Providing Nuclear Power Safely and Responsibly

To ensure that the plant continues to deliver reliable energy for many years, PG&E completed the largest construction project since Diablo Canyon was built—a $700 million initiative to replace its steam generators in both Units 1 and 2.

Diablo Canyon Unit 1 steam generators temporarily housed before installation. Photo: Jim Zimmerlin
These critical pieces of equipment drive the plant’s electric turbines. The four Unit 1 generators were replaced in early 2009 and Unit 2’s generators were replaced in early 2008. Power Engineering magazine recognized the Unit 1 project as the “Nuclear Project of the Year” for operational excellence.

(left) A steel and concrete container housing the used nuclear fuel is placed onto a 7-1/2 foot thick concrete pad. The container is bolted to the concrete pad as a seismic restraint.

(right) The new Unit 2 reactor head and integrated head assembly preparing to be raised into the reactor cavity. Diablo Canyon reached another significant milestone by loading used fuel to the plant's interim on-site storage facility for the first time. On-site dry cask storage systems, approved and licensed by the Nuclear Regulatory Commission, are being used at nuclear power plants across the country to safely store used fuel until the federal government fulfills its obligation to take ownership of the fuel by building a permanent storage facility. The on-site storage systems protect the used fuel against a range of threats, including severe weather, earthquakes and terrorism. In 2009, PG&E placed eight containers, containing 32 fuel assemblies each, at the plant's storage facility.

PG&E also successfully completed a challenging refueling outage for Unit 2 in which the reactor vessel head was replaced to improve performance and reliability. The company also replaced the unit's main generator rotor to further enhance reliability.

Diablo Canyon's current federal operating licenses for Units 1 and 2 expire in 2024 and 2025, respectively. Looking to the future, in late 2009 PG&E began the process of seeking 20-year license extensions for each of the two units through 2044 and 2045—a necessary step toward meeting the state's ambitious greenhouse gas reduction goals and the state's increasing demands for reliable, low-cost electricity for homes and businesses. In fact, closing Diablo Canyon and replacing it with conventional fossil fuel-burning plants would result in millions of tons of greenhouse gas emissions per year.

PG&E also plans to decommission its retired nuclear unit at the Humboldt Bay Power Plant near Eureka, California. PG&E began disassembling the unit last year as part of the first phase to remove radioactive components, piping and some structures. Subsequently, PG&E will decontaminate or remove the remaining structures and materials to permit building demolition and site restoration. PG&E expects to complete the decommissioning process in 2015. A facility will remain on site to safely store the used nuclear fuel until a permanent storage facility is available.

Current California law prohibits the building of any new nuclear power plants in the state until the federal government takes ownership of the used fuel. PG&E currently has no plans to develop new nuclear generating capacity.

(For additional information on waste storage and other issues associated with Diablo Canyon and Humboldt Bay, please see page 46 of PG&E's 2009 Annual Report to Shareholders.)

PG&E remains focused on ensuring that Diablo Canyon continues, and improves upon, its strong record of safe operations. This includes making the facility resilient to natural hazards, including earthquakes. PG&E’s permanent staff of seismic experts is currently partnering with the U.S. Geological Survey to update the seismic data for the area along the state’s Central Coast to ensure the facility remains one of the most seismically sound commercial nuclear facilities in the world.

We have enhanced security that meets Nuclear Regulatory Commission and other governmental standards. Diablo Canyon also works with San Luis Obispo County and the state of California on emergency preparedness. Each year, PG&E employees, along with a number of government agencies, participate in drills and exercises to test readiness to respond to a crisis along the Central Coast.

Diablo Canyon contributes greatly to the local community. In addition to the thousands of hours our employees volunteer for after-school athletic programs, environmental organizations, churches and other community organizations, the plant also makes significant contributions to the local economy. As a major employer and purchaser of goods and services, Diablo Canyon has a total economic impact of more than $640 million annually for San Luis Obispo County and another $100 million for the state.

As part of PG&E’s commitment to be a good neighbor, we also make local charitable contributions of more than $250,000 annually, which fund a wide variety of school programs, senior centers and other vital community projects.