As 10News' broadcast story explained, Southern California Edison had two options when it came to reporting to the Nuclear Regulatory Commission the extent of the changes at the plant when the old steam generators were replaced with new ones.
The experts for 10News' series of reports on SONGS helped explain the options as a comparison between a runner going up a steep hill or running on a flat surface.
It is up to the utility to choose where to run and how to report what is going to happen on the run.
This is the result of decisions made years ago that allow the industry to be self-regulated to a degree.
It's either a 50.59 or a 50.90
The options are described as either a 50.59 or a 50.90.
The 50.90 is a longer process, requiring much more detailed reporting to the NRC. There are public hearings and more oversight.
The other option is a 50.59. If a utility goes the 50.59 route, as SCE did at San Onofre, they are telling the NRC that in the case of replacing the old steam generators it is "a replacement in kind ... with no or minimal permanent modifications to the plant systems."
What the 50.59 designation does, in reality, is reduce the time from concept to completion of a project or projects at a plant. There are no lengthy and time consuming public hearings. The utility is, in effect, telling the NRC, 'we got it handled" and the utility is not anticipating any problems.
10News provided this link for another 50.59 request. This one is from Harris Nuclear Plant in North Carolina. (Click here: http://pbadupws.nrc.gov/docs/ML1312/ML13120A266.pdf)
This attachment describes a project that required the same level of oversight that SCE said was needed for the SONGS steam generators installation and operation.