What was going on when I was born?

After a flood of announcements of cancellations, cost overruns and safety problems, the nuclear power industry is looking eagerly to the next few months, when it expects to be able to announce the completions of a number of long-delayed plants. ''After some pretty dismal times, the industry is on a little bit of a roll,'' said Paul Turner, vice president of the Atomic Industrial Forum, a Washington-based trade group. The completions represent the result of decisions made up to 20 years ago, and do not reflect the long-term prospects for the industry. But they are the payoff for the investment of billions of dollars and tens of thousands of hours of labor.

Friday AN UP-TO-THE-MINUTE REVUE A topical revue dates quickly, but ''What's a Nice Country Like You Still Doing in a State Like This?'' has managed to keep on playing for 13 years, with fresh material inspired continuously by the day's news. The satirical musical revue begins performances this weekend in yet another incarnation, this time at the Actors' Playhouse, at 100 Seventh Avenue South, at Broome Street. Old favorites such as ''I'm Not Myself Anymore,'' ''How'm I Doin'?'' and ''Nuclear Winter'' - whose subjects are organ transplants, Mayor Koch and World War III - will be supplemented with such new numbers as ''Everyone Ought to Have a Gun,'' a look at modern modes of self-defense, and ''Born Again,'' which takes on religious cults. Performances are tonight and tomorrow night at 7 and 10 o'clock and Sunday at 3 P.M. Tickets are $12.50 and $15. Reservations: 691-6226. BACH IN NEW BRUNSWICK Bach lovers can celebrate the composer as well as the holiday weekend with a program called ''J. S. Bach and His World,'' sponsored by the Aston Magna Foundation for Music Inc. and held at the Douglass College campus of Rutgers University in New Brunswick. ''Bach, the Master'' is the title of an organ-recital program by Robert Parkins that includes the Toccata and Fugue in D minor. It will be given tonight at 8 o'clock in the Voorhees Chapel. Tomorrow at 4 P.M., Laurence Libin, an authority on 18th-century instruments, will give a lecture called ''The Keyboard Instruments for Which Bach Composed'' in the Nicholas Music Center.

A chart in Business Day June 25 accompanying an article on independent television stations misstated the call letters and market share of a station in Houston owned by Metromedia Inc. The station, KRIV-TV, has a 10 percent market share.

Seven years ago, when JoEllen Mayes was 36 years old and her husband, Gordon, was 44, they had a terrible fright: Mrs. Mayes thought she might be pregnant. It was a false alarm, but the idea of a ''second family,'' as Mr. Mayes put it, when their two daughters were nearly grown and their mortgage was almost paid, upset them so much that Mr. Mayes had a vasectomy. The Mayeses, who live in Los Angeles, thus joined an increasing number of Americans choosing sterilization. ''It was such an enormous relief for both of us,'' Mrs. Mayes said, ''especially when I had visions of another decade of P.T.A. and Girl Scouts.'' In 1983, the last year for which statistics were available, 622,000 women and 455,000 men were sterilized as a contraceptive measure, according to the Association for Voluntary Sterilization, a private educational and research center in New York.

Brazil's new Government announced a long-awaited package of austerity measures today aimed at reducing inflation and preparing the way for a credit agreement with the International Monetary Fund. The $6.5 billion austerity package is expected to result in the loss of some 200,000 jobs as well as postponement or cancellation of a number of major investments in oil, hydroelectric and nuclear energy, mining and steel. Today's announcement had been repeatedly postponed because of sharp differences within President Jose Sarney's Cabinet over the social and political impact of the cuts, although it is still not known whether they will satisfy the I.M.F. Brazil must reach agreement with the fund before it can conclude interrupted negotiations with foreign banks on restructuring $45.3 billion in foreign debt coming due for payment between 1985 and 1991. Brazil's total foreign debt of $103 billion is the developing world's largest.

Prime Minister Felipe Gonzalez appointed new foreign and economy ministers today in a Cabinet shakeup that dramatically altered his 31-month-old Government. Mr. Gonzalez replaced six of the 15 Cabinet members and the Government spokesman in what he said at a news conference tonight was an attempt to ''air out and give a little impulse'' to his Government as Spain prepares to join the European Economic Community in January. But aides to the Prime Minister and other officials said that what had begun as a light remodeling of the Cabinet had ended in bitter internal feuding. Departure Is a Surprise The Minister of Industry and Energy, Carlos Solchaga, was named to replace Economy Minister Miguel Boyer, the most powerful member of the Cabinet, whose departure caught political and business leaders by surprize.

International OPEC oil ministers assembled for a critical meeting in Vienna. Officials arranging today's meeting said that weeks of informal talks had apparently failed to yield any agreement on how to strengthen the troubled organization. [Page A1, Column 6.] Tighter security at Beirut's airport will be enforced to help restore international confidence in the facility, the Lebanese Government announced. It said it had erected earthen barriers to prevent unauthorized vehicles from driving onto the runways and would bar armed militia members from the airport's perimeter. [A1:2-3.]

Daiwa Securities said today that it would open a trust bank in the United States. Daiwa will be the first Japanese securities company allowed to enter the trust business overseas, and its entry is expected to trigger a rush among its competitors to the United States market. The move reflects the gradual financial deregulation now under way in Japan. As in the United States, the line between banking and securities businesses is beginning to erode in Japan, although at a much slower pace.

OPEC oil ministers assembled here today for a critical meeting after weeks of informal discussions apparently failed to yield any agreement on how to strengthen their organization, according to officials arranging the meeting for Friday. Saudi Arabia and its Persian Gulf allies have been urging other members of the Organization of Petroleum Exporting Countries to cut oil prices, stick to agreed production levels and perhaps reduce output a bit this summer. All of this would constitute an effort to re-establish OPEC's control of the world oil market at a time when demand is falling and production by its members is on the rise. Some Members Unconvinced At emergency talks in Algiers last weekend, however, the oil ministers of Kuwait and Venezuela failed to convince those of Algeria, Libya and Nigeria of the need for an oil price cut, according to the OPEC officials. Algeria, Libya and Nigeria believe a cut would discriminate against them, making their oil relatively harder to sell.

The Lebanese Government said today that in an effort to restore confidence in Beirut International Airport, it had erected earthen barriers to prevent unauthorized cars from driving onto runways and would ban armed militiamen from the airport perimeter. Officials also said President Amin Gemayel would send a note to the United Nations to complain that the United States effort to organize a boycott of the airport in the wake of the Trans World Airlines hostage crisis was a breach of international law. Campaign Against Airport The Reagan Administration has stopped flights to the United States by Middle East Airlines, Lebanon's national carrier, and Trans-Mediterranean Airways, a cargo carrier. It also said it would seek to persuade other nations to ''isolate'' the Beirut airport.

Once, the United States tire industry was all things to all people. The major companies found it easy to sell tires wherever they could: to Detroit, to the replacement market and to foreign markets. They also ran tire shop chains and auto service centers. In the past decade, however, all that changed. Escalating gasoline prices brought less driving, lower speeds and smaller cars - and slower growth in demand for tires. The radial tire took hold in popularity, and imports grew. The business turned fiercely competitive. Since 1975, 25 tire plants have closed in the United States. And imports from Japan, Korea, Brazil and Canada - brought in by wholesalers and sold at tire discount houses -which represented just 5 percent of the replacement market for radials 10 years ago, now have 31 percent.

The tax incentives for capital investment that were central to President Reagan's supply-side economics - and which he now proposes to cut back - have not produced the surge of investment in plant and equipment that Congress sought to promote four years ago, according to some economists who study trends in business investment. Business investment did increase rapidly, but investment spending is still short of what it was before the Reagan tax cuts took effect, the economists say. Furthermore, the types of investments that fueled the recent growth either did not benefit from the 1981 tax cuts at all or were not intended to be a leading beneficiary of the changes. ''The problem is that tax incentives get overwhelmed by variations in other things,'' said Barry Bosworth, a senior fellow at the Brookings Institution. Mr. Bosworth, who was director of the Council on Wage and Price Stability in the Carter Administration, found that new investment spending by business flowed mostly into computers and cars, where the tax rules were largely unchanged, and into commercial real estate such as office buildings and shopping centers, which were not the focus of the 1981 tax legislation.