(CNN) -- The Union of Concerned Scientists said Thursday that U.S. nuclear plant owners have failed to address known safety problems that have led to serious issues at certain plants, posing potential dangers to the public.
The organization's report, focusing on 14 incidents at U.S. nuclear facilities last year, concludes the Nuclear Regulatory Commission has a mixed record of responding to safety issues, sometimes catching deficiencies, other times overlooking or dismissing operational problems.
"That plant owners could have avoided nearly all 14 near-misses in 2010 had they corrected known deficiencies in a timely manner suggests that our luck at nuclear roulette may someday run out," the report concludes.
The Union of Concerned Scientists describes itself as "the leading U.S. science-based nonprofit organization working for a healthy environment and a safer world." It has been criticized by right-leaning groups as having a liberal orientation.
The report's chief author is David Lochbaum, a nuclear engineer and director of organization's Nuclear Safety Project.
Among the lapses cited in the report is a case in which critical safety components were disabled at the Calvert Cliffs nuclear power plant in Maryland because of the failure of an electrical device that had been in use beyond its service lifetime.
The report says this was the result of the reactor owners ending a program to routinely replace safety components. Only later, it says, did the plant initiate a new system for monitoring degradation of safety parts.
In another case, workers at the Brunswick nuclear plant in North Carolina didn't know how to activate the system summoning emergency workers to the site, the report says. As a result, when an emergency was declared, the response team was not properly staffed within the required amount of time.
None of the safety problems cited in the report caused harm to plant employees or the public.
The report applauds several cases in which Nuclear Regulatory Commission inspectors "made outstanding catches of safety problems."
For example, commission inspectors refused to accept the decision of supervisors at South Carolina's Oconee plant not to inspect safety systems on the facility's Units 2 and 3 after failure of the safety system on Oconee's Unit 1. Nuclear Regulatory Commission pressure led to further safety checks at Oconee, and those checks revealed system failures that the commission ensured were addressed and properly resolved.