The electric utility industry, saying it learned a lot from the accident last March at the Three Mile Island nuclear plant, yesterday announced formation of an institute to train and monitor the performance of all nuclear power plant operators.

The Nuclear Operations Institute will be funded by industry contributions but managed by a board of scientists, educators and engineers as well as industry representatives, Floyd Lewis, the head of a special utility group panel on the Pennsylvania accident, said the idea was to have an independent unit set and maintain "benchmarks of excellence" for the industry.

He told a press conference that the utilities also have contributed to a study on the impact of low-level radiation. Although there is little likelihood of damage from that source, in the industry's opinion, "it is important that the matter receive thorough scrutiny," Lewis said.

A newly formed Nuclear Safety Analysis Center, run by the industry's Electric Power Research Institute, is probing the events and causes of the nuclear breakdown in Pennsylvania, Lewis continued.

These are all part of what Lewis called a multimillion-dollar industry response to Three Mile Island. Another aspect, he said, involves a study of ways to set up an insurance plan that would protect consumers from having to shoulder the costs of replacing lost nuclear power with conventionally fired power, which is more expensive. The same plan would protect the industry as well.

"These are important necessary and achievable initiatives Lewis said.

The Nuclear Regulatory Commission's director of systems safety, Roger Mattson, applauded the training institute plan later as "potentially the single most important idea to come out of Three Mile Island."

Industry and regulatory analysts have agreed that errors by operators were a major factor at Three Mile Island and that more rigorous training, testing and monitoring procedures are needed.

The NRC staff is known to have been pressing the electric industry to come up with concrete evidence of its concern about nuclear safety, and yesterday's announcements were seen as partly a result of that pressure.

The industry spokesmen reaffirmed their faith in nuclear power. "Preservation of the nuclear option is imperative for the nation and its consumers," said Jack Pfister, president of the American Public Power Association.

William S. Lee, president of Duke Power Co. of North Carolina, which has 10 nuclear plants on order or operating, admitted that Three Mile Island "was a surprise to all of us," but said changes in the industry "began on that shift, at that time, that night" and had continued ever since.

"Operator readiness is 10 times to 100 times greater right now than it was prior to Three Mile Island," he said.