Posted on March 9, 2012

PG&E Reaffirms Commitment to Safety at Diablo Canyon Power Plant

By Tracy Correa

Diablo Canyon Power Plant

After the Fukushima accident, the Diablo Canyon Power Plant staff conducted extensive reviews of procedures, and both process and physical upgrades were made.

With the one-year anniversary of the earthquake and tsunami that devastated Japan and the Fukushima Daiichi nuclear power plant, understandably questions continue to emerge about the safety of all nuclear facilities.

While officials at PG&E want to ensure the public that its Diablo Canyon Power Plant is safe and secure, they also insist that much was learned from what happened at Fukushima on March 11, 2011, and afterward.  There always has been — and will continue to be — an ongoing effort to maximize and improve safety at the plant located in San Luis Obispo County.

PG&E, like the rest of the nuclear power industry, has and continues to take the Fukushima accident seriously. According to John Conway, PG&E’s senior vice president of energy supply and chief nuclear officer, “PG&E took immediate action and quickly launched a detailed and thorough review of our operations, specifically analyzing Diablo Canyon’s ability to respond to beyond-design-basis events.”

What happened at the Japanese plant is described as a “beyond design basis event.” That simply means that the events there were beyond what the plant was designed to handle.

In the hours, days and weeks following the events in Japan, PG&E and its Diablo team invested more than 10,000 employee hours in its post-Fukushima response. As a result, the following actions were taken:

  • Confirmed that Diablo Canyon’s design is appropriate and able to withstand regional environmental hazards, including tsunamis and the largest credible earthquakes that could potentially result from nearby faults, in light of what happened at Fukushima;
  • Verified the safety of the plant’s systems and emergency response procedures;
  • Created a team to examine opportunities to improve the facility’s ability to withstand beyond-design-basis events;
  • Initiated physical modifications and other enhancements to strengthen the ability of the plant to withstand beyond-design-basis events, including extended blackouts, without experiencing fuel damage;
  • Conducted rigorous emergency preparedness training, specifically for beyond-design-basis events. This includes the ability to initiate emergency procedures for multiple-unit events, as well as training and qualifications for beyond-design-basis events procedures;
  • Purchased additional emergency equipment such as pumps and pipes that the plant may need during a beyond-design-basis event.

PG&E’s ongoing focus on safety extends to continually evaluating seismic issues and applying new information to help assure that the facility remains seismically safe through the company’s Long Term Seismic Program and Advanced Seismic studies. PG&E is the only utility in the country that employs a full-time seismic department with a mission to continually assess the current state of seismic knowledge and to study local geographic features and regional and global seismic events and apply new information.

There are a number of differences between Fukushima and Diablo Canyon Power Plant. Most notably, the majority of the Diablo’s safety components are located 85 feet above sea level – well above the projected tsunami zone.

Both the California Coastal Commission and the Nuclear Regulatory Commission have stated the type of fault zones off of DCPP’s coastline are not “subduction” zones and therefore can’t produce the magnitude of earthquake and large tsunami that impacted Fukushima. The NRC also said it “does not believe the seismic hazards associated with the Diablo Canyon and San Onofre plants can be directly compared to the events at Fukushima.”

Jearl Strickland, director of nuclear projects at Diablo Canyon Power Plant, told Currents recently that the plant, “is very prepared” for a seismic event. But, he added: “I don’t want anyone to think we are complacent.  Under our Long Term Seismic Program, we continue to take the lessons learned from earthquakes worldwide and validate the safety of the power plant.”

Strickland said it should be noted that it was not the earthquake that caused the core damaging accident at Fukushima, but the tsunami and resultant loss of power that caused the inability to cool the reactors.

There are multiple backup systems in place at Diablo Canyon — including batteries and generators located well above the projected tsunami zone — that would supply power in the event of an outage. The systems were detailed in an article in the San Luis Obispo Tribune.

Also, PG&E supports and will move thoughtfully to implement new industry guidelines to ensure the continued safety of Diablo Canyon. This includes the recent requirement for all nuclear facilities to conduct new seismic risk assessments.

PG&E’s geosciences department is using new technologies to conduct advanced seismic studies, both on shore and offshore, to better understand how the earth moves in the area near Diablo Canyon.

As a result, PG&E already has begun its efforts to compile data needed to develop a new risk analysis. Even after that assessment is completed, PG&E’s geoscientists will continue their seismic research to give regulators and the public confidence that the facility remains safe.

Judith Bean, chief executive officer of the Arroyo Grande Chamber of Commerce and a longtime resident of the Central Coast, said she has no concerns about the safety of Diablo Canyon Power Plant.

“I am so impressed by the job they do at Diablo,” said Bean, who lives just north of the plant in Los Osos. She and her family have lived near the plant for 25 years.

She said she has toured Diablo Canyon several times and wishes more people would take the time to see it first hand, adding: “Your feelings of insecurity would be lessened a great deal.”

The 1,400 people who work at the plant have a vested interest in keeping it safe because they are members of the community, insisted Bean. “They raise their families here. They take their jobs seriously.”

Email Tracy Correa at tracy.correa@pge.com.

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"PG&E" refers to Pacific Gas and Electric Company, a subsidiary of PG&E Corporation.
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