President Reagan predicted today that there will be serious U.S.-Soviet arms control talks during his second term and said he would push again for a balanced budget amendment and a line-item veto.

In an Election Day interview with The Washington Post shortly after his aides told him he was winning a landslide reelection victory, Reagan also expressed his continuing commitment to a defense system in space that could shoot down missiles, a system labeled "Star Wars" by his opponent Walter F. Mondale and other critics.

He did not spell out his domestic agenda beyond saying he would press for enactment of a constitutional amendment requiring a balanced federal budget and would renew his request for a line-item veto on appropriations bills. Nor would Reagan spell out how he would deal with the federal budget deficit beyond his campaign commitment to continued economic growth.

The president was in a relaxed and cheerful mood as he answered questions and chatted with advisers in his 19th-floor suite in the Century Plaza Hotel.

As Reagan posed for photographs in his suite while the election returns rolled in, a reporter asked him: "What would you say to Walter Mondale? He must be feeling awful tonight."

"Well, I'm sure he does," Reagan replied. "I'm quite sure that there isn't anything I could say that would make him feel any better. I hope he can close ranks for the good of the country once the contest is over."

The only damper on his mood was the condition of Nancy Reagan, who aides said was suffering from dizziness and some difficulty in walking downstairs after she injured herself in a fall early Monday.

Otherwise, it was a day of triumph for Reagan and his entourage. As the president concluded his interview, White House chief of staff James A. Baker III brought the president survey results showing Republicans doing well in several Senate races and Reagan leading in states across the country.

In the interview, Reagan said he had mixed feelings about reaching the final campaign day of his career. While he said it was nostalgic like "that last football game, at the same time, also, there's kind of a good side to it, too, in saying, 'Oh, I don't have to do this anymore.' "

Reagan gave few specifics about what he would seek in a second term other than saying he would press both for the balanced-budget amendment and his proposal for a line-item veto of spending items similar to those enjoyed by a majority of the nation's governors.

He said that he thought both of these were realistic proposals even though the line-item veto idea has had little support from congressional leaders in either party.

Reagan compared his position in dealing with the Democratic-controlled House in 1985 with the situation he faced after he was reelected to a second term as governor of California in 1970 and confronted a Democratic legislature.

"I didn't really convince the speaker of the Assembly in California about our welfare reforms," Reagan said. "The people of California did."

In talking about his California experience, Reagan acknowledged that "contrary to all my promises," he had compromised and accepted a huge tax increase that he said was necessary to balance the state budget.

Asked if he might accept a similar compromise with the Democrats in Congress, Reagan responded: "No, no. You see . . . there it was safe to do that. But the safety was that you had that balanced budget . Now without that at the federal level to go for a tax increase, you just simply open the door for more spending."

But Reagan added that he wouldn't trade his balanced budget proposal for a tax increase.

U.S. relations with the Soviet Union seemed uppermost on Reagan's mind as he looked ahead to a second term.

On Monday, in Sacramento, Reagan said his first priority for another term was "peace, disarmament."

Today he said that he believed that the Soviets were ready to negotiate because they could no longer afford the arms race -- the same view the president expressed in a campaign interview with The Post four years ago.

"I think they know there are difficulties in matching us industrially in such a buildup," Reagan said today. "And therefore I'm hoping that they will see the common sense value in us achieving a mutual deterrence at a lower level -- by reducing the weapons instead of keeping on building them."

Reagan expressed an unrelenting commitment to the U.S. weapons idea most criticized by the Soviets, his Strategic Defense Initiative plan for finding a weapon that would destroy incoming missiles.

"I think this could be the greatest inducement to arms reduction," Reagan said. "It's the only weapons system that's ever been invented for which there has never been a defensive weapon created."

If such a weapons system can be devised, Reagan continued, it would be an incentive to the Soviets to reduce or eliminate missiles, "since we've proven that it's possible to be invulnerable to such an attack."

His goal in a second term, said Reagan, would be "to continue on the dual track of adequate defense but at the same time try to persuade the Soviet Union to join us in arms reductions, particularly in the field of nuclear weapons in a real search for peace."

Reagan voted today in bright, sunny weather in Solvang, a rural town of 2,000 known for its Danish pastry and curio shops nestled in the Santa Ynez Mountains near the president's ranch.

Hundreds of people had gathered outside the adobe Veterans Building, the polling place for Reagan's rural precinct, to watch the president and Nancy Reagan arrive. The Reagans flew 100 miles to Solvang by Marine helicopter from Los Angeles.

Actually, they need not have gone to Solvang at all since they had taken out absentee ballots several weeks ago when it was uncertain where the president would spend Election Day.

Michael K. Deaver, the White House deputy chief of staff, said that "when we decided to come out to California, he decided to go to the polling place to vote." Reagan had marked his ballot on Air Force One, Deaver said.

The voting "booths" at Solvang were cardboard boxes, each inscribed: "This voting booth saves taxpayers dollars."

Asked who he voted for, Reagan paused for effect, smiled, bobbed his head and said, "I can't remember his name."

Reagan seemed less concerned about the election outcome than about the condition of Nancy Reagan, who seemed unsure of her footing and had to be helped by the president out of the helicopter when they arrived to vote.

White House spokesman Larry Speakes said that early Monday morning Mrs. Reagan had struck her head on a chair when she got out of bed and was "still a bit woozy."

She was being treated by White House physician Daniel Ruge, Speakes said.

Except for the concern about Mrs. Reagan, the president and his party were in a jubilant mood today.

"The picture looks very bright," campaign press secretary James Lake told reporters at midday.

Reagan's strategists had been confident throughout the president's final week of campaigning as surveys showed him holding a double-digit lead in most states.