Diablo Canyon ‘open phase condition’ fears are unfounded

In an anxious Viewpoint in The Tribune (“Shut down Diablo Canyon nuclear power plant before it shuts itself down,” March 26), Jane Swanson and Linda Seeley of Mothers for Peace express concern that an “open phase condition” at Diablo Canyon nuclear power plant might result in a situation similar to the destruction at Japan’s Fukushima Dai-ichi nuclear plant as a result of the 2011 Tohoku earthquake and tsunami.

Their concerns are unfounded. In 2014, the U.S. Nuclear Regulatory Commission issued a comprehensive Standard Review Plan in response to a 2012 open phase condition at the Byron Nuclear Generating Station in Illinois. In the process of calculating a “safety significance of open phase condition,” the plan concluded: “The accident sequence precursor analyses conducted by the staff calculated a conditional core damage probability of 1 in 10,000.”

Seven open phase conditions have been reported globally since 2001, or an average of one every two years. If the odds estimated by NRC at Byron are typical, we could expect all such events around the world to result in an event causing at least partial core damage once every 20,000 years.

Standard Review Plans are often erroneously interpreted as a reason for concern. Instead, they serve as examples of NRC’s vigilance, and demonstrations of the highest regard for public safety.

This story was originally published April 8, 2016 at 8:15 PM with the headline "Diablo Canyon ‘open phase condition’ fears are unfounded."