Many of the government's top 121 personnel jobs, now held almost exclusively by career civil servants, could be opened up to noncareer or political appointees under the president's civil service "reform" plan.

Part of the government streamlining program Carter has sent Congress calls for creation of a Senior Executive Service. It would cover 9,200 top career and political appaintees and give management greater authority in hiring, moving rewarding and firing them. Those "supergraders" now range from Grades 16 through 18, earning from $42,523 to $47,500. The SES, if Congress approves it, would also cover both career and political executives earning more than $47,500.

Architects of the reform package - at the Civil Service Commission and Office of Management and Budget - say the SES by law would be 90 percent career and 10 percent political. Certain jobs would be legally reserved for career employes only. Being in a "reserved" job would not prevent an executive from being fired by an agency head.But the worker would have "parachute" rights back into a lower level job outside the SES if he or she has career job status.

SES members who went into "unreserved" jobs could be either career or political appointees. Career employes fired from them would have the same parachute rights. Noncareer appointees would not.

Officials have already concluded that certain key jobs - law enforcement, tax collection, contracting and procurement - would be reserved strictly for career workers. But they are undecided about the status of personnel director jobs that now, technically, are filled almost exclusive by career civil servants.

Some top reform planners, including CSC Chairman Alan K. Campbell, believe that it would be "appropriate" for many of the top personnel jobs to be in the unreserved category making it possible to fill those jobs with political appointees.

Campbell feels that many of the top personnel jobs should be clearly identified with management of departments and agencies. He believes the present career-only system "limits the ability of the head of the agency" to pick the people he or she wants to set and administer personnel policy.

Several department - HEW and VA among them - have already upgraded the top personnel job to the assistant secretary or assistant administrator level. That means they report directly to the top man, and work for him directly.

Campbell said the trend in private industry is for the "personnel director" to become vice presidents for personnel. This makes them clearly a member of the top management team and eligible to move higher in the organization.

Currently, only about 26 of 121 top federal personnel jobs are in the "supergrade" range that would put them within the proposed SES. But an upgrading of that job status, as part of the management team, would move many up the bureaucratic totem pole, a trade of security for better pay, the possibility of bonuses and more rapid promotion. Putting the jobs into the "unreserved" category - which would seem compatible with making them more part of management - would make it possible for noncareer appointees to take them.

The prospect of moving personnel jobs from career to political status has chilled some incumbents, and worried some federal employes. They believe it would be even easier for political managers to delve deeper into hiring and promotions down the line, if the personnel director was also a political appointee rather than a career executive.

Rep. Herbert Harris (D-Va.) has introduced legislation that would guarantee that personnel director jobs be "reserved" for career employes in the SES. Harris is a member of the Post is considering the entre reform package. He represents as many federal workers as anyone in Congress and, it should be noted, a large number of the government's career personnel directors, too.