The Senate, sitting grimly in judgment of one of its most powerful senior members, voted overwhemingly yesterday to "denounce" Sen. Herman E. Talmadge (D-Ga.) for "reprehensible" conduct of his official finances.

His face devoid of emotion, the 23-year Senate veteran listened dispassionately from near the center of the Senate chamber as his colleagues -- almost as though he was not there -- debated the events leading up to the eighth such action in the Senate's history.

Only after the vote-81 for the reprimand, 15 against it and 4 voting "present" -- did Talmadge rise to his own defense, confessing to errors of negligence but reiterating his earlier disavowal of intentional wrongdoing.

"I accept the . . . criticism because I believe that senators should be held to much higher standards than is commonplace," said Talmadge. "In the past, I have leveled heavy criticism at others. I also know how to take it." p

The Senate was hushed and somber as it voted, clearly uncomfortable in what Senate Ethics Committee Chairman Adlai E. Stevenson (d-iii.) had earlier called a "disagreeable duty."

But Talmadge did not speak of it that way. Despite recent personal trials that included the death of a son, a bitter divorce, a struggle with alcoholism and now a collegial denunciation, he vowed to fight to remain in the Senate -- which he described as "my life." And he beamed broadly as senators paused to shake hands and pat his back after the vote.

Talmadge, 66, who is chairman of the Agriculture Committee and second-ranking member of the Finance Committee, was accused by the Ethics Committee of five charges of financial misconduct.

The committee found that he knew or should have known that $43,435 in expense money had been falsely claimed in his name and that he failed to report $10,000 in campaign contributions. Talmadge, who has already paid back $37,125, was ordered to reimburse the Senate another $12,894. Evidence in the case is also being submitted to the Justice Department.

It was the first time the Senate has disciplined one of its members since Sen. Thomas J. Dodd (D-Conn.) was censured for unethical conduct in 1967. The term "denounce" rather than "censure" was used in Talmadge's case, implying a less severe rebuke in the parlance of the Ethics Committee.

Sen. Harrison Schmitt (R-N.M.), ranking Republican on the committee, said yesterday he thought a full censure would have been more appropriate in Talmadge's case, but neither he nor anyone else demanded it. The committee had rejected censure, 5 to 1.

"Had the committee sought censure or made a finding of intentional wrongdoing," said Talmadge yesterday, "Would have fought such action with every ounce of strength I possess. " He reaffirmed that he considers the committee's verdict a "personal victory."

The Senate's discomfort with its task surfaced in several complaints about the committee trial process and proposals for reform, including appointment of an outside fact-finder. Some senators also questioned the importance of testimony by former Talmadge aide and chief accuser Daniel Minchew, who was sentenced Wednesday to four months in prison for his role in the case. Talmadge also blamed Minchew, but Stevenson denied the committee relied on Minchew's evidence.

Gradually, toward the end of the hour of debate, Talmadge's defenders took the floor. "Are we going to acknowledge his good works here at all?" asked Sen. Strom Thurmond (R-S.C.). People who know Talmadge know he is "no crook," said Sen. Ernest F. Hollings (D.S.C.).

Senatorial courtesy being what it is, no one arose to denounce Talmadge or to belabor the language used by the Ethics Committee in accusing him of a "gross neglect of duty" and "reprehensible" conduct that "tends to bring the Senate into dishonor and disrepute."

The committee did so "with the hope that all who serve in the Senate hereafter will be the wiser and the public reassured by the Senate's discharge of a painful duty," said Stevenson.

The four who voted "present" included Talmadge as well as his Democratic colleague from Georgia, Sam Nunn, and Sens. Walter D. Huddleston (D-Ky.) and George McGovern (D-S.D.), the second ranking Democrat on the Agriculture Committee. All 100 senators were on hand for the vote.