The Navy's Trident missile submarine has become the most expensive weapons program in the history of warfare, according to the Pentagon's latest estimates.

Fourteen of these largest-ever submarines will cost $25.1 billion, or more than the B-1 bomber program President Carter canceled partly because of its cost.

A Pentagon study obtained by The Washington Post warns that the Navy will not have enough money to buy the submarines the nation needs unless changes are made.

Adm. James L. Holloway III, chief of naval operations, said in an interview that he sees "no alternative" to Trident, characterizing its high cost as "an industrial problem."

Critics contended that Trident, the submarine that is supposed to take over the sea-based nuclear deterrent role from the Polaris-Poseidon submarine fleet, veered off its intended course when Adm. H. G. Rickover insisted on powering it with a big nuclear reactor.

The nuclear plant Rickover designed, they said, is so large that only a mammoth, costly submarine could accommodate it.

The counterargument, one made in an interview by Adm. Thomas H. Moorer -- who was chief of naval operations from 1967 to 1970 when Trident was moving from a concept toward a firm design -- is that Rickover knows the realities of submarines.

"You can't knock success," said Moorer. He stated that Rickover's nuclear reactors in ships and submarines have never failed, in contrast to Soviet reactors which "have blown up and everything else."

Both Trident critics and backers agree that the new submarine is running far over estimated costs, is behind schedule and will keep the Navy strapped for shipbuilding money for a decade.

Although inflation has contributed significantly to making Trident the most expensive weapons program ever, the Navy acknowledged publicly in December that its first Trident was running 50 percent over the estimated cost: $1.2 billion instead of $800 million. The ultimate overrun could end up exceeding the record $2 billion on the Air Force C15 cargo plane.

Since December, Pentagon officials have concluded that not only will the first Trident be late and over the target cost but also that the following four subs of that first group will be late as well.

William J. Pery, director of Pentagon research, told Congress last month that "delays in construction have occurred primarily as a result of inefficiencies and lower than expected productivity." General Dynamics' Electric Boat Co. yard at Greton Conn., is building the Trident fleet.

Pery estimated that the First Trident would go to sea in 1981 rather than 1980 as the Navy had planned. "It is expected" that Trident will be back on schedule by the time the sixth sub is delivered in December 1982, he added.

Despite the delays and cost problems, the Navy on Monday excercised its option with Electric Boat to order an additional two Trident subs on top of the five previously under contract. That contract amounts to $899 million for the two Trident hulls, not counting the misiles and other equipment needed to put it in combat shape.

Trident's evolution from a slow, medium-sized and inexpensive submarine armed with long-range missiles to a fast, giant, expensive submarine, armed with shorter-range missiles, offers a revealing glimpse of the Pentagon decision-making process.

It is a story of interservice rivalries, and of one Washington bureaucracy anticipating another in the internal process that shapes the super-weapons the nation buys in the interest of "the common defense."

The launching ramp for Trident was a panel the Pentagon commissioned in 1966 to assess the most cost-effective way to hurl extra explosives at Russia in case Moscow's antiballistic missile system should prove effective.

Called Strat X for Strategic Experimental, this panel of experts sifted through about 125 ideas, participants recalled, ranging from hiding missiles under swimming pools to deploying them in abandoned coal mines.

Rear Adm. George H. Miller, then head of the Navy's strategic systems office, said in an interview that the Air Force and Navy submariners ganged up on him when he pushed the idea of moving Minuteman land missiles onto surface ships.

Miller contended the idea made sense both then and now, "but never got a fair trial because the Air Force and submariners fought me every step of the way" for fear of losing missions and money.

The Strat X panel, working under the Institute for Defense Analyses, a Pentagon think tank, filed its top secret report in August 1967. It concluded that a new missile submarine would be a cost-effective way to deliver additional nuclear punch.

The Washington Post, under a Freedom of Information Act request, obtained from the Defense Department a heavily censored version of that Strat X report. The censored report and interviews with Strat X panel participants depict a vessel sharply different from Trident:

Strat X would have had a speed of 10 to 15 knots, produced by the 15,000-horsepower nuclear reactor from the Thresher class submarine. It would have been 366 feet long, displacing 2,700 tons, and carrying 24 missiles with a range of up to 6,500 miles. The panel argued that high speed "is a minor consideration" since quietness and sonar countermeasures are the keys to evading an enemy killer sub.

Trident is expected to go about 20 to 25 knots -- still slower than 30-knot Soviet killer subs on the 90,000-horsepower nuclear reactor designed expressly for it. It will be 650 feet long (five feet more than the Washington Monument), displace 18,700 tons, and carry 24 missiles with a range of 4,000 miles. (A longer ranged Trident II missile of 6,000 miles is under consideration for the future.)

Adm. Elmo R. Zumwalt Jr., chief of naval operations from 1970 to 1974, said in his book, "On Watch," that Trident (originally called ULMS for underwater long range missile system) began to take on "a Rickover shape" in 1971 because the admiral was insisting on building a 90,000 horsepower nuclear plant for Trident rather than using an existing one.

"Designing a ship from the power plant out," said Zumwalt, "never has struck me as an ideal procedure." But Zumwalt said he acceded to Rickover to hasten the construction of a new sub because he feared that the State Department bureaucracy was yielding the U.S. strategic edge to the Soviets at the arms limitation talks.

Zumwalt and Strat X participants said the size and weight of the new reactor, plus a Navy decision against positioning the missiles outside the main hull in free floating capsules, forced Trident into its present giant size.

Robert M. Chapman, formerly an undersea warfare specialist in defense research and engineering, warned in a 1976 report that "the Navy will not sustain its submarine force level objectives" if it keeps building bigger and bigger submarines rather than finding ways to compress both the nuclear power plant and the hull.

"The submarine force building program has reached a critical" point where there soon will not be money to buy enough subs "unless a significant change can be achieved in cost/performance relationships of the submarine itself," according to the report.

The Polaris and Poseidon fleet is scheduled to wear out before enough Tridents are deployed to match the current force of 656 submarine missiles, posing a strategic gap in the future.