After almost 15 years of negotiations, the United States has agreed to pay the residents of the Marshall Islands a minimum of $183.7 million for damages caused by nuclear weapons tests conducted there between 1946 and 1963.

The agreement lifts the final barrier for the scattered Pacific islands to hold elections on the question of self-government that would end U.S. trusteeship over the strategically important atolls. The islands are remembered by many Americans as the site of bloody World War II battles with Japanese occupiers.

The pact, which must be approved by Congress, was signed Saturday in the Marshall Islands by U.S. presidential envoy Fred Zeder and Marshall Islands President Amata Kabua.

It represents the U.S. government's official recognition of responsibility for injuries and damages suffered by islanders who were either directly exposed to radioactive fallout from U.S. nuclear weapons tests or suffered personal or monetary losses as a result of the testing.

According to terms of the agreement, the more than 27,000 residents of the islands now will vote in a plebiscite to determine whether to accept the nuclear weapons damage award and establish a "free association" with the United States that would give the islanders sovereignty over internal affairs yet leave the United States in charge of military security.

Representatives of both sides said that the agreement does not affect the status of an earlier accord allowing the United States to use the Kwajalein atoll as a missile range for the next 30 years. The atoll is considered crucial to the U.S. long-range missile program.

Congress must approve the agreement on monetary damages for nuclear weapons testing, as well as any change in political relations between the islands and the United States. If Congress approves the settlements, the United Nations plans a final vote. Sources on Capitol Hill said it is likely that the Marshall Island agreements, if approved in the plebiscite, will be submitted for approval along with similar "free association" proposals already approved in plebiscites in Palau and the Federation of Micronesian States. The sources said that it is unclear whether the "free association" agreements will gain congressional approval.

They warned that the agreement on monetary awards for the Marshall islanders may be used as a precedent by Americans claiming damage resulting from domestic nuclear weapons tests. Currently, a suit filed on behalf of 24 alleged victims of fallout from nuclear bomb tests conducted 30 years ago in the Nevada desert seeks as much as $250 million from the U.S. government.

Under terms of the settlement, the United States is to establish a $150 million trust fund for the islanders, according to Al Short, director of the Micronesian status negotiations. Over the next 15 years, Short said, Marshall islanders are guaranteed a minimum of $183.7 million in income from the trust, and an additional $47.5 million will be made available to cover any further personal injury claims against the United States.

At the expiration of 15 years, 75 percent of the trust's income will be set aside in perpetuity to pay for claims that may arise, with the remainder being earmarked for medical and other human services.

More than 200 Marshallese from the atolls of Rongelap and Utirik were exposed to radioactive fallout in 1954 following the test of a 15-megaton bomb, and approximtely 100 of them have since developed variations of cancer and thyroid abnormalities. In addition, the property of thousands of others, notably on the Bikini and Enewatak atolls, was either obliterated or heavily contaminated with radiation from U.S.-conducted tests. Between 1947 and 1958, 43 nuclear weapons tests were conducted on the Enewetak atoll.

"We have paid our tab," Short said. A tentative agreement on nuclear test claims, reached between U.S. and Marshall Islands representatives last year, had been abandoned after the local leaders in the Marshall Islands expressed dissatisfaction with it. It was unclear whether representatives of the individual Marshallese atolls had consented to the new agreement.

Lawsuits asking damages totaling more than $4 billion have been filed with the U.S. Court of Claims on behalf of residents of the Marshall Islands, with the Bikini residents seeking $450 million in a class action suit filed in 1981. Settlement of such claims against the United States has been a major barrier to holding a plebiscite in the Marshall Islands, with islanders pursuing court cases that the U.S. government sought to solve through a compromise agreement. Under the agreement reached this weekend, the lawsuits are to be dropped, and future claims are to be judged by a special tribunal, according to Short.

In 1947 the United Nations granted the United States trusteeship over the Marshall Islands and three other Micronesian islands groups--the Northern Mariana Islands, Palau and the Federated States of Micronesia--thereby placing the sprawling Pacific island archipelago under U.S. control. The Micronesian islands, spread between Hawaii and the Far East, are considered strategically important to the security of Guam and Hawaii.

Last week the Federated States of Micronesia followed Palau by voting to end U.S. trusteeship and establish a "free association" with the United States.