As reported by Teri Sforza at the Orange County Register, concerns have lingered for well over a decade regarding the potential disastrous impact "friendly fire" could have at nuclear power plants. More powerful weaponry and ammunition allowed after the 9/11 attacks -- including recent significant escalations in the arsenals of nuclear power plant security guard forces -- means the risks to plant safety and cooling systems have increased. A key part of the risk is the lack of adequate training for the security guards so armed.
The article quotes such industry watchdogs as Dave Lochbaum at Union of Concerned Scientists, and Dan Hirsch at UC Santa Cruz.
Regarding the risk of "friendly fire" taking out a vital safety system, Lochbaum explains the U.S. Nuclear Regulatory Commission's attitude is that security guard just not miss their intended targets, such as terrorist attackers.
The article quotes Hirsch:
“Over the decades of dealing with the NRC, the pattern has never changed,” he said. “I’ve never seen them ahead of the risk rather than behind it. The NRC sees its job as keeping the burden low on the nuclear industry. This is an exceedingly dangerous mismatch between a captured regulatory agency and an adversary that is nimble, lethal and has absolutely no compunction.”