The espionage trial of former National Security Agency employe Ronald W. Pelton will include testimony on the potential damage caused by Pelton's alleged sale of highly sensitive U.S. intelligence information to the Soviet Union.

In court papers filed today, prosecutors said an unidentified expert witness would "provide examples or general descriptions" of potential harm to the United States caused by Pelton's alleged disclosures "without providing detailed descriptions or specific locations of NSA projects."

Pelton, 44, is charged with selling Soviet agents information about communications related to a U.S. intelligence gathering project that was directed at the Soviet Union. His espionage activities are alleged to have begun in January 1980, six months after he left his $24,500-a-year job at NSA, and to have continued until the time of his arrest Nov. 24.

A jury of five women and seven men was impaneled today after a painstaking 4 1/2-day selection process, which included individual questioning of 66 jurors on whether they have been influenced by the extensive publicity surrounding the Pelton case. Opening arguments are scheduled for Tuesday morning, and jurors, who have been told to avoid reading or listening to news accounts about the case, will be sequestered for the duration of the trial, which is expected to last five to eight days.

The court order filed today, agreed to by both the defense and the prosecution, outlines the few scraps of classified information that are expected to be introduced during the trial. The government has sought to restrict disclosures under the Classified Information Procedures Act.

One highly classified item the government intends to introduce as evidence is a part of a document that Pelton wrote while at NSA in 1978. He is alleged to have told the Soviets about what was in the document during two long debriefing sessions at the Soviet Embassy compound in Vienna, Austria, in 1980 and 1983. The government will introduce the "cover memo" and title page from that document, as well as a sample page from the text with all but the subject matter headings deleted.

CIA Director William J. Casey said Monday that he would ask the Justice Department to consider prosecuting NBC News for a report about Pelton that Casey said compromised national security by revealing sensitive details about Pelton's alleged espionage activities. Administration officials have also said they are weighing whether to prosecute The Washington Post for a story about the case in Wednesday editions.

In addition, Judge Herbert F. Murray ruled today that two classified tape recordings the government intends to use as evidence -- alleged conversations between Pelton and Soviet officials who invited him to their embassy in Washington -- cannot be played in open court.