Drug and alcohol violations at U.S. nuclear plants increased from about one a month to almost one every week over the last five years, with a majority of cases in southeastern states, a new study has found.A report by Vermont-based Fairewinds Energy Education set for release today cites dozens of violations reported to federal regulators each year from 2008 through 2013 that range from drinking alcohol in a "protected area" of the plant to positive tests for marijuana and cocaine.The report notes several incidents at Florida nuclear power stations, including Duke Energy's shuttered Crystal River plant and Florida Power & Light's Turkey Point and St. Lucie facilities.For instance, last November a contract supervisor at Crystal River tested positive for alcohol while another's access to the plant was terminated after the worker tried to enter with a "prohibited substance."In June, a contract supervisor at FPL's Turkey Point plant was arrested off site for possession of a controlled substance. In April and June 2012, three contract supervisors at Turkey Point tested positive for illegal drugs."Ten percent of the people who get caught, test positive for cocaine," said Arnie Gundersen, a Fairewinds co-founder and developer of the study. Gundersen, a nuclear engineer who worked at dozens of nuclear plants and now serves as a consultant on utility matters, said the growing incidence of drug and alcohol violations is disturbing because major nuclear accidents such as the one at Three Mile Island were in part the result of operator error."You're balancing dozens of things simultaneously," said Gundersen, a frequent critic of the nuclear industry. "Keeping all these balls in the air requires all your mental faculties."The U.S. Nuclear Regulatory Commission requires plant operators to report drug and alcohol incidents involving workers, whether on or off site.Roger Hannah, an NRC spokesman, said the commission had not seen the report but part of any increase in alcohol and drug incidents might be related to tougher standards implemented in 2008. He said the Southeast may have more cases because there are more nuclear plants than in other regions.Regulators, Hannah said, are confident the NRC and plant owners "have a similar standard for ensuring that employees and contractors are not under the influence of any substance that may inhibit their ability to safely carry out their responsibilities."Rita Sipe, a Duke Energy spokeswoman, said the utility had not seen the report and would not comment on specifics in it. But she said Duke has a policy of pre-employment drug and alcohol screenings, background investigations, random testing and other measures to ensure safety."Positive test results are not acceptable and violate our Fitness-for-Duty program," she said.Michael Waldron, an FPL spokesman, said the drug and alcohol incidents are rare. But all workers "from plant operator to an administrative position needs to meet the same requirements as an airline pilot. We don't tolerate a violation of any of these standards regardless of whether it is an employee or contractor."