Eighty-two students at Fairfax County's Thomas Jefferson High School for Science and Technology were named National Merit Scholarship semifinalists yesterday, making the magnet school in Annandale the biggest winner in the nation.

The number, announced by the National Merit Scholarship Corp., eclipses last year's tally of 55, when Jefferson led all schools in the Washington area.

Walt Whitman High School in Bethesda -- which traditionally produced the highest number of semifinalists in the region until Jefferson's arrival on the scene -- had 22 semifinalists this year, followed by Montgomery Blair High School in Silver Spring and St. Albans School for Boys in the District, with 18 each, and Langley High School in McLean, with 17.

"It's outstanding," said Jefferson Principal Geoffrey A. Jones. "It's exciting for the kids and it's sort of affirming for the people who are supporting the school."

The 36-year-old scholarship competition is based on a student's score on the Preliminary Scholastic Aptitude Test, a multiple-choice test taken during the junior year.

The 15,000 semifinalists across the nation represent the top 0.5 percent of each state's graduating seniors. Now they will compete for up to $25 million in scholarships.

Ostensibly, at least, the examination is more a measure of the innate ability of the students than a yardstick of any school's performance. Nonetheless, principals, parents and university admissions officers closely watch each year's results to judge which schools are producing the best candidates for college, and the semifinalist designation can open many ivy-covered doors for the students.

"Those students get a lot," said Georgia Booker, guidance director at Woodrow Wilson High School in Northwest Washington, where there are three semifinalists. "The colleges seek them out. They are inundated with information, offers. But it definitely is not a ticket into the college of one's choice."

John Keating, her counterpart at Walt Whitman, agreed.

"It's a nice calling card for the kids to have if they're applying to the more selective colleges," he said. "It's not a guarantee of anything, but it's a plus in your favor and in a close call can really help."

In the District, public school officials found hope in this year's results, even though the city's four semifinalists equaled last year's total.

For the first time in memory, a student from a school other than Wilson High was named a semifinalist, proof to school officials of the success of a new program started last year that pays 60 students to study all summer.

"It shows that every school can have a {National} Merit scholar, not just the white schools and the private schools," said Meta Jones, a senior at Calvin Coolidge High School, who credited the program with raising her verbal score by 16 points.

The $20,000, six-week summer program, started after there was no District public school semifinalist in 1988, pays students minimum wage for every hour they participate.

"We know now that we can make a difference," said Eugene Williams Sr., the D.C. school system's director of testing.

The cutoff score needed for semifinalist status varies by state depending on how well students perform in each state. In Maryland and the District, students needed 201 points out of a possible 240 -- the highest cutoff in the nation -- while those in Virginia needed 199 and those in the lowest state, Mississippi, needed 178.

In Fairfax, Jefferson's total not only surpassed the traditional national leaders, but also was nearly four times the closest Washington area school and larger than all the private schools in the District combined.

At the same time, though, this year's report from the National Merit Scholarship Corp. showed clearly how the five-year-old Jefferson regional magnet school has drained bright students from other Northern Virginia high schools. While the other 22 Fairfax County high schools had 146 semifinalists in 1987 -- before Jefferson students began taking the tests -- this year they had just 86.

Jefferson starts with a big advantage because it selects only a fraction of the students who want to attend based on test scores, essays, interviews and grades and provides those who do get in with rigorous classes that rival many college-level courses.

"It's bound to happen when you get a collection of the upper 10 percent or whatever of the students of the county," said Dino Haritos, a 17-year-old senior and semifinalist.

"A lot of it's because the people at Jefferson are already destined to do well," agreed classmate and fellow semifinalist Daniel Skovronsky, also 17.

"They were better to start out with on tests like this because that's how we got in." Jefferson's Principal Jones attributed part of the increase from last year to the fact that more of this year's seniors took the test first as sophomores for practice.

Skovronsky, for instance, scored 190 out of a possible 240 points on the selection index when he was a sophomore. But when he took it again last spring, he improved to 214.

Jones also said the increase may reflect Jefferson's maturing as a school. This year's seniors make up the third graduating class.

"As we have grown as a school, we've probably become more sophisticated at test-taking as a population," Jones said. The principal was particularly proud of the increase in the number of female semifinalists, which rose from 4 in 1988 to 14 last year to 24 this year.

In topping the nation, Jefferson outpaced the perennial champions Stuyvesant and Hunter College high schools, both in New York City , which had 73 and 66 semifinalists respectively, and the North Carolina School of Science and Mathematics, which had 65.

Staff writer Tom Bell contributed to this report.

................ CLASS OF 1991 ..............

DISTRICT OF COLUMBIA

School ............................... Number

Calvin Coolidge H.S. ...................... 1

The Field School .......................... 2

Georgetown Day ............................ 9

Gonzaga College H.S. ...................... 5

National Cathedral ........................ 7

Sidwell Friends .......................... 11

St. Albans ............................... 18

St. Anselm's Abbey ........................ 2

Washington International ...................1

Woodrow Wilson H.S. ....................... 3

MARYLAND

School ................................Number

Annapolis

Annapolis H.S. ............................ 4

Broadneck H.S. ............................ 2

Bel Air

Bel Air H.S. .............................. 2

John Carroll School ....................... 1

Bethesda

Bethesda-Chevy Chase H.S. ..................7

Holton Arms .............................. 13

Walter Johnson H.S. ...................... 14

Landon School ............................. 7

St. Andrew's Episcopal .................... 1

Stone Ridge Country Day ....................3

Walt Whitman H.S. ........................ 22

Bowie

Bowie H.S. ................................ 3

Burtonsville

Paint Branch H.S. ......................... 1

Capitol Heights

Central H.S. .............................. 1

Clinton

Grace Brethren Christian ...................1

Columbia

Atholton H.S. ............................ 5

Oakland Mills H.S. ........................ 4

Wilde Lake H.S. ........................... 4

Damascus

Damascus H.S. ............................. 2

Ellicott City

Centennial H.S. ........................... 9

Howard H.S. ............................... 3

Mount Hebron .............................. 3

Forestville

Bishop McNamara ........................... 1

Fort Meade

Meade H.S. ................................ 2

Fort Washington

Friendly H.S. ............................. 1

Frederick

Frederick H.S. ............................ 4

Governor Thomas Johnson H.S. ...............4

Gaithersburg

Gaithersburg H.S. ......................... 3

Quince Orchard H.S. ....................... 1

Watkins Mill H.S. ......................... 2

Gambrills

Arundel H.S. .............................. 1

Glen Burnie

Glen Burnie H.S. .......................... 1

Glenelg

Glenelg H.S. .............................. 3

Greenbelt

Eleanor Roosevelt H.S. ................... 10

Kensington

Albert Einstein H.S. .......................1

McDonogh

McDonogh H.S. ............................. 3

Millersville

Old Mill H.S. ............................. 4

Owings Mill

Bais Yaakov School ........................ 1

Oxon Hill

Oxon Hill H.S. ............................ 4

Potomac

Bullis School ............................. 1

Connelly School of the Holy Child ......... 1

Winston Churchill H.S. ................... 13

Heights School ........................... 1

Prince Frederick

Calvert H.S. .............................. 2

Rockville

Georgetown Preparatory .................... 3

Colonel Zadok Magruder H.S. ................2

Richard Montgomery H.S. ................... 7

Rockville H.S. ............................ 2

Charles E. Smith Jewish Day School ........ 3

Thomas Wootton H.S. ...................... 14

Sandy Spring

Sandy Spring Friends School ................1

Severna Park

Severna Park H.S. ......................... 1

Silver Spring

Montgomery Blair H.S. .................... 18

John F. Kennedy H.S. .......................1

Springbrook H.S. .......................... 3

Yeshiva H.S. .............................. 3

Upper Marlboro

Frederick Douglass H.S. ................... 1

Queen Anne School ........................ 2

Wheaton

Good Counsel ............................. 1

Wheaton H.S. .............................. 1

Williamsport

Williamsport H.S. ......................... 1

VIRGINIA

School ............................... Number

Alexandria

Episcopal H.S. ............................ 1

St. Agnes School 2

St. Stephen's School ...................... 8

T.C. Williams H.S. ....................... 8

Annandale

Annandale H.S. ........................... 5

Jefferson Science & Tech. H.S. ............82

Arlington

Bishop Denis J. O'Connell H.S. .............2

Wakefield H.S. ............................ 3

Washington-Lee H.S. ....................... 6

Yorktown H.S. ............................ 13

Burke

Lake Braddock Secondary School .............5

Chantilly

Chantilly H.S. ............................ 2

Fairfax

Bethlehem Baptist Christian Academy ....... 1

Fairfax H.S. .............................. 2

Paul VI H.S. .............................. 8

James E. Robinson Secondary School ........ 4

W.T. Woodson H.S. ........................ 12

Falls Church

Falls Church H.S. ......................... 2

George C. Marshall H.S. ................... 1

George Mason Jr.-Sr. H.S. ................. 3

J.E.B. Stuart H.S. ........................ 1

Herndon

Herndon H.S. .............................. 2

Huntly

Wakefield School .......................... 1

Manassas

Osbourn H.S. .............................. 1

Osbourn Park H.S. ......................... 4

Seton School .............................. 1

McLean

Langley H.S. ............................. 17

Maderia School ............................ 1

McLean H.S. ............................... 9

Potomac School ............................ 1

Mount Vernon

Mount Vernon H.S. ......................... 1

West Potomac H.S. ......................... 2

Reston

South Lakes H.S. .......................... 7

Springfield

Robert E. Lee H.S. ........................ 2

West Springfield H.S. ..................... 4

Stafford

North Stafford H.S. ...................... 3

Sterling

Park View H.S. ........................... 1

Vienna

James Madison H.S. ........................ 5

Oakton H.S. ............................... 2

Warrenton

Fauquier H.S. ............................. 1

SOURCE: National Merit Scholarship Corp.