"We haven't lived here very long," observed President Ronald Reagan as he toasted South Korean President Chun Doo Hwan with a lunch-time glass of Cabernet Sauvignon yesterday, "and looking about, I can't help but contrast this peaceful and rather elegant setting with the meeting that took place in your country 30 years ago in a building in your capital so badly damaged by war. . . "

Rapt attention from the crowd in the State Dining Room, arranged nine each around nine tables. "The miracle of modern Korea," Reagan continued "is well-known in the world." Suddenly, he stopped and looked stricken. So did the crowd, which until that moment had been lingering pleasantly over their fingerbowls.

"At this moment I have a terrible feeling," said the president, "that I have told the interpreters that I would break at different points than I have."

Relieved chuckles all around.

"Well, anyhow," said the president, "I'll give them a pause to catch up." And he did.

Yesterday's state luncheon for Chun Doo Hwan, although as formal and reserved as business lunches tend to be, still seemed festively upbeat. Certainly it was for Chun, who is said to want to use this visit to encourage foreign business and enhance his political standing at home.

A whole planeload of Korean reporters covered the luncheon, and one camera crew was actually filming it for live broadcast back home. It was the middle of the night there.

Chun -- whom the new administation agreed to invite for a state visit if he commuted, as he did, the death sentence of Korean political dissident Kim Dae Jung -- was effusive in his praise of Reagan. "A new era of great renewal for America will certainly succeed because of your statesmanship," he said through an interpreter. Later, Chun said that Reagan had promised him he had no intention of withdrawing the 39,000 U.S. troops in South Korea.

Chun's visit to the White House began in the pouring rain. Trumpeters nontheless played a flourish on the South Portico as the Korean president's limousine splashed up the driveway. A slight, smiling man, he got out, shook Reagan's hand, posed for photographers, then disappeared in less than 30 seconds for a meeting with Reagan in the Oval Office.

Mrs. Chun, or Lee Soon Ja as she's called in South Korea, arrived at the North Portico 50 minutes later. It was still raining. She was supposed to have sherry with Nancy Reagan, Barbara Bush and a few other women in the Red Room, but Nancy Reagan had soda water with lemon and the other women had either tomato juice or orange juice. They sat in formal chairs with their legs crossed and their hands clasped and looked, from all angles, formal.

Mrs. Chun speaks only halting English, and flashbulbs were popping everywhere as the women had their pre-lunch chat. They giggled occasionally. Mrs. Chun said something about music and Mrs. Reagan, in a kelly-green dress by Bill Blass, smiled appreciatively.

Patricia Haig, wife of the secretary of state, and Kyung Hee Kim, wife of the Korean ambassador to the United States, were included in the group.

The lunch itself consisted of fillet of beef, spinach souffle, green salad, orange sherbet and petit fours. One topic of conversation was the extensive newspaper advertising the Korean community had bought for Chun's visit. In yesterday's Washington Post, for instance, there were seven full pages costing approximately $20,000 each.

Said one Reagan official after the lunch: "We could all retire on today's newspapers ads alone."

The following were guests at President and Mrs. Reagan's luncheon for President Chun Doo Hwan and Mrs. Chun. Byong Hyun Shin, deputy prime minister and minister of economic planning Shin Yong Lho, minister of foreign afairs Yong Bock Choo, minister of national defense Yong Shik Kim and Mrs. Kim, Ambassador of Korea to the United States. Kyung Won Kim, secretary general to the president Gen. Byong Hion Lew, chairman, Joint Chiefs of Staff Brig. Gen. Dong Ho Chung, director general, presidential security force Jae Ik Kim, senior secretary to the president for economic affairs Woong Hee Lee, senior press secretary to the president Dr. Byong Sok Min, presidential physician Ro-Myung Gong, assistant minister for political affairs, Ministry of Foreign Affairs Hyung Kun Kim, chief of protocol, Ministry of Foreign Affairs Col. Hwa-pyung Her, adviser Jangnai Sohn and Mrs. Sohn, minister, Embassy of Korea Richard V. Allen and Mrs. Allen, assistant to the president for National Security Affairs Michael Armacost and Mrs. Armacost, acting assistant secretary of state for East Asian Affairs James A. Baker III and Mrs. Baker, chief of staff and assistant to the president Secretary of Commerce and Mrs. Baldrige Secretary of Agriculture and Mrs. Block James S. Brady and Mrs. Brady, assistant to the president and press secretary Vice President and Mrs. Bush Dr. Thomas Chun and Mrs. Chun, president, Korean Medical Association in America, Richmond, Va. Michael K. Deaver, deputy chief of staff and assistant to the president Fred J. Eckert and Mrs. Eckert, New York state senator William H. Gleysteen Jr., U.S. Ambassador to the Republic of Korea Donald Gregg and Mrs. Gregg, National Security Council staff member Secretary of State and Mrs. Haig Sen. S. I. Hayakawa (R-Calif.) and Mrs. Hayakawa John Holdridge and Mrs. Holdridge, assistant secretary of state-designate for East Asian Affairs Robert E. Kirby and Mrs. Kirby, chairman, Westinghouse Inc., Pittsburgh, Pa. Gen. David C. Jones, USAF, and Mrs. Jones, chairman, Joint Chief of Staff Edwin Meese III, counselor to the president Sen. Charles H. Percy (R-Ill.) and Mrs. Percy Nicholas Platt and Mrs. Platt, deputy assistant secretary of defense for Asian and Pacific Affairs Maxwell M. Rabb and Mrs. Rabb, lawyer -- Stroock and Stroock and Lavan, N.Y.C. Donald T. Regan, secretary of the Treasury Ron Schiavone, Secaucus, N.J. Gen. Richard Stillwell, USA, Ret. and Mrs. Stillwell, National Security Council staff member Walter yj. Stoessel Jr., under secretary of state-designate for Political Affairs

Dan Terra and Mrs. Terra, Chairman, Lawler Chemicals, Northbrook, Ill. Gen. John W. Vessey Jr., USA, and Mrs. Vessey, vice chief of staff of the Army Peter Voss and Mrs. Voss, Canton, Ohio Lloyd Waring and Mrs. Waring, Boston, Mass. Secretary of Defense and Mrs. Weinberger Rep. James Wright (D-Tex.) and Mrs. Wright Rep. Clement J. Zablocki (D-Wisc.)