That incident, initiated by rain falling through a roof, caused both reactors at Calvert Cliffs to shutdown.
The plant operator, Constellation Energy, was aware of the roof leaks since 2002, the report stated. But instead of fixing it, workers were simply expected to mop up any rain water during storms, and to cover critical electrical components with plastic"plastic that failed to prevent water penetration into key equipment.
The leaking roof in one reactor building produced an electrical short that shut one of the four pumps circulating water needed to cool the reactor. This caused an automatic shutdown of that reactor.
That auto shutdown produced a current surge in a second reactor which shut down all of that reactor's cooling water pumps, too, prompting a shutdown of the second reactor. That shutdown in turn triggered a backup generator for the pumps, but that emergency generator worked only for a few minutes, because plant operators, in a cost-cutting move, had failed to replace a time-delay relay in the generator.
Constellation Energy, the report states, "ended a program to routinely replace safety components before launching a new program to monitor degradation of those components. As a result, an electrical device that had been in use for longer than its service lifetime failed, disabling critical safety components."
The NRC cited Calvert Cliffs for failing to fix the leaking roof and for not replacing vital safety equipment.
A 2010 incident at the Peach Bottom nuclear plant in Pennsylvania incredibly produced no enforcement action by the NRC, the report states.
That incident involved workers at the plant finding that 21 of the 185 control rods needed to shutdown the reactor in the event of an emergency were slow to engage.
The federal operating license for Peach Bottom requires a shutdown of the reactor within 12 hours if 13 of the control rods are slow to engage. Yet, plant operators kept the reactor running as the problem rods were repaired.
The Union's report notes that instead of the required shutdown for such a safety flaw, Peach Bottom "workers conspired to keep the reactor operating, despite known safety flaws," creating a circumstance where if problems arose, the result "could have resembled Chernobyl," -- a reference to the Russian nuclear plant disaster recognized as the worst such incident to date.
The Peach Bottom incident prompted this harsh criticism of the NRC in the Union's report, which charged that the NRC was aware of the serious control-rod problems and the "slow response" by operators' in the facility owned by Exelon, yet the agency "did nothing except watch."
While commending the NRC for quick reaction in responding to potential problems at reactors in South Carolina last year, the Union's report chides the federal regulatory agency for tolerating safety problems at many of the nation's other nuclear power plants.
The Union's report states that over the course of 40 years of monitoring of the nuclear power industry, it has found NRC enforcement of safety regulations to be untimely, inconsistent or ineffective.
That Peach Bottom incident is particularly troubling in that it occurred at a facility with a record of past problems. Peach Bottom is located in close proximity to the Three Mile Island plant near Harrisburg, PA. Three Miles Island in March 1979 was the site of a partial reactor meltdown--America's worst and the world's second-worst nuclear power accident, until the current Japanese disaster at Fukushima.
In 1987 the NRC fined the Peach Bottom plant upon discovering that control room personnel were sleeping on duty. In 2007 security guards were discovered sleeping on the job too, but the NRC did nothing to discipline the guards or the plant, which had fired the whistle-blower who reported the sleeping guards.
President Obama and too many Capitol Hill politicians are still pushing nuclear power as an important part of the nation's electrical energy plan -- pledging billions of dollars in new funding and loan guarantees. The President and Congressional nuke advocates contend that nuclear power is needed as an alternative to fossil fuels for generating electricity.
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