The Bathtub Curve (referring to the graph's shape) for Nuclear Accidents, by David Lochbaum of Union of Concerned ScientistsThe U.S. Nuclear Regulatory Commission (NRC), which is supposed to protect public health, safety, and the environment, instead often prioritizes nuclear utility profits. As reported by the Rutland Herald, NRC has now approved Entergy inspecting its troubled Vermont Yankee (VY) steam dryer not once every 1.5 years, but rather once every 4.5 years. This, despite the fact that the steam dryer at VY has developed 65 cracks in the past 7 years alone, likely related to the 20% "power uprate" NRC has also rubberstamped there (this means that VY is being run at 120% hotter and harder than it was originally designed for, with consequently damaging vibrations).
A decade ago at Exelon's Quad Cities nuclear power plant in Illinois, another NRC-approved power uprate's vibrations led to a steam dryer's failure, sending chunks of metal hurtling down steam lines -- some of which were never recovered, even though the reactor has been permitted to keep operating.
VY's steam dryer is not the only age-degraded system, structure, or component at the 41-year-old Fukushima Daiichi twin (a General Electric Mark I Boiling Water Reactor). Its condensor is also on its last legs, begging for replacement. Entergy seems in no hurry to pay the tens of millions of dollars for that repair, either -- and NRC is not requiring it of them.
The Bathtub Curve for Nuclear Accidents (above left) shows that age-degradation significantly increases "break down phase" reactor risks. NRC rubberstamped "power uprates" exacerbate those risks even worse.