THIS HAS BEEN a landmark year in the debate over nuclear reactor safety. First came the Nuclear Regulatory Commission's renunciation of its own multi-year study of reactor safety, the now infamous Rasmussen Report. Shortly thereafter came the discovery of miscalculations incertain reactor designs that led the NRC to shut down five operating reactors because of vulnerability to earthquake. And then came Three Mile Island.

All the lessons to be learned from the country's first serious neclear accident are not yet clear -- they may well never be. But as least one important conclusion is evident. The level of care exercised by nuclear reactor vendors, builders, utility owners and operators, and by the federal regulatory structure, has been inadequate to the task of seeing to it that this potent technology is managed safely.

A glance at what the NRC calls "performance evaluations" -- reports based on field inspections of operating reactors -- tells much of the story. Typical comments on two reactors read as follows: "many repeat items of noncompliance . . . general attitude of plant appears to be compliance only as requirements . . . careless operations and poor maintenance . . . management lacks ability to discipline employees for operator errors and carelessness . . . personnel selection and discipline may be adversely affected by union relations . . . safety is substantially worse because of poor attitude and marginal management. . ."

Incredibly, the rating scale on which these and other reactors were graded for such items as overall safety, technical competence, emergency planning and radiation control ranged from Exceptional to Acceptable. There was no failing grade. Both the reactors described above rated well above Acceptable.

In the face of the evidence, and of widespread public doubts over whether nuclear power can be made safe, the industry ought to be an eager participant in efforts to correct past mistakes. Instead, we find advertisements like the one that ran earlier this week in The Post in which Dr. Edward Teller, a longtime nuclear proponent, stated flatly that "reactors are not dangerous." The problems with neclear power, he claimed, are "problems because of political indecision or public fear. Technically, they are non-problems." Statements like thes do nothing to alleviate public concern. Rather, they intensify it by confirming people's fears that the nuclear industry is blind to the realities of its own technology.

If the nuclear industry is to regain its health, it will only be because it has earned public acceptance. That will depend on clear indications that the industry is addressing past failings and unsolved problems like the disposal of nuclear waste. Assertions that critics are crazies should have been dropped long ago.