A control room error that violated safety rules at the state’s only commercial nuclear reactor was not dangerous to the public but is significant because it was committed by management, a federal report said Tuesday.

A Nuclear Regulatory Commission report on the April 9 incident did not say whether the Washington Public Power Supply System would be penalized for the mistake.

In the incident, a control-room supervisor apparently disregarded written procedures and opened a bypass valve in the reactor’s pressurized coolant-water cleanup system.

The incident was categorized as being at the least serious of four levels the NRC uses to assess potential danger to public health and safety. No radiation was released and the reactor was not damaged, but such disregard for safety rules is cause for concern, the NRC said.

“The significance of the event was that supervisory and management personnel were involved in not adhering to the requirements of a system operating procedure over the objections of reactor operators,” the report said in its conclusions.

The report also criticized the Supply System for its analysis of the incident, which did not include an evaluation of prior corrective actions for procedure compliance problems.

Supply System officials are reviewing the latest NRC report and likely will meet in a few weeks with NRC officials for an “enforcement conference” at the NRC’s Region 4 headquarters at Arlington, Texas, system spokesman Richard Romanelli said.

The two sides will “go over the conclusions and come to agreement on what action, if any, the Supply System needs to take to address weaknesses that have been identified,” Romanelli said.

WPPSS and NRC officials agree that the control room supervisor violated procedures and another manager overlooked the violation.