Sen. William L. Scott (R. Va.), an outgoing senator who is one of the 14 American delegates to the Interparliamentary Union conference here, began boning up on his law studies yesterday in preparation for his return to private practice when his term expires in January.

Scott spent part of this afternoon in his hotel room reading new decisions from the Virginia Supreme Court in an effort to "make up for time I've missed" during his 12 years in Congress.

The question of whether senators whose terms art expiring should be allowed to go on congressional junkets is being debated in the House this year, and under terms of proposed legislation, both Scott and Sen. John Sparkman (D-Ala.), the chairman of the U.S. delegation here, would be prohibited from attending this conference.

But the bill isn't likely to be accepted by the Senate, even if it should pass the House because the two bodies can't agree on what constitutes o lame duck.

Rep. Richardson Preyer (D-N.C.), another delegate to the IPU meeting, and chairman of the House ethics committee, said House rules define a nounced his intention not to seek relame duck as a member who has an-election.

Scott said the Senate defines a lame duck as a senator whose replacement has been chosen at the general election in November. Lame ducks, under the Senate rule, cannot use government aircraft for travel.

"That means I can't go on a government plane after the election," Scott said, "but it doesn't mean I can't go out of the country at government expense."

Scott was asked if he planned to make any more trips before his retirement - he has visited 38 nations during his three terms in the house and one on the Senate - and he said, "I'm not going to put myself in a box" by saying he won't.

Prayer said he believes the House bill will go to the floor for debate and a vote in a couple of weeks.

While Preyer supports the bill, he doesn't expect it will win approval in the Senote, and acknowledges that it does have some weaknesses.

Preyer said he is sympathetic to a Senate amendment that would add an "escape clause" to permit travel by lame ducks if approved in advance by the ethics committee.

Under those terms, Preyer said, "clearly ethics would allow Sen. Sparkman to attend" the IPU meeting.

Even though Sparkman, the chairman of the Senate Foreign Relations Committee, is weak and unable to attend all of the meetings, he is "the most known American associated with the IPU, and his presence adds real status to the sessions," Preyer said.

Another example of a "well justified" exception would have been former Sen. Mike Mansfield's trip to China, Preyer said.

The travel ban on lame ducks is now in force in the House, but Scott believes there is a difference in the two chambers because senators serve terms of six years and representatives two.

"Every one of the House members faces an election this year," Scott said, and therefore all of them are potential lame ducks.

"Besides, I could change my mind - Elizabeth Taylor not withstanding," Scott grinned. (Taylor's husband, John Warner, is one of many candidates seeking to succeed Scott.) The senator added, however, that he has no intention of changing his mind about running again, "even if my wife would let me."

Inez Scott, who was sitting next to her husband, shook her head and added, "which I wouldn't."

Scott attended all three half-day meetings of the IPU committee to which he was assigned, and yesterday delivered a three-page statement on his views on how to combat illiteracy, the topic the committee debated.

He and his wife have done some shopping here, but he hasn't found an elephant to add to his collection. Scott's Senate office features a large table that is covered with elephants of all sizes and materials that he has gathered during his globetrotting days in Congress.

"I've got so many now I don't know what I'll do with them," Scott said. But "if I see something special, well, I might get another one."

Preyer, who served on the illiteracy study group with Scott, said "There's no question there has been some abuse of these trips, but junketing may be overplayed, as opposed to the benefits of the trips."

He described a junket as a trip "when you don't do substantive work." He insidted that has not been the case on this one.

"None of us has seen any of the countryside," Preyer said before he left the conference Thursday night on an assignment in connection with his work on the House assassination committee.

If no one in the 46-member delegation has seen much of Portugal, all of return here tomorrow to pick up the France on this trip, which is now in its 10th day.

The full delegation spent last weekend in London and Paris, and yesterdy morning, 14 members of the party, including Sen. and Mrs. Sparkman, Sen. and Mrs. Abraham Ribicoff (D-Conn.), and Rep. and Mrs. Liones Van Deerlin (D-Calif.) returned to London.

Other members of the party will stay here throug tomorrow morning, which should give those who want to a chance to see Lisbon and its nearby beach resorts.

The Air Force jet and its 22-member crew that is hopscotching the delegation around Western Europe will return here tomorrow to pick up the 29 who remain, and then the full party will be reunited in London for the return flight to Washington later that day.

Asked about his feelings on the circuitous route taken by the delegation. Preyer said that another provision of the proposed new travel code "increases the emphasis on finding a direct route."