The U.S. Nuclear Regulatory Commission found a minor violation during an inspection at the Ameren Missouri Callaway Plant completed on Sept. 30.
NRC inspectors documented one finding of very low safety significance. This finding involved a violation of NRC requirements. The violation involves the nuclear plant's tornado-generated missile protection system, which is essentially a scaled-up, super-sturdy chainlink fence that protects important plant components from debris flung by tornadoes.
The NRC is treating this violation as non-cited, because the violation was identified during the discretion period covered by a guidance memorandum, and because the licensee was implementing measures to compensate for the violation. The NRC is exercising enforcement discretion by not issuing an enforcement action and is allowing continued reactor operation.
More details can be found at adams.nrc.gov/wba, accession number ML17304A950.