A draft report previously withheld from the public found stark contrasts between the replacement steam generators at the shuttered San Onofre and operational Diablo Nuclear plants, with flaws unique to San Onofre. The steam generators at Southern California Edison’s San Onofre and Pacific Gas & Electric’s Diablo nuke are significantly different, including in size, number and power output, concluded a draft report by Robert Budnitz Lawrence National Berkeley Laboratory scientist. “This size difference by itself places very different constraints on the [steam generator] design in terms of flows, stresses, material properties, and the like,” Budnitz stated. He concluded errors were made in the San Onofre units, but his analysis does not include where they likely occurred along the design-installation-operation chain. The analysis was conducted for the California Public Utilities Commission in December 2013, but initially kept confidential. After a Public Records Act request, the four-page draft report was released Aug. 1. Budnitz, who also sits on the Diablo Canyon Independent Safety Committee, pointed out there are four replacement steam generators in each Diablo unit, but two in each of the San Onofre units. As a result, the amount of water and energy used at the plants when at full operation was twice as large at Edison’s nuclear facility. He compared the replacement steam generators at the two facilities to evaluate the safety of Diablo generators following the leaks and unprecedented wear at San Onofre, which led to its closure in January 2012. He also noted other significant differences between the two plants, including the manufacturer. Mitsubishi made the San Onofre steam generators and Equipos Nuclear manufactured Diablo’s steam generators. Edison sued Mitusibishi for more than $2 billion for alleged design flaws (Current, July 19, 2013). The Diablo steam units installed in 2008 and 2009 are considered to be in “excellent health.” Budnitz reiterates findings by the independent review committee’s annual report released in August 2012, adding that since then inspections and other information related to the safety of Diablo steam generators has not challenged the findings.