The announcement that the John F. Kennedy Memorial Library will be located on the site of the Bennett Sreet MBTA Yards is expected sometime this week or next.

A source close to the Kennedy family said yesterday that details of the transfer of land were expected to be ironed out at a meeting held yesterday. The land transfer question was the only thing blocking an immediate decision to put the Library on the MBTA Yards.

The Yards site is six times as large as the two-acre plot on the Business School side of the river selected by President Kennedy in 1963.

Purchase of the MBTA yards would permit the construction of the larger library now considered necessary and would still leave room for substantial parking space. But the land has been valued at $6 million, and its purchase would greatly increase the $20 million price tax Library officials had estimated would be required to build the Library complex and endow the Institute of politics that will be connected with it.

If the Library fund drive does not produce enough exrta money, the Library may get Foundation help in endowing the Institute, which will be a part of Harvard's Graduate School of Public Administration.