NRC "supplemental inspection" begins at Palisades

The scorched control room panel involved in the Sept. 25, 2011 accident at Palisades which NRC concluded was of "substantial significance to safety"As reported by the Associated Press, an eight member "supplemental inspection team" from the U.S. Nuclear Regulatory Commission (NRC) began two weeks of work today at Entergy Nuclear's problem-plagued Palisades atomic reactor in Covert, Michigan on the Lake Michigan shoreline. Last Valentine's Day, NRC lowered Palisades' safety status to among the four worst-run reactors in the U.S. This came after a September 25, 2011 near-electrocution, caused by short cuts on safety, that plunged half the control room into a power outage, instantly throwing 22 safety related plant systems into chaos (see photo, left).

It took control room operators hours to bring the reactor under control, all the while straining age-degraded systems, structures, and components to the breaking point. This included the worst embrittled reactor pressure vessel (RPV) in the U.S. If subjected to emergency core cooling system (ECCS) water, the RPV could fracture like a hot glass under cold water, due to "pressurized thermal shock." Such a fracture would lead to a loss of coolant accident in the core, very likely leading to a meltdown. If the containment structures then failed, a catastrophic radioactivity release would result. Frighteningly, the electrical fault inadvernently activated the ECCS. Fortunately, the ECCS failed to inject cooling water, which would have tested NRC's decades of repeated weakenings of PTS safety standards, which has allowed Palisades to keep operating as its RPV embrittlement has worsened. Of course, the failure of the ECCS to work, when ordered to (even inadvertently) raises its own red flags -- the ECCS is one of the last lines of defense against nuclear fuel overheating in the core that can also lead to meltdown.

NRC allowed Entergy to tell it when it was ready for this special inspection. Entergy took over seven months to prepare itself.