Now that peace has broken out in Europe, the U.S. Peace Corps is getting big ideas.

The 30-year-old, 6,000-person corps is planning to include 18 new countries to the list of places where volunteers are based in the next year. Among those countries are several in Eastern Europe, including Romania and Bulgaria.There are now about 200 volunteers in Eastern Europe, a number that will soon grow to about 300.

According to corps director Paul Coverdell, informal talks have begun with the Soviet Union about sending a Peace Corps contingent there and on-again, off-again talks about sending volunteers to China have resumed.

The talks were suspended in June 1989 after the Chinese government crushed the pro-democracy movement. Coverdell said, "The Chinese are now prepared to proceed with the program," which will start out with a small group of English-language instructors.

At a time when most federal agencies are shrinking or frozen at their present levels, the Peace Corps budget was increased by 11 percent in the last budget to $186 million.

Coverdell talks of a Peace Corps that might be 9,000 strong in the mid-1990s. Others talk about 12,000 volunteers around the world in as many as 90 countries.

The most dramatic increases have come in Eastern Europe, where volunteers are now serving in Poland, Hungary and Czechoslovakia, mainly teaching English. Next year, the first group of volunteers is scheduled to go to Romania, where they will work with the heartbreaking job of dealing with the country's orphaned children, many of them stunted in mind and body because of neglect and disease.

Although the first wave of volunteers is made up mainly of teachers, the Eastern Europeans are now requesting that the next Peace Corps groups include some who can give basic instruction in how to start and run a small business, as well as volunteers who can help clean the monumental environmental mess in some of the countries.

About 10 percent of current Peace Corps volunteers are over age 50 and there have been volunteers in their 80s. The only requirement is that they must be over 18, healthy and U.S. citizens.

Coverdell said that although peace has followed the end of the Cold War in Eastern Europe, other countries in the Third World remain unstable and occasionally dangerous for American volunteers. Peace Corps contingents have had to be pulled out of the Philippines and Yemen because of the possibility of violence against Americans.

"The one thing that we can't tolerate is a defenseless Peace Corps volunteer in a hazardous situation. When in doubt, we pull them out," he said.