Perhaps the longest, hardest look at the dilemma of nuclear power was taken in the aftermath of the Three Mile Island accident by a presidential commission of scientists, politicians, educators, industrialists -- and a resident of Middletown, Pa., the town that spent six days in March and April 1979 in the terrifying shadow of the TMI nuclear plant.

In the six months that followed, the commission headed by John G. Kemeny studied the evidence, interviewed the experts and witnesses, and struggled to weigh the benefits and risks of nuclear power.

In the end, it was unable to give a simple, thumbs-up or thumbs-down verdict. On three occasions, it came within one vote of calling for a flat moratorium on nuclear-plant construction while new safety recommendations were developed. But the moratorium did not pass. The commission concluded that the costs of freezing so important a source of energy were too great.

The conflicts that divided the commission on that issue are worth revisiting as the Soviet's nuclear disaster stirs the old anxieties. Proponents of a moratorium saw that as the best way to drive home the commission's concern about the way the industry and the Nuclear Regulatory Commission had handled plant safety.

"The only way to wake them up was to hit them over the head," said commission member Gov. Bruce Babbitt of Arizona. "No more new nuclear plant permits until the whole environment is changed," he told reporters.

But another panel member, Thomas H. Pigford, chairman of the nuclear engineering department at the University of California at Berkeley, said that a moratorium would impose costs that society could not bear.

"If you are worried about safety, I think we would all agree -- at least I have told you my opinion -- that the plants operating now are not as safe as the ones that are being built, the new ones. Why don't you shut down the present ones and then allow the new ones to be built? Why? I know the answer. Because you are afraid of the cost . . . . We are stumbling around beyond left field, playing with something we don't know the magnitude of. It is a great mistake."

Instead of a moratorium, the commission called for a fundamental change in the way nuclear power plants were regulated. The NRC, whose policies are set by five commissioners through a process of negotiation and compromise, should be run instead by a single, powerful administrator, the commission proposed.

The recommendation was not accepted. But in response to the TMI accident, the NRC did dig far more deeply into basic safety issues, taking responsibilities away from plant operators. "After TMI, the balance of decision-making power shifted sharply from the utilities to the regulators," Carl Walski, head of the Atomic Industrial Forum, told Forbes magazine last year.

The resulting uncertainty greatly added to the cost and time required for construction -- and actually may have impaired safety margins by restricting operators' ability to respond in accidents, AIF Vice President Paul Turner said. "This industry would lose its credibility without the NRC," he added. But the industry deeply feels that ultimate authority over safety issues should remain with the operator, he said.

Had the nuclear industry turned a corner after the TMI accident and established an unblemished record of competence and dependability, it might have buried much of the anxiety. But instead, it has had to face recurring embarrassments.

"The ineptitude had no pattern, and virtually anything could go wrong, and did," Forbes commented in a February 1985 report. "How could an experienced contractor like Bechtel . . . have installed the reactor backwards at San Onofre [California]? How could Brown & Root have got the reactor supports 45 degrees out of whack at Comanche Peak [Texas]? How could experienced operators pour defective concrete at Marble Hill [Indiana] and the South Texas project? How could the NRC itself approve designs for the Mark II reactor when what Grand Gulf [Mississippi] was building was a Mark III? . . .

The struggle to build nuclear plants soured even the best in the business, such as officials at Duke Power Co. in North Carolina, which has completed plants for one-third the U.S. average cost and established a solid operating record. "We would not have gone into the nuclear business if we had realized the instability of the licensing process," said William Grigg, a Duke Power executive vice president. "A nuclear plant, with all the regulatory uncertainties, all the investor concern, the environmental concerns, I just don't think would be a viable option for us," he told Forbes.

As the Kemeny commission found, the root of the nuclear-power dilemma is not in its technology. The report noted that more than 100 alarms went off in the early minutes of the TMI accident, "with no way of suppressing the unimportant ones and identifying the important ones. . . . There was almost a total ignoring of the human element in the entire system," said Kemeny, chairman of the commission and, at that time, president of Dartmouth College. "It became clear that the fundamental problems are people-related problems.".

Some commentators have asked whether the human problems of nuclear power -- the interconnected problems of owners, builders, customers and regulators -- are simply too complex for such an open, disorderly government and society as ours. But no one is looking to trade places with the Soviets.