There was a small explosion at the Palo Verde Nuclear Power Plant late last year but plant officials didn't report it to federal officials until six days ago.
APS said at no point was public health and safety in danger.
The incident happened on a non-nuclear side of the plant and there was no damage to the reactors' components.
William Londrie has had no fear in calling the Palo Verde nuclear power plant his next door neighbor of nine years.
"They got so many back up systems that pretty much nothing wrong could happen," Londrie said.
On the contrary, something did go wrong at the plant back on Nov. 6 of last year.
APS officials said there was a leak in a hydraulic fluid tank that's about the size of a file cabinet. When a worker opened the tank to inspect it, there was a small explosion by rapid decompression. APS said there was only damage to the tank, but no flames and no one was injured.
"What you had here was equipment failure," thinks Steve Brittle, an environmentalist and former volunteer with the Maricopa County emergency planning committee.
Plant officials didn't consider it an explosion by nuclear standards, and therefore didn't publicly report it or notify the U.S. Nuclear Regulatory Commission.
"There's something fishy there. They should notify them within that week I'd say," Londrie said.
But just six days ago, APS finally reported it to the feds as an "unusual event." When NRC inspectors joined the investigation, APS discovered it had been an explosion.
"This is six months later. What were you doing?" Brittle asked. "For them to not realize that it should be classified as an explosion raises questions about their safety and their training," he added.
The U.S. Nuclear Regulatory Commission considers the incident a "failure to report an unusual event." There will be no fines, neither for the explosion, nor for failing to report it.
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