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 Dai-ichi nuclear power plant, questions understandably continue to emerge about the safety of all nuclear facilities.
While officials at PG&E want to assure 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 in San Luis Obispo County.
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-designbasis 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-designbasis event.
There are a number of differences between Fukushima and Diablo Canyon Power Plant. Most notably, the majority of the Diablo’s safety components are 85 feet above sea level — well above the projected tsunami zone.
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.
Multiple backup systems are 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.
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 onshore 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.
Tom Cuddy is senior manager of external and nuclear communications for Pacific Gas & Electric Co.
