The Senate Monday passed a bill to grant cancer benefits to military veterans who took part in U.S. atomic weapons tests 30 years ago as "service-connected." Up to 250,000 servicemen took part in the atomic bombing of Japan, its aftermath, or tests on atomic weapons in the Pacific or Nevada.

The measure, which was approved by a 48-30 roll call, would not benefit civilians living around the test areas who were struck by radioactive fallout from the tests.Sen. Orrin Hatch, R-Utah, voted for the bill. Sen. Jake Garn, R-Utah, was not pres-ent for the vote.

The bill now goes to the House.

President Reagan has said he would veto the bill. The administration contends that there is no medical basis to link many cancer cases to the atomic explosions the men witnessed.

The cost of the bill has been estimated at $36 million a year in Veterans Administration medical expenses.

Sen. Alan Cranston D-Calif., a sponsor of the bill, said during debate "it is time to be fair to these men."

Many medical experts have testified that soldiers stationed in trenches close to some of the Nevada weapons tests may have been exposed to excessive radiation. Most of the troops that participated, however, never got close to the bursts, or to radiation on the ground or in the air. Atomic Energy Commission test officials monitored winds near the tests carefully and evacuated participants if the fallout cloud doubled back on observation points.

Civilians living or working off the test reservation were in many cases struck by higher levels of radiation as the fallout cloud drifted north and west of the test area.

The Senate-passed measure would describe 13 types of cancer as radiogenic and give test veterans a presumption that if they have such cancer that it was test-caused.

Only 28 of 5,000 veterans who have filed claims with the VA for alleged test-caused illness have received compensation.