Tens of thousands of civilian jobs at the Defense Department would be better protected from takeover by private contractors under an amendment Rep. Bill Nichols (D-Ala.) will offer to the Defense authorization bill being considered by the House today.

About 25 percent of this area's civil servants work for the Navy, Army, Air Force or other Defense units. Nearly half the government's civilian employes work for Defense.

The department is trying to determine if jobs being performed by civil servants could be handled better and cheaper by contractors, because the administration favors the "privitization" of many federal jobs.

Under current policy only management positions held by some of Defense's 1 million civilians worldwide are excluded from consideration.

At the center of the fight is the definition of "core logistics," those jobs directly related to the management and performance of depot maintenance and equipment essential to military operations.

A Navy study last year estimated that between 70 and 90 percent of the Navy's civilian jobs, particularly at shipyards, were part of core logistics and should be excluded from consideration.

Congress enacted legislation last year that it thought would protect many essential Defense civilian jobs from automatic contracting-out review studies. It gave the Secretary of Defense authority to consider any jobs or functions, but stipulated that Congress was to be given a chance to object before studies began.

In a surprise move earlier this year, however, the Pentagon declared that core logistics functions included only management personnel, as well as those concerned with real estate and industrial equipment.

If Nichols' amendment is adopted, many more civilian Defense jobs would be excluded from contracting-out reviews than under current Pentagon guidelines. Nichols is the fifth-ranking member of the House Armed Services Committee and represents Anniston, Ala., a major federal civilian job center.