The Senate Appropriations Committee yesterday approved production funds for the Pentagon's proposed neutron "killer" warhead, but only after an amendment sponsored by Sen. Mark O. Hatfield (R-Ore.) to delete the money failed on a 10-to-10 tie.

The committee also approved $150 million to continue work on the Clinch River breeder reactor, the experimental plutonium-burning nuclear power plant that President Carter has called on Congress to halt.

Both actions came as the committee approved a $10.2 billion public works money bill that also contains a compromise with Carter on 18 water projects he wants canceled. The committee agreed to delete funds for nine of the projects on the President's "hit list." But Carter has indicated that may not be enough to avert a veto.

The committee, in seeking to avoid a veto, also cut out all new water-project construction starts in this year's bill.Normally up to 25 new projects are approved.

It also recommended a halt in spending of 1977 money approved last year for four of the Carter "hit list" projects it agreed should be halted.

Sen. John C. Stennis (D-Miss.), chairman of the appropriations subcommittee which made the water project cutback recommendations, said previously he hoped the deletions would avoid a conflict with the President.

Sen. Daniel K. Inouye (D-Hawaii), who lost a new project start in the committee's action, called the decision "a correct one." But he pleaded with Stennis to recognize "the concern of those of us who had construction starts halted" and asked they be funded in a supplemental or next year's money bill.

President Carter and his aides have threatened a veto of the public works money bill if Congress fails to cut funds for all 18 projects he wants halted.

Despite that threat, the House last week voted to cut money for only one project on Carter's "hit list" and approved funding the rest.

An amendment, introduced on the House floor during last week's public works bill debate to cut out 16 more projects, lost, but by only 24 votes. The narrow margin showed clearly that a Carter veto of the bill would be all but impossible to override.

Yesterday, Stennis said that if the full Senate approves he will push to have the House agree to raise the number. He has been reported telling a congressional delegation recently that he made his compromise when he cut his original "hit list" from 32 to 18.

The Coalition for Water Project Review, made up of environmental and wildlife groups, said yesterday that the committee's compromise was unacceptable. A spokesman said "some of the worst projects" remain funded, including the $267 million Richard Russell Dam in Carter's home state of Georgia.

The White House, according to the coalition, is looking for Senate sponsors for an amendment that would knock out funds for the remaining "hit list" projects. It would be introduced when the bill gets to the Senate floor, probably next week.

The committee, at the request of Stennis, who is also chairman of the Senate Armed Services Committee, went into closed session to discuss the neutron warhead, the first tactical nuclear weapon designed expressly to kill people rather than produce general devastation.

Prior to the closed session, Hatfield said he planned to propose deleting funds for the new enhanced radiation warhead until Carter decides whether he wants to go ahead with the program.

Then, under Hatfield's language, Congress would decide whether to fund the program, taking into consideration the President's recommendation.

Although funds for production of the 56-mile-range Lance enhanced-radiation warhead were in the fiscal 1978 money bill sent to Capitol Hill last January, either the President nor his Defense Secretary knew of it until they read news stories about the weapon.

Carter, through his spokesmen, has said he will make his own decision before Oct. 1, 1977, on whether to go ahead with production. Nevertheless, he wants Congress to give him the money in the bill now under debate so that, according to a recent Pentagon letter, "he will have maximum flexibility if he chooses" to permit production.

Hatfield said yesterday he questioned the process by which the Congress was giving Carter money before his decision was made. He also brought out that an impact statement of the new warhead's affect on the Strategic Arms Limitation Talks had not been presented to Congress, as required by law.

Stennis led the opposition to the Hatfield amendment, but would not discuss his remarks.

He said the warhead is a "matter so highly classified" that he questioned whether the committee would break some precedent by releasing how each senator voted. Stennis relented and the vote was made available.

When the matter gets to the floor, Hatfield said he expects that Stennis will again call for a closed session, this time of the whole Senate.