Aerial view of Diablo Canyon Power Plant

Nuclear Operations

Diablo Canyon Power Plant is a safe, clean and reliable energy resource for California and generates carbon-free energy for more than 3 million people. Diablo Canyon also serves as one of the main employers and buyers of goods in the San Luis Obispo County region.

Our Approach

We remain strongly committed to the highest levels of safety, performance and security at Diablo Canyon. The Nuclear Regulatory Commission’s (NRC) 2015 assessment places Diablo Canyon among the higher performing plants in the U.S. nuclear industry. This reflects the hard work and dedication of our employees and our commitment to meeting PG&E’s and the NRC’s high performance standards.

Demonstrating Earthquake, Flooding and Tsunami Safety

New and extensive analyses performed at the direction of the NRC reaffirmed that Diablo Canyon can safely withstand extreme natural events, including potential earthquakes, tsunamis and flooding. The analyses used the latest regulatory guidance, scientific methods and models, site-specific information and independent expertise to reevaluate the impacts that earthquakes, large waves and flooding could have on the facility. The updated findings represent the culmination of years of study and analysis, and further confirm the safety of the plant’s design.

The updated seismic assessment represents a more extensive evaluation of the seismic hazard than previously performed. Using the NRC’s Senior Seismic Hazard Analysis Committee process, independent seismic experts publicly re-evaluated existing and new seismic information to reevaluate how earthquakes could potentially impact the facility. The result provides additional confirmation that the plant is seismically safe.

The assessment also informs PG&E’s Long-Term Seismic Program, led by a geosciences team of professionals that partners with independent seismic experts on an ongoing basis to evaluate regional geology and global seismic events to ensure that the facility remains safe.

PG&E’s flooding hazard re-evaluation determined that the plant’s key safety systems and components continue to be safe from tsunamis, including those generated from underwater landslides and earthquakes.

Used Fuel Storage

Visitors at the Pecho Trail

Visitors can learn about the plant and a range of energy-related topics at our Energy Education Center and the Diablo Canyon website. Also, guided tours of Diablo Canyon provide an opportunity to speak directly with employees and learn how the plant provides safe, reliable and clean energy.

Photo by John Lindsey

At both Diablo Canyon and a former nuclear unit at Humboldt Bay Power Plant, PG&E safely stores used fuel in on-site dry cask storage systems approved and licensed by the NRC. Diablo Canyon also safely and securely stores used fuel in wet storage facilities. These on-site storage systems are used at nuclear power plants around the world.

These two on-site interim storage solutions are federally monitored and follow industry best standards to ensure that they are safe and effective. The ability to store used fuel safely on-site, however, should not be a long-term alternative to the federal government assuming its responsibility to accept the fuel for permanent storage. To that end, PG&E will continue to advocate that the federal government meet its commitment and take charge of managing the nation’s used fuel.

Water Management

PG&E actively manages the water used in the electric generation process in accordance with the water discharge limit set by Diablo Canyon’s Clean Water Act permit.

2015 Milestones

Beyond energy: Giving back to the local community

PG&E employees volunteer thousands of hours of their personal time each year to after-school athletic programs, environmental organizations, churches and other community organizations. In 2015, PG&E also made charitable contributions of nearly $900,000 to more than 110 nonprofit organizations in San Luis Obispo and Northern Santa Barbara Counties. Local PG&E employees pledged more than $730,000 to nonprofit organizations through PG&E’s Campaign for the Community.

In a typical year, at least one of Diablo Canyon’s two reactor units safely undergoes a planned refueling and maintenance outage. Once every five years—most recently in 2014—both units undergo a planned refueling and maintenance outage, due to their separate operating schedules.

In 2015, Unit 1 at Diablo Canyon underwent a safe and successful refueling and maintenance outage.

PG&E also continued decommissioning the former nuclear unit at Humboldt Bay Power Plant. PG&E has completed removal of prior operational nuclear systems and equipment, as well as demolition and removal of some structures on-site. Final site restoration and remediation plans have been approved by the NRC, and permits to support that work also have been approved.

Measuring Progress

Diablo Canyon consistently achieves strong performance as gauged by the plant’s capacity factor, a measure of generation reliability. In 2015, the plant’s capacity factor saw a marked increase, which can be attributed to a continued focus on operational excellence and the fact that we held planned outages to refuel both units at the plant in 2014.

Nuclear Power Plant Performance
Average Capacity Factor Footnote 1
2013 92%
2014 87%
2015 94%
  • 1. Refers to the ratio of the actual output of the plant relative to the output if the plant had operated at full capacity for the year. Return to table

Diablo Canyon is a vital local economic engine and brings significant benefits to San Luis Obispo and Northern Santa Barbara counties. Planned refueling outages can bring almost 1,000 temporary workers to the Central Coast where they spend money on local housing, dining and shopping. In advance of planned outages, PG&E holds jobs fairs at our Energy Education Center in San Luis Obispo to help fill the temporary positions.

Beyond these temporary jobs, PG&E is the largest private employer in the area, with nearly 1,500 workers and operations that contribute more than $900 million to the region through the funds that we directly spend and the subsequent economic activity in the community from those investments. Tax revenues from the plant, the largest property tax payer in San Luis Obispo County, help fund schools, public works projects, public safety, and health and other vital services.

Looking Ahead

California’s energy landscape is changing dramatically with energy efficiency, renewables and storage being central to the state’s energy policy. In step with this policy, PG&E announced a joint proposal with labor and leading environmental organizations in June 2016 that would increase investment in energy efficiency, renewables and storage beyond current state mandates while phasing out PG&E’s production of nuclear power in California by 2025.

The parties to the joint proposal are PG&E, the International Brotherhood of Electrical Workers Local 1245, the Coalition of California Utility Employees, Friends of the Earth, the Natural Resources Defense Council, Environment California and the Alliance for Nuclear Responsibility.

The parties jointly propose that Diablo Canyon be replaced with a cost-effective greenhouse gas-free portfolio of energy efficiency, renewables and energy storage. It includes a PG&E commitment to a 55 percent renewable energy target in 2031, an unprecedented voluntary commitment by a major U.S. energy company.

Recognizing that the procurement, construction and implementation of a greenhouse gas-free portfolio of energy efficiency, renewables and storage will take years, the parties recognize that PG&E intends to operate Diablo Canyon until the end of its current NRC operating licenses, which expire on November 2, 2024 (Unit 1) and August 26, 2025 (Unit 2).

This eight- to nine-year transition period will provide the time to begin the process to plan and replace Diablo Canyon’s energy with new greenhouse gas-free resources.

As part of the joint proposal, PG&E immediately ceased any efforts on its part to renew the Diablo Canyon operating licenses, and asked the NRC to suspend consideration of the pending Diablo Canyon license renewal application. PG&E will withdraw the application if the CPUC approves the joint proposal.

PG&E currently does not believe that long-term customer rates will increase as a result of the joint proposal. The company believes that it is likely that implementing the proposal will have a lower overall cost than relicensing Diablo Canyon and operating it through 2044. Factors affecting this include, in addition to lower demand, declining costs for renewable power and the potential for higher renewable integration costs if Diablo Canyon is relicensed.

The parties to the agreement are jointly committed to supporting a successful transition for Diablo Canyon employees and the community. PG&E's Diablo Canyon retention program will provide, among other things, incentives to retain employees during the remaining operating years of the plant, a retraining and development program to facilitate redeployment of a portion of plant personnel to the decommissioning project or other positions within the company, and severance payments upon the completion of employment.

In addition, the joint proposal includes payments by PG&E to San Luis Obispo County totaling nearly $50 million. The proposed payments are designed to offset declining property taxes through 2025 in support of a transition plan for the county.

During the transition period, we will continue our efforts to ensure the safety of our operations at the power plant.





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