown, (626) 302-2255

ROSEMEAD, Calif., Dec. 11, 2014 — Southern California Edison (SCE) has selected Holtec International to expand the San Onofre nuclear plant’s storage of used nuclear fuel in a robust underground facility.

The contract with Holtec represents a major step in the decommissioning of the nuclear plant. It sets the stage to transfer San Onofre’s used fuel from steel-lined concrete storage pools to steel-and-concrete-encased canisters, with a goal of completing the work by mid-2019. 

“After reviewing leading designs with the San Onofre Community Engagement Panel, we concluded this underground design is best suited to safely and securely store used nuclear fuel at San Onofre until the federal government removes the fuel from site, as required,” said Chris Thompson, SCE vice president of Decommissioning. “Our decision to move expeditiously to transfer the fuel also reflects feedback from community leaders who prefer dry storage of used nuclear fuel.”

Thompson noted the robust Holtec design exceeds California earthquake requirements and protects against hazards such as water, fire or tsunamis.

“I especially want to thank the Community Engagement Panel for its thoughtful questions and enormous time commitment during SCE’s evaluation,” said Thompson, noting that SCE ultimately focused on cask designs licensed by the Nuclear Regulatory Commission for both storage and transport of used nuclear fuel.

While dry storage of nuclear fuel is a proven technology used for almost three decades in the United States, Thompson said SCE will go beyond industry practices by partnering with the Electric Power Research Institute to develop new inspection techniques to monitor cask integrity.

Holtec’s HI-STORM UMAX underground storage system features corrosion-resistant, stainless-steel fuel canisters topped with a 24,000-pound steel and concrete lid. The canisters will be encased in a concrete monolith. Holtec is a global supplier and has nuclear fuel storage systems at two other California locations, Humboldt Bay and Diablo Canyon. More information is available in this fact sheet.

Thompson said engineering work begins immediately, followed by fabrication of canisters. Completion of the dry storage project facilitates major dismantlement work SCE plans to complete within 20 years.

SCE announced in June 2013 that it would retire San Onofre Units 2 and 3, and begin preparations to decommission the facility. SCE has established core principles of safety, stewardship and engagement to guide decommissioning. For more information about SCE, visit

About Southern California Edison

An Edison International (NYSE:EIX) company, Southern California Edison is one of the nation’s largest electric utilities, serving a population of nearly 14 million via 4.9 million customer accounts in a 50,000-square-mile service area within Central, Coastal and Southern California.