Misplaced '<' in emergency plan earns Ginna plant an F
Is it ">" or "<"?
Remember those vexing "greater than-less than" problems in middle-school math? Seems they have trouble with the concept at the Ginna nuclear plant too.
Federal regulators have cited plant owner Exelon Corp. for a safety violation because the Wayne County generating station's emergency plan contained a sentence that misused less-than symbols.
Had there been a serious accident at Ginna, that little boo-boo in the written emergency management decision flowchart, could have led control-room operators to mistakenly call for a mass evacuation because they thought the nuclear fuel core was headed for meltdown.
D'oh!
The mistake proved harmless, as there was no serious accident. The plant, located on the Lake Ontario shoreline about 17 miles northeast of downtown Rochester, pretty much hummed like a top the 2½ years the error existed in the tree-like graph, intended to support decision-making during critical incidents. The mistake was discovered by an Exelon supervisor this spring as plant personnel prepared for an emergency drill.
"The error, which never impacted safe operations of the facility, was self-identified and promptly entered into our corrective action program. Ginna has a robust corrective action program that identifies and addresses issues, including those of low safety significance, before they impact operations," company spokeswoman Maria Hudson said. "We look forward to demonstrating to the Nuclear Regulatory Commission (NRC) that our corrective actions were appropriate to ensure safety and prevent recurrence."
The U.S. Nuclear Regulatory Commission classified the error as a low-to-moderate level violation. If upheld, the plant would receive heightened scrutiny by inspectors, spokesman Neil Sheehan said.
The NRC also cited Exelon for an incident — caused by "an apparent lapse in attention," Sheehan said — that occurred as spent nuclear fuel rods were being loaded into a cask for long-term storage on Ginna's grounds. The rods, no longer useful for generating power, are still very radioactive and must be kept secure and on site, indefinitely.
When rods are placed into one of the 15-foot-long casks, Sheehan said, water from the reactor vessels winds up inside as well. As the water is pumped out, workers are supposed to replace it with helium gas to keep the fuel rods intact and safe. The workers failed to inject the gas for 17 hours, Sheehan said, though no harm was done.
The emergency-plan violation stemmed from a change to a portion of Ginna's emergency plan that deals with the classification of an accident. The NRC has four emergency classifications, ranging from the lowest; unusual event, to the most severe; a general emergency.
The Ginna plan lays out accident scenarios and specifies which level of emergency must be declared in each case. The mistake was in a section dealing with the integrity of the containment structure that surrounds the nuclear reactor. A loss of containment integrity is cause for an emergency declaration — but the degree of loss dictates which classification is used.
The error was in a complicated sentence that discussed what should be done if some, or all, three pieces of containment safety equipment failed at the same time. The sentence included two "<" (less than) symbols that weren't used properly, the NRC inspection report said.
As a result of that error, the NRC said plant operators could have mistakenly declared a general emergency — which means they've lost control of the reactor, a widespread release of radioactivity is imminent and an evacuation of people living and working near the facility may be in order. No U.S. nuclear plant has ever declared a general emergency.
Conversely, regulators said the the misplaced "<" could have led operators to fail to declare a site area emergency, the second-most-dire classification, when they should have. A site area emergency means there's been a major failure at the plant and low levels of radioactivity may be released.
Such declarations have been made only twice at U.S. nuclear plants. One of them was at Ginna in January 1982, when a tube ruptured in a steam generator and led to the release of a small amount of radioactive steam.