A giant nuclear power plant runs amok, and a 43-year-old bureaucrat is summoned to the rescue by an anxious White House. Out of his swivel chair and into a helicopter he goes, as cool and collected as if he were off to fix a stubborn duplicating machine rather than defuse a potential disaster. Once at the plant, he goes on TV to soothe an anguished populace with the aplomb of an anchorman. Finally the President arrives and the crisis gradually abates.

That, of course, was the improbable scenario of Harold Denton's triumph at Harrisburg. Leaving behind the somber offices of the Nuclear Regulatory Commission, where he had served in relative anonymity for 16 years, Denton was thrust into a nightmare and swiftly took charge. He coped not only with a frighteningly overheated reactor but with a power company that seemed unwilling to face the enormity of the crisis, a governor baffled by misinformation and a confused and angry public-in-waiting. In the worst nuclear crisis in the nation's history, Harold Denton was one of the few public officials to emerge with his reputation not only intact but enhanced.

Maintaining the habit of an orderly lifetime, Denton refused to be hurried. First he deployed some 100 hand-picked scientists to make sure he had reliable information on which to base decisions. Then, despite the mounting tension on Three Mile Island, he insisted on examining all contingencies before committing himself to a course of action. When Metropolitan Edison, the utility which operates the reactor, announced it was ready to reduce the dangerous hydrogen bubble, Denton held up the operation until his staff had been briefed and a preoperational check had been made. "We wanted to insure that it would do exactly what it was intended to do," he explained.

His calm reassurance in the face of such danger came as no surprise to his wife, Lucinda, 42. "This is the kind of thing his career has prepared him for," she says. "Harold is very conservative in his judgments. He gives himself a lot of leeway." Denton's three children—Elizabeth, 18, Harold Jr., 16, and Spencer, 13—were more impressed. "I just can't think of that guy on TV as the same guy who plays baseball with me," Spencer admits. "He sure seems more important now."

Born in Rocky Mount, N.C., Denton showed his scientific bent as a teenager. "Harold wrote his senior theme on UFOs," recalls Lucinda, who went to the same high school but didn't meet him socially until a blind date in college, "and he concluded there were no such things." At North Carolina State he planned to study civil engineering but changed his mind after discovering the school had the world's first research reactor. "Nuclear was such a promising field that I switched over and went to work for Du Pont after graduation in 1958," he says.

Denton helped design and operate the nuclear reactors at Du Pont's Savannah River plant in South Carolina, then joined the Atomic Energy Commission. He concedes that moving from industry to government involved "some internal switching" but insists he feels no ambivalence now. "I am indifferent to whether this industry succeeds or not," he declares. "My job is to protect the public safety." He does not, however, cavalierly reject the nuclear option. "If you can produce electricity in a cleaner and more efficient way, do it," he says, "but apart from oil, the two fuels indigenous to this country are uranium and coal. Coal miners die in cave-ins, air pollution causes illness. These costs are not quite so attention-getting."

Though the near catastrophe at Three Mile Island has made Denton a kind of celebrity, he seems unruffled by the experience. A colleague calls him "the fair-haired boy who has had a meteoric career," but Lucinda insists her husband has no ambitions beyond his job as the NRC's director of reactor regulation. "Right now," she says, "he seems like the same old Harold."