April 30, 1983

The committee of American Roman Catholic bishops preparing a pastoral letter on nuclear arms has reversed itself and will suggest language to intensify the letter's opposition to such weapons, according to a committee staff member. The five members of the committee have decided that the letter should call for a ''halt'' to the ''testing, production and deployment'' of new nuclear weapons, said the Rev. Brian Hehir, the staff member of the United States Catholic Conference who is attached to the committee. In a meeting beginning Monday in Chicago, the country's 284 Catholic bishops will debate the 44,000-word pastoral letter, a document that has placed the bishops in the forefront of the wideranging discussion about the morality of nuclear arms. They are expected to approve a final version of the letter at their two-day meeting.

The explanations offered by the Argentine military for the disappearance of thousands during its campaign against leftist terrorists in the 1970's were roundly rejected today by many Argentines. A wide range of political and labor leaders as well as church officials, intellectuals and major human rights groups said in separate statements that the military's television broadcast to the nation Thursday failed to give details of what happened to the people, estimated at more than 6,000, who had disappeared or to say how many were dead. Most of the officials acknowledged the gravity of the leftist threat in the mid-1970's, but many accused the military of having used ''state terrorism'' to counteract the threat. Despite widespread expectations after the broadcast, the Government did not give details today on the fate of any of the missing people. About 20 families, in response to the broadcast, went to the Interior Ministry this morning to look at a list the Government promised to provide of those who are missing. They were told to come back later.

The Reagan Administration is trying to head off a ban on covert American aid to Nicaraguan rebels by seeking changes in a bill before the House intelligence committee, according to Administration officials. These officials said Deputy Secretary of State Kenneth W. Dam was in touch with Representative Edward P. Boland, the committee chairman. Mr. Boland is the principal author of a bill to ban all covert aid through the Central Intelligence Agency to groups operating ''in and against'' Nicaragua. The committee is to vote on the measure next week. Committee members met at the White House with President Reagan on Tuesday. After the meeting Mr. Boland, a Massachusetts Democrat, and Clement J. Zablocki, a Wisconsin Democrat and chairman of the House Foreign Affairs Committee, formally submitted the legislative ban. But they coupled it with a proposal for $80 million in aid to Central American nations to help them halt the flow of arms and munitions from Nicaragua to insurgents in neighboring countries.

The Board of Education waited an extra day to choose Anthony J. Alvarado as Schools Chancellor because city lawyers thought they might have new grounds to reinstate the Board of Education's first choice, Deputy Mayor Robert F. Wagner Jr. The board was told Wednesday that it might have grounds to circumvent the Education Commissioner's rejection of Mr. Wagner. But the next day, according to participants, it received contrary advice and chose Mr. Alvarado. In any case, Mr. Wagner said yesterday that he had decided Thursday morning that it would be unwise and potentially damaging to begin a legal challenge, even if he could win it.

Harold Washington was sworn in today as the city's 42d Mayor in an unusual and emotional inauguration ceremony. In his remarks, the new Mayor described the city's financial problems as ''enormous'' and said he would order sweeping cutbacks and layoffs in the government, beginning on Monday. Higher Deficits Reported Flanked on the flower-draped stage at Navy Pier by former Mayor Jane M. Byrne and dozens of state and national officials, the 61-year-old Mr. Washington, the first black to lead the city, stunned many people when he said the city's finances were in much worse shape than Mrs. Byrne had acknowledged. But the estimated 3,200 people watching the ceremony cheered the new Mayor as he recited the city's budget troubles and his plans to relieve them. ''Our school system,'' he said, ''is not $100 million short next year as we believed during the mayoral campaign, for we now find that the income may be $200 million less than the expenditures of that vast bureauracy.