Briefing Report: Nuclear Power in California

Where We've Been and Where Are We Going?
Thursday, January 16, 2014


Since the late 1950s nuclear power plants have operated within California and provided electricity to its residents.  Today, California has only one operating nuclear power plant, Diablo Canyon near San Luis Obispo. 

While nuclear power has provided California with a reliable and greenhouse gas-free energy resource, it is not without controversy.  Environmental and safety concerns have surrounded this power source for years, particularly as it relates to the storage of nuclear fuel and seismic activity.  This issue came to the forefront after a 2011 earthquake and tsunami heavily damaged the Fukushima Daiichi Nuclear Power Plant in Japan.  The disaster disabled the reactor cooling systems and led to radiation releases and widespread evacuations.  In fact, toxic water continues to flow into the Pacific Ocean.  The clean-up and decommissioning of the plant is expected to take 40 years and cost billions of dollars. 

Diablo Canyon Power Plant (DCPP)

The Fukushima disaster renewed concerns about the seismic safety of the Diablo Canyon plant, which is built near four faults (San Andreas, Hosgri, Los Osos, and Shoreline).  The DCPP is owned by the Pacific Gas and Electric Company (PG&E) and has been in operation since 1985.  The plant consists of two operating units with the power capacity of 2,160 megawatts (MW), enough power to meet the needs of three million Californians. 

Both units are pressurized water reactors, which pump water under high pressure into the reactor core to absorb the heat generated by the fission of atoms and carry the heat to the steam generators.  Within the steam generators, water in a secondary circulating system is heated to create steam and drive the steam turbine to produce electricity.  A third water system draws water from the Pacific Ocean to cool and condense the steam in the turbine.  The ocean water is used once and then returned to the Pacific Ocean at a slightly higher temperature; this process is known as “once through cooling.”

The DCPP units are licensed to operate until 2024 and 2025 respectively.  The Nuclear Regulatory Commission (NRC) licenses commercial power reactors to operate for up to 40 years and allows the licenses to be renewed for up to another 20 years.

In 2009 PG&E filed a license renewal application with the NRC for the DCPP.  The license renewal process is lengthy, requiring numerous submissions of general, environmental, and technical information.  In addition, the process requires public meetings to ensure the renewal process is open and transparent.

In response to the Fukushima disaster and public concerns regarding the seismic safety of the DCPP, PG&E requested the NRC delay the final processing of the license renewal application.  PG&E requested the delay until 3D seismic studies could be completed and a report addressing the results of the studies could be submitted to the NRC.

The California Public Utilities Commission (CPUC) authorized PG&E to conduct additional seismic studies and authorized PG&E to recover costs through rates for these studies.[1]  The 2D/3D onshore and 3D low-energy offshore studies were completed in 2012.  However, PG&E’s application to conduct 3D high-energy offshore studies was denied by the California Coastal Commission in November 2012.[2]  At this time it is unknown what timeline PG&E will follow with regard to further seismic studies and their pending license renewal application.

San Onofre Nuclear Generating Station (SONGS)

California had two operating nuclear power plants until January 2012 when the San Onofre Nuclear Generating Station (SONGS) was taken offline due to excessive wear on the steam tubes.  SONGS is owned by Southern California Edison (SCE – 78.2%), San Diego Gas and Electric (SDG&E – 20%), and City of Riverside Utilities Department (1.85%).  It is located near San Clemente and consists of three electric generator units.  Unit 1 went into service in 1968 and was retired in 1992.  Units 2 and 3 became operational in the early 1980s and were permanently taken offline in June 2013.  These units provided approximately 2,200 MW of power capacity until they were taken offline.

The steam generators for Units 2 and 3 were replaced in 2009 and 2010, respectively. Both steam generators were manufactured by Mitsubishi Heavy Industries and each contained over 9,000 tubes to carry high pressure, high velocity steam.  Excessive wear was discovered on the Unit 2 steam tubes during a scheduled refueling outage.  In January 2012, tubes in the Unit 3 steam generator failed and vented a small amount of radioactive steam within the containment dome.  Upon inspection, significant wear was also found on the Unit 3 steam tubes.  Units 2 and 3 were taken offline while SCE and the NRC investigated the cause of the excessive tube wear and developed a plan to restart the plant. 

A restart plan was submitted to the NRC after months of analysis and tests. In the spring of 2013, SCE submitted a license amendment request to the NRC seeking approval to restart Unit 2 at 70% power for a five month period.  SCE believed operating at 70% power would prevent the conditions that caused the tube wear that initially shut down Units 2 and 3.  However, on June 7, 2013 SCE announced it would permanently retire SONGS Units 2 and 3.  SCE stated, “SONGS has served this region for over 40 years, but we have concluded that the continuing uncertainty about when or if SONGS might return to service was not good for our customers, our investors, or the need to plan for our region’s long-term electricity needs.”

The unplanned shut down of SONGS raised reliability and economic issues - issues that remain even as the decommissioning process begins.  SONGS provided a large amount of power to southern California, which needed to be replaced on a short-term and now, long-term basis.  This replacement power, whether it comes from rooftop solar, conservation, natural gas, or other sources, comes at a cost. 

The CPUC must now determine whether the utilities will be allowed to charge the ratepayers for the cost of the replacement power and the operations and maintenance of SONGS and possibly recoup the cost of investment in steam generators that failed.  A proposed decision is expected to come before the CPUC early this year.

Decommissioning Process

SCE filed a Certificate of Permanent Cessation of Power Operations with the NRC in June 2013 and set the stage for the beginning of the decommissioning process.  The NRC has strict rules governing the decommissioning process, including the cleanup of radioactively contaminated plant systems and structures and the removal of radioactive fuel.

The decommissioning process is costly and lengthy.  The cost to decommission SONGS Units 2 and 3 is estimated at $4.1 billion.  The NRC requires nuclear power plants to set aside funds for decommissioning while the plant is operational.  SCE has been collecting funds from their ratepayers, as authorized by the CPUC, to pay for the decommissioning of SONGS.

In decommissioning a facility, the owner has three options:  DECON or immediate dismantling of the facility; SAFSTOR or “deferred dismantling” maintains the facility and allows the radioactivity to decay and then be dismantled; or ENTOMB which permanently encases the radioactive contaminants on site until the radioactivity decays to safe levels.  By 2015 SCE must submit to the NRC a detailed decommissioning plan and schedule, including cost estimates and potential environmental impacts.  Public meetings are held near the facility to allow for comment on the proposed plan.  It is expected the decommissioning process will be completed within 60 years of the plant ceasing operations.   

For more information on the decommissioning process, please visit the NRC’s website at:

Once Through Cooling (OTC)

Nineteen power plants in California, including SONGS and DCPP, utilize a process known as “once through cooling” (OTC).  OTC uses water from nearby sources and is a controversial process because of its impacts on the environment.  Wildlife has become trapped by the intake screens as a result of the force of the intake water (impingement), while smaller organisms have been carried through the entire cooling system (entrainment).  Additionally, the water being returned to the ocean is warmer and thus has altered the local ecosystems.

In 2010 the State Water Resources Control Board (SWRCB) approved an OTC policy and new regulations became effective on October 1, 2010.  The new policy requires power plant owners/operators to reduce the impact of the use of seawater by 93%.  Recognizing the unique nature of California’s nuclear facilities the OTC policy required SONGS and DCPP to undertake special studies to investigate alternatives for the facilities to meet the policy requirements.  An advisory body, the Review Committee for Nuclear Fueled Power Plants, was established to oversee the special studies. 

DCPP has until 2024 to comply with the OTC regulations.  These changes will be costly and will ultimately be borne by the ratepayers.  

The Future

The future of nuclear power in California is limited.  The licenses for the remaining commercial nuclear fission reactors will expire in 2045, assuming the license renewals are approved by the NRC.  A nuclear fusion reactor is unforeseeable in the near future since fusion technology is still in the research and development stages.  New construction of a nuclear power facility in California has been restricted until certain conditions have been met.  Complying with California’s OTC policy will be expensive and will likely raise controversy regardless of the option chosen.  Finally, an initiative impacting the operation of DCPP was cleared for circulation.[3]

The initiative proposes to extend statutory preconditions, currently applicable to the operation of a new nuclear power plant, to the operation of DCPP.  Therefore, under this initiative, continued electricity production at DCPP would require the California Energy Commission (CEC) to make specified findings.  The CEC must find the federal government has approved technology for the permanent disposal of high-level nuclear waste and, for nuclear power plants requiring reprocessing of fuel rods, the CEC must find the federal government has approved technology for nuclear fuel rod reprocessing plants.  The proposed initiative is in circulation until February 10, 2014 and requires 504,760 signatures. 

Regardless of the outcome for the initiative, California must plan for the day when nuclear power generation ceases in California.  California will have to prepare to replace large amounts of power that will likely be more costly to its ratepayers.

For more information on this report or other Energy, Utilities, & Communications  issues, contact Kerry Yoshida, Senate Republican Office of Policy at 916/651-1501.

[1] CPUC Decision 10-08-003.

[2] California Coastal Commission, November 2012 Agenda, Application No. E-12-005 and CC-027-12.

[3] Initiative 1599 (13-0009).  Nuclear Power.