EVERY YEAR that the debate drags on, the case against the Clinch River Breeder Reactor gets stronger. The technical, economic and nonproliferation arguments are solid and persuasive. The large budgetary savings - $1.5 billion - should put the final nail in the Clinch River breeder's coffin.

The issue before Congress is not whether the country needs a breeder. That is a separate question. The issue now is wheteher the country needs this breeder and on the timetable that has been set for it. The right date for commercial deployment of a breeder depends on three key factors: demand for nuclear power; available uranium-ore resources; and the capital cost of the breeder in particular - how much more expensive it is than current teactor types. What do we now know about each of these?

In 1970, when the Clinch River breeder was first authorized, projected nuclear demand for the United States in the year 2000 was about 1 million megawatts. The most recent figures for that same year project about 20,000 megawatts. And these were calculated before Three Mile Island. Regarding resources, in 1970 the United States estimated its uranium reserves at 1.36 million tons. In 1979, the estimate is 4.3 million tons, of which 2.4 million fall into the most certain categories. So that even taking the most conservative view, our reserves of uranium ore have doubled in this decade, despite substantial production. Both these trends - the dramatic decline in demand and the growth in resources - have been mirrored worldwide.

The third factor, the likely cost of the breeder, is harder to predict. The administration's view, confirmed by many outside experts, is that the breeder will be between 1.2 and 1.7 times more expensive than current reactors. What all these numbers mean is that the breeder break-even point, the point at which a breeder becomes competitive and therefore economically justified, will come when uranium ore costs about $150 a pound. Today it costs $40 a pound. Putting these cost estimates together with the supply-and -demand figures, experts can calculate that the break-even point for breeders in this country will not come until after the year 2020 - perhaps long after. Why then build the Clinch River breeder? It is a costly demonstration plant of a design that is almost 10 years old already. In the year 2020, its design will be 50 years old - a Model-T of reactors.

Supporters of Clinch River argue that if it isn't built, the United States will lose its leadership position in this potnetially important technology. The opponents reply, soundly, that from a technological view money spent on the Clinch River breeder is wasted, since it is already an obsolete design, and that the U.S. position can be preserved and strengthened through a sensible R & D program that emphasizes safety and improved alternatives to current breeder designs. This makes good sense.

The administration's program, though still over-funded, will put the United States in a position to build a breeder reactor if and when it is needed. No one can responsibly predict today how far in the future that may be. But given the breeder's cost and undeniable proliferation risk, it would certainly be bad policy to encourage its premature use.

For far too long the Clinch River breeder has diverted the attention of Congress and the administration from other nuclear issues - especially safety and waste disposal - as well as from other energy issues that are far more important to the national welfare. This year Clinch River should be sent once and for all to its grave.