Southern California Edison has spent the last year telling nuclear regulators and the public that major problems with its generators at San Onofre that leaked radiation last year were a complete surprise. But later today, the U.S. Nuclear Regulatory Commission (NRC) is expected to release a report that may radically change that picture.

The group Friends of Earth presented about 40 different slides – mostly technical data – at a Nuclear Regulatory Commission hearing Wednesday outside Washington, D.C. But the crux of their case can be summed up by just one slide: a drawing of a cart before the horse.

A nuclear watchdog group presented arguments Wednesday that operators of the San Onofre power plant improperly avoided a full government review of redesigned generators installed in recent years. Problems with those generators have idled the facility for nearly a year. The coastal plant, located in northern San Diego County, suffered a radiation leak on Jan. 31 that was traced to a steam-generator tube leak. Further inspections turned up rapid degradation of tubing within generators that were replaced in 2010 and 2011.