It is the thalidomide, the Tet, the Hindenburg of nuclear power? Is the Three Mile Island disaster one of those rare cataclysms that instantly and unalterably remake public opinion so that, in this case, the nation's chronic ambiguity about nuclear power with be replaced by decisive opposition?

With the crippled reactor still not under control, and the vindicated doomsayers of nuclear energy promoted from crank fringe to respected center in media esteem,it is inviting to conclude that the nuclear option has been rendered psychologically and politically unacceptable.

However, I doubt it, and not because-as the nuclear apologists are contending-nuclear power is indispensable to national well-being or amaneable to a radical upgrading of safety performance. Despite what they say, the fact is that, given the political will, public cooperation and shrewd exploitation of non-nuclear energy sources, we would get by without nuclear power for the next couple of decades, and eventually ease into an energy economy based on renewable sources and fusion power. As for the argument that engineering redesigns will preclude another major mishap, just recall that commercial aviation, with its extraordinarily high engineering and training standards, has never been able to eliminate the "idiot factor." There is no plausible basis for assuming that the nuclear industry can uniquely develop error-free operation of a complex technology.

Thus, the case for backing off from nuclear power, if only temporarily and, admittedly, at some considerable disruption, is a credible one, in view of the actual occurence of what has been depicted as virtually impossible.

It is not likely, though, that prudence and cool reason will dictate the decision in the inevitable debate over a nuclear moratorium. Because when the Three Mile Island drama has been finnaly resolved-whether that takes days or, as ti might, months-the determinants will be the porosityof public memory and the fact that while nuclear power may not be indispensable, it is very, very useful for a country that likes to live high.

In fine-tuning the metaphors of catastrophe, it may out to be that the aforementioned classics are off the mark, and that what we ought to be thinking of is the Titanic disaster. The sinking of the unsinkable, it's worth recalling, had no long-term effect on transoceanic passenger traffic, the plain reason being that until many years later, there was no other way to get there. To pursue the oceanic and nuclear parallel, the sinking did have a beneficial effect on marine engineering and navigation services, and, in the same way, we can expect that a lot of nuclear plumbing will be refashioned in response to the lessons of Three Mile Island. However, with the usefulness argument so easily invoked for nuclear power, reform, rather than abolition, is going to have an appeal that is difficult to beat down.

One reason, of course, is that the public is so saturated with demands for its attention that the threshold for notice in this clamorous country is ever upward-to the point that a reactor has to blow before most people give serious attention to the joys and sorrows of nuclear power. It is instructive to consider, too, how perishable noticeability can be. Man in space, not too many years ago, was considered to be a most extraordinary event. Two Russians went into orbit recently, but, if at all noticed, this was relegated to other news of the day. The same can be said of heart transplants, and it's even getting to be the case with airplan crashes, which are no longer immediately followed by a decline in passenger bookings.

Is it too much to expect that the day will come when nuclear mishaps, even very serious ones, will be noted with concern and regret, but basically taken in stride as just one of those awful costs that now and then have to paid for the benefits of industralized society" Not so farfetched, given all the horrors that have become commonplace. The most obvious-over 50,000 highway deaths a year-is cited so often that it's become tiressome.

The origins of our nuclear mess can be traced to a regulatory system that, in effect, cast Typhoid Mary in the role of health commissioner. Coming out of World War II as the world's only nuclear power, the United States-with industry, government, academe and the military in harmonious alliance-vigorously promoted the development of atomic energy. And to make certain that nothing got in the way, some of the most assiduous promoters were put in charge of safety standards and regulation. The situation is somewhat less scandalous since the Nuclear Regulatory Commission became automous. But when nuclear power figure large in the basic planning of government and industry, the issue is formulated as how, rather than whether.

The disaster that we're all now brooding over provides an opportunity-though one of short duration-to rethink and perhaps re-legislate the role of nuclear energy in American life. But if the opportunity is not quickly exploited, it will fade along with memories of the Three Mile Island catastrophe. Nuclear power is devilishly dangerous, but only intermittently. The rest of the time it is extremely advantageous for good living. CAPTION: Illustration, No caption, By Zarko Karabatic for The Washington Post