Secretary of Energy James Watkins has informed the Senate Armed Services Committee that he wants to build and operate two new nuclear reactors to produce warhead materials. He also wants to restart the three remaining aging production reactors that have been shut down for safety reasons and to operate them until the new reactors are ready. The price tag for this strategy could run to $90 billion.

In fact, the Energy Department is marching ahead with its plan prior to any persuasive analysis of what our nuclear-weapon materials requirements will be in a post-Cold War world. Before Congress follows the administration down this multibillion-dollar path, it should explore an alternative course that would safeguard our national security at a fraction of the cost.

At issue is the need for continued production of two ingredients of modern weapons -- plutonium and tritium. Unless we plan to enlarge our arsenal, further production of plutonium -- which lasts for tens of thousands of years and is already in oversupply -- is pointless.

Tritium, on the other hand, decays at a relatively rapid pace -- half of a given amount disappears in 12 years. Thus, the tritium used in nuclear weapons must be replenished every few years to keep the warheads operational. At a time of arms reductions, however, new tritium need be produced for this purpose only if reductions fail to keep pace with tritium's decay. If the number of nuclear weapons is reduced by at least one-half every 12 years -- we can get by without new tritium production by using instead the tritium recovered from retired weapons.

Construction of new reactors should be deferred until it becomes clear how much smaller our future nuclear arsenal will be and how much new tritium will actually be needed to sustain it. Substantial quantities of tritium needed to replenish our remaining nuclear weapons are already being recovered from weapons now being retired, such as the obsolete naval tactical missiles, and the process can be continued with soon-to-be retired weapons, including short-range nuclear artillery shells that have no target in a unified Germany and strategic warheads to be retired under START.

Assuming we continue to reduce our nuclear arsenal, enough tritium can be recovered from retired weapons to meet the tritium requirements of 3,000 warheads for more than 50 years. Clearly, we need not rush into restarting the reactors at Savannah River, S.C., or into building two replacements.

To be safe, we must be prepared to restart tritium production in the event that arms reduction breaks down. We should continue to repair and restore the three Savannah River reactors at a relative bargain-basement price of $2.5 billion and hold them on "cold standby." Once repaired, these three reactors have "no life-limiting features," according to the Department of Energy. Operating at half power, they would provide more than enough tritium to replenish our entire existing nuclear arsenal.

The Energy Department estimates the cost of two new large rectors it wants at $7.4 billion (in 1990 dollars), but a recent congressional study of Energy Department construction projects suggests the price will come in as much as 500 percent higher -- at about $40 billion. Add to this the $42 billion cost (in 1990 dollars) of operating these reactors over their 40-year lives, and the total cost becomes $80 billion. Add to this the $2.5 billion for repairing the Savannah River reactors and the $10 billion cost of operating them for 10 years until the new reactors are ready, and taxpayers can look forward to spending $90 billion for resuming tritium production we may never need.

In the face of the federal deficit, the savings and loan bailout, the costs of cleaning up our nuclear-weapons production sites and the calls to shift defense spending into social and environmental programs, the prudent course is to avoid premature commitment to renewed production of nuclear weapons materials. That is why Congress should cut back sharply on initial funding for the two new production reactors and require the Energy Department to certify that there is a real need for new tritium or plutonium before restarting the existing reactors or breaking ground for their replacements.

The writer, a Democratic representative from Illinois, is a member of the Defense Nuclear Facilities Panel of the House Armed Services Committee.