(AP) -- The federal agency responsible for safety at the nation's 61 nuclear power plants routinely downplays warnings from plant workers and its own experts about problems, including some with potential for disaster, a Better Government Association investigation found.
Employees from U.S. nuclear power plants filed nearly 700 complaints with the United States Nuclear Regulatory Commission in recent years, claiming retaliation for raising safety concerns, records show. The agency found no wrongdoing.
NRC officials also overruled recommendations from their own technical experts on how to protect plants from potential catastrophe spurred by floods, equipment failures, power outages and other problems.
This article was provided to The Associated Press by the nonprofit news outlet Better Government Association.
Interviews with more than 20 current and former NRC and nuclear plant employees reveal a pattern of top officials dismissing safety warnings rather than impose costly fixes on plant operators. Some said careers suffered as potential threats were never fully addressed.
"It's the NRC's longstanding practice to consistently declare the plants are safe and to avoid directly answering any questions that might suggest otherwise," said Lawrence Criscione, an NRC risk analyst.
NRC officials would not consent to an interview. But NRC spokeswoman Viktoria Mitlyng responded in writing to BGA questions.
"All U.S. nuclear power plants have multiple appropriate procedures and resources in place to maintain key safety functions if severe events" occur, Mitlyng said. "These conclusions are based on extensive agency reviews and inspections."
In 2012, Criscione shared with Congress a letter raising doubts over adequacy of flood protections at Duke Energy's Oconee Nuclear Station in South Carolina and other plants built decades ago near dams.
Soon after, Criscione said, he was accused by the NRC inspector general of compromising confidential information, interrogated by armed agents and saw his case referred to federal prosecutors. They opted not to act, and he remains on the job.
Internal NRC surveys underscore a climate of fear among employees. A report on a 2015 questionnaire of NRC employees stated most felt "if you disagree with your manager it can, and most likely will, affect your career path and advancement."
Records and interviews also show that:
— In 2016, NRC brass overturned a proposed safety analysis for the Byron and Braidwood nuclear plants in Illinois after multiple appeals by Exelon, the Chicago-based owner of the facilities and the nation's largest nuclear operator.
The action undid an order issued after agency technical staff concluded Exelon did not prove critical pressure-relieving valve systems were safe to use in an emergency. The same problem may exist at other nuclear plants, said one of the NRC engineers who ordered the safety testing.
— Also in 2016, seven NRC electrical engineers publicly urged the agency to order an immediate fix or a complete shutdown of most U.S. nuclear plants after discovering a problem with an emergency power system at the Byron plant that was common to other nuclear facilities as well.
Exelon quickly addressed the problem at its plants, but the NRC acceded to a request from other U.S. operators to give them an additional two years to devise a fix.
— Separately, the NRC took only two months to reject a staff petition in March 2017 urging the agency to reverse a decision allowing Arizona Public Service Co.'s Palo Verde nuclear plant near Phoenix to operate even though an agency expert said it lacked sufficient emergency backup power to run safely.
Complaints from plant whistleblowers raised issues ranging from security problems to inadequate radiation monitoring.
— The U.S. Department of Labor ordered the Palisades nuclear plant near South Haven, Michigan, to rehire veteran security guard Chris Mikusko who claimed he was laid off in retaliation for pointing out security problems. Mikusko filed a similar whistleblower complaint with the NRC, which rejected his allegations as unsubstantiated.
— NRC investigators concluded supervisors at Exelon's shuttered Zion plant in Illinois had "greatly exaggerated" claims of disruptive behavior they had used to discipline Marilyn Lingle, hired to help dismantle the facility. Yet the agency rejected these findings and declined to discipline Lingle's managers.
The nuclear industry, through its trade group and individual companies, often downplays the seriousness of problems highlighted by NRC experts. Exelon and others in the industry bat down potential rules and regulations by pleading to NRC's top managers.
"Safety is the highest priority for both Exelon Generation and the NRC," spokesman David Tillman said in a statement. "We are equally committed to protecting our people and our communities and to suggest otherwise is a disservice to the authority of the NRC and our shared commitment to public health and safety."
The problem, say people who conduct government reviews, is that the NRC's final rulings often don't reflect warnings from its experts.
"Management tells you where they want the answer to go. If you push, you're not going to get promoted again — there are other people who are willing to say it's not a serious issue," said Richard Perkins, one of Criscione's NRC colleagues involved in exposing flooding concerns.
One case in point is the emergency safety valve issue at Exelon's Byron and Braidwood plants.
After Exelon moved in 2013 to increase power, NRC experts concluded the plants' pressure valves to relieve water in an emergency would stick open and allow cooling water to escape and not do its function to cool the reactor. They ordered Exelon to prove the valves would work, but the company blocked that with a successful appeal to the NRC's executive director.
Exelon says the valves work fine. But Samuel Miranda, an NRC expert who disagreed, said the company and NRC were rolling the dice on valves because it risks melting the reactor.
He said dozens of other U.S. nuclear plants are equipped with similarly problematic equipment.
"They either won't close or they will leak," Miranda said. "That will relieve about a million pounds per hour. It's a hole in the system. Now you're losing water that you need to cool the core."
Underscoring that frustration is the NRC's record of handling whistleblower complaints lodged by plant employees. From 2010 through 2016, workers filed 687 complaints. The NRC investigated just 235 and upheld none.
The largest number of complaints, 84, were filed by employees at the two nuclear plants operated in Georgia by Southern Nuclear, records show. Next were the 70 complaints lodged by nuclear workers in South Carolina, 58 by workers in Tennessee and 50 in California. Illinois ranked 12th, with 21 whistleblower cases filed.