Republicans will gain three to 10 more seats in the Senate in the 1982 election, even if the President's economic program fails, even if "there is 12 percent inflation . . . and the sky is falling," Sen. Robert Packwood of Oregon, chairman of the Republican Senatorial Campaign Committee, predicted yesterday.

At a breakfast meeting with reporters, Packwood also predicted: a filibuster of the Helms-Hyde antiabortion bill; passage of the controversial tuition tax credits bill; and cancellation of the sale of both the F15 jet fighters and the airborne warning and control system (AWACS) reconnaissance airplanes to Saudia Arabia if they are linked in one bill.

Packwood said he was confident of the GOP Senate gains for several reasons, first of which is that there are only 12 Republicans seats up for election in 1982, compared to 20 Democrats and one independent, Harry F. Byrd Jr. of Virginia.

The 12 Republican campaigns will be "well-managed and well-financed," he said, with help on both counts from the Republican campaign committee. The committee's aid will total between $8.5 million and $9.5 million, compared to only $5.5 million in 1980, according to Packwood.

There is now a much greater willingness to vote Republican in the nation, independent of any coattail phenomenon by which Reagan might pull in congressional candidates, Packwood contended. He said a good indication of that tendency can be found in recent polls which show that the percentage of people who call themselves Democrats has dropped from 45 percent a few years ago to 38 percent. At the same time, the Republican percentage has held steady in the mid-20s, with independents making up the balance.

Another important factor will be age, Packwood said; the Democrats as a group are much older than the Republicans.

Only three of the 12 Republicans trying to save their seats are over 60, and only one of those three is over 70. Among the 20 Democrats, however, 10 are over 60, and four of the 10 are over 70. "The Democrats in many cases will come up against 35-year-old candidates who can run them ragged," Packwood said.

"I'm afraid it will pass," said Packwood when asked about the two identical anti-abortion bills that have been introduced in the Senate and House, called "Helms-Hyde" after the sponsors, Sen. Jesse A. Helms of North Carolina and Rep. Henry J. Hyde of Illinois, both Republicans. "It will mean that women [who have abortions] can be brought into court charged with homicide if it's interpreted in its broadest sense." He also acknowledged that the bill might outlaw some forms of contraception.

"I don't generally like filibusters, and I don't participate in them, but in this case I think the issue of a woman's right is so important that I may [join the filibuster] against the bill," Packwood said.